GB2360890A - Reconfigurable optical add/drop multiplexer - Google Patents

Reconfigurable optical add/drop multiplexer Download PDF

Info

Publication number
GB2360890A
GB2360890A GB0023469A GB0023469A GB2360890A GB 2360890 A GB2360890 A GB 2360890A GB 0023469 A GB0023469 A GB 0023469A GB 0023469 A GB0023469 A GB 0023469A GB 2360890 A GB2360890 A GB 2360890A
Authority
GB
United Kingdom
Prior art keywords
input
signal
output
multiplexer
signals
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.)
Withdrawn
Application number
GB0023469A
Other versions
GB0023469D0 (en
Inventor
Dimitra Simeonidou
Kenneth Guild
Anna Tzanakaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ILOTRON Ltd
Original Assignee
ILOTRON Ltd
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 GBGB0005021.1A external-priority patent/GB0005021D0/en
Priority claimed from GB0007551A external-priority patent/GB0007551D0/en
Application filed by ILOTRON Ltd filed Critical ILOTRON Ltd
Publication of GB0023469D0 publication Critical patent/GB0023469D0/en
Publication of GB2360890A publication Critical patent/GB2360890A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H04J14/0202—Arrangements therefor
    • H04J14/0204—Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H04J14/0202—Arrangements therefor
    • H04J14/0205—Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H04J14/0202—Arrangements therefor
    • H04J14/021—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0283—WDM ring architectures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0287—Protection in WDM systems
    • H04J14/0289—Optical multiplex section protection
    • 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
    • H04Q2011/0015—Construction using splitting combining
    • 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
    • H04Q2011/0022—Construction using fibre gratings
    • 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
    • H04Q2011/0035—Construction using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical
    • 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
    • H04Q2011/0037—Operation
    • H04Q2011/0041—Optical control
    • 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
    • H04Q2011/0079—Operation or maintenance aspects
    • H04Q2011/0081—Fault tolerance; Redundancy; Recovery; Reconfigurability

Landscapes

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

Abstract

An optical signal add/drop multiplexer for wavelength division multiplexed (WDM) signals comprises routing means capable of selecting different wavelength signals for adding or dropping. A splitter directs incoming WDM signals along several paths, each path including a switch for allowing or preventing passage of the signal and wavelength selection means, e.g. one or more Bragg gratings. Circulators are used to effect the adding/dropping of reflected signals. Routing means for adding wavelengths also comprises a splitter and switch arrangement. The switching devices may be gain clamped semiconductor optical amplifier (SOA) gates. The invention is suitable for use in fast network reconfiguration and ring protection in WDM systems.

Description

2360890 Optical Signal Add/Drop Multiplexer This invention relates to an
optical signal add/drop multiplexer (OADM) suitable for use in architecture for fast network reconfiguration and ring protection in wavelength division multiplex (WDM) signal transmission systems.
optical transmission systems employing WDM currently employ fixed wavelength OADMs to implement Bus-network functionality. The present invention is concerned with enhancing networking functionality.
According to the invention there is provided an optical signal add/drop multiplexer for wavelength division multiplex (WDM) signals, comprising routing means for permitting selectable different wavelength signals of the WDM signals to be directed to a drop signal output.
The invention permits considerable enhancement of WDM transmission systems by permitting selectability of which wavelength signals from the multiple wavelength WDM signals are to be dropped to a spur.
The multiplexer may comprise second routing means for permitting selectable different wavelength signals of an add signal to be directed to an output. By means of this enhancement selectability of which wavelength signals from multiple wavelength WDM add signals are to be added from a spur. Normally the wavelengths to be added will correspond with the wavelengths which are dropped but this need not necessarily be the case.
The multiplexer may comprise an input for an optical fibre transmission line, a splitter coupled to the input and arranged to direct the signal along a plurality of paths, each including particular different wavelength selection means, to the drop output, wherein a switching device is provided in each path to permit or prevent passage of the signal thereby to determine which signal wavelength(s) is/are dropped. The wavelength selection means in each path may comprise one or more Bragg gratings.
The arrangement may be such that the individual paths from 2 the splitter are each coupled to an input/output port of an individual circulator, the next input/output port of which is coupled to the path Bragg grating(s) which are effective to reflect particular wavelength(s) back into the circulator and out through a third input/output port to the drop signal output. The third input/output ports of the circulators may be coupled via a combiner to the drop signal output. The second routing means may comprise a splitter coupled to an add signal input and arranged to direct the add signal along a plurality of paths to the output, each path including an individual switching device to permit or prevent passage of the signal thereby to determine which of the wavelength signals are added.
The add/drop multiplexer arrangement may be such that the second routing means comprises a splitter coupled to an add signal input and arranged to direct the add signal along a plurality of paths to the output each path including an individual switching device to permit or prevent passage of the signal to a first input/output port of an individual circulator, the second input/output port of which circulator is connected to individual ones of the Bragg gratings of one path of the split input signal but on the opposite side of the Bragg grating thereby to reflect only particular add signal wavelengths back into the circulator and out through a third input/output port of the output. The third input/output ports of the circulators may be coupled via a combiner to the output.
The switching devices may be semiconductor optical amplifier (SOA) gates and are preferably gain clamped.
In order that the invention and its various other preferred features may be understood more easily, an embodiment thereof will now be described, by way of example only, with reference to the drawing, the single figure of which is a schematic block diagram of an add/drop multiplexer constructed in accordance with the invention.
In the drawing an input coupler 10 in the form of a 1x2 protection switch for WM traffic signals is connected via an optical amplifier 12 to a split and gate switch 14.
The coupler 10 also has an input for a protection fibre 16 3 from the opposite line direction. The split and gate switch 14 comprises 1xN optical splitter 18 which splits the signal and directs it along N individual branches, in the illustrated case 4 branches each including an individual switch device 20, 22, 24, 26. The switch devices are preferably SOA gates which are gain clamped in order to avoid cross-gain modulation. Current SOAs can have polarisation sensitivity as low as 0.2 dB and high output saturation power. By controlling the injection current to a signal SOA gate it is possible to select which branch the traffic will follow. Optionally one branch, as illustrated at 28, can be reserved as a through branch which can be selected by SOA 20 to permit all traffic wavelengths to pass straight through the multiplexer. The other branches are each routed via a circulator 30, 32, 34 to a Bragg grating 36 or to a plurality of Bragg gratings 38, 40; 42, 44, 46 connected in series. Each Bragg grating is arranged to reflect a particular wavelength X, - XK - When a particular branch is selected by control of the injection currents to its associated SOA, eg 22, the WDM transmission signal is directed with a first input/output port of the circulator 30 out through a second input/output port to the Bragg grating 36 where the wavelength X, is reflected back into the second input/output port and out through a third output port to a combiner 48 the output of which is coupled to an amplifier 50. This signal then constitutes a dropped signal wavelength for coupling to a spur terminal. Selection of alternative branches will result in A, XK and X, 1 XJ 1 ?K being dropped respectively. The non-dropped wavelengths pass through the Bragg grating(s) to a first input/output of a circulator 52, 54, 56 in each branch. The second input/output of each circulator is coupled to a combiner 58 the output of which is coupled via an amplifier 60 to a coupler 62, in the form of a 1x2 protection switch, for connection to an ongoing line 1 - The coupler also includes an output 64 for a protection fibre towards the opposite direction. A third input/output port of each circulator 52, 54, 56 is coupled to a second split and gate switch 66. This comprises an 4 SOA 68, 70, 72 coupled to the third input/output port of the circulators 52, 54 and 56 respectively, which switches are coupled via a splitter 74 to an amplifier 76 to an input for connection to add fibre from a spur station. The spur station can thereby provide WDM add signals and particular wavelengths to add can be selected by controlling the injection current to the SOAs 68, 70, 72 to select an appropriate branch in which the appropriate Bragg grating (s) reflect the wavelength (s) through the associated circulator 52, 54, 56 to the combine 58. In this way the add and through wavelengths are directed to the output coupler 62 via the combiner 58.
The add wavelengths could be directly coupled to the output coupler without the need to use circulators.
However, the preferred configuration employing circulators safeguards the main fibre traffic in case conflicting wavelengths propagate in the add-port.
The reflectivities of the Bragg gratings can be chosen such that they correct or counter any gain imbalance, eg such as may be introduced by the SOAs, and thereby give an improved or overall flat wavelength response for the OADM.
The drawing depicts one direction of the OADM node that can be used in a unidirectional ring. Another symmetrical module can be linked to the opposite direction for a bidirectional ring configuration. Protection switching is achieved by means of the 1x2 protection switches at the input and output.
The advantages of this architecture are:
1. It is simple 2. It contains no mechanical parts.
3. The very fast switching capability of the SOA (ins) can suppress switching transients.
4. The on-off cross-talk of the SOA gate and of the Bragg gratings is low.
5. The insertion losses are low due to the SOA gain. This relaxes the design requirements of the node EDFAs. It may even be possible to eliminate the EDFAs at certain ports.
6. It has a built-in power management capability.
7. The utilised component technology is already mature and well proven.
on the undesirable features side is the additional amplified spontaneous emission (ASE) noise introduced by the SOA gates. However, recent studies have proven that gain clamped SLAs can be cascaded in large numbers. The power consumption of the two gates that are in transmission may be also a concern but is surmountable.
The present invention enables the provision of a novel OADM node architecture which satisfies not only steady state transmission requirements but also deals with the dynamic (transient) behaviour of reconfigurable networks, thus providing a complete solution to transmission related networking problems.
6

Claims (11)

CLAIMS:
1. An optical signal add/drop multiplexer for wavelength division multiplex (WDM) signals, comprising routing means for permitting selectable different wavelength signals of the WDM signals to be directed to a drop signal output.
2. A multiplexer as claimed in claim 1, comprising second routing means for permitting selectable different wavelength signals of an add signal to be directed to an output.
3. A multiplexer as claimed in claim 2, comprising an input for an optical fibre transmission line, a splitter coupled to the input and arranged to direct the signal along a plurality of paths, each including particular different wavelength selection means, to the drop signal output wherein a switching device is provided in each path to permit or prevent passage of the signal thereby to determine which signal wavelength(s) is/are dropped.
4. A multiplexer as claimed in claim 3, wherein the wavelength selection means in each path comprise one or more Bragg gratings.
5. A multiplexer as claimed in claim 4, wherein the individual paths from the splitter are each coupled to an input/output port of an individual circulator, the next input/output port of which is coupled to the path Bragg grating(s) which are effective to reflect particular wavelength(s) back into the circulator and out through a third input/output port to the drop signal output.
6. A multiplexer as claimed in claim 5, wherein the third input/output ports of the circulators are coupled via a combiner to the drop signal output.
7. A multiplexer as claimed in claim 3, 4, 5 or 6, wherein the second routing means comprises a splitter 7 coupled to an add signal input and arranged to direct the add signal along a plurality of paths to the output, each path including an individual switching device to permit or prevent passage of the signal thereby to determine which of the wavelength signals are added.
8. A multiplexer as claimed in claim 5, wherein the second routing means comprises a splitter coupled to an add signal input and arranged to direct the add signal along a plurality of paths to the output each path including an individual switching device to permit or prevent passage of the signal to a first input/output port of an individual circulator, the second input/output part of which circulator is connected to individual ones of the Bragg gratings of one path of the split input signal but on the opposite side of the Bragg grating thereby to reflect only particular add signal wavelengths back into the circulator and out through a third input/output port of the output.
9. A multiplexer as claimed in claim 8, wherein the third input/output ports of the circulators are coupled via a combiner to the output.
10. A multiplexer as claimed in any one of claims 3 to 9, wherein the switching devices are semiconductor optical amplifier (SOA) gates.
11. A multiplexer as claimed in claim 10, wherein the SOA gates are gain clamped.
GB0023469A 2000-03-02 2000-09-25 Reconfigurable optical add/drop multiplexer Withdrawn GB2360890A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB0005021.1A GB0005021D0 (en) 2000-03-02 2000-03-02 Data reader
GB0007551A GB0007551D0 (en) 2000-03-28 2000-03-28 An OADM architecture for fast network reconfiguration and ring protection

Publications (2)

Publication Number Publication Date
GB0023469D0 GB0023469D0 (en) 2000-11-08
GB2360890A true GB2360890A (en) 2001-10-03

Family

ID=26243784

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0023469A Withdrawn GB2360890A (en) 2000-03-02 2000-09-25 Reconfigurable optical add/drop multiplexer

Country Status (1)

Country Link
GB (1) GB2360890A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1317084A2 (en) * 2001-10-26 2003-06-04 Nortel Networks Limited Optical amplifier arrangement
EP2437087A1 (en) * 2010-09-29 2012-04-04 Alcatel Lucent A tunable optical filter, an optical device integrating such filter and a method of filtering an optical signal
ES2530888A1 (en) * 2013-09-06 2015-03-06 Univ Madrid Politecnica Passive optical multiplexer

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5612805A (en) * 1994-06-07 1997-03-18 Alcatel Cit Add-drop optical spectrum-division multiplexer
US5712932A (en) * 1995-08-08 1998-01-27 Ciena Corporation Dynamically reconfigurable WDM optical communication systems with optical routing systems
US5726785A (en) * 1995-02-28 1998-03-10 France Telecom Optical add-drop multiplexer using optical circulators and photoinduced Bragg gratings
US5771112A (en) * 1995-06-21 1998-06-23 France Telecom Reconfigurable device for insertion-extraction of wavelengths
WO1998052306A2 (en) * 1997-05-13 1998-11-19 Nokia Telecommunications Oy Optical add/drop device
WO1999007097A1 (en) * 1997-07-30 1999-02-11 Ciena Corporation Dynamically reconfigurable optical add-drop multiplexers for wdm optical communication systems
WO1999027673A1 (en) * 1997-11-21 1999-06-03 Uniphase Telecommunications Products, Inc. A programmable add-drop module for use in an optical circuit
EP0926853A2 (en) * 1997-12-23 1999-06-30 Lucent Technologies Inc. Article comprising a wavelength selective add-drop multiplexer
US5953141A (en) * 1996-10-03 1999-09-14 International Business Machines Corporation Dynamic optical add-drop multiplexers and wavelength-routing networks with improved survivability and minimized spectral filtering
WO2000057665A1 (en) * 1999-03-22 2000-09-28 Chorum Technologies Lp Optical wavelength add/drop multiplexer

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5612805A (en) * 1994-06-07 1997-03-18 Alcatel Cit Add-drop optical spectrum-division multiplexer
US5726785A (en) * 1995-02-28 1998-03-10 France Telecom Optical add-drop multiplexer using optical circulators and photoinduced Bragg gratings
US5771112A (en) * 1995-06-21 1998-06-23 France Telecom Reconfigurable device for insertion-extraction of wavelengths
US5712932A (en) * 1995-08-08 1998-01-27 Ciena Corporation Dynamically reconfigurable WDM optical communication systems with optical routing systems
US5953141A (en) * 1996-10-03 1999-09-14 International Business Machines Corporation Dynamic optical add-drop multiplexers and wavelength-routing networks with improved survivability and minimized spectral filtering
WO1998052306A2 (en) * 1997-05-13 1998-11-19 Nokia Telecommunications Oy Optical add/drop device
WO1999007097A1 (en) * 1997-07-30 1999-02-11 Ciena Corporation Dynamically reconfigurable optical add-drop multiplexers for wdm optical communication systems
WO1999027673A1 (en) * 1997-11-21 1999-06-03 Uniphase Telecommunications Products, Inc. A programmable add-drop module for use in an optical circuit
EP0926853A2 (en) * 1997-12-23 1999-06-30 Lucent Technologies Inc. Article comprising a wavelength selective add-drop multiplexer
WO2000057665A1 (en) * 1999-03-22 2000-09-28 Chorum Technologies Lp Optical wavelength add/drop multiplexer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1317084A2 (en) * 2001-10-26 2003-06-04 Nortel Networks Limited Optical amplifier arrangement
EP1317084A3 (en) * 2001-10-26 2005-06-08 Nortel Networks Limited Optical amplifier arrangement
EP2437087A1 (en) * 2010-09-29 2012-04-04 Alcatel Lucent A tunable optical filter, an optical device integrating such filter and a method of filtering an optical signal
ES2530888A1 (en) * 2013-09-06 2015-03-06 Univ Madrid Politecnica Passive optical multiplexer

Also Published As

Publication number Publication date
GB0023469D0 (en) 2000-11-08

Similar Documents

Publication Publication Date Title
US8457497B2 (en) Optimized directionless optical add/drop module systems and methods
US7899334B2 (en) Signal distribution module for a directionless reconfigurable optical add/drop multiplexer
EP2255542B1 (en) Constructing large wavelength selective switches using parallelism
JPH09113940A (en) Optical submarine branching device
US20020015551A1 (en) Optical switch network, optical cross connecting device, and optical add/drop multiplexer
JP2013258530A (en) Bidirectional monitor module, optical module, and optical add-drop multiplexer
US6081368A (en) Optical amplifier for bi-directional WDM optical communications systems
Tran et al. Reconfigurable multichannel optical add-drop multiplexers incorporating eight-port optical circulators and fiber Bragg gratings
KR20100040532A (en) Apparatus and method for distribiting optical path in wavelength division multiplexing system
JPH0936834A (en) Optical branching and inserting circuit
US6859576B2 (en) Optical cross-connect system
GB2360890A (en) Reconfigurable optical add/drop multiplexer
JPH0586711B2 (en)
Kim Bidirectional optical cross connects for multiwavelength ring networks using single arrayed waveguide grating router
KR100480276B1 (en) Bi-directional optical cross-connect
US6034800A (en) NXN light matrix switch
Takashina et al. Wavelength-tunable filters utilizing arrayed waveguide gratings for colorless/directionless/contentionless optical signal drop in ROADMs
Ueda et al. Large-scale optical-switch prototypes utilizing cyclic arrayed-waveguide gratings for datacenters
CA2440442C (en) Signal addition to a wave division multiplex system
JP3855691B2 (en) Optical switch module
JPH0293436A (en) Wavelength selective space switch
KR100230112B1 (en) ADM device of photo-communication network
Kim et al. A new all-fiber bidirectional optical cross-connect with tunable fiber Bragg gratings
US20030228092A1 (en) Wavelength-selective optical switch
JP2003124888A (en) Wavelength light signal supervisory mechanism and its method, supervisory system for optical add-drop device, and supervisory system for optical cross connect device

Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)