|Publication number||US7692852 B2|
|Application number||US 11/689,352|
|Publication date||Apr 6, 2010|
|Filing date||Mar 21, 2007|
|Priority date||Jul 23, 1998|
|Also published as||EP1018666A1, EP1018666A4, EP1018666B1, EP2306604A2, EP2306604A3, EP2306604B1, EP2306605A1, EP2306605B1, EP2315073A1, EP2315073B1, US6292288, US6501593, US6636344, US6646787, US6654162, US6775057, US7548368, US8437074, US9281654, US20010046083, US20020021487, US20020085267, US20030053199, US20030058524, US20040190909, US20070247701, US20100067099, US20110141553, US20130286468, WO2000005622A1|
|Publication number||11689352, 689352, US 7692852 B2, US 7692852B2, US-B2-7692852, US7692852 B2, US7692852B2|
|Inventors||Youichi Akasaka, Yoshihiro Emori, Shu Namiki|
|Original Assignee||The Furukawa Electric Co., Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (71), Non-Patent Citations (44), Referenced by (13), Classifications (23), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a divisional of application Ser. No. 10/824,402, filed Mar. 17, 2000, which is a divisional of Ser. No. 10/120,173, filed Apr. 11, 2002; which is a continuation of application Ser. No. 09/886,212 filed Jun. 22, 2001, now U.S. Pat. No. 6,654,162; which is a continuation of application Ser. No. 09/527,748 filed Mar. 17, 2000, now U.S. Pat. No. 6,292,288; which is a Continuation-in-Part of PCT/JP99/03944 filed Jul. 23, 1999.
1. Field of the Invention
The present invention relates to a Raman amplifier capable of being used for amplification of optical signal in various optical communication systems, and optical repeater and Raman amplification method using such a Raman amplifier, and more particularly, it relates to Raman amplifier, optical repeater and Raman amplification method suitable for amplification of wavelength division multiplexing signals.
2. Related Background Art
Almost all of optical amplifiers used with present optical fiber communication systems are rare earth doped fiber amplifiers. Particularly, erbium doped optical fiber amplifier (referred to as “EDFA” hereinafter) using Er (erbium) doped fibers have been used frequently. However, a practical gain wavelength band of the EDFA has a range from about 1530 nm to 1610 nm (refer to “Electron. Lett,” vol. 33, no. 23, pp. 1967-1968). Further, the EDFA includes gain having wavelength dependency, and, thus, when it is used with wavelength division multiplexing signals, difference in gain is generated in dependence upon a wavelength of optical signal.
The gain flattening filter is a filter designed so that loss is increased in a wavelength having great gain, and the loss profile has a shape substantially the same as that of the gain profile. However, As shown in
On the other hand, among optical amplifiers, there is an amplifier referred to as a Raman amplifier utilizing Raman scattering of an optical fiber (refer to “Nonlinear Fiber Optics, Academic Press). The Raman amplifier has peak gain in frequency smaller than frequency of pumping light by about 13 THz. In the following description, it is assumed that pumping light having 1400 nm band is used, and the frequency smaller by about 13 THz will be expressed as wavelength longer by about 100 nm.
Further, the Raman amplifier has polarization dependency of gain and amplifies only a component (among polarized wave components) coincided with the polarized wave of the pumping light. Accordingly, it is required for reducing unstability of gain due to polarization dependency, and, to this end, it is considered that a polarization maintaining fiber is used as a fiber for amplifying or an pumping light source having random polarization condition.
Furthermore, enlargement of the gain band is required in the Raman amplifier. To this end, Japanese Patent Publication No. 7-99787 (1995) teaches in
On the other hand, there is an optical repeater for simultaneously compensating for transmission loss and chromatic dispersion in an optical fiber transmission line, which optical repeater is constituted by combination of an Er doped fiber amplifier (EDFA) and a dispersion compensating fiber (DCF).
By the way, on designing the optical repeater, it is required that a repeater input level, a repeater output level and a dispersion compensating amount (loss in the dispersion compensating fiber A) be set properly, and, there is limitation that the input level of the dispersion compensating fiber A has an upper limit, because, when the input power to the dispersion compensating fiber A is increased, influence of non-linear effect in the dispersion compensating fiber A is also increased, thereby deteriorating the transmission wave form considerably. The upper limit value of the input power to the dispersion compensating fiber A is determined by self phase modulation (SPM) in one wave transmission and by cross phase modulation (XPM) in WDM transmission. Thus, regarding the optical repeater, an optical repeater having excellent gain flatness and noise property must be designed in consideration of the several variable factors.
In the optical fiber communication system, although the Er doped optical fiber amplifiers have widely been used, the Er doped optical fiber amplifier also arises several problems. Further, the Raman amplifier also has problems that, since output of ordinary semiconductor laser is about 100 to 200 mW, gain obtained is relatively small, and that the gain is sensitive to change in power or wavelength of the pumping light. So that, when a semiconductor laser of Fabry-Perot type having relatively high output is used, noise due to gain fluctuation caused by its mode hopping becomes noticeable, and that, when the magnitude of the gain is adjusted, although drive current of the pumping laser must be changed, if the drive current is changed, since the fluctuation in the central wavelength is about 15 nm at the maximum, the wavelength dependency of gain will be greatly changed. Further, such shifting of the central wavelength is not preferable because such shifting causes change in joining loss of a WDM coupler for multiplexing the pumping light. In addition, the optical repeater also has a problem that the Er doped optical fiber amplifiers B, C must be re-designed for each system. Further, the deterioration of the noise property due to insertion of the dispersion compensating fiber is hard to be eliminated in the present systems.
In a Raman amplification method for amplifying optical signal by using a stimulated Raman scattering phenomenon, a communication optical fiber is used as an optical fiber acting as an amplifying medium, and, in a distributed amplifying system, a wavelength of pumping light and a wavelength of the optical signal are arranged in 1400 nm-1600 nm band having low loss and low wavelength dependency within a wide band of the communication optical fiber. In this case, regarding the loss of wavelength dependency of the optical fiber as the amplifying medium, a difference between maximum and minimum values is below about 0.2 dB/km in the above band, even in consideration of loss caused by hydroxyl ion (OH) having peak at 1380 nm. Further, even if each pumping powers in a multi-wavelength pumping system are not differentiated according to the wavelength dependence of the loss, the gain of the signals amplified by the pumping lights are substantially the same, there is no problem in practical use.
On the other hand, in a Raman amplifier operating as a discrete amplifier such as EDFA (rare earth doped fiber amplifier) it is necessary to pay attention to the package of the amplifier fiber, for a length of the fiber is about 10 km to about several tens of kilometers in order to obtain the required gain. Thus, it is convenient that the length of the fiber is minimized as less as possible. Although the length of the fiber can be shortened by using an optical fiber having great non-linearity, in the optical fiber having great non-linearity, it is difficult to reduce the transmission loss caused by (OH) generally having a band of 1380 nm, and Rayleigh scattering coefficient becomes great considerably in comparison with the communication fiber, with the result that the difference between the maximum and minimum values of fiber loss within the above-mentioned wavelength range becomes very great such as 1.5 to 10 dB/km. This means that, when the optical fiber having length of 3 km is used, the loss difference due to the wavelength of the pumping light becomes 4.5 dB to 30 dB. Thus, the wavelength division multiplexing signals cannot be uniformly amplified by using the pumping lights having the same intensities.
As one of means for multiplexing the number of pumping lights, there is a wavelength combiner of Mach-Zehnder interferometer type. Since the Mach-Zehnder interferometer has periodical response property regarding frequency, the wavelength of the pumping light must be selected among wavelengths having equal intervals in frequency. Accordingly, the wavelength combiner of Mach-Zehnder interferometer type has limitation in degrees of freedom of wavelength setting, but has an advantage that, when a device of waveguide type or fiber fusion type, if the number of wavelength division multiplexing is increased, insertion loss is not changed substantially.
An object of the present invention is to provide a Raman amplification method capable of uniformly amplifying wavelength division multiplexing signals and suitable to be incorporated as a unit.
Another object of the present invention is to provide a Raman amplifier which can obtain required gain and can reduce wavelength dependency of gain to the extent that usage of a gain flattening filter is not required and which can be used in a band of EDFA.
A further object of the present invention is to apply the Raman amplifier to an optical repeater constituted by an Er doped fiber amplifier (EDFA) and a dispersion compensating fiber (DCF) thereby to provide an optical repeater in which the EDFA is not required to be re-designed for each system and which can compensate dispersion in transmission line loss and/or DCF loss without deteriorating property of the optical repeater.
Further, by Raman-amplifying the DCF, the deterioration of noise property due to insertion of the DCF which could not avoided in the conventional techniques is reduced.
An example of a Raman amplifier according to the present invention is shown in
Further, by selecting the interval between the central wavelengths of the pumping light to a value greater than 6 nm and smaller than 35 nm, the wavelength dependency of gain can be reduced to the extent that the gain flattening filter is not required. The central wavelength λ c in this case is a value defined regarding the single pumping light and is represented by the following equation when it is assumed that a wavelength of an i-th longitudinal mode of laser oscillating is λi and light power included in that mode is Pi:
The reasons why the interval between the central wavelengths of the pumping light is selected to a value greater than 6 nm is that the oscillating band width of the semiconductor laser 3 of Fabry-Perot type connected to an external resonator 5 having narrow reflection band width is about 3 nm as shown in
According to a second aspect of the present invention, since a Raman amplifier has a control means 4 for monitoring input light or output light with respect to the Raman amplifier and for controlling pump powers of the pumping means 1 on the basis of a monitored result to maintain output light power of the Raman amplifier to a predetermined value, given output can be obtained regardless of fluctuation of input signal power to the Raman amplifier and/or dispersion in loss of a Raman amplifier fiber.
According to a third aspect of the present invention, since a Raman amplifier has a controlling means 4 for flattening Raman gain, the gain can be flattened. Particularly, as shown in
According to a fourth aspect of the present invention, since a Raman amplifier has a control means 49 for monitoring input signal power and output signal power and for controlling pumping light power to make a ratio between the input signal power and the output signal power constant thereby to maintain gain of the Raman amplifier to a predetermined value, given output can be obtained regardless of fluctuation of the input signal power to the Raman amplifier and/or dispersion in loss of a Raman amplifier fiber.
According to a fifth aspect of the present invention, in a Raman amplifier, since an optical fiber having non-linear index n2 of refraction of 3.5E−20 [m2/W] or more is used as an optical fiber 2, adequate amplifying effect can be obtained, from the result of investigation.
According to a sixth aspect of the present invention, in a Raman amplifier, since the optical fiber 2 exists as a part of a transmission fiber for propagating the optical signal, the amplifier can be incorporated into the transmission optical fiber as it is.
According to a seventh aspect of the present invention, a Raman amplifier utilizes a part of a dispersion managed transmission line and can constitute an amplifier as it is as a amplifying medium.
According to an eighth aspect of the present invention, in a Raman amplifier, since the optical fiber 2 exists as an amplifier fiber provided independently from a transmission fiber for propagating the optical signal and inserted into the transmission fiber, an optical fiber suitable for Raman amplification can easily be used for the optical fiber 2 and the chromatic dispersion compensating fiber can easily be utilized, and a discrete amplifier can be constituted.
In an optical repeater according to the present invention, since is loss of an optical fiber transmission line 8 is compensated by using the Raman amplifier, an optical repeater having the function of the Raman amplifier can be provided.
Among optical repeaters of the present invention, in a repeater in which rare earth doped fiber amplifier(s) 10 is (are) provided at preceding or following stage or at both stages of the Raman amplifier, since the loss of the optical fiber transmission line 8 is compensated by the Raman amplifier 9 and the rare earth doped fiber amplifier(s) 10, desired amplifying property suitable for various transmission systems can be obtained.
Among optical repeaters of the present invention, in accordance with an arrangement in which the Raman amplifier 9 and the rare earth doped fiber amplifier 10 are combined, a repeater adapted to various systems can be obtained. This fact will be explained hereinbelow as an example that DCF is used as the amplifier fiber of the Raman amplifier 9.
In the optical repeater according to the present invention, when a Raman amplifier using an pumping light source in which wavelengths are not combined is provided, although an operating wavelength range is narrower, a construction can be simplified and the same property as the aforementioned optical repeaters can be obtained, except for the band width, in comparison with an optical repeater having a Raman amplifier pumped by a plurality of wavelengths.
In the Raman amplifier according to the present invention, when a difference between maximum and minimum values of the central wavelength of the pumping light is within 100 nm, overlapping between the pumping light and the optical signal can be prevented to prevent wave form distortion of the optical signal. If the wavelength of the pumping light is similar to the wavelength of the optical signal, since the wave form of the optical signal may be deteriorated, the wavelength of the pumping light and the wavelength of the optical signal must be selected so that they are not overlapped. However, in a case where the pumping light has band of 1.4 μm, when the difference between the maximum and minimum values of the central wavelength of the pumping light is smaller than 100 nm, as shown in
In the Raman amplifier according to the present invention, when the pumping lights having adjacent wavelengths are propagated through the optical fiber 2 toward two different directions so that the optical signal pumped bi-directionally, the wavelength property required in the WDM coupler 11 shown in
In the Raman amplifier according to the present invention, when the wavelength stabilizing external resonator 5 such as fiber grating is provided at the output side of the semiconductor laser 3 of Fabry-Perot type, noise due to fluctuation of caused by mode hopping of the semiconductor laser 3 of Fabry-Perot type can be suppressed. In consideration of one pumping light source, it makes the bandwidth narrower to connect the wavelength stabilizing external resonator 5 to the semiconductor laser 3. Since it also results the smaller wavelength interval in case of combining pumping light sources by the WDM coupler 11 (
In the Raman amplifier according to the present invention, when the pumping light of the semiconductor laser 3 is used to be polarization-combined for each wavelength, not only polarization dependency of gain can be eliminated but also the pump power launched into the optical fiber 2 can be increased. In the Raman amplification, only the components matched with the polarized of the pumping light can be given the gain. When the pumping light is linear-polarized and the amplifier fiber is not a polarization maintaining fiber, the gain is changed due to fluctuation of relative state of polarization of the signal and the pumping light. Therefore, the polarization dependence of gain can be eliminated by combining two linear-polarized pumping lights so that the polarization planes are perpendicular to each other. Further, it increases the pumping light power launched into the fiber.
In the Raman amplifier according to the present invention, in the case where a wavelength combiner of planar lightwave circuit based on a Mach-Zehnder interferometer is used as a means for wave-combining MOPA or a semiconductor laser of Fabry-Perot type, DFB type or DBR type having a plurality of wavelengths, even when the number of the wavelengths to be combined is large, the wave-combination can be achieved with very low loss, and pumping light having high output can be obtained.
In the Raman amplifier according to the present invention, as shown in
In the optical repeater according to the present invention, when the Raman amplification is utilized by coupling residual pumping light of the Raman amplifier to the optical fiber transmission line 8, a part of loss of the optical fiber transmission line 8 can be compensated.
In the optical repeater according to the present invention, when the residual pumping light of the Raman amplifier is utilized as pumping light for the rare earth doped fiber amplifier 10, the number of the semiconductor lasers to be used can be reduced.
In the optical repeater according to the present invention, when a dispersion compensating fiber is used as the optical fiber 2 of the Raman amplifier 9, the chromatic dispersion of the optical fiber transmission line 8 can be compensated by the Raman amplifier 9, and a part or all of the losses in the optical fiber transmission line 8 and the amplifier fiber 2 can be compensated.
According to a twenty-ninth aspect of the present invention, in a Raman amplification method by stimulated Raman scattering in an optical fiber through which two or more pumping lights having different central wavelengths and said optical signals are propagated, the pumping power launched into said optical fiber increases as the central wavelengths of said pumping lights is shorter.
According to a thirtieth aspect of the present invention, in a Raman amplification method by stimulated Raman scattering in an optical fiber through which two or more pumping lights having different central wavelengths and said optical signals are propagated, total pumping power on the shorter wavelength side with respect to the center between the shortest and longest central wavelengths among said two or more pumping lights is greater than on the longer side.
According to a thirty-first aspect of the present invention, in a Raman amplification method by stimulated Raman scattering in an optical fiber through which three or more pumping lights having different central wavelengths and said optical signals are propagated, the number of the pumping light sources on the shorter wavelength side with respect to the center between the shortest and longest central wavelengths among said three or more pumping lights is greater than on the longer side, and the total pumping power on the shorter wavelength side is greater than on the longer side.
To achieve the above object, according to thirty-second to thirty-fourth aspects of the present invention, when the shortest pumping wavelength is defined as a first channel and, from the first channel, at respective intervals of about 1 THz toward the longer wavelength, second to n-th channels are defined, pumping lights having wavelengths corresponding to the first to n-th channels are multiplexed and pumping light having a wavelength spaced apart from the n-th channel by 2 THz or more toward the longer wavelength is combined with the multiplexed light, and light obtained in this way is used as the pumping light of the Raman amplifier. When the shortest pumping wavelength is defined as the first channel and, from the first channel, at respective intervals of about 1 THz toward the longer wavelength, the second to n-th channels are defined, light obtained by combining all of the wavelengths corresponding to the channels other than (n-1)-th and (n-2)-th channels is used as the pumping light of the Raman amplifier. Alternatively, light obtained by combining all of the wavelengths corresponding to the channels other than (n-2)-th and (n-3)-th channels is used as the pumping light of the Raman amplifier.
The pumping means 1 includes semiconductor lasers 3 (3 1, 3 2, 3 3, 3 4) of Fabry-Perot type, wavelength stabilizing fiber ratings (external resonators) 5 (5 1, 5 2, 5 3, 5 4), polarization coupler (polarization beam combiner) 6 (6 1, 6 1), and a WDM coupler 11. Oscillating wavelengths of the semiconductor lasers 3 1, 3 2 and permeation wavelengths of the fiber gratings 5 1, 5 2 are the same wavelength λ1, and central wavelengths of the semiconductor lasers 3 3, 3 4 and permeation wavelengths of the fiber gratings 5 3, 5 4 are the same wavelength λ2, and the oscillating wavelengths of the semiconductor lasers 3 1, 3 2, 3 3, 3 4 can be subjected to the action of the wavelength stabilizing fiber gratings 5 1, 5 2, 5 3, 5 4 so that the central wavelengths are stabilized to λ1, λ2. Further, a wavelength interval between the wavelength λ1 and the wavelength λ2 is selected to be greater than 6 nm and smaller than 35 nm.
Pumping lights generated by the semiconductor lasers 3 1, 3 2, 3 3, 3 4 are polarization-combined by the polarization coupler 6 for each wavelength λ1, λ2, and output lights from the polarization coupler 6 are combined by the WDM coupler 11 to obtain output light of the pumping means 1. Polarization maintaining fibers 17 are connected between the semiconductor lasers 3 and the polarization coupler 6 to obtain two pumping lights having different polarization planes. The output light of the pumping means 1 is coupled to the amplifier fiber 2 via the WDM coupler 13; on the other hand, an optical signal (wavelength division multiplexing signal) is incident on the amplifier fiber 2 from the optical signal input fiber 12 and then is combined with the pumping light of the pumping means 1 in the amplifier fiber 2 to be Raman-amplified, and the Raman-amplified light is passed through the WDM coupler 13 and is sent to the monitor light branching coupler 14, where a part of the light is branched as a monitor signal, and the other is outputted to the optical signal output fiber 16. The monitor signal is monitored in the monitor signal detecting and LD control signal generating circuit 15, and the circuit 15 generate a signal for controlling drive currents for the semiconductor lasers 3 so that gain deviation in the signal wavelength band becomes small.
The amplifier fiber 2 may be a special fiber suitable for Raman amplification (for example, a fiber having non-linear index of refraction n2 of 3.5 E−20 [m2/W] or more) or may be an extension of the signal input fiber 12 by which the optical signal is received. Further, as shown in
In the Raman amplifier, the amplifier fiber 2 may be connected to and inserted into a transmission fiber (not shown) to which the optical signal is transmitted, and the amplifier fiber 2, pumping means 1, WDM coupler 13, monitor light branching coupler 14, and monitor signal detecting and LD control signal generating circuit 15 may be incorporated to constitute a concentrated Raman amplifier.
Central wavelengths of semiconductor lasers 3 1, 3 2 included in the first group A of the pumping means 1 and central wavelengths of semiconductor lasers 3 5, 3 6 included in the second group B are the same, and central wavelengths of semiconductor lasers 3 3, 3 4 included in the first group A and central wavelengths of semiconductor lasers 3 7, 3 8 included in the second group B are the same. Further, fiber gratings 5 1 to 5 8 are matched with the central wavelength of the semiconductor lasers 3 to which the fiber gratings are connected, respectively.
In the embodiment shown in
In the above-mentioned embodiments, the output light power controlling means 4 may be designed as shown in
In an arrangement shown in
In the Raman amplifiers having the above-mentioned constructions, in place of the fact the pumping lights are combined by the polarization wave composing coupler 6, as shown in
In the optical repeater shown in
In an optical repeater according to a sixth embodiment of the present invention, a dispersion compensating fiber is used as the amplifier fiber 2 of the Raman amplifier shown in
In the above-mentioned embodiment of the optical repeater, a Raman amplifier 9 using an pumping means 1 shown in
As shown in
As shown in
An embodiment of a Raman amplifying method according to the present invention will now be fully explained with reference to
When the optical signal having wavelength of 1500 nm to 1600 nm is propagated to the DCF having a length of 6 km from one end thereof and the pumping lights having wavelengths of 1400 nm, 1420 nm, 1440 nm, 1460 nm, and 1480 nm are inputted to the DCF thereby to Raman-amplify the optical signal, the input optical signal and an output optical signal outputted from the other end of the DCF (Raman-amplified optical signal) were checked to evaluate total loss of the wavelength and DCF. The following Table 3 shows a relationship between the wavelength and DCF total loss. From this, it is apparent that there is wavelength dependency:
unit loss (dB/km)
total loss (dB)
Here, when it is considered that effect total loss is given by adding the loss of the semiconductor laser to the loss of the optical signal amplified by the semiconductor laser at the side of the longer wavelength greater by about 100 nm, a relationship between the wavelength and the effect total loss becomes as shown in the following
effect total loss (dB)
40.56 + 4.14
19.68 + 3.72
10.44 + 3.42
6.96 + 3.30
5.10 + 3.24
Since there is substantially no wavelength dependency of the Raman amplification itself, when it is regarded that amplifying efficiency for each wavelength is influenced by the effect total loss, by adding the effect total loss to the outputs of the semiconductor lasers required for desired amplifying properties, the wavelengths can be Raman-amplified substantially uniformly, and the wavelength dependency of the gain can be eliminated. Thus, in this embodiment, the shorter the central wavelength of the pumping light the higher the light power.
In a Raman amplifying method according to a second embodiment of the present invention, in order to Raman-amplify substantially uniformly the optical signals having wavelengths of 1500 nm to 1600 nm transmitted by the DCF, among two or more pumping lights incident on the DCF, light powers of pumping lights having wavelengths smaller than center (middle) between the shortest central wavelength and the longest central wavelength are increased. More specifically, central wavelengths of the pumping lights generated by the pumping light source 51 shown in
Light power of 1435 nm
Light power of 1450 nm
Light power of 1465 nm
Light power of 1480 nm
As a result, the gain profile of the optical signal having wavelength of 1500 nm to 1600 nm (after Raman-amplified) transmitted by the DCF provides gain of about 11 dB from 1540 nm to 1590 nm, with the result that the flatness becomes 1 dB, as shown in
Incidentally, when the central wavelengths of the pumping lights generated by the pumping light source 51 and incident on the DCF are selected to 1435 nm, 1450 nm, 1465 nm and 1480 nm and the light powers thereof are selected to 563 mW uniformly, the gain profile of the optical signal having wavelength of 1500 nm to 1600 nm (after Raman-amplified) transmitted by the DCF becomes as shown in
In an embodiment described hereinbelow, the shortest wavelengths of the pumping lights to be used are selected to 1420.8 nm (211 THz). The reason is that the wavelength greater than 1530 nm (frequency below about 196 THz) which has been utilized in the present WDM systems is considered to be used as an amplification band. Accordingly, when a wavelength greater than 1580 nm (frequency below about 190 THz) which is referred to as an L-band is supposed as the amplification band, since the pumping band may be shifted by 6 THz, the shortest wavelength may be selected to 1462.4 nm (205 THz). Regarding the other amplification bands, the shortest wavelengths can be determined in the similar manner.
In the Raman amplifier according to the present invention, by selecting the wavelengths of the pumping light sources so that the interval between the central wavelengths becomes greater than 6 nm and smaller than 35 nm and the difference between the maximum central wavelength and the minimum central wavelength becomes within 100 nm, there can be provided an optical amplifier in which the wavelength dependency of gain is reduced to the extent that the gain flattening filter is not required and in which, if the gain is changed, the flatness can be maintained. Further, this amplifier can be applied to an optical repeater for compensating loss of a transmission line and wavelength dispersion. In a repeater constituted by the combination of the amplifier and EDFA, fluctuation of the EDFA due to fluctuation of input of the repeater and/or fluctuation in loss of DCF can be suppressed to avoid deterioration of gain flatness and the repeater can be applied to various systems.
In the Raman amplifying method according to the present invention, since the shorter center wavelength of the pumping light among two or more pumping lights incident on the DCF the greater the power, or, since the power of the pumping light at the short wavelength side with respect to the center between the shortest central wavelength and the longest central wavelength among two or more pumping lights incident on the DCF is increased, in any cases, even when an optical fiber having high non-linearity is used, wavelength multiplexing lights of about 1500 nm to about 1600 nm can be amplified with substantially the same gain. In other words, by using the optical fiber having high non-linearity, the required gain can be obtained even with a short optical fiber. Further, since the optical fiber can be shortened, a Raman amplifier which can be unitized can be provided.
As described in connection with the prior art, the wavelength combiner of Mach-Zehnder interferometer type is very useful for multiplexing the pumping lights efficiently. One of reasons why the pumping lights having the equal frequency interval are used is that such a wave combiner can be used.
Since the limit of the gain deviation is determined by undulation and/or unevenness of the gain curves to be overlapped, it is considered that the gain profile having good flatness and small gain deviation can be obtained by combining gain curves having less unevenness. Accordingly, this can be achieved by combining the gain curve obtained by multiplexing the pumping lights at interval of 1 THz with the gain curve of the pumping light at the long wavelength side with respect to said pumping wavelength. In this case, it is desirable that the peaks of two gain curves are moderately spaced apart from each other in the viewpoint of the widening of the band.
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|US20010036004||Jan 25, 2001||Nov 1, 2001||David Ackerman||Optical communication system with co-propagating pump radiation for raman amplification|
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|41||Takesue, H. et al. "Stabilization of Pulsed Ligthwave Circulating Around an Amplified Fiber-Optic Ring Incorporating a LOYT Depolarizer." IEEE Photonic Tech. Lett. Dec. 1998. pp. 1748-1750.|
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|43||Wang, L.J. et al. "Analysis of Polarization-Dependent Gain in Fiber Amplifiers." IEEE J. of Quantum Elect., vol. 34, No. 3, Mar. 1998. pp. 413-418.|
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7920793 *||Jun 17, 2005||Apr 5, 2011||Nippon Telegraph And Telephone Corporation||Inline repeater and optical fiber communication system|
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|US8199399||Jun 14, 2011||Jun 12, 2012||Lockheed Martin Corporation||Optical gain fiber having segments of differing core sizes and associated method|
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|U.S. Classification||359/341.31, 359/337.4|
|International Classification||H01S3/067, H01S3/23, H01S3/30, H01S3/094, H04B10/291|
|Cooperative Classification||H04B10/2916, H01S2301/04, H01S3/2383, H01S3/2375, H01S3/10007, H01S3/094096, H01S3/094015, H01S3/094011, H01S3/06754, H01S3/10015, H01S3/06758, H01S3/302, H01S3/0912|
|European Classification||H04B10/2916, H01S3/067G, H01S3/30F|
|Nov 16, 2010||CC||Certificate of correction|
|Sep 4, 2013||FPAY||Fee payment|
Year of fee payment: 4


text: Special Offers Take advantage of these special, limited-time offers from Virginia Credit Union. Holiday Shopping Rate We’ll take 6% off your standard purchase APR* when you use your VACU credit card on purchases made November 25–November 30, 2015. *For qualified members. See conditions of offer. Learn More Credit Card Balance Transfer Special balance transfer offer through December 31, 2015 – Special balance transfer rates of 2.99% - 4.99% APR. Save money when you transfer balances from higher-rate credit cards and loans to your VACU credit card. *For qualified members. See conditions of offer. Learn More Cash Rewards MasterCard Cash Rewards MasterCard – Earn a 1% rebate on all purchases. Special cash back offer through September 30, 2016: Earn a total of 3% on gas, 2% on groceries, and 2% on restaurant purchases with no annual fee. Net purchase restriction applies. Learn More Flex Rewards MasterCard Flex Rewards MasterCard – Earn 1 point for each $1 spent on every purchase and 2 points for each $1 spent on travel, entertainment and dining. Spend $2,500 within the first 90 days of opening a new card and earn 7,500 bonus points. Learn More Bill Pay $1,000 Giveaway Congratulations to Kiesha Walker of King George, Virginia who won the Bill Pay $1,000 Giveaway contest! Complete rules and additional information are available online.

domain: economics


Canada's Peace Tower Flag Will Fly Half-Mast Until Further Notice For The 63 Canadians
It's in memory of Canadians that lost their lives.
As Canada and the world are still reeling from news of a passenger jet going down, Parliament Hill is showing respect for the victims. The Iran plane crash deaths of 63 Canadians have led to the Canadian flag on the Peace Tower being lowered to half-mast until further notice.
On January 8, the Canadian flag on Parliament Hill's Peace towered was lowered to pay respects to the people from Canada who lost their lives in the plane crash.
"The flag on the Peace Tower will be flown at half-mast from now until further notice in memory of the victims of the plane crash in Tehran," the Senate of Canada tweeted.
Ukraine International Airlines flight PS752 was supposed to go from Tehran's main international airport to Kiev on the morning of January 8 but crashed just minutes after takeoff.
All passengers and crew on board the aircraft died, including 63 Canadians.
Other victims were from Iran, Ukraine, Sweden, Afghanistan, Germany and the U.K., according to Ukrainian minister for foreign affairs Vadym Prystaiko.
"This morning, I join Canadians across the country who are shocked and saddened to see reports that a plane crash outside of Tehran, Iran, has claimed the lives of 176 people, including 63 Canadians," Prime Minister Justin Trudeau said in a statement.
The 63 Canadian victims in this plane crash came from all over Canada.
Schools like the University of Alberta and Carleton University announced that students and members of the school communities were among those who died in the crash., the University of Waterloo, the
Condolences and tributesfrom politicians, institutions like universities that have lost people in the tragedy, and the Canadian people.
Trudeau, Jagmeet Singh and François-Philippe Champagne, Canada's minister of foreign affairs, all tweeted about the plane crash.
Following the crash, Air Canada, the only Canadian carrier that operates in the region,to ensure the security of its flights.
"Our government will continue to work closely with its international partners to ensure that this crash is thoroughly investigated and that Canadians' questions are answered," Trudeau said.
The investigation into the crash is ongoing.


text:
President Vladimir Putin publicly says he is remaining neutral in the Ukraine crisis, but he has ordered an urgent drill to test the combat at “readiness of his armed forces.”
Now that the very public Olympics are over in Sochi, sources close to the situation predict more of the same, short of military intervention.
Russia did avoid intervention during the ouster of the Ukrainian president who turned his back on the European Union seeking closer ties to the Russians, much to the dismay of many in western Ukraine more aligned with the West.
Putin’s feeble excuse for his latest actions is his “worries” of western military intervention.
There is no indication of this happening at present or the near future.
Defence Minister Sergei Shoigu said, “In accordance with an order from the president of the Russian Federation, forces of the Western Military District were put on alert at 1400 (0500 ET) today," according to the Interfax news agency.
He claimed the military maneuvers had been previously planned involving approximately 150,000 armed personnel.
The western district encompasses most of western Russia and borders Ukraine, which lies between NATO nations and Russia.
Putin has made no public comment on Ukraine since President Viktor Yanukovich was driven from power over the weekend. The removal came after months of political turmoil that began with overtures from the European Union for closer ties with the country.
The United States and European nations have warned Russia against military intervention in Ukraine, but little can be done beyond weak sanctions.
Russia’s next move could include tactical exercises and involve warships from the Northern and Baltic Fleets. Warplanes would move to combat airfields.
Shoigu said the drill will test the counter-terrorism measures in place at military units. They have described the weak Ukrainian forces as "terrorists."
* If you have enjoyed this column, may I suggest you scroll down this page and press the SUBSCRIBE box? It's FREE. Thank you for your patronage.
** Send your comments to: email@example.com

domain: news


text:
Farm loan waiver UPSC: Relevance
- GS 3: Issues related to direct and indirect farm subsidies
Loan waiver in India: Context
- Recently, National Bank for Agriculture and Rural Development (NABARD) and Bharat Krishak Samaj has jointly released a report on recent farm loan waivers by the three state governments— Punjab, Uttar Pradesh and Maharashtra.
NABARD report on loan waiver: Key findings
- Borrowing by states: The study revealed that an average farmer of Punjab borrows four times more money than those in Uttar Pradesh (UP) and over five times more money than those in Maharashtra.
- The study also revealed that a marginal farmer in Punjab borrows Rs 3.4 lakh annually, as compared to Rs 84,000 and Rs 62,000 in UP and Maharashtra, respectively.
- A marginal farmer is one who has the landholding of <1 ha.
- According to the report, more than 40 per cent of the “very highly” distressed farmers in these states did not receive any farm loan waiver (FLW) benefits.
- Among the three states, Punjab farmers borrowed the largest amounts per farmer category and their dependence on non-institutional sources was also the highest across all farmer categories.
- The average amount of loan taken from institutions increased with the landholding size.
- Loan waiver promoted wilful defaults: The study also revealed that the waivers increased the chances of wilful defaults by farmers and the waiver pushed even the honest farmers to default on agricultural loans.
- Institutional borrowings: Among the three states, the proportion of farmers of Punjab borrowing from the institutional sources were more than those in UP and Maharashtra.
- Interest rates: The interest rates on non-institutional loans were found to be much more than the institutional loans.
- Default on institutional loans: The possibility of default was higher on institutional loans than on non-institutional loan.
- Kisan Credit card: The diversion of KCC (Kisan Credit Card) funds for non-agricultural use was highest in the case of Punjab and lowest in the case of UP.
- The study also revealed that for an average farmer diversion of funds is inevitable and critical for survival.
- Waiver and political connections: During the election campaigns, political parties race to become the first to promise a waiver on agricultural loans.
- Moreover, these waivers are positioned as a ‘ram-baan’ solution to any distress faced by Indian farmers.
- The study has, however, revealed that despite several successive governments implementing these loan waivers, the farmer distress has become more acute, let alone reducing it.
- Effect on state finances: The study revealed that loan waivers in Punjab has affected the expenditure on other departments.
- In Punjab, both developmental expenditure and capital outlay (as a percentage of GSDP) fell due to outstanding liabilities and market borrowings.
- Reasons of farmer suicides: The study highlighted that due to restrictions imposed by COVID-19, in all the three states, successive crop loss, indebtedness and excessive reliance on agricultural income together were the prime causes of farmer suicides.
Loan waiver as a solution
- Loan waiver is not an efficient way to alleviate farmer distress and it is only a short-term solution after which farmers will go back to taking loans.
- The waivers worsened the credit discipline among the farmers in the medium and long run.
- Farm loan waivers were designed as a reaction to acute agrarian distress and to ensure the continuity of future credit but it has evolved to emerge as a political tool that is strategically used by political parties to influence rural voters.
- The design of loan waivers is such that a large section of the people whose loan should have been waived were unable to benefit from the process.
Read current affairs for UPSC


text:
This issue features a “micro-interview” with Brad Neely. Neely has created many consistently hilarious animation miniseries, including I Am Baby Cakes, The Professor Brothers, and China, Illinois, which have appeared on Adult Swim and at SuperDeluxe.com. Neely is also known for Wizard People, Dear Readers, a spoken DVD commentary that reinterprets the film Harry Potter and the Sorcerer’s Stone. Currently at work on a novel involving the American Civil War, Neely used the micro-interview format as an opportunity to answer a handful of classroom-discussion questions taken from the website for Ken Burns’s documentary The Civil War.
KEN BURNS: Do your students agree or disagree with Lincoln’s idea that in a constitutional democracy no section of the nation is free to break away—that to attempt to leave is rebellion?
BRAD NEELY: I don’t really have students, Ken, but I live in Texas and we really want to be freer down here. Somebody in the past stole this land fair and square and now we want to turn it into something much sweeter. There could be floating Alamo Palaces, something else, and something else. Have you even seen our governor, Ken? He is really, really handsome. He looks like a cowboy who owns a car lot full of spaceships. He looks like his handsomeness will know what to do in a fight or in a fuck. He looks a little blurry because all the women in parallel universes are crowding his face with their asses. I think a guy like that should be allowed to diss the Union. Sometimes the squares need to be shocked into understanding a newer cool. The South sure did. And you know, I think Lincoln did what he had to. When your grandma is a sick hoarder it’s a natural urge to just torch the house and let the rats burn with the trash. But: What about the dog? The kids? The sleepers? We gotta take the time to clean out the shit, preserve what we can, and get the home livable.
We hope you enjoy this excerpt.
To read the full piece, please contact us to purchase a copy of the magazine.

domain: artistic


Younger people are more likely to use an analytical approach in search engines until they have achieved the desired results, compared to older people, suggested a new study by researchers at University of Miami.
Joseph Sharit of University of Miami said, "This type of sustained online information-seeking could be more cognitively taxing for users than simple search tasks because they must find, filter, comprehend, and integrate health information that was often distributed across multiple sources."
For the research, Sharit and fellow researchers Jessica Taha, Ronald Berkowsky, Halley Profita, and Sara asked 60 adults between the ages of 18 and 85 years to complete cognitive ability tests that measured skills such as processing time, reasoning ability, and executive function. The study participants were asked to use the internet to research and answer a series of questions related to a complex health information problem. Their responses were evaluated on the basis of age, internet experience, and cognitive test results.
It was seen that younger participants and those who scored higher on the cognitive tests were more likely to use an analytical approach by manipulating key words in search engines until they achieved the desired results. However, the older participants took longer to complete their tasks, their searches were more efficient and their responses were just as accurate as those of the younger respondents.
Sharit said, "Despite the increasing power of search engines, it should not be underestimated how difficult health-related problem solving using the internet could be for many individuals. Consideration should be given to new ways of supporting consumers of health information, especially older adults, who were susceptible to normal age-related declines in cognitive abilities."
The study appeared in the Journal of Cognitive Engineering and Decision Making.


text:
City of Chicago Pilot Project for Dockless Bike Rental Starts Today to Serve Residents in Far South Side
May 1, 2018
Pilot Project Designed to Test Operational Impacts and Demand for Dockless Bikeshare Services in Far South Side Neighborhoods Not Currently Served by Divvy
CDOT: Mike Claffey 312.744.0707 Michael.Claffey@cityofchicago.org
BACP: Lilia Chacon 312-744-5365 Lilia.Chacon@cityofchicago.org
The City of Chicago’s Department of Transportation (CDOT) and the Department of Business Affairs and Consumer Protection (BACP) announced today that they are conducting a six-month pilot of a dockless bikeshare rental program this year on the far South Side. The pilot is designed to explore the operational impacts of dockless bikes and gauge demand for the service in areas not served by the City’s popular Divvy bikeshare program.
“The success of Divvy and our partnership with Blue Cross & Blue Shield of Illinois have proven that there is great support for bikeshare in Chicago,” CDOT Commissioner Rebekah Scheinfeld said. “Dockless bike technology is a new option in the bikeshare market and it makes sense to test it in areas of the City that are not yet fully served by Divvy. We are eager to see firsthand how these programs work and whether there is a robust demand for bikeshare in these far South Side communities.”
CDOT and BACP have worked with far South Side Aldermen to identify neighborhoods that will be served by the dockless pilot that will run from May 1 through November 1. The pilot area will extend south and east from 79th Street and Western Avenue and south of South Chicago Avenue to serve neighborhoods including Auburn Gresham, Chatham, Calumet Heights, Roseland, Pullman, Hegewisch, Beverly, Morgan Park and Mt. Greenwood. Dockless bikes will be required to stay in and serve those communities.
Unlike Divvy trips that begin and end at a Divvy station, dockless bikes do not have stations and instead are located in public locations wherever it is legal to lock a bike. Customers use a smart phone to sign up on a company’s website or app to locate and rent a bike. Rates are set by the companies, and the City is requiring an option for those residents wanting to use cash. Any bikes that are parked outside of the pilot area or parked improperly must be retrieved and moved by the vendor within two hours.
The pilot is made possible through an Emerging Business Permit issued by BACP.
“This is another example of Chicago’s entrepreneurial spirit leading the way with creative big-city transportation options.” said BACP Commissioner Rosa Escareno. “We are looking forward to implementing this six-month pilot program through BACP’s Emerging Business Permit (EBP) process as a way to learn how dockless bikeshare can complement existing transportation service offerings.”
“We’ve seen Divvy embraced in other parts of the City, and my constituents will appreciate the opportunity to test bikesharing services out in their own neighborhoods as well,” said Alderman Carrie Austin (34thWard). “I’d like to thank BACP and CDOT for working to make this dockless bikeshare pilot project happen. This will give us an opportunity to see how much demand there is for bikeshare in the 34th Ward.”
“The communities of Beverly, Morgan Park and Mt. Greenwood are excited to welcome dockless bikesharing,” said Alderman Matthew O’Shea (19th Ward). “We look forward to this pilot program and promoting healthier lifestyles throughout the ward.”
BACP’s permit has been issued to the following firms: Limebike, Zagster (Pace) and Ofo. Each company has committed to begin operations May 1 or soon thereafter. Other applications have been received and are still being reviewed for completion and compliance with the City’s permit terms. Each company participating in the dockless pilot will have a maximum of 250 bikes. The companies will be responsible for rebalancing the bikes and implementing a marketing and community outreach plan to help educate residents in the pilot area on how to use the system. Companies will also be required to share data with the City, so that bike usage and the success of the program can be evaluated.
To test the operational impacts of different locking technologies of dockless bikes, until July 1, companies can introduce dockless bikes with wheel locks as well as those that are required to lock to something in the pilot area. After July 1, only bikes with lock-to technology will be allowed. Lock-to bikes will secure the bike to an immovable object so that it does not block pedestrians or traffic at the end of the rental trip. Bikes can easily be secured to bike racks, bike corrals, light poles, retired parking meters and street signs in the designated pilot area. This will ensure that the public right-of-way remains clear and hazard-free for pedestrians and people with disabilities.
Participating companies will be required to pay a $50 per bike fee to support the installation of new bike parking racks within the pilot area and to help cover administrative costs of the pilot program. Every bike will have a visible phone number on it that will allows citizens to report bikes parked in illegal or unsafe locations. Residents are encouraged to call the companies directly with their concerns.
The dockless pilot will leverage Chicago’s public transit system to help commuters complete the first or last few miles of their trip. The most frequent Divvy trips are made to or from public transit stations. The bikes are envisioned for those parts of the multi-mode commute or for other short point-to-point trips.
Over the past four years, Divvy, with the strong support of Blue Cross & Blue Shield of Illinois, has become an integral part of the Chicago transportation network, providing people an opportunity to explore the city in a way that is safe, fun and equitable, and creating good jobs for Chicagoland residents.
The dockless pilot program further supports Chicago's goal to remain the best large city for cycling by expanding access to bikeshare to more communities. This will encourage active transportation, increase transportation options and improve public health.
For more information, go to:

domain: geography


text:
Work on being ambidextrous. In this guide, weve compiled the most effective ways to improve memory by harnessing the power of the brains ability to change. Try me again.
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domain: biology


text:
BY PHIL WHEELER
Port Clinton Mayor Mike Snider has established a task force to raise awareness of the issue of blight in the city.
“Blight comes in many forms, in my mind,” said Mayor Snider. “There are obviously dilapidated structures, but there are also overgrown weeds and high grass, and people putting furniture on the curbside. I drove around Sunday, making stops all over the city, and I stopped counting at 51 trash cans still sitting out on the curb. It may be a minor thing, but some still had trash overflowing.
“That’s not fair to the other people who live in our city.”
Not only does it look bad, but it can also lead to certain health issues. The Center for Disease Control (CDC) has identified key environmental factors that affect our well-being. The link is clear and compelling. The concept of healthy homes extends beyond the four walls of a dwelling to include its surroundings—to the land immediately around the house, to adjacent structures and amenities.
Safety Service Director Tracy Colston said that “what we want to do is make people aware.
The problem isn’t just old, rundown buildings, pointed out Colston.
“People cut their grass, and it ends up in the street. That doesn’t sound like much,” he said, “but the grass ends up in the sewer and is washed into the water system.
“A couch sits on the curb. It isn’t automatically picked up any more. It could sit there for weeks.”
The task force is jokingly referred to as the “Sunday Blight Brunch” because of the meetings that have been taking place at the Mayor’s home over breakfast.
“This will work because city officials can sit around the table and look at what works and what doesn’t, and look at what can be done about it,” said Mayor Snider.
The city is compiling a list of blighted properties, and will be reviewing existing legislation on the issue.
“Current laws to address these issues are cumbersome, and take time to enforce.” said the Mayor Snider. “New or modified legislation to address these problems may be in order.”
The Mayor’s task force will approach the issue in two ways. Potential assistance could be offered to those who choose to address a problem on their own property themselves. The task force will also look into tools available to the city that can otherwise remedy a situation not addressed by the property owner.
One positive impact seen already is that, since the first initial discussions began, some of the instances of blight have been taken care of.
“There are 3,200-plus properties in the city of Port Clinton, and we are really only talking about 100,” said Mayor Snider. “We want property owners to take pride in their properties, and to be proud to be a resident of Port Clinton. We just want to raise awareness.”
Once the task force has completed its review, it is anticipated that a comprehensive package addressing it will be brought before the Port Clinton City Council.
To find out more, or to report a problem, go to www.portclinton.com/contact-us/.

domain: sociology


text:
Celebrities tell us how counselling changed their lives
Counselling on TV and radio
A collaboration between Public Health England’s Every Mind Matters and the FA and Heads Together's Heads Up campaigns encourages football fans to look after their mental health.
BBC Like Minds talks about why the relationship with your therapist matters, and how you can find someone who fits the bill.
Nick Thatcher reports on how talking about your mental health can help transform your outlook and wellbeing.
There's no stronger evidence that counselling changes lives than those whose lives have been turned around. Here's your stories of how therapy has helped you.
What therapy can help with
An A-Z list of issues and concerns which may be helped by talking to a counsellor.
How to use our online therapist directory to search for a counsellor or psychotherapist by location, services or specialisms

domain: psychology


text:
The story of Ummadantí. The story was related in connection with a backsliding brother who, having seen a very beautiful woman as he was going his alms-rounds in Sávatthi, gave himself up to despair and had to be led to the Buddha for admonition (J.v.209ff).
The story is also found, with certain slight variations, in the Játakamálá under the title of Ummádayantí Játaka (No.xiii).
The tale of a maiden who made all who saw her mad, and of the love-smitten monarch who preferred walking in the right path and even meeting death itself to indulging in passion, is found also in the Kathásaritságara. E.g., in the 15th, 23rd and 91st taranga.

domain: library


text:
Vero Beach, FL is a charming community that truly has something for everyone. If you are seeking the outdoor lifestyle, you can take advantage of full access to the beach and the Atlantic Ocean or explore our Indian River lagoon. We have a multitude of extraordinary golf courses, nature trails, botanical gardens and parks.
For those seeking more in-town activities, Vero Beach has museums, a state-of-the-art theater, elegant boutique shopping and an array of restaurants.
The miles of pristine beaches and the Indian River Lagoon offer endless amounts of outdoor activities. In addition, consider taking advantage of the many attractions Vero Beach has to offer.
The Vero Beach Museum of Art is a local museum that hosts the work of distinguished artists in all mediums. The museum is an established destination in Vero Beach. Enjoy exploring new artists, taking one of the many art classes offered or dining in the delicious café.
Riverside Theatre has been a longtime staple in the Vero Beach art culture. Each season, the theatre brings professional actors to the area and puts on award-winning Broadway musicals and plays. For those looking for some laughs, look up the Comedy Zone’s schedule and see what comedians will be traveling through town that weekend.
McKee Botanical Gardens is an 18-acre lush landscape filled with native and exotic plants and flowers. You can walk through the gardens and take in the beautiful waterfalls, scenery and artistic elements. Be on the lookout for fun displays and activities McKee Botanical Gardens hosts throughout the year!
Vero Beach has the best outlet shopping in the surrounding areas. With high-end brands like Restoration Hardware, William-Sonoma, Coach and J. Crew, you will be able to get your holiday shopping done while treating yourself as well.
Ocean Drive on Vero Beach’s barrier island is the epitome of upscale beachside living. Many of the best hotels, restaurants and shopping can be found in this area. Enjoy the afternoon strolling down the street, popping into local boutiques and sampling some of the delicious food. Don’t forget to stop by the farmer’s market taking place every Saturday morning.

domain: travel


text:
US judge eases wildfire safety plan for California utility
SAN FRANCISCO (AP) — A U.S. judge overseeing a criminal case against Pacific Gas & Electric Co. called the California utility’s efforts to prevent trees from hitting its power lines and starting wildfires “dismal” but scaled back his proposals to prevent its equipment from causing more blazes.
Judge William Alsup said in an order late Tuesday that he’s now considering making PG&E comply with targets in a wildfire mitigation plan that the company submitted to California regulators.
He also proposed that a court-appointed monitor oversee the utility’s efforts to clear trees and branches.
The judge previously considered ordering PG&E to reinspect its entire electric grid, remove or trim all trees that could fall on its power lines and cut off power during certain wind conditions.
PG&E pushed back against those proposals, saying in court documents that they would endanger lives, could cost as much as $150 billion and would interfere with the work of federal and state regulators.
In response to Alsup’s latest order, the company said it’s committed to completing work on its wildfire plan.
“We continue to work with regulators, lawmakers and our community partners across all sectors and disciplines to develop comprehensive, long-term safety solutions for our state,” a company statement said.
In the plan submitted last month, PG&E promised to spend more than $2 billion this year to improve wildfire prevention. The utility said it would step up its tree cutting and trimming and expand its use of blackouts.
Alsup on Tuesday also proposed ordering PG&E not to pay any dividends to shareholders until it meets his vegetation management requirements, including compliance with a state law requiring the utility to clear vegetation within certain distances of electric lines.
The judge, however, noted that PG&E had previously suspended cash dividends.
Alsup is overseeing a criminal conviction against PG&E stemming from a 2010 gas line explosion that killed eight people in the San Francisco Bay Area. The judge’s proposals follow devastating wildfires in California in 2017 and 2018 — some of which investigators have blamed on PG&E equipment — and would be part of the utility’s probation in the criminal case.
Alsup said his goal is to prevent PG&E equipment from causing any wildfires during the 2019 fire season.
The company sought bankruptcy protection in January in the face of billions of dollars in potential liability from recent wildfires.
The Western Journal has not reviewed this Associated Press story prior to publication. Therefore, it may contain editorial bias or may in some other way not meet our normal editorial standards. It is provided to our readers as a service from The Western Journal.
Truth and Accuracy
We are committed to truth and accuracy in all of our journalism. Read our editorial standards.

domain: law


text:
Release: Sunday, March 13, 1927
Written by: Thea von Harbou
Directed by: Fritz Lang
Starring: Alfred Abel; Gustav Fröhlich; Brigitte Helm; Rudolf Klein-Rogge
Austrian-German filmmaker Fritz Lang’s critique of capitalism and class structure in his classic silent epic Metropolis is a sight to behold, even if it is far from graceful. He imagines a dystopian city in the year 2026, a self-contained universe starkly divided between the weak and the powerful, the have’s and the have-not’s. When the son of the city’s visionary planner crosses the threshold into the world of the machine workers after being lured there by a beautiful woman, he learns the terrible truth about the city and his position within it and seeks to change the status quo.
Despite universal praise for its technical prowess, most notably a sprawling and immersive visual aesthetic, Metropolis was far from being embraced as an instant classic upon its release, some 90 years ago. The now famous line “The Mediator between Head and Hands must be the Heart!” was a particular bone of contention for critics of the late 1920s and early ’30s who viewed the sentiment as an oversimplification of existent tensions between the working class proletariat and the privileged bourgeoisie.
The very idea that such disparate groups could ever find common ground was deemed unrealistic, even naïve. Among the most notable dissenters was English writer H.G. Wells, who dismissed it as “quite the silliest film.” But the most damning criticisms were lodged against the film’s alleged pro-fascist stance, the thrust of the narrative seemingly drawing parallels between the revolt against the aforementioned visionary Joh Fredersen (Alfred Abel) and the rise of the National Socialist German Workers’ Party.
Before diving into all of that, an interrogation of the narrative itself might be helpful. The story concerns itself primarily with the relationship between the good-hearted but privileged Feder (Gustav Fröhlich in his breakout role) and the poor prophet Maria (Brigitte Helm), who find themselves caught up in a bitter revolt inspired by a robot built in the likeness of the latter — the result of a scientific experiment carried out by the inventor Rotwang (Rudolf Klein-Rogge). The robot, originally designed to replicate his beloved, is brought to life after Maria falls into Rotwang’s clutches at the behest of Joh, who senses growing unrest in the subterranean realm.
Of course, Joh is unaware of the inventor’s ulterior motives, as he actually plans to use the replicated Maria to destroy Metropolis. He plans to have her lead the workers in a violent uprising that will see the destruction of many machines, including The Heart Machine, which . . . well, you can probably guess why it’s important. In the heat of passion, the outraged leave their children behind in the wreckage for Feder and Maria to save before the city floods in the ensuing chaos.
Throughout the two-and-a-half hour running time (Metropolis manifests as one of cinema’s earliest full-length features and is indeed sizable even by today’s standards) we are bombarded with Biblical references and homages to Mary Shelley’s seminal science fiction Frankenstein. This seemingly incongruous mixture of elements, as set against the backdrop of the German expressionist movement, combines to form a uniquely visual tapestry that tends to obscure, rather than enhance, the beating heart of humanity at the film’s core.
Given this, Metropolis can hardly be deemed a film of subtlety. In fact it’s massively unsubtle. Lang’s suggestion of the apocalypse is a prime example. Feder’s vision of Maria riding a seven-headed beast confesses to the unfettered nature of period expressionism, and provides Lang’s most solid alibi for taking the film to so many different extremes. It’s altogether too much clutter. In a film where so many other dynamics are to be considered, heavy-handed interpretations of scripture seem, at best, superfluous.
I don’t view Metropolis as being overtly one thing or another. It’s a veritable amalgam of thematic material and visual spectacle. It’s about communism. No, it’s not — it’s about fascists. No it’s not, it’s about artificial intelligence. No wait, it’s about sinning and the second coming of Christ. I can’t fathom having to process all of this in a time where film reviews could only be found in the paper. At a time when the mobilization of the Nazis was an event taking place in the present. And while we’re on the subject, I also don’t subscribe to the notion that Metropolis supports Nazism. Perhaps there’s a reading here that the inevitable uprising in the lower ranks is a metaphor for the eventual birth and spread of fascism in Europe, but I don’t want to give that too much credit.
The fact that the film fails to shift its emotional weight convincingly proved most problematic for me. I was never convinced by Joh’s sudden concern for his son when violence took hold of society. Remorse for his oppressive leadership was never palpable during the hand-shake — the mediation, as it were, between the head of the city and its tired hands, here represented by the foreman of the Heart Machine, Grot (Heinrich George). Because Joh remained a fundamentally unchanged man come the end, I wasn’t able to buy the denouement as anything other than a physical commitment to honor the film’s thematic contract: Show that love can conquer all. (Even the most bitter ideological divides like class warfare.)
In the end, I liken Lang’s optimism to John Lennon’s insistence that all you need is love. In the context of the world in which we live, their idealism does seem naïve but for whatever reason it almost seems in poor taste to describe visionaries like them in such a way.
Curious about what’s next? Check out my Blindspot List here.
Moral of the Story: Mightily ambitious and perhaps to a fault, Metropolis I find a film with much to praise and almost as much to criticize. And yet, considering the times in which it was released, I can’t do anything but admire it. A rare silent film viewing experience for me, one I’m glad I have finally had.
Running Time: 148 mins.
Fucked-up Factoid: Unemployment and inflation were so bad in Germany at the time that the producers had no trouble finding 500 malnourished children to film the flooding sequences.
All content originally published and the reproduction elsewhere without the expressed written consent of the blog owner is prohibited.
Photo credits: http://www.impawards.com; http://www.imdb.com


When a long intermediate string of casing is to be cemented it is sometimes necessary to split the cement sheath in the annulus into two, with one sheath extending from the casing shoe to some point above potentially troublesome formations at the bottom of the hole, and the second sheath covering shallower troublesome formations. The placement of these cement sheaths is known as a multi-stage cementing operation (Figure 13).
The reasons for using a multi-stage operation are to reduce:
• Long pumping times
• High pump pressures
• Excessive hydrostatic pressure on weak formations due to the relatively high density of cement slurries.
The procedure for conducting a multi-stage operation is as follows:
The procedure for the first stage of the operation is similar to that described in Section 4.3 above, except that a wiper plug is not used and only a liquid spacer is pumped ahead of the cement slurry. The conventional shut-off plug is replaced by a plug with flexible blades. This type of shut-off plug is used because it has to pass through the stage cementing collar which will be discussed below. It is worth noting that a smaller volume of cement slurry is used, since only the lower part of the annulus is to be cemented. The height of this cemented part of the annulus will depend on the fracture gradient of the formations which are exposed in the annulus (a height of 3000′ – 4000′ above the shoe is common).
The second stage of the operation involves the use of a special tool known as a stage collar (Figure 14), which is made up into the casing string at a pre-determined position. The position often corresponds to the depth of the previous casing shoe.The ports in the stage collar are initially sealed off by the inner sleeve. This sleeve is held in place by retaining pins. After the first stage is complete a special dart is released form surface which lands in the inner sleeve of the stage collar. When apressure of 1000 – 1500 psi is applied to the casing above the dart, and therefore to the dart, the retaining pins on the inner sleeve are sheared and the sleeve moves down, uncovering the ports in the outer mandrel. Circulation is established through the stage collar before the second stage slurry is pumped.
The normal procedure for the second stage of a two stage operation is as follows:
1 Drop opening dart
2 Pressure up to shear pins
3 Circulate though stage collar whilst the first stage cement is setting
4 Pump spacer
5 Pump second stage slurry
6 Release closing plug
7 Displace plug and cement with mud
8 Pressure up on plug to close ports in stage collar and pressure test the casing.
To prevent cement falling down the annulus a cement basket or packer may be run on the casing below the stage collar. If necessary, more than one stage collar can be run on the casing so that various sections of the annulus can be cemented. One disadvantage of stage cementing is that the casing cannot be moved after the first stage cement has set in the lower part of the annulus. This increases the risk of channelling and a poor cement bond.
Institute of Petroleum Engineering, Heriot-Watt University


What can we expect to see happening in the world of road tolling, user charging and pricing schemes? This article presents the views of several policymakers, users and operators. A common thread is the belief that governments are expected to retain the primary responsibility to provide safe, reliable and efficient mobility for passengers and goods, because a good transportation infrastructure is so critical to economic growth. A central constraint is the funding of this infrastructure: traffic congestion and long commuting times are frustrating parts of big city living, the social and economic demands for mobility are increasing, carbon emission concerns are escalating, and the burden to build and maintain infrastructure becomes increasingly problematic for government agencies. The toll concession model is a widely used solution to these challenges. It relieves the fiscus of the funding obligation and allows the concessionaire to collect from all road users, local and foreign. In Europe, EU Directive 2014/23 established a framework for toll concessions to provide new services, introduce dedicated lanes for collective use, leverage the interfaces to other transport modes, develop facilities for autonomous and electric vehicles, and implement electronic (free flow) toll collection (ETC). In short, an incentive to innovate.
The operating costs of toll stations manned by humans are a constraint for toll operators, besides the inherent inefficiencies and risks. Simple economics suggest that, like in many other industries, automation is going to touch and change road tolling in unavoidable ways. Radio-Frequency Identification (RFID) is still a cost-effective solution for tolling and collections, congestion charging, parking control and a host of other applications, and is foreseen to remain the platform most widely used by toll operators. But, the growing sciences of communications, video image capture and artificial intelligence (AI), in concert with Global Navigation Satellite System (GNSS), smartphone technologies and on-board computing, will eventually replace tags to collect charges. And, these new capabilities can classify vehicles, perform traffic counts, enhance law enforcement, introduce emission- and per-distance
charging, and conduct security and safety surveillance. The lower cost, flexibility and real-time versatility of these solutions will enable the more widespread use of dynamic pricing models
Developments in Information and Communications Technology (ICT), automation and AI are rapidly propelling the world’s road tolling industry towards a critical goal – to make tolling ‘invisible’. Users do not have to slow down or stop at gates, monitoring and enforcement happen in free-flow mode, and the operator is enabled to offer better services – and more efficient facilities. At least in theory, as we have discovered in South Africa, this vision should make road tolling more acceptable.
The commentators agree that, as automation and advanced ICT solutions penetrate and transform their industry, several imperatives become apparent:
- Protection of individual road users’ right to privacy of their data, movements and transactional information;
- Security of the road user charging system across its complete value chain – from its edge devices, network and communication channels, to the authorization for data access, encryption, transmittal and storage;
- Compliance with international on-line payment and data security standards.
Road tolling, meaning to charge users for a utility, has become an effective mechanism to sustain and develop the infrastructure we so desperately need to build vibrant communities and economies. ICT, automation and AI are going to change the face and soul of this world in fundamental ways – for the better. But, as with all things, not without its pitfalls and risks.


text:
216 W. Main Street,
No one has favorited this theater yet
Mills Theater (Official)
Functions: Movies (First Run)
Styles: Art Deco
News About This Theater
- Jan 19, 2006 — Mills Theatre Could Be Razed, Replaced by New Theater
The 400-seat Mills Theater opened in Fall of 1937 and closed in Spring of 2001 after falling into disrepair.
It was renovated and reopened in 2008.
Just login to your account and subscribe to this theater.

domain: entertainment