CA2235915A1 - Optical signal amplification control system - Google Patents
Optical signal amplification control system Download PDFInfo
- Publication number
- CA2235915A1 CA2235915A1 CA002235915A CA2235915A CA2235915A1 CA 2235915 A1 CA2235915 A1 CA 2235915A1 CA 002235915 A CA002235915 A CA 002235915A CA 2235915 A CA2235915 A CA 2235915A CA 2235915 A1 CA2235915 A1 CA 2235915A1
- Authority
- CA
- Canada
- Prior art keywords
- wavelength
- multiplexed
- control system
- different wavelengths
- amplification control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0221—Power control, e.g. to keep the total optical power constant
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0795—Performance monitoring; Measurement of transmission parameters
- H04B10/07955—Monitoring or measuring power
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
- Lasers (AREA)
Abstract
Disclosed is an optical signal amplification control system for amplifying in the lump a wavelength-multiplexed signal that several optical signals with different wavelengths to be transmitted through an optical fiber cable are multiplexed, the system having:
means for detecting always the number of the different wavelengths multiplexed in the wavelength-multiplexed signal; and means for amplifying in the lump the wavelength-multiplexed signal; wherein the optical signal amplification control system controls the amplifying means to amplify in the lump the wavelength-multiplexed signal up to a desired level according to the detected number of the different wavelengths.
means for detecting always the number of the different wavelengths multiplexed in the wavelength-multiplexed signal; and means for amplifying in the lump the wavelength-multiplexed signal; wherein the optical signal amplification control system controls the amplifying means to amplify in the lump the wavelength-multiplexed signal up to a desired level according to the detected number of the different wavelengths.
Description
CA 0223~91~ 1998-07-21 OPTICAL SIGNAL AMPLIFICATION CONTROL SYSTE~
F'T~T.T~ r~F 'r~ TNVT~'N'rTt~N
This invention relates to an optical signal amplification control system for amplifying wavelength-multiplexed optical signal withdifferentwavelengths tobetransmitted through an opticalfiber cable, and more particularly to, an optical signal amplification control system used in amplifying wavelength-multiplexed optical signal in the lump.
RArKr.~7nrTNn ~F 'rTr~ TNVT'NmTnN
It is well known that an optimum output power of optical signal is required in the long-distance transmission through an optical fiber cable since the output power to be too low or high causes a S trouble.
Therefore, in the long-distance transmission of an optical signal through an optical fiber cable, a wavelength-multiplexed signal is amplified in the lump to get an optimum output power ~y using repeating amplifiers placed at several repeating points.
The first one of conventional amplification control systems is operated by storing apredetermined referencelevel in a repeating amplifier, amplifying an optical signal to be input up to the reference level, then outputting it.
The second system is operated by transmitting wavelength 2s multiplexing number information from a transmitting end to a repeating amplifier, conducting the amplifying of the repeating amplifier according to the wavelength multiplexing number information.
CA 0223~9l~ l998-07-2l Meanwhile, in such a conventional optical signal amplification control system, the whole output power of a wavelength-mul~iplexed optical signal is controlled to be constant even when amplifying the optical signal where several signals with different wavelengths are s wavelength-multiplexed.
However, in such controlling, the output power per each signal (wavelength) must be varied depending upon the number of multiplexed wavelengths. Namely, the larger the number of multiplexed wavelengths is, the more the light output power per one waveleng.h o is reduced. The optimum output power per one wavelength must be varied depending upon the number of multiplexed wavelengths.
Thus, it is desired that a value of optimum output power can be determined according to the wavelength multiplexing number information when amplifying awavelength-multiplexed signal. Also, 15 it is desired that a value of optimum output power can be changed on real time according to a variation in the number of multiplexed wavelengths in such optical communication that the number of multiplexed wavelengths may be varied. However, the first system cannot be adapted to the variation in number of multiplexed 20 wavelengths.
The second system requires transmitting wavelength multiplexing number information from a transmitting end to a repeating amplifier, thereby increasing the guantity of information to be transmitted through the optical fiber cable as well as 25 complicating the system that much.
Also, when a light-wave network using only light is constructed in the future, the number of multiplexed wavelengths to be transmittedthroughanopticalfibercablewillbedynamicallyvaried CA 0223~91~ 1998-07-21 In such case, the number of wavelengths in the second system is very difficult to manage.
Furthermore, wrong wavelength number information may be transmitted due to a noise etc. If the second system is controlled 5 by such wrong information, the transmission error of an optical signal may occur.
.'~rTMMARY f~F ~r~TT~ TNVF'l~T'rTt~N
Accordingly, it is an object of the invention to provide an o optical signal amplification control system thatcan conductoptimum controls on output power according to the number of multiplexed wavelengths without transmitting wavelength multiplexing number information from a transmitting end.
It is a further object of the invention to provide an optical ~s signal amplification control system that can conduct optimum controls on output power on real time even when the number of wavelengths in a wavelength-multiplexed optical signal to be input is dynamically varied.
According to the invention, an optical signal amplification 20 control system for amplifying in the lump a wavelength-multiplexed signal that several optical signals with different wavelengths to be transmitted through an optical fiber cable are multiplexed, comprises:
means for detecting always the number of the different 2S wavelengths multiplexed in the wavelength-multiplexed signal; and means for amplifying in the lump the wavelength-multiplexed signal;
wherein the optical signal amplification control system CA 0223~9l~ l998-07-2l controls the amplifying means to amplify in the lump the wavelength-multiplexed signal up to a desired level accordi~g to the detected number of the different wavelengths.
R~ T F~ nF.~r~ T Pl'T~N nF 'T'~TF n~ AWTN(~
The invention will be explained in more detail in conjunction with the appended drawings, wherein:
FIG.lisablockdiagramshowinganopticalsignalamplification control system in a preferred embodiment according to the invention.
nF~ TPrrTtlN nF l'~F PRFFF~FT7 FMR~nTMFN'r.
An optical signal amplification control system in thepreferred embodiment will be explained in FIG.l.
Referring to FIG.l, 1 is an input-monitoring optical coupler, 15 2 iS a WDM (wavelength division multiplex) optical coupler for multiplexing an input signal and excitation laser light, and 3 is an erbium-doped fiber (EDF) which is obtained by doping erbium ion into an optical fiber and amplifies a 1.55 ~m band optical signal when 1.48~m excitation light is supplied thereinto.
Further, 4 is an output-monitoring optical coupler, 5 is an arrayed wave guide (AWG) for demultiplexing wavelength-multiplexed light to be input into lights with different wavelengths, 6 is an excitation laser light source (hereinafter referred to as 'excitation LD'), 7 is an automatic output power control (APC) 25 circuit, 8 is a photodetector (PD), and 9 is an arrayed photodetector (hereinafter referred to as 'array PD').
Meanwhile, a wavelength number detecting means, which is defined herein, is composed of the input-monitoring optical coupler CA 0223~9l~ l998-07-2l 1, AWG 5 and the array PD 9. Also, an amplifying means, which is defined herein, is composed of the excitation LD 6, the WDM-optical coupler 2 and the erbium-doped fiber 3. Further, the control of the amplifying means according to thenumber of multiplexed wavelengths, 5 which is defined herein, is conducted by the output-monitoring optical coupler 4 and the APC circuit 7 to which wavelength number information is input from the wavelength number detecting means.
In operation, an optical signal that several signals with different wavelengths are multiplexed (wavelength-multiplexed o signalJ is input to the input side (IN), and then part of the wavelength-multiplexed signal is separated from its main signal by the input-monitoring optical coupler 1, input to the arrayed wave guide (AWG) 5.
The arrayed wave guide (AWG) 5 divides the wavelength-15 multiplexedsignal input thereto into several signals with differentwavelengths, and the divided several signals with different wavelengths are received, as they are, by the arrayed photodetector (array PD) 9.
Thus, the number of wavelengths in the wavelength-multiplexed 20 signal to be input to the input side (IN) can be detected.
Meanwhile, theinput-monitoringopticalcouplerl, arrayedwave guide (AWG) 5 and array PD 9 can be operated on real time. Therefore, even when the number of wavelengths in the wavelength-multiplexed signal to be input to the input side (IN) can be varied, the variation 2s can be detected on real time.
Then, information about the number of wavelengths (number of signals) to be detected by the array PD 9 is sent to the APC circuit 7 to control automatically the light output power. The APC circuit CA 0223~91~ 1998-07-21 7 selects an optimum output power according to the number of wavelengths based upon this information, controlling the exeitation LD 6 to provide the selected optimum output power.
On the other hand, the main signal is multiplexed with the s optical output of the excitation LD 6 by the WDM optical coupler 2, input to EDF 3, amplified by the EDF 3, then output through the output-monitoring optical coupler 4 to the output side (OUT). At this time, part of the output signal is divided by the output-monitoring optical coupler 4, monitored of the output level by PD
8. The monitored information is then input to APC 7, thereby conducting feedback control.
Thus, APC 7 determines an optimum value of whole amplification level to the wavelength-multiplexed signal according to the multiplexing wavelength number information obtained from the array S PD 9, and feedback-controls the control current of the excitation LD 6 so that the output signal level can have this optimum value while monitoring the output signal level.
Although, in this embodiment, the wavelength number detecting means is composed of the input-monitoring optical coupler 1, AWG 5 20 and the array PD 9, it is not limited to this composition. The wavelength number detecting means may be any means that is composed of means for separating part of a wavelength-multiplexed signal to be transmitted, means for dividing the separated part of the wavelength-multiplexed signal into lights with different 25 wavelengths, and means for detecting the divided lights with different wavelengths to count the number of wavelengths.
Although, in this embodiment, the amplifying means is composed of the excitation LD 6, theWDMoptical coupler 6 and theerbium-doped CA 0223~91~ 1998-07-21 fiber 3, it is not limited to this composition. The amplifying means may be any means that can amplify in the lump the wavelengtn-multiplexed signal up to a desired level.
s Although the invention has been described with respect to specific embodiment for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modification and alternative constructions that may be occurred to one skilled in the art which fairly fall within the basic teaching o here is set forth.
F'T~T.T~ r~F 'r~ TNVT~'N'rTt~N
This invention relates to an optical signal amplification control system for amplifying wavelength-multiplexed optical signal withdifferentwavelengths tobetransmitted through an opticalfiber cable, and more particularly to, an optical signal amplification control system used in amplifying wavelength-multiplexed optical signal in the lump.
RArKr.~7nrTNn ~F 'rTr~ TNVT'NmTnN
It is well known that an optimum output power of optical signal is required in the long-distance transmission through an optical fiber cable since the output power to be too low or high causes a S trouble.
Therefore, in the long-distance transmission of an optical signal through an optical fiber cable, a wavelength-multiplexed signal is amplified in the lump to get an optimum output power ~y using repeating amplifiers placed at several repeating points.
The first one of conventional amplification control systems is operated by storing apredetermined referencelevel in a repeating amplifier, amplifying an optical signal to be input up to the reference level, then outputting it.
The second system is operated by transmitting wavelength 2s multiplexing number information from a transmitting end to a repeating amplifier, conducting the amplifying of the repeating amplifier according to the wavelength multiplexing number information.
CA 0223~9l~ l998-07-2l Meanwhile, in such a conventional optical signal amplification control system, the whole output power of a wavelength-mul~iplexed optical signal is controlled to be constant even when amplifying the optical signal where several signals with different wavelengths are s wavelength-multiplexed.
However, in such controlling, the output power per each signal (wavelength) must be varied depending upon the number of multiplexed wavelengths. Namely, the larger the number of multiplexed wavelengths is, the more the light output power per one waveleng.h o is reduced. The optimum output power per one wavelength must be varied depending upon the number of multiplexed wavelengths.
Thus, it is desired that a value of optimum output power can be determined according to the wavelength multiplexing number information when amplifying awavelength-multiplexed signal. Also, 15 it is desired that a value of optimum output power can be changed on real time according to a variation in the number of multiplexed wavelengths in such optical communication that the number of multiplexed wavelengths may be varied. However, the first system cannot be adapted to the variation in number of multiplexed 20 wavelengths.
The second system requires transmitting wavelength multiplexing number information from a transmitting end to a repeating amplifier, thereby increasing the guantity of information to be transmitted through the optical fiber cable as well as 25 complicating the system that much.
Also, when a light-wave network using only light is constructed in the future, the number of multiplexed wavelengths to be transmittedthroughanopticalfibercablewillbedynamicallyvaried CA 0223~91~ 1998-07-21 In such case, the number of wavelengths in the second system is very difficult to manage.
Furthermore, wrong wavelength number information may be transmitted due to a noise etc. If the second system is controlled 5 by such wrong information, the transmission error of an optical signal may occur.
.'~rTMMARY f~F ~r~TT~ TNVF'l~T'rTt~N
Accordingly, it is an object of the invention to provide an o optical signal amplification control system thatcan conductoptimum controls on output power according to the number of multiplexed wavelengths without transmitting wavelength multiplexing number information from a transmitting end.
It is a further object of the invention to provide an optical ~s signal amplification control system that can conduct optimum controls on output power on real time even when the number of wavelengths in a wavelength-multiplexed optical signal to be input is dynamically varied.
According to the invention, an optical signal amplification 20 control system for amplifying in the lump a wavelength-multiplexed signal that several optical signals with different wavelengths to be transmitted through an optical fiber cable are multiplexed, comprises:
means for detecting always the number of the different 2S wavelengths multiplexed in the wavelength-multiplexed signal; and means for amplifying in the lump the wavelength-multiplexed signal;
wherein the optical signal amplification control system CA 0223~9l~ l998-07-2l controls the amplifying means to amplify in the lump the wavelength-multiplexed signal up to a desired level accordi~g to the detected number of the different wavelengths.
R~ T F~ nF.~r~ T Pl'T~N nF 'T'~TF n~ AWTN(~
The invention will be explained in more detail in conjunction with the appended drawings, wherein:
FIG.lisablockdiagramshowinganopticalsignalamplification control system in a preferred embodiment according to the invention.
nF~ TPrrTtlN nF l'~F PRFFF~FT7 FMR~nTMFN'r.
An optical signal amplification control system in thepreferred embodiment will be explained in FIG.l.
Referring to FIG.l, 1 is an input-monitoring optical coupler, 15 2 iS a WDM (wavelength division multiplex) optical coupler for multiplexing an input signal and excitation laser light, and 3 is an erbium-doped fiber (EDF) which is obtained by doping erbium ion into an optical fiber and amplifies a 1.55 ~m band optical signal when 1.48~m excitation light is supplied thereinto.
Further, 4 is an output-monitoring optical coupler, 5 is an arrayed wave guide (AWG) for demultiplexing wavelength-multiplexed light to be input into lights with different wavelengths, 6 is an excitation laser light source (hereinafter referred to as 'excitation LD'), 7 is an automatic output power control (APC) 25 circuit, 8 is a photodetector (PD), and 9 is an arrayed photodetector (hereinafter referred to as 'array PD').
Meanwhile, a wavelength number detecting means, which is defined herein, is composed of the input-monitoring optical coupler CA 0223~9l~ l998-07-2l 1, AWG 5 and the array PD 9. Also, an amplifying means, which is defined herein, is composed of the excitation LD 6, the WDM-optical coupler 2 and the erbium-doped fiber 3. Further, the control of the amplifying means according to thenumber of multiplexed wavelengths, 5 which is defined herein, is conducted by the output-monitoring optical coupler 4 and the APC circuit 7 to which wavelength number information is input from the wavelength number detecting means.
In operation, an optical signal that several signals with different wavelengths are multiplexed (wavelength-multiplexed o signalJ is input to the input side (IN), and then part of the wavelength-multiplexed signal is separated from its main signal by the input-monitoring optical coupler 1, input to the arrayed wave guide (AWG) 5.
The arrayed wave guide (AWG) 5 divides the wavelength-15 multiplexedsignal input thereto into several signals with differentwavelengths, and the divided several signals with different wavelengths are received, as they are, by the arrayed photodetector (array PD) 9.
Thus, the number of wavelengths in the wavelength-multiplexed 20 signal to be input to the input side (IN) can be detected.
Meanwhile, theinput-monitoringopticalcouplerl, arrayedwave guide (AWG) 5 and array PD 9 can be operated on real time. Therefore, even when the number of wavelengths in the wavelength-multiplexed signal to be input to the input side (IN) can be varied, the variation 2s can be detected on real time.
Then, information about the number of wavelengths (number of signals) to be detected by the array PD 9 is sent to the APC circuit 7 to control automatically the light output power. The APC circuit CA 0223~91~ 1998-07-21 7 selects an optimum output power according to the number of wavelengths based upon this information, controlling the exeitation LD 6 to provide the selected optimum output power.
On the other hand, the main signal is multiplexed with the s optical output of the excitation LD 6 by the WDM optical coupler 2, input to EDF 3, amplified by the EDF 3, then output through the output-monitoring optical coupler 4 to the output side (OUT). At this time, part of the output signal is divided by the output-monitoring optical coupler 4, monitored of the output level by PD
8. The monitored information is then input to APC 7, thereby conducting feedback control.
Thus, APC 7 determines an optimum value of whole amplification level to the wavelength-multiplexed signal according to the multiplexing wavelength number information obtained from the array S PD 9, and feedback-controls the control current of the excitation LD 6 so that the output signal level can have this optimum value while monitoring the output signal level.
Although, in this embodiment, the wavelength number detecting means is composed of the input-monitoring optical coupler 1, AWG 5 20 and the array PD 9, it is not limited to this composition. The wavelength number detecting means may be any means that is composed of means for separating part of a wavelength-multiplexed signal to be transmitted, means for dividing the separated part of the wavelength-multiplexed signal into lights with different 25 wavelengths, and means for detecting the divided lights with different wavelengths to count the number of wavelengths.
Although, in this embodiment, the amplifying means is composed of the excitation LD 6, theWDMoptical coupler 6 and theerbium-doped CA 0223~91~ 1998-07-21 fiber 3, it is not limited to this composition. The amplifying means may be any means that can amplify in the lump the wavelengtn-multiplexed signal up to a desired level.
s Although the invention has been described with respect to specific embodiment for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modification and alternative constructions that may be occurred to one skilled in the art which fairly fall within the basic teaching o here is set forth.
Claims (6)
1. An optical signal amplification control system for amplifying in the lump a wavelength-multiplexed signal that several optical signals with different wavelengths to be transmitted through an optical fiber cable are multiplexed, comprising:
means for detecting always the number of said different wavelengths multiplexed in said wavelength-multiplexed signal; and means for amplifying in the lump said wavelength-multiplexed signal;
wherein said optical signal amplification control system controls said amplifying means to amplify in the lump said wavelength-multiplexed signal up to a desired level according to said detected number of said different wavelengths.
means for detecting always the number of said different wavelengths multiplexed in said wavelength-multiplexed signal; and means for amplifying in the lump said wavelength-multiplexed signal;
wherein said optical signal amplification control system controls said amplifying means to amplify in the lump said wavelength-multiplexed signal up to a desired level according to said detected number of said different wavelengths.
2. An optical signal amplification control system, according to claim 1, wherein:
said wavelength number detecting means comprises means for separating part of said wavelength-multiplexed signal to be transmitted, means for dividing said separated part of said wavelength-multiplexed signal into lights with different wavelengths, and means for counting said number of said different wavelengths multiplexed in said wavelength-multiplexed signal by detecting said divided lights with different wavelengths.
said wavelength number detecting means comprises means for separating part of said wavelength-multiplexed signal to be transmitted, means for dividing said separated part of said wavelength-multiplexed signal into lights with different wavelengths, and means for counting said number of said different wavelengths multiplexed in said wavelength-multiplexed signal by detecting said divided lights with different wavelengths.
3. An optical signal amplification control system, according to claim 2, wherein:
said separating means comprises an arrayed wave guide (AWG), and said counting means comprises an arrayed photodetector.
said separating means comprises an arrayed wave guide (AWG), and said counting means comprises an arrayed photodetector.
4. An optical signal amplification control system, according to claim 1, wherein:
said amplifying means comprises an excitation laser light source, a WDM optical coupler to multiplex the excitation light from said excitation laser light source with said wavelength-multiplexed signal, and an erbium-doped fiber.
said amplifying means comprises an excitation laser light source, a WDM optical coupler to multiplex the excitation light from said excitation laser light source with said wavelength-multiplexed signal, and an erbium-doped fiber.
5. An optical signal amplification control system, according to claim 1, further comprising:
means for feedback-controlling said amplifying means to provide said wavelength-multiplexed signal to be output with said desired level according to said detected number of said different wavelengths while monitoring the output level after amplification.
means for feedback-controlling said amplifying means to provide said wavelength-multiplexed signal to be output with said desired level according to said detected number of said different wavelengths while monitoring the output level after amplification.
6. An optical signal amplification control system, according to claim 5, wherein:
said feedback-controlling means determines said desired level according to said detected number of said different wavelengths and controls said amplifying means to amplify in the lump said wavelength-multiplexed signal up to said desired level.
said feedback-controlling means determines said desired level according to said detected number of said different wavelengths and controls said amplifying means to amplify in the lump said wavelength-multiplexed signal up to said desired level.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9121505A JPH10303821A (en) | 1997-04-25 | 1997-04-25 | Optical signal amplification and transmission system |
| JP09-121505 | 1997-04-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2235915A1 true CA2235915A1 (en) | 1998-10-25 |
Family
ID=14812863
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002235915A Abandoned CA2235915A1 (en) | 1997-04-25 | 1998-04-24 | Optical signal amplification control system |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH10303821A (en) |
| CA (1) | CA2235915A1 (en) |
| FR (1) | FR2762733A1 (en) |
| GB (1) | GB2324667B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3166695B2 (en) | 1998-01-05 | 2001-05-14 | 日本電気株式会社 | Wavelength division multiplex transmitter |
| KR100322125B1 (en) | 1999-01-14 | 2002-02-04 | 윤종용 | AWG module and method for monitoring optical signal using AWG module |
| KR20010003638A (en) * | 1999-06-24 | 2001-01-15 | 윤종용 | Apparatus and method for stabilizing output power of wavelength division multiplexed erbium doped fiber amplifier in respect of channel number |
| GB2360654A (en) * | 2000-03-25 | 2001-09-26 | Marconi Comm Ltd | Power controlling network element for adding new channels in a controlled manner |
| GB2362525B (en) * | 2000-05-18 | 2002-07-24 | Marconi Comm Ltd | Radiation power equalization in wavelength division multiplexing (WDM) optical communication system |
| GB2366925A (en) * | 2000-09-13 | 2002-03-20 | Marconi Comm Ltd | Power control and equalisation in an optical WDM system |
| JP4074750B2 (en) * | 2001-02-20 | 2008-04-09 | 株式会社日立製作所 | Optical amplification apparatus and gain characteristic monitoring method thereof |
| US6826331B2 (en) * | 2001-09-28 | 2004-11-30 | Bookham Technology Plc | Method of extracting spectral parameters of channels from non-channelized light |
| US8208812B2 (en) | 2006-05-25 | 2012-06-26 | Mitsubishi Electric Corporation | Optical relay device and optical relay transmission system |
| JP4864771B2 (en) * | 2007-03-06 | 2012-02-01 | 日本電信電話株式会社 | Optical signal monitoring apparatus, optical system, and optical signal monitoring method |
| JP5188512B2 (en) * | 2008-01-22 | 2013-04-24 | 三菱電機株式会社 | Optical transmission system and repeater |
| JP5858465B2 (en) * | 2011-12-19 | 2016-02-10 | 富士通株式会社 | Optical communication device, wavelength number measuring device, optical repeater, and wavelength number measuring method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2280561B (en) * | 1993-07-31 | 1997-03-26 | Northern Telecom Ltd | Optical transmission system |
| JP3379052B2 (en) * | 1994-09-26 | 2003-02-17 | 富士通株式会社 | WDM optical amplifier, WDM transmission system, and WDM transmission method |
| JPH09185091A (en) * | 1995-12-28 | 1997-07-15 | Nec Corp | Transmitting equipment for wavelength-multiplexed light |
| JP2910667B2 (en) * | 1996-04-09 | 1999-06-23 | 日本電気株式会社 | Linear repeater optical amplification transmission equipment |
| JPH09321701A (en) * | 1996-05-31 | 1997-12-12 | Fujitsu Ltd | Optical communication system and optical amplifier |
| JP2904131B2 (en) * | 1996-07-04 | 1999-06-14 | 日本電気株式会社 | WDM optical amplifier and WDM optical transmission equipment |
-
1997
- 1997-04-25 JP JP9121505A patent/JPH10303821A/en active Pending
-
1998
- 1998-04-24 FR FR9805188A patent/FR2762733A1/en not_active Withdrawn
- 1998-04-24 GB GB9808861A patent/GB2324667B/en not_active Expired - Fee Related
- 1998-04-24 CA CA002235915A patent/CA2235915A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10303821A (en) | 1998-11-13 |
| GB2324667A (en) | 1998-10-28 |
| FR2762733A1 (en) | 1998-10-30 |
| GB9808861D0 (en) | 1998-06-24 |
| GB2324667B (en) | 1999-06-16 |
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