WO1999017485A1 - Regulateur de voies optiques et procede correspondant - Google Patents

Regulateur de voies optiques et procede correspondant Download PDF

Info

Publication number
WO1999017485A1
WO1999017485A1 PCT/US1998/020747 US9820747W WO9917485A1 WO 1999017485 A1 WO1999017485 A1 WO 1999017485A1 US 9820747 W US9820747 W US 9820747W WO 9917485 A1 WO9917485 A1 WO 9917485A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
signal
tapped
output
channel
Prior art date
Application number
PCT/US1998/020747
Other languages
English (en)
Inventor
J. M. Dugan
Kenneth Y. Maxham
Original Assignee
Alcatel Network Systems, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alcatel Network Systems, Inc. filed Critical Alcatel Network Systems, Inc.
Priority to CA002273020A priority Critical patent/CA2273020C/fr
Priority to JP52058699A priority patent/JP2001508990A/ja
Publication of WO1999017485A1 publication Critical patent/WO1999017485A1/fr

Links

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
    • H04B10/079—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
    • 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
    • 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

Definitions

  • This invention relates in general to optical communication systems, and more particularly to an optical channel regulator and method.
  • optical amplifiers are used to boost signal powers to provide for longer transmission spans.
  • WDM wavelength division multiplexed
  • it is important to balance the channels at the input to the amplifiers to assure that the available amplifier output power is shared equally among the channels. If the channels are not balanced across each amplifier input, the weaker signals reduce the transmission span distance.
  • optical amplifiers used in multiple channel wavelength division multiplexed communication systems often do not have uniform gain across all of the optical channels. This creates some channel imbalance.
  • the cascade of the amplifiers results in signal inequalities even when they are well balanced at the head end.
  • BDLA bidirectional line amplifier
  • the receive signals from each direction needs to be balanced to assure proper gain and power sharing in the amplifier.
  • significant power level imbalances between channels at the end of a cascade of amplifiers may require attenuation of the strong channels to keep the signal level to the receiver at an acceptable level .
  • the present invention provides an optical channel regulator method that substantially eliminates or reduces disadvantages and problems associated with previously developed optical channel regulation schemes.
  • the present invention provides a method for regulating an optical channel.
  • the optical ⁇ channel regulator includes an electrically variable optical attenuator receiving an optical signal.
  • the attenuator attenuates the optical signal responsive to a feedback control signal and yields an attenuated optical signal.
  • a tapped optical coupler receives the attenuated optical signal of the attenuator and provides substantially all of the attenuated optical signal as an output .
  • the tapped optical coupler also provides a remaining portion of the attenuated optical signal as a tapped output.
  • An optical detector receives the tapped output and provides an electrical signal representing the attenuated optical signal.
  • a comparator receives the electrical signal of the optical detector and a reference signal. Finally, the comparator compares the electrical signal to the reference signal and provides a feedback control signal to the attenuator.
  • the present invention provides an important technical advantage by eliminating the need for manual measurement and selection of fixed attenuators required for balancing the channels.
  • the present invention provides another technical advantage by solving the problem of balancing the power levels at bi-directional line amplifiers using a single amplifier.
  • FIGURE 1 is a block diagram of one embodiment of a conventional four-channel wavelength division multiplexed communication system with optical amplification using unidirectional transmission on the optical fiber;
  • FIGURE 2 is a block diagram of one embodiment of an improved four-channel wavelength division multiplexed communication system with optical regulators according to the present invention
  • FIGURE 3 is a block diagram of one embodiment of an optical regulator according to the present invention.
  • FIGURE 4 is a block diagram of one embodiment of a four-channel wavelength division multiplexed system using bi-directional transmission on the optical fiber according to the present invention
  • FIGURE 5 is a block diagram of one embodiment of a bi-directional wavelength division multiplexed line amplifier with a single amplifier according to the present invention
  • FIGURE 6 is a block diagram of one embodiment of a wavelength division multiplexed communication system with end-to-end channel power control feedback according to the present invention.
  • FIGURES Preferred embodiments of the present invention are illustrated in the FIGURES, like numerals being used to refer to like and corresponding parts of the various drawings .
  • the optical channel regulator of the present invention electronically performs a power level measurement for each channel of a wavelength division multiplexed communication system.
  • the optical channel regulator of the present invention also electronically varies the path attenuation to bring all optical channels into balance before being combined in a multiplexer and before being amplified. If the balance changes at a later time, the control system automatically readjusts to maintain the balance.
  • the present invention provides a method for regulating an optical channel.
  • the optical channel regulator includes an electrically variable optical attenuator receiving an optical signal .
  • the attenuator attenuates the optical signal responsive to _a feedback control signal and yields an attenuated optical signal.
  • a tapped optical coupler receives the attenuated optical signal of the attenuator and provides substantially all of the attenuated optical signal as an output .
  • the tapped optical coupler also provides a remaining portion of the attenuated optical signal as a tapped output.
  • An optical detector receives the tapped output and provides an electrical signal representing the attenuated optical signal.
  • a comparator receives the electrical signal of the optical detector and a reference signal. Finally, the comparator compares the electrical signal to the reference signal and provides a feedback control signal to the attenuator.
  • FIGURE 1 is a block diagram of one embodiment of a conventional unidirectional four-channel wavelength division multiplexed system, indicated generally at 10, with optical amplification.
  • System 10 includes terminal equipment 12 having a plurality of transmit channels 14. Although only transmit channels 14 are shown in FIGURE 1, terminal equipment 12 may also include receive channels. Each transmit channel 14 is connected and provides an optical signal to a fixed attenuator 16. Each attenuator 16 is manually selected or adjusted, and provides fixed attenuation of the optical signal. The attenuators 16 are connected to an optical combiner 18 that provides an output to an optical amplifier 20 which wavelength division multiplexes the plurality of optical signals.
  • Optical amplifier 20 feeds an amplified signal to an optical amplifier 22.
  • Optical amplifier 22 then feeds an optical amplifier 24.
  • Optical amplifier 22 may be located at a line amplifier repeater site, as shown. The number of optical amplifiers in the transmission path are dependent upon a number of factors, including the length over which the signal must travel.
  • Optical amplifier 24 provides an output to an optical demultiplexer 26 that recovers the plurality of optical signals and provides each optical signal to one of a plurality of fixed attenuators 28.
  • the attenuators 28 are also manually selected or adjusted, and provide fixed attenuation of the optical signal.
  • Each attenuator 28 is connected to a receive channel 30 of terminal equipment 32.
  • Fixed attenuators 16 and 28 operate to balance the optical channels, but are manually selected and installed or manually adjusted variable attenuators.
  • the selection or adjustment of attenuators 16 and 28 involves manual measurement of each optical channel since the source transmitter power level for each channel varies, and is not precisely known beforehand.
  • FIGURE 2 is a block diagram of one embodiment of an improved four-channel wavelength division multiplexed system, indicated generally at 40, with optical regulators according to the present invention.
  • system 40 is similar to system 10 of FIGURE 1.
  • an optical regulator assembly 42 and an optical regulator assembly 44 have replaced the fixed attenuators 16 and 28 of FIGURE 1.
  • each transmit channel 14 is connected to an optical regulator 46 which then feeds optical combiner 18.
  • each optical regulator 46 receives an input from a microprocessor controller 48.
  • the outputs of optical demultiplexer 26 are connected to optical regulators 50 that receive an input from a microprocessor controller 52.
  • optical regulators 46 and 50 electronically perform a power level measurement for each channel and electronically vary the path attenuation to bring the optical channels into balance before being combined in optical combiner 18 and after being separated by optical demultiplexer 26.
  • the input from microprocessor controllers 48 or 52 provide a level against which to compare the level of the respective channel. If the balance changes at a later time, system 40 can thus automatically readjust to maintain the balance.
  • FIGURE 3 is a block diagram of one embodiment of an optical regulator 46 (or 50) according to the present invention.
  • Optical regulator 46 may include a tapped optical coupler 60 that receives an optical line carrying the optical signal. Tapped optical coupler 60 provides substantially all of the optical signal (e.g., 95%) as an output to an electrically variable optical attenuator 64. The remaining portion of the signal (e.g., 5%) is provided to an optical detector 62 that provides an input monitor level signal, as shown.
  • Optical attenuator 64 operates to attenuate the optical signal responsive to a feedback control signal .
  • a second tapped optical coupler 66 receives the output of optical attenuator 64 and provides substantially all of the received optical signal (e.g., 95%) as an output.
  • the remaining portion of the optical signal (e.g., 5%) is provided as a tapped output.
  • An optical detector 68 receives the tapped output and provides an output signal (output monitor level) representing the optical signal to a comparator 70.
  • Comparator 70 compares the output signal of optical detector 68 with a microprocessor controlled reference signal (microprocessor controlled power level) and, in response, provides the feedback control signal to optical attenuator 64.
  • optical regulator 46 taps the optical line and compares the signal with a controlled power level.
  • the controlled power level is provided by a microprocessor controller, for example as shown in FIGURE 2.
  • the microprocessor controller receives the input monitor level from optical detector 62 and the output monitor level from output detector 68.
  • the microprocessor controller then processes those inputs according to executed program code and generates the microprocessor controlled power level used as a reference by comparator 70.
  • feedback may be provided to electrically vary optical attenuator 64 to regulate the power level of the optical signal. It should be noted that optimum balance often can be best determined at the received end of the systems. This may mean that the channels at the transmit end are deliberately unequal. It also should be noted that often the optimum balance at the receive end may be determined by signal-to-noise ratio rather than power level.
  • FIGURE 4 is a block diagram of one embodiment of a bi-directional four-channel wavelength division multiplexed system, indicated generally at 80, according to the present invention.
  • System 80 includes terminal equipment 82 located at a first site.
  • Terminal equipment 80 provides transmit channels 84 and receive channels 86.
  • Each transmit channel 84 is connected to an optical regulator 88.
  • Outgoing signals are multiplexed by a combiner 90, and incoming signals are separated by demultiplexer 91.
  • Optical amplifiers 92 provide signals to or receive signals from a multiplexer 94, as shown.
  • System 80 includes a bi-directional optical transmission line having a plurality of bi-directional line amplifiers 96 located at repeater sites.
  • a multiplexer 98 provides signals to and receives signals from amplifiers 100. Incoming signals are provided to .a demultiplexer 102 to separate the multiplexed signals. Outgoing signals are provided to a combiner 103 by optical regulators 104, as shown. Optical regulators 104 are connected as shown to terminal equipment 106 that provides receive channels 108 and transmit channels 110. It should be understood that microprocessor control of optical regulators 88 and 104, although not shown, is similar to that shown in FIGURE 2.
  • FIGURE 5 is a block diagram of one embodiment of a bi-directional wavelength division multiplexed line amplifier with a single amplifier according to the present invention.
  • a multiplexer 120 communicates across a bi-directional line.
  • Multiplexer 120 is connected to an optical regulator 122 which is connected to another multiplexer 124.
  • Multiplexer 124 is also connected to a second optical regulator 122, as shown.
  • An optical amplifier 126 receives a signal from multiplexer 124 and provides an amplified signal to a multiplexer 128.
  • the use of optical regulators 122 according to the present invention allows balancing of the power levels at bi-directional line amplifiers using a single amplifier 126.
  • FIGURE 6 is a block diagram of one embodiment of a wavelength division multiplexed system, 140, with end-to- end channel power control feedback according to the present invention.
  • System 140 is similar to system 40.of FIGURE 2.
  • optical regulators 50 of FIGURE 2 are shown as optical monitors 142. Note that the detector 62 in the optical regulator can be used for the optical monitor 142.
  • microprocessor controller 52 is linked to microprocessor controller 48 by a data communication link 144.
  • the link provided by data communication link 144 allows feedback from one end point to the other concerning the channel power control provided by optical regulators 46 and optical monitors 142.
  • This data communication link is typically provided by an optical supervisory channel that is integrated into the optical communication system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention se rapporte à un régulateur de voies optiques (46). Selon l'invention, le régulateur de voies optiques (46) comprend un coupleur optique à prise (60) sur lequel est branchée une ligne optique transportant un signal optique. Le coupleur optique à prise (60) fournit la quasi-totalité du signal optique en forme de signal de sortie. Un atténuateur optique (64) à régulation électrique reçoit la sortie du coupleur optique à prise (60) et atténue le signal optique en fonction d'un signal de commande par rétroaction. Un deuxième coupleur optique à prise (66) reçoit une sortie de l'atténuateur (64). Le deuxième coupleur (66) fournit la quasi-totalité du signal optique reçu sous forme de signal de sortie et fournit une partie restante du signal optique en forme de signal de sortie pour prise. Un détecteur optique (68) reçoit le signal de sortie pour prise et fournit un signal de sortie qui représente le signal optique. Un comparateur (70) reçoit le signal de sortie provenant du détecteur optique (68) et un signal de référence. Le comparateur (70) compare le signal de sortie et le signal de référence puis fournit à l'atténuateur (64) un signal de commande par rétroaction, et ce en réponse à la comparaison. En tant que partie d'un système de communication multivoies, le régulateur est utilisé pour ajuster le niveau de chacune des voies afin de maintenir automatiquement la balance et l'équilibrage entre les voies.
PCT/US1998/020747 1997-09-30 1998-09-30 Regulateur de voies optiques et procede correspondant WO1999017485A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CA002273020A CA2273020C (fr) 1997-09-30 1998-09-30 Regulateur de voies optiques et procede correspondant
JP52058699A JP2001508990A (ja) 1997-09-30 1998-09-30 光チャネル調整器およびその方法

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6052697P 1997-09-30 1997-09-30
US60/060,526 1997-09-30

Publications (1)

Publication Number Publication Date
WO1999017485A1 true WO1999017485A1 (fr) 1999-04-08

Family

ID=22030051

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/020747 WO1999017485A1 (fr) 1997-09-30 1998-09-30 Regulateur de voies optiques et procede correspondant

Country Status (3)

Country Link
JP (1) JP2001508990A (fr)
CA (1) CA2273020C (fr)
WO (1) WO1999017485A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1076434A2 (fr) * 1999-08-12 2001-02-14 Fujitsu Limited Dispositif et procédé d'amplification optique pour l'amplification de lumière d'une BANDE DE LONGUEUR D'ONDE ETENDUE
GB2360654A (en) * 2000-03-25 2001-09-26 Marconi Comm Ltd Power controlling network element for adding new channels in a controlled manner
US7596315B2 (en) 2004-03-24 2009-09-29 Fujitsu Limited Wavelength division multiplexing optical transmission system and transmission wavelength control method therefor
US8064771B2 (en) 2005-06-30 2011-11-22 Infinera Corporation Active control loop for power control of optical channel groups

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5815299A (en) * 1995-09-08 1998-09-29 Alcatel N.V. Method and system for equalizing respective power levels of channels of a received optical frequency division multiplexed signal

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5815299A (en) * 1995-09-08 1998-09-29 Alcatel N.V. Method and system for equalizing respective power levels of channels of a received optical frequency division multiplexed signal

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1076434A2 (fr) * 1999-08-12 2001-02-14 Fujitsu Limited Dispositif et procédé d'amplification optique pour l'amplification de lumière d'une BANDE DE LONGUEUR D'ONDE ETENDUE
EP1076434A3 (fr) * 1999-08-12 2004-05-26 Fujitsu Limited Dispositif et procédé d'amplification optique pour l'amplification de lumière d'une BANDE DE LONGUEUR D'ONDE ETENDUE
US6885499B1 (en) 1999-08-12 2005-04-26 Fujitsu Limited Optical amplifying apparatus for amplifying wide-wavelength-band light, optical sending apparatus, optical transmission system, and optical amplifying method
GB2360654A (en) * 2000-03-25 2001-09-26 Marconi Comm Ltd Power controlling network element for adding new channels in a controlled manner
US7254339B2 (en) 2000-03-25 2007-08-07 Ericsson Ab Power controlling network element
US7596315B2 (en) 2004-03-24 2009-09-29 Fujitsu Limited Wavelength division multiplexing optical transmission system and transmission wavelength control method therefor
US8064771B2 (en) 2005-06-30 2011-11-22 Infinera Corporation Active control loop for power control of optical channel groups

Also Published As

Publication number Publication date
CA2273020C (fr) 2003-04-01
JP2001508990A (ja) 2001-07-03
CA2273020A1 (fr) 1999-04-08

Similar Documents

Publication Publication Date Title
US5923450A (en) Optical channel regulator and method
US5790289A (en) WDM optical communication method with pre-emphasis technique and an apparatus therefor
US7515829B2 (en) Wavelength division multiplexing optical transmission system
US6323994B1 (en) WDM system equalization with EDFA optical amplifiers
US6819875B2 (en) Optical wavelength multiplexing transmission apparatus and optical output control method for optical wavelength multiplexing transmission apparatus
US6404523B1 (en) Wavelength division multiplexing system and its termination
US6400475B1 (en) Optical transmission system and optical communications device
US7650072B2 (en) Method of upgrading optical node, and an optical node apparatus
US6173093B1 (en) Optical add/drop wavelength division multiplex systems
US20070166052A1 (en) Wavelength division multiplexing optical transmission equipment and method of amplifying optical wavelength division multiplexed signals
US6839518B1 (en) Level adjustment method and wavelength division multiplexing device and system
EP1364478A2 (fr) Procede et systeme de manipulation de signaux optiques
US7020092B1 (en) Method for channel adjustment of transmission signal power in a wavelength division multiplexing transmission system
US6633430B1 (en) Booster amplifier with spectral control for optical communications systems
US11368239B2 (en) Wavelength conversion device and wavelength conversion method
CA2273020C (fr) Regulateur de voies optiques et procede correspondant
CN1742453B (zh) 用于wdm消息传输的输出级以及用于调换这种输出级中的全光源的方法
US6552845B2 (en) Optical gain equalizer and optical fiber transmission line
KR100305757B1 (ko) 파장분할다중화시스템용이득평탄유지형광증폭기
KR100328128B1 (ko) 파장분할다중 광전송시스템에서 광전력 증폭기의 동적이득제어장치
JP2011010015A (ja) 波長分割多重光伝送装置
US20020122226A1 (en) Network element and method for compensation of tilting
JPH11252048A (ja) 波長多重光伝送システム
AU677330B2 (en) AGC for broadband transmitter
WO2002080318A1 (fr) Commande de gain a compensation de bruit pour amplificateur optique

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP

ENP Entry into the national phase

Ref document number: 2273020

Country of ref document: CA

ENP Entry into the national phase

Ref country code: JP

Ref document number: 1999 520586

Kind code of ref document: A

Format of ref document f/p: F