WO2001074112A1 - Filtre accordable - Google Patents

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Publication number
WO2001074112A1
WO2001074112A1 PCT/GB2001/001372 GB0101372W WO0174112A1 WO 2001074112 A1 WO2001074112 A1 WO 2001074112A1 GB 0101372 W GB0101372 W GB 0101372W WO 0174112 A1 WO0174112 A1 WO 0174112A1
Authority
WO
WIPO (PCT)
Prior art keywords
wavelength
tunable filter
optical
wavelength converter
output
Prior art date
Application number
PCT/GB2001/001372
Other languages
English (en)
Inventor
Kenneth Guild
Michael O'mahony
Anna Tzanakaki
Dimitra Simeonidou
Original Assignee
Ditech Communications Corporation
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
Priority claimed from GBGB0007549.9A external-priority patent/GB0007549D0/en
Priority claimed from GB0007554A external-priority patent/GB0007554D0/en
Priority claimed from GB0019868A external-priority patent/GB0019868D0/en
Application filed by Ditech Communications Corporation filed Critical Ditech Communications Corporation
Priority to GB0224889A priority Critical patent/GB2377331A/en
Priority to AU42609/01A priority patent/AU4260901A/en
Publication of WO2001074112A1 publication Critical patent/WO2001074112A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2/00—Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light
    • G02F2/004—Transferring the modulation of modulated light, i.e. transferring the information from one optical carrier of a first wavelength to a second optical carrier of a second wavelength, e.g. all-optical wavelength converter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2/00—Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light
    • G02F2/004—Transferring the modulation of modulated light, i.e. transferring the information from one optical carrier of a first wavelength to a second optical carrier of a second wavelength, e.g. all-optical wavelength converter
    • G02F2/006—All-optical wavelength conversion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • H04Q2011/0007—Construction
    • H04Q2011/0009—Construction using wavelength filters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • H04Q2011/0007—Construction
    • H04Q2011/0011—Construction using wavelength conversion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • H04Q2011/0007—Construction
    • H04Q2011/0013—Construction using gating amplifiers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • H04Q2011/0007—Construction
    • H04Q2011/0016—Construction using wavelength multiplexing or demultiplexing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005—Switch and router aspects
    • H04Q2011/0007—Construction
    • H04Q2011/0018—Construction using tunable transmitters or receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0073—Provisions for forwarding or routing, e.g. lookup tables
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0086—Network resource allocation, dimensioning or optimisation

Definitions

  • This invention relates to optical signal transmission and more particularly to a tunable filter incorporating a wavelength converter useable in optical cross-connects and optical add-drop multiplexers.
  • WDM wavelength division multiplexing
  • the separation and detection of specific wavelengths carrying traffic is carried out at the receiving stations.
  • Network traffic allocation and routing are performed and managed in optical add-drop multiplexers/optical cross-connects, and optical packet switch nodes.
  • the traffic for each particular desired destination is allocated a particular wavelength and may be in the form of a continuous stream of data or in the form of packets, of variable or fixed length, having different wavelengths.
  • the nodes should provide routing or reconfiguration of the network such that the incoming signal is routed on per wavelength (circuit switches) or per packet (packet switches) basis in order to allow for traffic allocation, network growth and survivability of the data.
  • This invention seeks to provide a combined wavelength converter and tunable filter configuration suitable for enabling appropriate traffic routing in optical add-drop multiplexers, optical cross-connects and optical packet switches.
  • a tunable filter comprising an optical input for a wavelength division multiplexed (WDM) signal, a number of wavelength converters, a demultiplexer for routing each of a number of individual wavelength channels on the WDM signal to a respective wavelength converter, and an optical coupler coupled to each of the wavelength converters and to an optical output, wherein each wavelength converter is adapted to convert the wavelength of an input signal and/or effect selective switching of an input signal to the optical coupler.
  • WDM wavelength division multiplexed
  • the wavelength converter comprises one or more semiconductor optical amplifiers (SOAs).
  • SOAs semiconductor optical amplifiers
  • the wavelength converter may be arranged as a single SOA or as an interferometer arrangement utilising a number of SOAs.
  • One or more SOAs are gated to provide selective switching so as to provide a filtering function.
  • an optical tunable filter/wavelength converter comprising an input for multiple wavelength traffic carrying signals, an output for converted wavelength carrying signals, means for routing each of the traffic carrying signals to a de-multiplexer and an individual semiconductor optical amplifier (SOA) or to an interferometer arrangement utilising SOAs, a laser source providing a further input wavelength to each of the SOAs or interferometer arrangements, to enable cross-gain or cross-phase modulation from the input signal, thereby to provide the converted signal and means for routing the converted signals to the output.
  • SOA semiconductor optical amplifier
  • the means for selectively routing the converted signals to the output may comprise injection current control means to prevent or enable operation of individual SOAs thereby to effect selective switching of converted signal to the output.
  • the tunable filter/converter may be provided with a more elaborate SOA configuration, the arrangement being such as to provide 2R regeneration conversion by cross-phase modulation.
  • the wavelength(s) of the laser source may be variable to change the wavelength of the output signals. This variability may be effected by means of one or more variable wavelength lasers or by a plurality of lasers of different wavelengths, which lasers are individually selectable to provide the further input wavelength.
  • the invention may include a demultiplexer having an input for an optical fibre line, several outputs each for a different wavelength signal each of which outputs is coupled via an optical coupler having an output for connection to an optical fibre line.
  • Figure 1 illustrates a combined tunable filter/wavelength converter constructed in accordance with the invention and incorporating a demultiplexer
  • Figure 2 illustrates an individual wavelength converter for incorporation in the tunable filter/wavelength converter of Figure 1 ;
  • Figure 3 illustrates an alternative individual wavelength converter for incorporation in the tunable filter/wavelength converter of Figure 1 ;
  • Figure 4 illustrates an alternative laser source useable in the individual wavelength converters of Figures 2 and 3.
  • Figure 1 shows an optical wavelength converter which has a de-multiplexer 10 having an input connected to an input optical fibre 12 from which it receives a WDM signal comprising wavelengths ⁇ 1 - ⁇ m .
  • the signal is demultiplexed and each wavelength is provided on an individual output of the demultiplexer.
  • Each output is coupled via an individual wavelength converter 14, to a coupler or combiner 16 the output of which provides wavelengths A., - ⁇ J to an output optical fibre 1 B.
  • One converter 14 is illustrated in more detail in Figure 2 where it can be seen that an input wavelength A., from the demultiplexer 10 is fed to an input of a circulator 20 and is routed out via its next terminal to a semiconductor optical amplifier (SOA) 22.
  • SOA semiconductor optical amplifier
  • a continuous wave laser source 24 having a wavelength A*,' is also provided as another input to the SOA which amplifier is switched on or off by an injection current control means 26 and when switched on the wavelength A/ is cross-gain modulated by the traffic signal on A., and is routed back into the circulator and emerges from the third terminal where it is coupled to the combiner 16.
  • any one or more of the demultiplexed signals can be routed to the combiner 16.
  • any other suitable coupling arrangement may be employed e.g. an optical coupler/isolator.
  • An alternative individual wavelength converter 14 is illustrated in Figure 3 and comprises first and second SOAs 30 and 32 connected in parallel so as to form a Mach-Zender interferometer.
  • One side of these SOAs receives the data carrying signal A., from the demultiplexer 10 and the other side receives the carrier wavelength A-,' from the laser source 24.
  • the SOAs are each provided with an injection current by a control means 26 and when switched on the A-.' signal is cross phase modulated in the two SOAs.
  • the combined output of the SOAs 30 and 32 is routed via a third SOA 34 which again has injection current control by a control means 26 and acts as a wavelength gate for selectively routing the converted signal to the coupler 16.
  • the input data signal A., and carrier wave signal A*,' from the laser source 24 are also coupled to SOAs 30 and 32 via individual SOAs 36 and 38 again having injection current provided by control means 26.
  • Alternative interferometer configurations may be employed, for example a Michelson interferometer arrangement.
  • the laser source 24 employed in Figures 2 and 3 may be a variable wavelength laser or alternatively a laser source 40 may comprise a plurality of lasers 42 such as is shown in Figure 4. These lasers are coupled via a combiner 44 to provide the continuous wave input of the combiner. The lasers may be individually switched on/off to select the desired wavelength or may be on continuously and be coupled selectively by optical switches in the combiner 44.
  • the arrangements described enable the provisions of a circuit-switched and packet switched network employing optical wavelength routing. The wavelength routing may be facilitated by the combination of the demultiplexer and wavelength converter acting as a tuneable filter that enables dynamic reconfiguration of the network.
  • the proposed configuration permits implementations of both tuneable filtering, where any one or more wavelengths is selected for routing and tunable or fixed all-optical wavelength conversion.
  • the tuning speed of the filter is determined by the switching time of the SOA gates ( ⁇ 2ns) and therefore very fast tuning is feasible.
  • the tuning speed of the wavelength converter is determined by the tuning speed of the tunable laser source.
  • An additional feature of this design is the reduction of the penalty due to crosstalk at the output combiner.
  • the conventional configuration for fast tunable filters comprises a demultiplexer, SOA gates and a combiner at the output which may introduce significant interferometric crosstalk originating from the input demultiplexer.
  • the crosstalk penalty may be considerably high depending on the number of wavelengths supported and the crosstalk performance of the demultiplexer. However, this penalty can be eliminated with the use of the wavelength conversion stage at the output of the demultiplexer.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Optics & Photonics (AREA)
  • Optical Communication System (AREA)

Abstract

Cet ensemble filtre optique accordable/convertisseur de longueur d'ondes comprend une entrée de signaux porteurs de trafic à plusieurs longueurs d'ondes μ1-μm, une sortie destinée aux signaux porteurs de la longueur d'onde convertie (μ1'-μm'), ainsi que des moyens (20) d'acheminement de chacun des signaux porteurs, à travers un démultiplexeur et en direction d'un amplificateur optique à semi-conducteur (SOA) (22) ou d'un agencement d'interféromètre. Une source laser (26) fournit une longueur d'ondes d'entrée subséquente à l'amplificateur optique à semi-conducteur, ou à l'agencement d'interféromètre, de manière à permettre une modulation de gain croisé ou de phase croisée, à partir du signal d'entrée, et à produire ainsi le signal converti. L'invention concerne encore des moyens d'acheminement sélectif du signal converti, vers la sortie.
PCT/GB2001/001372 2000-03-28 2001-03-28 Filtre accordable WO2001074112A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0224889A GB2377331A (en) 2000-03-28 2001-03-28 A tunable filter
AU42609/01A AU4260901A (en) 2000-03-28 2001-03-28 A tunable filter

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
GBGB0007549.9A GB0007549D0 (en) 2000-03-28 2000-03-28 A wavelength converter
GB0007549.9 2000-03-28
GB0007554A GB0007554D0 (en) 2000-03-28 2000-03-28 A tunable filter
GB0007554.9 2000-03-28
GB0019868A GB0019868D0 (en) 2000-08-11 2000-08-11 A tunable filter/wavelength converter
GB0019868.9 2000-08-11

Publications (1)

Publication Number Publication Date
WO2001074112A1 true WO2001074112A1 (fr) 2001-10-04

Family

ID=27255627

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2001/001372 WO2001074112A1 (fr) 2000-03-28 2001-03-28 Filtre accordable

Country Status (3)

Country Link
AU (1) AU4260901A (fr)
GB (1) GB2377331A (fr)
WO (1) WO2001074112A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6624929B2 (en) * 2000-12-19 2003-09-23 Korea Institute Of Science And Technology All-optical logic AND operation in a SOA-based Mach-Zehnder interferometer
CN100352187C (zh) * 2002-11-22 2007-11-28 三星电子株式会社 波长变换器及利用波长变换器的光交叉连接系统

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0946077A2 (fr) * 1998-03-26 1999-09-29 Nec Corporation Appareil de commutation optique utilisant la technologie de multiplexage en longueur d'onde

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0946077A2 (fr) * 1998-03-26 1999-09-29 Nec Corporation Appareil de commutation optique utilisant la technologie de multiplexage en longueur d'onde

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
ASGHARI M ET AL: "WAVELENGTH CONVERSION USING SEMICONDUCTOR OPTICAL AMPLIFIERS", JOURNAL OF LIGHTWAVE TECHNOLOGY,US,IEEE. NEW YORK, vol. 15, no. 7, 1 July 1997 (1997-07-01), pages 1181 - 1190, XP000693475, ISSN: 0733-8724 *
GLANCE B ET AL: "APPLICATIONS OF THE INTEGRATED WAVEGUIDE GRATING ROUTER", JOURNAL OF LIGHTWAVE TECHNOLOGY,US,IEEE. NEW YORK, vol. 12, no. 6, 1 June 1994 (1994-06-01), pages 957 - 962, XP000484211, ISSN: 0733-8724 *
KLOCH A ET AL: "WAVELENGTH CONVERTERS", IEICE TRANSACTIONS ON ELECTRONICS,INSTITUTE OF ELECTRONICS INFORMATION AND COMM. ENG. TOKYO,JP, vol. E82-C, no. 8, August 1999 (1999-08-01), pages 1475 - 1485, XP000930705, ISSN: 0916-8524 *
YOSHIDA J -I ET AL: "RECENT RESEARCH TRENDS AND ISSUES IN PHOTONIC SWITCHING DEVICES", NTT REVIEW,TELECOMMUNICATIONS ASSOCIATION, TOKYO,JP, vol. 7, no. 5, 1 September 1995 (1995-09-01), pages 24 - 29, XP000536276 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6624929B2 (en) * 2000-12-19 2003-09-23 Korea Institute Of Science And Technology All-optical logic AND operation in a SOA-based Mach-Zehnder interferometer
CN100352187C (zh) * 2002-11-22 2007-11-28 三星电子株式会社 波长变换器及利用波长变换器的光交叉连接系统

Also Published As

Publication number Publication date
GB2377331A (en) 2003-01-08
GB0224889D0 (en) 2002-12-04
AU4260901A (en) 2001-10-08

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