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WO1999003015A1 - Commutateur thermo-optique monte en cascade comprenant des portes - Google Patents

Commutateur thermo-optique monte en cascade comprenant des portes Download PDF

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Publication number
WO1999003015A1
WO1999003015A1 PCT/EP1998/004020 EP9804020W WO9903015A1 WO 1999003015 A1 WO1999003015 A1 WO 1999003015A1 EP 9804020 W EP9804020 W EP 9804020W WO 9903015 A1 WO9903015 A1 WO 9903015A1
Authority
WO
WIPO (PCT)
Prior art keywords
switch
switches
gates
cascaded
optical
Prior art date
Application number
PCT/EP1998/004020
Other languages
English (en)
Inventor
Albert Borreman
Berend Hendriksen
Tsjerk Hans Hoekstra
Anthony J. Ticknor
Original Assignee
Akzo Nobel N.V.
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 Akzo Nobel N.V. filed Critical Akzo Nobel N.V.
Priority to CA002292509A priority Critical patent/CA2292509A1/fr
Priority to AU88038/98A priority patent/AU8803898A/en
Priority to EP98939575A priority patent/EP0996866A1/fr
Publication of WO1999003015A1 publication Critical patent/WO1999003015A1/fr
Priority to US09/478,510 priority patent/US6389191B1/en

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
    • 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
    • H04Q2011/0049—Crosstalk reduction; Noise; Power budget
    • 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
    • H04Q2011/0052—Interconnection of switches

Definitions

  • thermo-optical switch comprising a cascade of 1xM optical switches, gates for selectively blocking and unblocking the output paths of the cascaded switch, and means for driving the 1xM switches (M being an integer, preferably 2 or 3) and the gates, which means are arranged to switch a data signal from an input path of the cascaded switch to one of the output paths.
  • thermo-optical switch with "additional branches" forming y-junctions with the actual output paths.
  • the additional branch is used to direct unwanted light away from the actual output path when this output is in the off-state.
  • the detrimental effect of the said light on both crosstalk and extinction (which are defined as 10 * log(optical power in an output in the off-state/optical power in the input) and 10 * log(optical power in an output in the on-state/optical power in an output in the off-state), respectively) is dispensed with before it reaches the output in the off-state.
  • WO 96/08932 describes a cascaded 1x8 switch consisting of three switch stages of 1x2 switches (1st stage: 1 switch, 2nd stage: 2 switches, and 3rd stage: 4 switches) and one shutter stage of 8 1x2 switches, functioning as gates for selectively blocking and unblocking the output paths of the cascaded switch.
  • the cascaded switch according to WO 96/08932 is also said to exhibit greatly improved crosstalk suppression.
  • a signal at the input path is directed to the selected output path by operating the 1xM, usually 1x2 switches, which are comprised in the cascaded or tree-structured switch.
  • thermo-optical cascaded switches are becoming ever more stringent. Reliability and life-expectancy should increase, the number of output paths (at present usually 8, in the future probably 16, 32 or 64) of the cascaded switches should also increase, and power consumption should decrease, all at an equal or, preferably, improved extinction ratio.
  • the object of the present invention is to meet said demand, and this is achieved in the thermo-optical cascaded switch described in the opening paragraph wherein the means for driving the 1xM switches and the gates are also arranged to switch an unwanted signal (generated by 1xM switch through which the data signal passes), by means of a number of the remaining 1xM switches (i.e., those switches which are not used to switch the data signal to the output in the on-state), to at least one of the remaining output paths (i.e., the output paths in the off-state) and to block these output paths.
  • the activated 1xM switches and gates are no longer concentrated in a small area, but instead distributed more evenly over the area of the cascaded switch. This is all the more advantageous since the gates are normally located near the pigtails (interconnections between the switch and the optical fibres), which are sensitive to high temperatures and temperature changes. In contrast, the 1xM switches are further removed from the pigtails and, hence, high temperatures and large temperature changes in these 1xM switches will have considerably less effect on the pigtails. Also, the even distribution of activated 1xM switches and gates will result in improved transportation of heat into the substrate on which the switch is built.
  • the means for driving the 1xM switches and the gates are so arranged as to switch the unwanted signals generated in each of the 1xM switches through which the data signal passes to at least one of the remaining output paths by means of a number of the remaining 1xM switches.
  • all first order crosstalk originating from the data signal is consistently (and actively) switched to a blocking gate.
  • the number of activated heaters in cascaded switches consisting of 1x2 switches and having 8, 16, 32, or 64 activated heaters is (considerably) reduced by using the drive tables according to the present invention.
  • the number of activated heaters is at least 11 , 20, 37, and 70, respectively, whereas the drive tables of the above-mentioned preferred embodiment of the present invention allow activating only 10, 15, 21 , and 28 heaters, i.e., a reduction of 1 , 5, 16, and 42 activated heaters, respectively.
  • Tables 1 and 2 accompanied by Figures 1 and 2 (aspect ratio 1 :60, i.e., the width over length ratio is much smaller in reality) give the drive tables for a cascaded thermo-optical 1x8 switch comprising a gate at each output (1x8 solid state optical switch BeamboxTM ex Akzo Nobel NV).
  • Table 1 shows a drive table which activates all gates
  • Table 2 shows a drive table in accordance with the present invention.
  • the activated heaters are denoted by a thick line, whereas the non-activated heaters are denoted by a thin line.
  • the means for driving the 1xM switches and the gates are arranged so that for at least half of the states of the cascaded switch at least one of the unwanted signals is switched to different blocked output paths.
  • the cascaded switch could be looked upon as comprising two "sub-cascades," one sprouting from and including switch no. 2 (having heaters R2 and S2 in Figure 3) leading to output paths 1-4 and one sprouting from and including switch no. 3 (having heaters R3 and S3 in Figure 3) leading to output paths 5-8. If the state of the cascaded switch is changed from, say, state 1 to state 3, the unwanted signal is switched towards output path 5 instead of output path 8, and the state of the gates is altered accordingly.
  • the cascaded switch is a thermo-optical 1xN or Nx1 switch preferably with N being equal to 8, 16, 32, or 64, because such switches can be readily used as basic building blocks in optical matrices and networks.
  • the invention also pertains to a device (e.g., an NxN optical switch matrix) equipped with a thermo-optical switch as described above and to a method for driving a thermo-optical switch comprising a cascade of 1xM optical switches, gates for selectively blocking and unblocking the output paths of the cascaded switch, and means for driving the 1xM switches and the gates, which method comprises switching a data signal from an input path of the cascaded switch to a selected output path, switching an unwanted signal, by means of a number of the remaining 1xM switches, to at least one of the remaining output paths, and blocking these remaining output paths.
  • an unwanted signal generated in each of the 1xM switches through which the signal passes is switched to at least one of the remaining (and blocked) output paths by means of a number of the remaining 1xM switches.
  • thermo-optical switches For details concerning the theory on which the operation of thermo-optical switches is based and details about suitable materials and manufacturing methods reference may be had to WO 96/38756.
  • WO 90/00757 concerns a "binary tree switching network.”
  • the network consists of a number of stages each of which comprises a number of switches. There is simultaneous (“binary") operation of the switches per stage and, therefore, distributed driving as suggested by the present invention is excluded.
  • thermo-optical switch is defined as a switch in which the operation of both the elementary 1xM optical switches and the gates for selectively blocking and unblocking the output paths of the cascaded switch is based on thermally induced refractive index differences or changes in the waveguides of the said 1xM switches and gates.
  • the gates serve to selectively block and unblock the output paths of the cascaded switch to either let a data signal pass or to prevent unwanted signals from reaching the outputs of the cascaded switch.
  • Other suitable terms for gates are, e.g., “shutter” and “idle port” (depending, amongst others, on the configuration of the gates).
  • Suitable configurations are, e.g., additional branches, cut-off waveguides, and Mach-Zehnder interferometers.
  • switches includes both the 1xM switches for switching the data signal to one of the outputs and switchable combinations of a gate and an output path.
  • a cascaded or tree-structured switch is a PxN switch (with N normally being 8, 16, 32, or 64 and P preferably being 1) built up of stages of 1xM switches and a shutter stage.
  • the term "unwanted signal” comprises the signals resulting from crosstalk in the 1xM switches and captured stray light.
  • the "means for driving the 1xM switches and the gates” may take the form of, e.g., a personal computer, EPROM, Programmable Array Logic, Discrete Logic or a Micro Controller.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)

Abstract

La présente invention concerne commutateur thermo-optique comprenant une cascade d'un million de commutateurs optiques, des portes permettant le blocage ou le déblocage sélectif des voies de sortie du commutateur monté en cascade et un organe de pilotage du million de commutateurs et de leurs portes. Cet organe est agencé de façon à commuter, sur l'une des voies de sortie du commutateur en cascade, un signal de données provenant d'une voie d'entrée du commutateur en cascade. En l'occurrence, cet organe est également agencé de façon à commuter, sur au moins l'une des voies de sortie restante, un signal inopportun en utilisant plusieurs des commutateurs du million restant. Dans le dispositif de commutation monté en cascade de la présente invention, la chaleur produite est uniformément répartie sur la surface du commutateur ce qui permet de réduire le dégagement global de chaleur.
PCT/EP1998/004020 1997-07-07 1998-06-29 Commutateur thermo-optique monte en cascade comprenant des portes WO1999003015A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CA002292509A CA2292509A1 (fr) 1997-07-07 1998-06-29 Commutateur thermo-optique monte en cascade comprenant des portes
AU88038/98A AU8803898A (en) 1997-07-07 1998-06-29 Thermo-optical cascaded switch comprising gates
EP98939575A EP0996866A1 (fr) 1997-07-07 1998-06-29 Commutateur thermo-optique monte en cascade comprenant des portes
US09/478,510 US6389191B1 (en) 1997-07-18 2000-01-06 Thermo-optical cascaded switch comprising gates

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US88873197A 1997-07-07 1997-07-07
US08/888,731 1997-07-07
EP97202243.8 1997-07-18
EP97202243 1997-07-18

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US09/478,510 Continuation US6389191B1 (en) 1997-07-18 2000-01-06 Thermo-optical cascaded switch comprising gates

Publications (1)

Publication Number Publication Date
WO1999003015A1 true WO1999003015A1 (fr) 1999-01-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/004020 WO1999003015A1 (fr) 1997-07-07 1998-06-29 Commutateur thermo-optique monte en cascade comprenant des portes

Country Status (4)

Country Link
EP (1) EP0996866A1 (fr)
AU (1) AU8803898A (fr)
CA (1) CA2292509A1 (fr)
WO (1) WO1999003015A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2365703A3 (fr) * 2010-03-08 2015-12-23 Mitsubishi Electric Corporation Commutateur optique et procédé de commande de commutateur optique

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0353871A1 (fr) * 1988-07-08 1990-02-07 BRITISH TELECOMMUNICATIONS public limited company Réseau de commutation en arbres binaires
WO1996008932A1 (fr) * 1994-09-14 1996-03-21 Siemens Aktiengesellschaft Matrice de commutation optique 1xn et nxn arborescente
WO1996023389A1 (fr) * 1995-01-27 1996-08-01 Siemens Aktiengesellschaft PROCEDE DE FONCTIONNEMENT D'UN SYSTEME DE COMMUTATION SPATIALE NxN MULTINIVEAU
WO1996038756A1 (fr) * 1995-06-02 1996-12-05 Akzo Nobel N.V. Dispositif thermo-optique en cascade

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0353871A1 (fr) * 1988-07-08 1990-02-07 BRITISH TELECOMMUNICATIONS public limited company Réseau de commutation en arbres binaires
WO1996008932A1 (fr) * 1994-09-14 1996-03-21 Siemens Aktiengesellschaft Matrice de commutation optique 1xn et nxn arborescente
WO1996023389A1 (fr) * 1995-01-27 1996-08-01 Siemens Aktiengesellschaft PROCEDE DE FONCTIONNEMENT D'UN SYSTEME DE COMMUTATION SPATIALE NxN MULTINIVEAU
WO1996038756A1 (fr) * 1995-06-02 1996-12-05 Akzo Nobel N.V. Dispositif thermo-optique en cascade

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
OKAYAMA H ET AL: "OPTICAL SWITCH MATRIX WITH SIMPLIFIED N X N TREE STRUCTURE", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 7, no. 7, July 1989 (1989-07-01), pages 1023 - 1028, XP000053505 *
OKAYAMA H ET AL: "POLARISATION-INDEPENDENT OPTICAL SWITCH WITH CASCADED OPTICAL SWITCH MATRICES", ELECTRONICS LETTERS, vol. 24, no. 15, 21 July 1988 (1988-07-21), pages 959 - 961, XP000031776 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2365703A3 (fr) * 2010-03-08 2015-12-23 Mitsubishi Electric Corporation Commutateur optique et procédé de commande de commutateur optique

Also Published As

Publication number Publication date
CA2292509A1 (fr) 1999-01-21
EP0996866A1 (fr) 2000-05-03
AU8803898A (en) 1999-02-08

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