WO1999055023A1 - Procedes et appareil permettant d'attenuer selectivement un signal de communication optique a l'aide d'un materiau electrochromique - Google Patents

Procedes et appareil permettant d'attenuer selectivement un signal de communication optique a l'aide d'un materiau electrochromique Download PDF

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Publication number
WO1999055023A1
WO1999055023A1 PCT/US1999/007389 US9907389W WO9955023A1 WO 1999055023 A1 WO1999055023 A1 WO 1999055023A1 US 9907389 W US9907389 W US 9907389W WO 9955023 A1 WO9955023 A1 WO 9955023A1
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WO
WIPO (PCT)
Prior art keywords
signal
optical
passing
processing
set forth
Prior art date
Application number
PCT/US1999/007389
Other languages
English (en)
Inventor
Paul Eliot Green, Jr.
Original Assignee
Tellabs Operations, 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 Tellabs Operations, Inc. filed Critical Tellabs Operations, Inc.
Priority to EP99918459A priority Critical patent/EP1104601A1/fr
Priority to AU36377/99A priority patent/AU3637799A/en
Publication of WO1999055023A1 publication Critical patent/WO1999055023A1/fr

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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
    • H04B10/29—Repeaters
    • H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
    • H04B10/293—Signal power control
    • H04B10/294—Signal power control in a multiwavelength system, e.g. gain equalisation
    • H04B10/296—Transient power control, e.g. due to channel add/drop or rapid fluctuations in the input power
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/25—Distortion or dispersion compensation
    • H04B2210/258—Distortion or dispersion compensation treating each wavelength or wavelength band separately
    • 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

  • the present invention relates to optical communication networks. More particularly, the present invention relates to methods and apparatus for processing optical communication signals, including selective attenuation of an optical communication signal using a body of electrochromic material.
  • Optical communication networks typically comprise sources of electromagnetic radiation (or light), optical waveguides, optical couplers and other components such as, for example, switches, multiplexers, modulators and attenuators, which together operate to generate, carry and appropriately route optical communication signals along optical links of the communication network.
  • Operating wavelengths for such commumcation networks may be on the order of approximately 0.85 microns for a local area network (LAN), for example, or may be longer for applications such as telecommunications.
  • Wavelengths used in communication networks for long distance telecommunication transmission for example, may be on the order of approximately 1.3 to 1.6 microns.
  • Such networks may carry optical communication signals of a particular wavelength, or alternatively may carry optical communication signals that comprise a multiplicity of discrete wavelengths or bands of wavelengths.
  • Networks that use one wavelength may require that the optical power at that wavelength be adjusted or reset along the route, either attenuated or amplified, in order to deliver to the ultimate receiver a power level lying within the receiver's 2 dynamic range.
  • networks that use multiple wavelengths of light, wavelength division networks typically require that the relative power levels in at least certain ones of the various bands of wavelengths be adjusted or reset at frequent intervals along a given optical link to ensure that the network is operating with a power versus wavelength profile that is suitably flat.
  • a suitably flat profile helps to ensure that each receiver sees a power level lying within its dynamic range. Periodic adjustment of this sort is particularly important in optical networks that employ optical amplifiers, as such amplifiers often possess a gain versus wavelength profile that does not have the desired level of flatness.
  • Prior methods and systems for attenuating the optical signal to compensate for such non- ideal characteristics typically are relatively costly, cumbersome and prone to failure.
  • An example prior art system employs a transparent film having gray scale thereon spanning in graduated fashion a range of densities from one end of the film to the other end.
  • the film is manipulated relative to the light path using a mechanical stepper motor such that the film intersects the light path of interest at a particular gray scale point along the length of the film.
  • the opacity of the film absorbs certain electromagnetic energy from a signal traveling along the light path, thus resulting in signal attenuation.
  • the ability to selectively manipulate the film using a stepper motor, and in turn the degree of gray scale intersecting the light path provides control over the degree of signal attenuation.
  • the use of a stepper motor and film device in this manner can be relatively cumbersome and costly.
  • the system, with its moving parts, is also prone to mechanical failure.
  • Electrochromic devices previously have been proposed for use in optical communications systems.
  • the attenuator described by Johnson et al. involves relatively expensive waveguide technology and attenuates light in a rather indirect manner.
  • the attenuator disclosed by Johnson et al. attenuates radiation propagating in a waveguide through the use of a cladding layer of electrochromic material disposed parallel to the waveguide to absorb a certain fraction of energy. Such arrangements are less practical for many optical communications systems, for reasons of cost and complexity.
  • the present invention relates to new methods and apparatus for processing optical communication signals in a communications network, which include the use of an electrochromic medium to provide optical signal attenuation.
  • An optical signal corresponding to voice and/or data information and traveling in a communications network is selectively attenuated through the use of a body of electrochromic material that is disposed to intersect the propagation path.
  • the amount by which optical network traffic is attenuated can be varied through variable application of an electric field in such a way as to affect the body of electrochromic material.
  • the applied electric field operates to affect a change in the color or opacity of the electrochromic material, and thus the degree of attenuation that is provided by the electrochromic medium.
  • the optical signal passes through the electrochromic medium, where it is attenuated, and is thereafter communicated to the commumcation network for further processing.
  • the present invention provides for selective attenuation of optical communication signals in a flexible, efficient, reliable, and cost-effective manner.
  • the present invention also 4 may, in the appropriate applications, operate to relax requirements imposed upon optical amplifiers relative to the flatness of the amplifier's gain versus wavelength profile.
  • FIGURE 1 illustrates schematically, in side view, an electro-optic attenuation device in accordance with one example embodiment of the present invention
  • FIGURE 2 illustrates an end and partial cross-sectional view of the electro-optic attenuation device embodiment shown in Figure 1 ;
  • FIGURE 3 illustrates schematically a first example communication network link of the present invention that provides selective attenuation of an optical signal traveling along the link;
  • FIGURE 4 shows schematically a first example embodiment of an optical transport system of the present invention that provides selective attenuation of constituent optical signals of a wavelength division multiplexed signal;
  • FIGURE 5 shows schematically a second example embodiment of an optical transport system of the present invention that provides selective attenuation of constituent optical signals of a wavelength division multiplexed signal
  • FIGURE 6 shows schematically a third example embodiment of an optical transport
  • FIGURE 7 illustrates schematically a second example communication network link of the present invention that provides selective attenuation of constituent optical signals of a wavelength division multiplexed signal traveling on the link.
  • the electrochromic effect involves the ability to adjust the relative color of a material through chemical changes in an electrochromic material, these changes being caused by introducing into the body of the material a number of ions supplied by the adjacent conductive layer, the density of ions so supplied being controlled by the intensity of an applied electric field.
  • a layer of electrochromic material and a compatible ion conducting layer may be together sandwiched between two layers of transparent conductors.
  • Electrochromic materials may include a suitable inorganic material, such as WO3 for example, or a suitable organic material.
  • the ion conducting layer may be realized using, for example, an electrolyte or an ion rich solid.
  • the two conductors which effectively sandwich the layer of electrochromic material and the ion conducting layer may be, for example, layers of indium tin oxide (ITO).
  • ITO indium tin oxide
  • the electrochromic material may be controllable between at least a first state that passes some or all of incident light, and a second state that results in a complete or at least partial reduction of
  • Figures 1 and 6 provide schematic illustrations of an electro-optic attenuation device 10 constructed in accordance with one example embodiment of the present invention.
  • FIGs 1 and 6 provide schematic illustrations of an electro-optic attenuation device 10 constructed in accordance with one example embodiment of the present invention.
  • a substrate 11 constructed from transparent silica or other suitable material, supports an electrochromic sandwich 12 that comprises an electrochromic region 14, an adjacent conductive
  • Substrate 11, region 14, region 16, electrode 18 and electrode 20 of device 10 preferably are adjacent, substantially parallel, planar layers.
  • Graded index lenses 22 and 24 are disposed on either side of the sandwich 12 as shown in
  • Graded index lenses 22 and 24 each communicate optically with optical fibers 26 and
  • Optical fibers 26 and 28 each comprise a length of an optical core 30 and 31, respectively, that is surrounded by a cladding material 32 and 33, respectively.
  • the cladding material 32 and 33 is shown partially removed in Figure 1 to more clearly illustrate the inner cores 30 and 31.
  • Electrical leads 34 and 36 extend from electrodes 18 and 20, respectively, and
  • variable voltage source 37 that is adapted to apply various voltage potentials across electrodes 18 and 20 as desired.
  • a casing 38 is used in this example
  • casing 38 which may be constructed from a polymer or other suitable material, serves as a protective exterior for at least a portion of the electro-optic attenuation device 10.
  • Casing 38 has apertures 40, 42, 44, and 46 through which pass fiber 26,
  • Region 14 of sandwich 12 is a layer comprising a suitable inorganic electrochromic
  • Electrodes 18 7 and 20 each comprise a transparent conductive coating of suitable transparent electrode material. Indium tin oxide (ITO), zinc oxide and tin oxide are example transparent electrode
  • Leads 34 and 36 communicate electrically with electrodes 18 and 20, and are used to establish a desired potential difference across, and resultant electric field between, the electrodes
  • the thickness of the sandwich 12 and range of voltages applied to the electrodes 18 and 20, two factors which can affect the range and degree of transmission and attenuation provided by device 10, are preferably selected so that the device 10 satisfies the operating requirements of the particular application. Further, particular applications of the present invention may warrant the selection of alternative materials and/or material relationships within device 10 that are apparent to persons of ordinary skill in the art.
  • the present invention is preferably used to process an optical signal in an optical link of a communications network, such as a local area network or
  • lens 22 and lens 24, as well as associated fibers 26 and 28, operate to define and establish a propagation path 48 along which a digital or analog optical communication signal travels.
  • An optical communication signal travels along fiber 26 towards lens 22 along path 48.
  • Lens 22 collimates the light of the optical signal traveling in fiber 26. The collimated light is then delivered to the
  • planar electrochromic sandwich 12 and, more particularly, to an incident planar surface 13 of the region 14 through substrate 11 and electrode 18 along path 48.
  • Path 48 preferably is
  • Electrochromic sandwich 12 is disposed along and intersects the path 48 such that
  • sandwich 12 effectively bisects the path 48 into a first portion 48a and a second portion 48b.
  • the optical signal thus traveling along path 48 is passed through the sandwich 12, including the 8 region 14, where it may be attenuated by absorption.
  • Selective application of an appropriate voltage potential V across, and resultant electric field between, electrodes 18 and 20 is used to
  • the desired color or opacity i.e., electrochromic or attenuating effect
  • region 14 be switchable between at least two color states to provide for variable attenuation.
  • An attenuated optical signal is thereafter received in lens 24 following passage through electrode 20, and communicated along
  • path 48 into fiber 28 for further processing in the communication link and/or communication network.
  • Such further processing may include, for example, downstream reception and detection of the optical signal to facilitate the successful transfer of voice and/or data information to its intended destination.
  • Figure 3 depicts an example communication network link 60 comprising a transmitter
  • Link 60 may form a part of a larger communication network such as, for example, a local area network or local and/or long distance telecommunication network.
  • Figure 4 is a schematic illustration of an example embodiment of an optical transport
  • system 80 of the present invention that may be used to provide selective attenuation of constituent optical signals in a wavelength division multiplexed communications link.
  • system 80 comprises an optical line 82 through which a wavelength division multiplexed optical
  • Optical line 82 communicates the received signal to 9 demultiplexer 84.
  • Constituent optical signals are each delivered by demultiplexer 84 to
  • each of optical lines 1, 2, ... L communicates the respective constituent signal to a device 10 which, in turn, is used to provide a level of attenuation that is particularly suited for the constituent signal, as described above for example.
  • the constituent signal is thereafter provided to the corresponding line of optical lines 1', 2', ... L'.
  • each of the constituent signals of a wavelength division multiplexed optical communication signal may be independently adjusted or reset within the optical transport system 80 to the extent necessary to ensure a suitably flat power versus wavelength profile.
  • Figure 5 is a schematic illustration of another example embodiment of an optical transport system 90 of the present invention that also may be used to provide selective attenuation of constituent optical signals in a wavelength division multiplexed communications
  • the system 90 comprises an array of optical lines 1, 2, ... M through which constituent optical communication signals are respectively received.
  • Each of the optical lines 1, 2, ... M are respectively received.
  • multiplexer 92 multiplexes the various signals to form a wavelength division multiplexed optical signal for communication on optical line 94.
  • each of the constituent signals of the wavelength division multiplexed optical communication signal may be independently adjusted or reset
  • Figure 6 is a schematic illustration of yet another embodiment of an optical transport
  • the system 100 may be used to provide selective attenuation of 10 constituent optical signals in a wavelength division multiplexed communications link.
  • the system 100 comprises an optical line 102 through which a wavelength division multiplexed
  • optical communication signal is received.
  • Optical line 102 communicates the received signal to demultiplexer 104.
  • Constituent optical signals are each delivered by demultiplexer 104 to respective optical lines 1, 2, ... N.
  • Each of optical lines 1, 2, ... N communicates the respective
  • the constituent signal to a device 10 which is used to provide a level of attenuation that is particularly suited for the constituent signal.
  • the constituent signal is thereafter provided to multiplexer 106 through the corresponding line of optical lines V, V, ... N'.
  • Multiplexer 106 multiplexes the various signals to form a wavelength division multiplexed optical signal for communication on optical line 108.
  • Each of the constituent signals of the wavelength division multiplexed optical communication signal may be independently adjusted or reset
  • Figure 7 depicts an example wavelength division multiplexed optical communication network link 110 comprising a transmitter 112, a receiver 114, and an intermediately disposed
  • optical transport system 116 that, on a first side, communicates through optical medium 118 with the transmitter 112 and, on a second side, communicates through optical medium 120 with
  • optical transport system 116 might be, for example, optical transport system 80 from Figure 4, wherein system 80 might further communicate
  • optical transport system 116 might be, for example, optical transport
  • system 90 from Figure 5, wherein system 90 might receive respective constituent signals from
  • optical transport system 116 might be, for example, optical transport system 100 from Figure 6, wherein both lines 118 and 120 carry a wavelength division multiplexed optical
  • Link 110 may form a part of a larger communication network such as, for example, a local area network or local and/or long distance telecommunication network.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)

Abstract

On décrit des procédés et un appareil permettant de traiter des signaux optiques dans un réseau de communication en vue d'ajuster ou de remettre à zéro le niveau de puissance d'un signal, dans lesquels on utilise un corps réalisé dans un matériau électrochromique qui est placé sur un chemin de propagation de signal de communication optique. Un signal de communication optique circulant sur le chemin de propagation est atténué par le corps réalisé en matériau électrochromique. Le corps est de préférence capable de changer de couleur et peut adopter au moins deux états de couleur au moyen de l'application sélective d'un potentiel de tension de telle sorte qu'il affecte le corps, ceci ayant pour effet de produire chacun des deux états de couleur minimum permettant un passage atténué à travers le corps du signal de communication optique. Des applications de la présente invention comprennent, par exemple, l'atténuation sélective de signaux de communication optique MRL constitutifs au moyen de l'utilisation de multiplexeurs et/ou de démultiplexeurs.
PCT/US1999/007389 1998-04-23 1999-04-23 Procedes et appareil permettant d'attenuer selectivement un signal de communication optique a l'aide d'un materiau electrochromique WO1999055023A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP99918459A EP1104601A1 (fr) 1998-04-23 1999-04-23 Procedes et appareil permettant d'attenuer selectivement un signal de communication optique a l'aide d'un materiau electrochromique
AU36377/99A AU3637799A (en) 1998-04-23 1999-04-23 Methods and apparatus for selective attenuation in an optical communication using electrochromic material

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6525098A 1998-04-23 1998-04-23
US09/065,250 1998-04-23

Publications (1)

Publication Number Publication Date
WO1999055023A1 true WO1999055023A1 (fr) 1999-10-28

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EP (1) EP1104601A1 (fr)
AU (1) AU3637799A (fr)
WO (1) WO1999055023A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2376531A (en) * 2001-06-13 2002-12-18 Bookham Technology Plc Multichannel wavelength monitoring apparatus
US6625378B2 (en) 1999-02-01 2003-09-23 Jds Uniphase Corporation Variable optical attenuator device
US6906842B2 (en) 2000-05-24 2005-06-14 Schott North America, Inc. Electrochromic devices
EP1958199A2 (fr) * 2005-07-29 2008-08-20 Kestrel Wireless, Inc. Dispositifs et processus pour support optique

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2523734A1 (fr) * 1982-03-17 1983-09-23 Commissariat Energie Atomique Attenuateur electrolytique de flux lumineux
US4938571A (en) * 1987-06-18 1990-07-03 Cogan Stuart F Solid state electrochromic light modulator
WO1995020847A2 (fr) * 1994-01-26 1995-08-03 British Telecommunications Public Limited Company Reseau multiplex a division des longueurs d'ondes avec longueur d'ondes de commande
EP0766358A1 (fr) * 1995-09-28 1997-04-02 Siemens Aktiengesellschaft Amplificateur à fibre optique pour une multitude de signaux à longueurs d'onde différentes comprenant un démultiplexeur et un multiplexeur
US5657151A (en) * 1993-12-09 1997-08-12 Lucent Technologies Inc. Polarization scrambler/modulator

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2523734A1 (fr) * 1982-03-17 1983-09-23 Commissariat Energie Atomique Attenuateur electrolytique de flux lumineux
US4938571A (en) * 1987-06-18 1990-07-03 Cogan Stuart F Solid state electrochromic light modulator
US5657151A (en) * 1993-12-09 1997-08-12 Lucent Technologies Inc. Polarization scrambler/modulator
WO1995020847A2 (fr) * 1994-01-26 1995-08-03 British Telecommunications Public Limited Company Reseau multiplex a division des longueurs d'ondes avec longueur d'ondes de commande
EP0766358A1 (fr) * 1995-09-28 1997-04-02 Siemens Aktiengesellschaft Amplificateur à fibre optique pour une multitude de signaux à longueurs d'onde différentes comprenant un démultiplexeur et un multiplexeur

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6625378B2 (en) 1999-02-01 2003-09-23 Jds Uniphase Corporation Variable optical attenuator device
US6906842B2 (en) 2000-05-24 2005-06-14 Schott North America, Inc. Electrochromic devices
GB2376531A (en) * 2001-06-13 2002-12-18 Bookham Technology Plc Multichannel wavelength monitoring apparatus
EP1958199A2 (fr) * 2005-07-29 2008-08-20 Kestrel Wireless, Inc. Dispositifs et processus pour support optique
EP1958199A4 (fr) * 2005-07-29 2009-07-08 Kestrel Wireless Inc Dispositifs et processus pour support optique

Also Published As

Publication number Publication date
AU3637799A (en) 1999-11-08
EP1104601A1 (fr) 2001-06-06

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