GB2324667A - Wavelength multiplexed optical signal amplification control system - Google Patents
Wavelength multiplexed optical signal amplification control system Download PDFInfo
- Publication number
- GB2324667A GB2324667A GB9808861A GB9808861A GB2324667A GB 2324667 A GB2324667 A GB 2324667A GB 9808861 A GB9808861 A GB 9808861A GB 9808861 A GB9808861 A GB 9808861A GB 2324667 A GB2324667 A GB 2324667A
- Authority
- GB
- United Kingdom
- Prior art keywords
- wavelength
- multiplexed
- control system
- signal
- optical signal
- 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.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 51
- 230000003321 amplification Effects 0.000 title claims abstract description 24
- 238000003199 nucleic acid amplification method Methods 0.000 title claims abstract description 24
- 239000000835 fiber Substances 0.000 claims abstract description 5
- 230000005284 excitation Effects 0.000 claims description 12
- 238000012544 monitoring process Methods 0.000 claims description 10
- 239000013307 optical fiber Substances 0.000 claims description 9
- 239000000470 constituent Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 claims 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 229910052691 Erbium Inorganic materials 0.000 abstract description 2
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 abstract 1
- 230000005540 biological transmission Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Lasers (AREA)
- Optical Communication System (AREA)
Abstract
A wavelength multiplexed optical signal is input to an erbium doped fibre amplifier 3. A fraction of the input signal is split off at a coupler 1, demultiplexed by an arrayed waveguide 5, then the number of different wavelength signals in the multiplexed signal is detected by a photo detector array 9. This information, in combination with a standard feedback control system, 4 and 8, is used to control the level of amplification and to achieve a desired output level.
Description
OPTICAL SIGNAL AMPLIFICATION CONTROL SYSTEM
FIELD OF THE INVENTION
This invention relates to an optical signal amplification control system for amplifying wavelength-multiplexed optical signal with different wavelengths to be transmitted through an optical fiber cable, and more particularly to, an optical signal amplification control system used in amplifying wavelength-multiplexed optical signal in the lump, that is to say without dividing it into its constituent parts, So that all wavelengths are anplified.
BACKGROUND OF THE INVENTION 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 if the output power is too low or tco high, problems are caused.
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 by using repeating amplifiers placed at several repeating points.
The first one of conventional amplification control systems is operated by storing a predetermined reference level 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 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.
Meanwhile, in such a conventional optical signal amplification control system, the whole output power of a wavelength-multiplexed optical signal is controlled to be constant even when amplifying the optical signal where several signals with different wavelengths are 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 wavelength 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 a wavelength-multiplexed signal. Also, 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 wavelengths.
The second system requires transmitting wavelength multiplexing number information from a transmitting end to a repeating amplifier, thereby increasing the quantity of information to be transmitted through the optical fiber cable as well as 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 transmitted through an optical fiber cable will be dynamically varied.
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 by such wrong information, the transmission error of an optical signal may occur.
SUMMARY OF THE INVENTION AccorXy, it is an object of at least the preferred embodiments of the invention to provide an optical signal amplification control system that can conduct opting 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 such object to provide an optical 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 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 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.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail in conjunction with the appended drawings, wherein: FIG.1 is a block diagram showing an optical signal amplification control system in a preferred embodiment according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical signal amplification control system in the preferred embodiment will be explained in FIG.1.
Ref erring to FIG.1, 1 is an input-monitoring optical coupler, 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 Am 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) 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 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 the number of multiplexed wavelengths, 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 signal) 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) S.
The arrayed wave guide (AWG) 5 divides the wavelengthmultiplexed signal input thereto into several signals with different wavelengths, 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 signal to be input to the input side (IN) can be detected.
Meanwhile, the input-monitoring optical coupler 1, arrayed wave 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 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 7 selects an optimum output power according to the number of wavelengths based upon this information, controlling the excitation
LD 6 to provide the selected optimum output power.
On the other hand, the main signal is multiplexed with the 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 outputmonitoring 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
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 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 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, theWDM optical coupler 6 and the erbium-doped fiber 3, it is not limited to this composition. The amplifying means may be any means that can amplify in the lump the wavelength.
multiplexed signal up to a desired level.
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 here is set forth.
Each feature disclosed in this specification (which term includes the claims)
and/or shown in the drawings may be incorporated in the invention independently of
other disclosed and/or illustrated features.
The description of the invention with reference to the drawings is by way of
example only.
The text of the abstract filed herewith is repeated here as part of the
specification.
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.
Claims (8)
1. An optical signal amplification control system for amplifying in the lump (as herein defined) a wavelengUheLltiplexed signal in which å plurality of optical signals with different wavelengths to be transmitted through an optical fiber cable are multiplexed, comprising:
means for detecting 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.
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.
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.
5. An optical signal amplification control system, according to claim 1, further comprising:
means for feedback-controllingsaidamplifying 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.
7. A method of amplifying a wavelength-multiplexed optical signal comprising
determining the number of different-wavelength constituents of the multiplexed signal, and
amplifying the signal without demultiplexing it to a level dependent on the said number of
constituents.
8. A control system or a method substantially as herein described with reference
to or as shown in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9121505A JPH10303821A (en) | 1997-04-25 | 1997-04-25 | Optical signal amplification and transmission system |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9808861D0 GB9808861D0 (en) | 1998-06-24 |
| GB2324667A true GB2324667A (en) | 1998-10-28 |
| GB2324667B GB2324667B (en) | 1999-06-16 |
Family
ID=14812863
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9808861A Expired - Fee Related GB2324667B (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) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2346024A (en) * | 1999-01-14 | 2000-07-26 | Samsung Electronics Co Ltd | Arrayed waveguide grating (AWG) module for monitoring optical signals |
| GB2351387A (en) * | 1999-06-24 | 2000-12-27 | Samsung Electronics Co Ltd | Output power stabilization of wdm optical fibre amplifier |
| GB2360654A (en) * | 2000-03-25 | 2001-09-26 | Marconi Comm Ltd | Power controlling network element for adding new channels in a controlled manner |
| GB2366925A (en) * | 2000-09-13 | 2002-03-20 | Marconi Comm Ltd | Power control and equalisation in an optical WDM system |
| WO2003030426A2 (en) * | 2001-09-28 | 2003-04-10 | Measurement Microsystems A-Z Inc. | Method for extracting spectral parameters of channels from non-channelised light |
| US20100284694A1 (en) * | 2008-01-22 | 2010-11-11 | Mitsubishi Electric Corporation | Optical transmission system and repeater |
Families Citing this family (6)
| 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 |
| GB2362525B (en) * | 2000-05-18 | 2002-07-24 | Marconi Comm Ltd | Radiation power equalization in wavelength division multiplexing (WDM) optical communication 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 |
| EP2020767B1 (en) | 2006-05-25 | 2017-08-02 | 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 |
| 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 |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2280561A (en) * | 1993-07-31 | 1995-02-01 | Northern Telecom Ltd | Optical transmission system |
| GB2294170A (en) * | 1994-09-26 | 1996-04-17 | Fujitsu Ltd | Optical amplification of wavelength-division-multiplexed signals |
| EP0782289A1 (en) * | 1995-12-28 | 1997-07-02 | Nec Corporation | Wavelength multiplexing optical transmission device |
| EP0801475A2 (en) * | 1996-04-09 | 1997-10-15 | Nec Corporation | Optical amplifying apparatus and linear relay optical amplifier transmitter |
| EP0812078A2 (en) * | 1996-05-31 | 1997-12-10 | Fujitsu Limited | Optical communication system and optical amplifier |
| EP0817415A2 (en) * | 1996-07-04 | 1998-01-07 | Nec Corporation | Wavelength-division-multiplexing optical amplifier device |
-
1997
- 1997-04-25 JP JP9121505A patent/JPH10303821A/en active Pending
-
1998
- 1998-04-24 CA CA002235915A patent/CA2235915A1/en not_active Abandoned
- 1998-04-24 GB GB9808861A patent/GB2324667B/en not_active Expired - Fee Related
- 1998-04-24 FR FR9805188A patent/FR2762733A1/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2280561A (en) * | 1993-07-31 | 1995-02-01 | Northern Telecom Ltd | Optical transmission system |
| GB2294170A (en) * | 1994-09-26 | 1996-04-17 | Fujitsu Ltd | Optical amplification of wavelength-division-multiplexed signals |
| EP0782289A1 (en) * | 1995-12-28 | 1997-07-02 | Nec Corporation | Wavelength multiplexing optical transmission device |
| EP0801475A2 (en) * | 1996-04-09 | 1997-10-15 | Nec Corporation | Optical amplifying apparatus and linear relay optical amplifier transmitter |
| EP0812078A2 (en) * | 1996-05-31 | 1997-12-10 | Fujitsu Limited | Optical communication system and optical amplifier |
| EP0817415A2 (en) * | 1996-07-04 | 1998-01-07 | Nec Corporation | Wavelength-division-multiplexing optical amplifier device |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2346024A (en) * | 1999-01-14 | 2000-07-26 | Samsung Electronics Co Ltd | Arrayed waveguide grating (AWG) module for monitoring optical signals |
| US6701042B1 (en) | 1999-01-14 | 2004-03-02 | Samsung Electronics Co., Ltd. | Arrayed waveguide grating module and device and method for monitoring optical signal using the same |
| GB2346024B (en) * | 1999-01-14 | 2001-04-11 | Samsung Electronics Co Ltd | Device for monitoring optical signal using an arrayed waveguide grating module |
| GB2351387B (en) * | 1999-06-24 | 2001-09-05 | Samsung Electronics Co Ltd | Output power stabilization of WDM optical fibre amplifier |
| GB2351387A (en) * | 1999-06-24 | 2000-12-27 | Samsung Electronics Co Ltd | Output power stabilization of wdm optical fibre amplifier |
| GB2360654A (en) * | 2000-03-25 | 2001-09-26 | Marconi Comm Ltd | Power controlling network element for adding new channels in a controlled manner |
| WO2001073982A1 (en) * | 2000-03-25 | 2001-10-04 | Marconi Communications Limited | Power controlling network element |
| US7254339B2 (en) | 2000-03-25 | 2007-08-07 | Ericsson Ab | Power controlling network element |
| GB2366925A (en) * | 2000-09-13 | 2002-03-20 | Marconi Comm Ltd | Power control and equalisation in an optical WDM system |
| WO2003030426A2 (en) * | 2001-09-28 | 2003-04-10 | Measurement Microsystems A-Z Inc. | Method for extracting spectral parameters of channels from non-channelised light |
| WO2003030426A3 (en) * | 2001-09-28 | 2003-12-18 | Measurement Microsystems A Z I | Method for extracting spectral parameters of channels from non-channelised light |
| US6826331B2 (en) | 2001-09-28 | 2004-11-30 | Bookham Technology Plc | Method of extracting spectral parameters of channels from non-channelized light |
| US20100284694A1 (en) * | 2008-01-22 | 2010-11-11 | Mitsubishi Electric Corporation | Optical transmission system and repeater |
| US8320771B2 (en) * | 2008-01-22 | 2012-11-27 | Mitsubishi Electric Corporation | Optical transmission system and repeater |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2235915A1 (en) | 1998-10-25 |
| GB2324667B (en) | 1999-06-16 |
| JPH10303821A (en) | 1998-11-13 |
| GB9808861D0 (en) | 1998-06-24 |
| FR2762733A1 (en) | 1998-10-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |