WO2001078281A2 - An information compressor for fiber-optic lines - Google Patents

An information compressor for fiber-optic lines Download PDF

Info

Publication number
WO2001078281A2
WO2001078281A2 PCT/CA2001/000471 CA0100471W WO0178281A2 WO 2001078281 A2 WO2001078281 A2 WO 2001078281A2 CA 0100471 W CA0100471 W CA 0100471W WO 0178281 A2 WO0178281 A2 WO 0178281A2
Authority
WO
WIPO (PCT)
Prior art keywords
wavelength
optical
discrete
signal
array
Prior art date
Application number
PCT/CA2001/000471
Other languages
French (fr)
Other versions
WO2001078281A3 (en
Inventor
Gennadii Ivtsenkov
Original Assignee
Light Management Group 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 Light Management Group Inc. filed Critical Light Management Group Inc.
Priority to AU2001248186A priority Critical patent/AU2001248186A1/en
Publication of WO2001078281A2 publication Critical patent/WO2001078281A2/en
Publication of WO2001078281A3 publication Critical patent/WO2001078281A3/en

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4215—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
    • G02B6/29305—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
    • G02B6/2931—Diffractive element operating in reflection
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
    • G02B6/29305—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
    • G02B6/29311—Diffractive element operating in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
    • G02B6/29361—Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
    • G02B6/29361—Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
    • G02B6/29362—Serial cascade of filters or filtering operations, e.g. for a large number of channels
    • G02B6/29365—Serial cascade of filters or filtering operations, e.g. for a large number of channels in a multireflection configuration, i.e. beam following a zigzag path between filters or filtering operations
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29371—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating principle based on material dispersion
    • G02B6/29373—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating principle based on material dispersion utilising a bulk dispersive element, e.g. prism
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29395—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device configurable, e.g. tunable or reconfigurable

Definitions

  • This invention relates to wavelength division multiplexing in fiber optic systems, and in particular, to apparatus for generating wavelength division multiplexed signals with increased channel density.
  • Fiber optic transmission typically involves modulating an optical source (e.g. single mode semiconductor laser) whose unmodulated output is at a specific wavelength.
  • modulation of a single wavelength optical source is limited to several tens of Giga Hertz which is significantly low in contrast to the approximate 30 Tera Hertz bandwidth of optical fiber.
  • Wavelength division multiplexing provides a means for combining several different wavelengths of separately modulated light into a single fiber. Each modulated wavelength is referred to as a channel. Consequently, WDM utilizes the bandwidth of the optical fiber more efficiently, thus enabling simultaneous data transmission of multiple high speed channels.
  • the combined modulated wavelength components are transmitted along a single optical fibre to a designated receiver, where, they are separated back (dem ⁇ ltiplexed) into individual wavelength components. The separated wavelength components are then individually demodulated.
  • Typical WDM systems use a separate single wavelength optical source to generate each channel.
  • Each single wavelength optical source requires wavelength stabilization circuitry in order to avoid cross talk between adjacent channels. This impacts system cost and complexity as the number of channels are increased.
  • single source WDM systems have been developed, which avoid the cost and complexity issues associated with increased channels in typical WDM systems.
  • U. S. Patent 5,936,752 discloses an apparatus and method for generating a wavelength division multiplexed signal from a single optical source.
  • a multiple wavelength or broadband optical source is delivered over a plurality of optical fibers arranged in a row to a diffraction grating.
  • the diffraction grating spatially separates the spectral components of the multiple wavelength source from each optical fiber. Consequently, for each optical fiber, the diffraction grating produces a one dimensional array of spectral components.
  • the array of discrete wavelength components are coupled onto an array of optical modulators where they are encoded with data.
  • the encoded discrete wavelength components are spatially recombined into a single optical fibre, thus, forming a wavelength division multiplexed signal.
  • U.S. Patents 5,526,155 and 5,912,751 also use a single optical source to generate multiple wavelength channels.
  • the present invention relates to an apparatus for generating multiple modulated wavelength channels in wavelength division multiplexed (WDM) optical interconnect systems such as optical fiber.
  • An optical light source generates a broadband optical signal having a plurality of wavelength signal components
  • an optical coupling device collects the broadband optical signal, and directs this signal onto a wavelength separation device that spatially separates the incident broadband optical signal into a two-dimensional array of discrete wavelength signal components.
  • Each discrete wavelength signal is coupled from the wavelength separation device to a two dimensional array of optical modulators.
  • the array of optical modulators generate an array of modulated discrete wavelength signal components, wherein each individual modulator within the modulator array receives and modulates a discrete wavelength signal component.
  • An output optical coupling device couples the two dimensional array of modulated discrete wavelength signal components received from the optical modulator array, to an optical fiber.
  • the wavelength separation device may comprise a first dispersion device and a second dispersion device, wherein the first dispersion device and second dispersion device are oriented so as to generate a two- dimensional array of discrete wavelength signal components.
  • the wavelength separation device may comprise a two- dimensional array of optical filters.
  • Another aspect of the present invention is an apparatus for . generating a wavelength division multiplexed signal, wherein an input optical coupling device couples an incident broadband optical signal to a wavelength separation device comprising a linear array of wavelength selective mirrors. Each mirror within the linear array reflects a selected wavelength signal component, and transmits the remaining wavelength signals components within the incident broadband optical signal.
  • An array of optical modulators receive the discrete wavelength signal components, wherein each modulator is arranged to receive and modulate one of the discrete wavelength signal components so as to generate a discrete optically modulated wavelength signal component.
  • An optical coupling device couples the optically modulated discrete wavelength signal components to an optical waveguide.
  • the present invention also relates to an apparatus for receiving and spatially separating wavelength division multiplexed signals into an array of individually modulated channels.
  • a coupling device shapes a wavelength division multiplexed signal received from an optical medium such as an fiber into a collimated beam. The collimated beam is incident on a wavelength separation device.
  • the wavelength separation device spatially separates the collimated wavelength division multiplexed signal into a two dimensional array of discrete wavelength components.
  • a matrix of photodetectors detects optically coupled data from the modulated discrete wavelength components, wherein each photodetector detects data from a discrete wavelength component.
  • Another aspect of the invention involves an optical repeater apparatus, whereby the repeater apparatus increases the WDM system's transmission range.
  • the optical repeater comprises an apparatus, for receiving a wavelength division multiplexed signal from an optical fiber and spatially separating it into individual modulated channels for optical detection.
  • the demodulated information from these channels are electronically processed. Once processed, the information from each channel is wavelength division multiplexed and re-coupled back into the optical fiber in its original channel format.
  • Figure 1 is a schematic view of apparatus for generating a wavelength division multiplexed optical signal according to the present invention
  • Figure 2 is a schematic view of apparatus made in accordance with a preferred embodiment of the present invention, incorporating a combination of prism and diffraction grating in the wavelength separation device;
  • Figure 3 is a schematic view of another preferred embodiment of the present invention, incorporating a two-dimensional array of optical filters in the wavelength separation device;
  • Figure 4 is a schematic view of a further embodiment of the present invention, incorporating two diffraction gratings in the wavelength separation device and;
  • Figure 5 is a schematic view of an alternative embodiment of the present invention, incorporating single array of wavelength selective mirrors in the wavelength separation device;
  • Figure 6 is a schematic view of another alternative embodiment of the present invention, incorporating a combination of prism and wavelength selective mirrors in the wavelength separation device;
  • Figure 7 is a schematic view of a system for receiving a wavelength division multiplexed signal made in accordance with the present invention and;
  • Figure 8 is a schematic view of an optical repeater system made in accordance with the present invention.
  • Figure 1 illustrates apparatus 10 for generating and coupling a wavelength division multiplexed signal to an optical waveguide such as an optical fiber 17.
  • An optical source 12 produces a broadband optical signal 13 comprising a plurality of wavelength signal components.
  • a collimating lens system 14 couples the broadband optical signal 13 to a wavelength separation device 28, wherein the wavelength separation device 28 generates a two-dimensional array of discrete wavelength signal components 15.
  • a focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto a two-dimensional optical modulator array 22, where each discrete wavelength signal component 35 focuses onto an individual modulator 32. Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20.
  • An optical focusing device 16 couples the modulated discrete wavelength signal components 26 generated by the optical modulator array 22 into an optical waveguide such as an optical fiber 17.
  • the wavelength separation device 28A comprises a prism 38 and diffraction grating 48.
  • the collimating lens system 14 couples a broadband optical signal 13 to the wavelength separation device 28A, where the prism 38 spatially disperses the optical signal 13 into a plurality of optical wavelength signal components 39.
  • the diffraction grating 48 spatially disperses each wavelength signal component received from the prism 39 into multiple wavelength signal components 15 where, the angular dispersion of multiple wavelength signal components occur in a plane perpendicular to the plane of angular dispersion produced by the operation of the prism 38.
  • a two-dimensional array of wavelength signal components 15 is produced where, each row of wavelength signals occurs as a result of the diffraction grating 48 spatially dispersing each wavelength component 39 received from the prism 38.
  • the relative orientation of the prism 38 and diffraction grating 48 forms a 'cross dispersion' wavelength separation device, where the dispersion elements 38, 48 produce spatial dispersion in a crossed plane relative to each other.
  • the focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto the two- dimensional optical modulator array 22, where each discrete wavelength signal component 35 focuses onto an individual modulator 32.
  • Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20.
  • High speed electrical interconnects 40 apply data to each modulator within the array.
  • An optical focusing device 16 couples the modulated discrete wavelength signal components 26 generated by the optical modulator array 22 into an optical fiber 17. It is anticipated that wavelength separation device 28A incorporating cross dispersion is capable of generating 1,000 or more wavelength channels.
  • FIG. 3 shows another preferred embodiment 10B, wherein the wavelength separation device 28B comprises an array of monochromatic interference filters 58.
  • a collimating lens system 14 couples the broadband optical signal 13 from an optical source 12 to each monochromatic filter element 60 within the filter array 58.
  • Each filter element 60 transmits a single wavelength of the optical signal 13.
  • a 3dB bandwidth in the region of lnm, and adjacent channel suppression of 50dB ensures sufficient wavelength selectivity for each filter element 60.
  • An array size of 10X10 is achievable using the monochromatic filter array 58, where the physical dimension of each filter element 60 is 2X2mm.
  • An array of discrete wavelength signal components 36 transmitted from the two-dimensional filter array 58 is received by the two-dimensional optical modulator array 22.
  • Each modulator 32 intensity modulates each discrete wavelength signal component 36 with data received from a data information source 20.
  • High speed electrical interconnects 40 apply data to each modulator within the array.
  • An optical focusing device 16 couples the modulated discrete wavelength signal components generated by the optical modulator array 22 into an optical fiber 17.
  • FIG 4 shows a variant of the apparatus shown in Figure 3, in which a diffraction grating 50 replaces the prism 38.
  • Apparatus 10C includes wavelength separation device 28C comprising a primary diffraction grating 50 and a secondary diffraction grating 48.
  • the collimating lens system 14 couples the broadband optical signal 13, from an optical source 12 to the wavelength separation device 28, where the primary diffraction grating 50 spatially disperses the optical signal into a plurality of optical wavelength signal components 39.
  • the secondary diffraction grating 48 spatially disperses each wavelength signal component received from the primary grating 50 into multiple wavelength signals 15.
  • the relative orientation of the primary diffraction grating 50 and secondary diffraction grating 48 forms a 'cross dispersion' wavelength separation device, generating a two-dimensional array of discrete wavelength signal components, as mentioned in the description of Figure 3.
  • the focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto the two-dimensional optical modulator array 22, where each discrete wavelength signal component 25 focuses onto an individual modulator 32.
  • Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20.
  • High speed electrical interconnects 40 apply data to each modulator within the array.
  • An optical focusing device 16 couples the modulated discrete wavelength signal components generated by the optical modulator array 22 into an optical fiber 17.
  • a wavelength separation device 28D comprises a linear array of dichroic mirrors 68.
  • the collimating lens system 14 couples a broadband optical signal 13 from an optical source 12 to the linear array of dichroic mirrors 68.
  • the linear array of dichroic mirrors 68 separates the spectrum of the broadband optical signal into discrete wavelength signal components 71.
  • Each dichroic mirror element 70 reflects a single wavelength signal 71 within the broadband optical signal 13, transmitting all remaining wavelength signal components 72. Consequently, as the broadband optical signal propagates 13 through the array of mirrors 68, each mirror element 70 reflects a single discrete wavelength signal component 71 from the plurality of wavelength signal components comprising the broadband optical signal 13.
  • the reflected discrete wavelength signal components 71 are received by an optical modulator array 22, where each wavelength signal 71 is modulated by an individual modulator 32.
  • a data information source 20 modulates each discrete wavelength signal component 71 at its designated modulator, wherein transparent modulators 32 pass the modulated wavelength signal components 73 to a second dichroic mirror array 69.
  • the second array of dichroic mirrors 69 reflect each discrete modulated wavelength signal component 73, combining all modulated wavelength signal components 74 along the same path to a focusing lens 16.
  • the focusing lens couples the modulated wavelength signal components 73 into an optical fiber 17.
  • Figure 6 shows a further alternative embodiment of the present invention, wherein the wavelength separation device comprises a prism 38 and, multiple linear arrays of dichroic mirrors 78.
  • the broadband optical signal 13 is dispersed spatially by the prism 38 into a plurality of wideband wavelength signal components 39.
  • Each of the wideband wavelength signal components 39 are received by a linear array of dichroic mirrors 68, where each wideband wavelength signal component 41 splits into its constituent discrete wavelength signal components 71 as it propagates through the array of mirrors 68.
  • Each wideband wavelength signal component 41 generated by the prism 38 propagates through an individual array of dichroic mirrors 68.
  • a two-dimensional structure of dichroic mirrors 78 is formed, where each row in the structure receives an individual wideband signal component from the prism 38. Consequently, the discrete wavelength signal components 71 from each row are reflected onto the modulator array 22.
  • the modulated wavelength signal components 73 transmitted through each row of the modulator array 22 are recombined by a second two-dimensional dichroic mirror structure 88 identical to that described above.
  • a focusing lens 16 receives the modulated discrete wavelength signal components 74 from each row of the two-dimensional mirror structure 88, and focuses all modulated discrete wavelength signal components 74 into an optical fibre 17.
  • a WDM receiver apparatus 100 made in accordance with the present invention which receives and detects data information, from each individual wavelength signal component within a wavelength division multiplexed (WDM) signal.
  • the WDM signal is coupled from an optical fibre 126 to a collimating lens system 104.
  • a wavelength separation device 128 receives the collimated WDM signal from the lens system 104 and spatially separates the WDM signal into a two-dimensional array of modulated discrete wavelength signal components.
  • a focusing lens 108 couples the two-dimensional array of modulated wavelength signal components onto a two-dimensional array of photodetectors 122, where the photodetector array 122 detects data from each received discrete wavelength signal component.
  • High speed interconnect cables 140 connect the detected data to an information data source 150.
  • FIG 8 shows an optical repeater apparatus 200 made in accordance with the present invention, which regenerates data information carried by the WDM signal.
  • Optical repeater apparatus 200 comprises a WDM receiver 205, electrical processing device 209 and WDM signal generating apparatus 207.
  • An optical lens system 203, 204 couples a WDM signal received from an optical fiber 226 to a wavelength separation device 228.
  • the wavelength separation device 228 spatially separates the WDM signal into a two-dimensional array of modulated discrete wavelength signal components.
  • a focusing lens 208 couples the two-dimensional array of modulated wavelength signal components onto a two-dimensional array of photodetectors 222, where the photodetector array 222 detects data from each received discrete wavelength signal component.
  • High speed interconnect cables 240 connect the detected data to an electrical processing device 250.
  • the electrical processing device 250 regenerates data received from each discrete wavelength signal component.
  • High speed electrical interconnect cables 242 connect the regenerated data to the apparatus 207 generating a WDM signal for re-transmission over the optical fiber.
  • An optical source 112 produces a broadband optical signal 113 comprising a plurality of wavelength signal components.
  • a collimating lens system 114 couples the broadband optical signal 113 to a wavelength separation device 129, wherein the wavelength separation device 129 generates a two- dimensional array of discrete wavelength signal components.
  • a focusing lens 118 concentrates the array of discrete wavelength signal components onto a two-dimensional optical modulator array 123.
  • Each modulator 132 intensity modulates each focused discrete wavelength signal component with regenerated data received from the electrical processing device 250.
  • the wavelength separation devices made in accordance with the current invention offer an increased spatial resolution over that of prior art devices. Resolving the broadband optical signal into multiple channels across two dimensions offers a significant advantage in comparison to spatial wavelength separation achieved by using a single dispersive element within the wavelength separation device.
  • the two dimensional approach to creating wavelength channels enables the current invention to have up to 20 times the channel capacity of existing prior art.

Landscapes

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

Abstract

Apparatus for generating a wavelength division multiplexed optical signal for fiber-optic systems comprises an input optical coupling device for receiving an incident broadband optical signal, a wavelength separation device for spatially separating the incident optical signal into a two-dimensional array of discrete wavelength components, an array of optical modulators for modulating the discrete wavelength components, wherein each individual modulator generates a discrete optically modulated wavelength component, an output optical coupling device for coupling the optically modulated two-dimensional array of discrete wavelength components to an optical waveguide.

Description

Title: An Information Compressor for Fiber-Optic Lines
FIELD OF THE INVENTION
This invention relates to wavelength division multiplexing in fiber optic systems, and in particular, to apparatus for generating wavelength division multiplexed signals with increased channel density.
BACKGROUND OF THE INVENTION
Optical fiber technology has emerged as a core solution to providing reliable, high speed and high capacity communications. Fiber optic transmission typically involves modulating an optical source (e.g. single mode semiconductor laser) whose unmodulated output is at a specific wavelength. However, modulation of a single wavelength optical source is limited to several tens of Giga Hertz which is significantly low in contrast to the approximate 30 Tera Hertz bandwidth of optical fiber. Wavelength division multiplexing (WDM) provides a means for combining several different wavelengths of separately modulated light into a single fiber. Each modulated wavelength is referred to as a channel. Consequently, WDM utilizes the bandwidth of the optical fiber more efficiently, thus enabling simultaneous data transmission of multiple high speed channels. Within a WDM system, the combined modulated wavelength components are transmitted along a single optical fibre to a designated receiver, where, they are separated back (demμltiplexed) into individual wavelength components. The separated wavelength components are then individually demodulated. Typical WDM systems use a separate single wavelength optical source to generate each channel. Each single wavelength optical source requires wavelength stabilization circuitry in order to avoid cross talk between adjacent channels. This impacts system cost and complexity as the number of channels are increased. Recently, single source WDM systems have been developed, which avoid the cost and complexity issues associated with increased channels in typical WDM systems. For example, U. S. Patent 5,936,752 discloses an apparatus and method for generating a wavelength division multiplexed signal from a single optical source. A multiple wavelength or broadband optical source is delivered over a plurality of optical fibers arranged in a row to a diffraction grating. The diffraction grating spatially separates the spectral components of the multiple wavelength source from each optical fiber. Consequently, for each optical fiber, the diffraction grating produces a one dimensional array of spectral components. The array of discrete wavelength components are coupled onto an array of optical modulators where they are encoded with data. The encoded discrete wavelength components are spatially recombined into a single optical fibre, thus, forming a wavelength division multiplexed signal. U.S. Patents 5,526,155 and 5,912,751 also use a single optical source to generate multiple wavelength channels. However, the number of potential wavelength channels that can be created by these systems is limited by the number of spectral components that can be created by the diffraction grating. Accordingly, there is a need for single source WDM systems that are capable of generating an increased number of spatial channels.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for generating multiple modulated wavelength channels in wavelength division multiplexed (WDM) optical interconnect systems such as optical fiber. An optical light source generates a broadband optical signal having a plurality of wavelength signal components, and an optical coupling device collects the broadband optical signal, and directs this signal onto a wavelength separation device that spatially separates the incident broadband optical signal into a two-dimensional array of discrete wavelength signal components. Each discrete wavelength signal is coupled from the wavelength separation device to a two dimensional array of optical modulators. The array of optical modulators generate an array of modulated discrete wavelength signal components, wherein each individual modulator within the modulator array receives and modulates a discrete wavelength signal component. An output optical coupling device couples the two dimensional array of modulated discrete wavelength signal components received from the optical modulator array, to an optical fiber.
The wavelength separation device may comprise a first dispersion device and a second dispersion device, wherein the first dispersion device and second dispersion device are oriented so as to generate a two- dimensional array of discrete wavelength signal components. Alternatively, the wavelength separation device may comprise a two- dimensional array of optical filters.
Another aspect of the present invention is an apparatus for . generating a wavelength division multiplexed signal, wherein an input optical coupling device couples an incident broadband optical signal to a wavelength separation device comprising a linear array of wavelength selective mirrors. Each mirror within the linear array reflects a selected wavelength signal component, and transmits the remaining wavelength signals components within the incident broadband optical signal. An array of optical modulators receive the discrete wavelength signal components, wherein each modulator is arranged to receive and modulate one of the discrete wavelength signal components so as to generate a discrete optically modulated wavelength signal component. An optical coupling device couples the optically modulated discrete wavelength signal components to an optical waveguide.
The present invention also relates to an apparatus for receiving and spatially separating wavelength division multiplexed signals into an array of individually modulated channels. A coupling device shapes a wavelength division multiplexed signal received from an optical medium such as an fiber into a collimated beam. The collimated beam is incident on a wavelength separation device. The wavelength separation device spatially separates the collimated wavelength division multiplexed signal into a two dimensional array of discrete wavelength components. A matrix of photodetectors detects optically coupled data from the modulated discrete wavelength components, wherein each photodetector detects data from a discrete wavelength component. Another aspect of the invention involves an optical repeater apparatus, whereby the repeater apparatus increases the WDM system's transmission range. The optical repeater comprises an apparatus, for receiving a wavelength division multiplexed signal from an optical fiber and spatially separating it into individual modulated channels for optical detection. The demodulated information from these channels are electronically processed. Once processed, the information from each channel is wavelength division multiplexed and re-coupled back into the optical fiber in its original channel format.
DETAILED DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example only, with reference to the following drawings, in which:
Figure 1 is a schematic view of apparatus for generating a wavelength division multiplexed optical signal according to the present invention;
Figure 2 is a schematic view of apparatus made in accordance with a preferred embodiment of the present invention, incorporating a combination of prism and diffraction grating in the wavelength separation device;
Figure 3 is a schematic view of another preferred embodiment of the present invention, incorporating a two-dimensional array of optical filters in the wavelength separation device;
Figure 4 is a schematic view of a further embodiment of the present invention, incorporating two diffraction gratings in the wavelength separation device and;
Figure 5 is a schematic view of an alternative embodiment of the present invention, incorporating single array of wavelength selective mirrors in the wavelength separation device;
Figure 6 is a schematic view of another alternative embodiment of the present invention, incorporating a combination of prism and wavelength selective mirrors in the wavelength separation device;
Figure 7 is a schematic view of a system for receiving a wavelength division multiplexed signal made in accordance with the present invention and;
Figure 8 is a schematic view of an optical repeater system made in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is first made to Figure 1, which illustrates apparatus 10 for generating and coupling a wavelength division multiplexed signal to an optical waveguide such as an optical fiber 17.
An optical source 12 produces a broadband optical signal 13 comprising a plurality of wavelength signal components. A collimating lens system 14 couples the broadband optical signal 13 to a wavelength separation device 28, wherein the wavelength separation device 28 generates a two-dimensional array of discrete wavelength signal components 15. A focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto a two-dimensional optical modulator array 22, where each discrete wavelength signal component 35 focuses onto an individual modulator 32. Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20. An optical focusing device 16 couples the modulated discrete wavelength signal components 26 generated by the optical modulator array 22 into an optical waveguide such as an optical fiber 17. Reference is next made to Figure 2, which shows a preferred embodiment 10A of the present invention, wherein the wavelength separation device 28A comprises a prism 38 and diffraction grating 48. The collimating lens system 14 couples a broadband optical signal 13 to the wavelength separation device 28A, where the prism 38 spatially disperses the optical signal 13 into a plurality of optical wavelength signal components 39. The diffraction grating 48 spatially disperses each wavelength signal component received from the prism 39 into multiple wavelength signal components 15 where, the angular dispersion of multiple wavelength signal components occur in a plane perpendicular to the plane of angular dispersion produced by the operation of the prism 38. Consequently, a two-dimensional array of wavelength signal components 15 is produced where, each row of wavelength signals occurs as a result of the diffraction grating 48 spatially dispersing each wavelength component 39 received from the prism 38. The relative orientation of the prism 38 and diffraction grating 48 forms a 'cross dispersion' wavelength separation device, where the dispersion elements 38, 48 produce spatial dispersion in a crossed plane relative to each other. The focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto the two- dimensional optical modulator array 22, where each discrete wavelength signal component 35 focuses onto an individual modulator 32. Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20. High speed electrical interconnects 40 apply data to each modulator within the array. An optical focusing device 16 couples the modulated discrete wavelength signal components 26 generated by the optical modulator array 22 into an optical fiber 17. It is anticipated that wavelength separation device 28A incorporating cross dispersion is capable of generating 1,000 or more wavelength channels.
Reference is made to Figure 3, which shows another preferred embodiment 10B, wherein the wavelength separation device 28B comprises an array of monochromatic interference filters 58. A collimating lens system 14 couples the broadband optical signal 13 from an optical source 12 to each monochromatic filter element 60 within the filter array 58. Each filter element 60 transmits a single wavelength of the optical signal 13. A 3dB bandwidth in the region of lnm, and adjacent channel suppression of 50dB ensures sufficient wavelength selectivity for each filter element 60. An array size of 10X10 is achievable using the monochromatic filter array 58, where the physical dimension of each filter element 60 is 2X2mm. An array of discrete wavelength signal components 36 transmitted from the two-dimensional filter array 58 is received by the two-dimensional optical modulator array 22. Each modulator 32 intensity modulates each discrete wavelength signal component 36 with data received from a data information source 20. High speed electrical interconnects 40 apply data to each modulator within the array. An optical focusing device 16 couples the modulated discrete wavelength signal components generated by the optical modulator array 22 into an optical fiber 17.
Figure 4 shows a variant of the apparatus shown in Figure 3, in which a diffraction grating 50 replaces the prism 38. Apparatus 10C includes wavelength separation device 28C comprising a primary diffraction grating 50 and a secondary diffraction grating 48. The collimating lens system 14 couples the broadband optical signal 13, from an optical source 12 to the wavelength separation device 28, where the primary diffraction grating 50 spatially disperses the optical signal into a plurality of optical wavelength signal components 39. The secondary diffraction grating 48 spatially disperses each wavelength signal component received from the primary grating 50 into multiple wavelength signals 15. The relative orientation of the primary diffraction grating 50 and secondary diffraction grating 48 forms a 'cross dispersion' wavelength separation device, generating a two-dimensional array of discrete wavelength signal components, as mentioned in the description of Figure 3. The focusing lens 18 concentrates the array of discrete wavelength signal components 15 onto the two-dimensional optical modulator array 22, where each discrete wavelength signal component 25 focuses onto an individual modulator 32. Each modulator 32 intensity modulates each focused discrete wavelength signal component 35 with data received from a data information source 20. High speed electrical interconnects 40, apply data to each modulator within the array. An optical focusing device 16 couples the modulated discrete wavelength signal components generated by the optical modulator array 22 into an optical fiber 17.
Referring now to Figure 5, illustrated therein is an alternative embodiment 10D of the present invention, wherein a wavelength separation device 28D comprises a linear array of dichroic mirrors 68. The collimating lens system 14 couples a broadband optical signal 13 from an optical source 12 to the linear array of dichroic mirrors 68. The linear array of dichroic mirrors 68 separates the spectrum of the broadband optical signal into discrete wavelength signal components 71. Each dichroic mirror element 70 reflects a single wavelength signal 71 within the broadband optical signal 13, transmitting all remaining wavelength signal components 72. Consequently, as the broadband optical signal propagates 13 through the array of mirrors 68, each mirror element 70 reflects a single discrete wavelength signal component 71 from the plurality of wavelength signal components comprising the broadband optical signal 13. The reflected discrete wavelength signal components 71 are received by an optical modulator array 22, where each wavelength signal 71 is modulated by an individual modulator 32. A data information source 20 modulates each discrete wavelength signal component 71 at its designated modulator, wherein transparent modulators 32 pass the modulated wavelength signal components 73 to a second dichroic mirror array 69. The second array of dichroic mirrors 69 reflect each discrete modulated wavelength signal component 73, combining all modulated wavelength signal components 74 along the same path to a focusing lens 16. The focusing lens couples the modulated wavelength signal components 73 into an optical fiber 17. . Figure 6 shows a further alternative embodiment of the present invention, wherein the wavelength separation device comprises a prism 38 and, multiple linear arrays of dichroic mirrors 78. The broadband optical signal 13 is dispersed spatially by the prism 38 into a plurality of wideband wavelength signal components 39. Each of the wideband wavelength signal components 39 are received by a linear array of dichroic mirrors 68, where each wideband wavelength signal component 41 splits into its constituent discrete wavelength signal components 71 as it propagates through the array of mirrors 68. Each wideband wavelength signal component 41 generated by the prism 38, propagates through an individual array of dichroic mirrors 68. By vertically stacking the linear array of mirrors, a two-dimensional structure of dichroic mirrors 78 is formed, where each row in the structure receives an individual wideband signal component from the prism 38. Consequently, the discrete wavelength signal components 71 from each row are reflected onto the modulator array 22. The modulated wavelength signal components 73 transmitted through each row of the modulator array 22 are recombined by a second two-dimensional dichroic mirror structure 88 identical to that described above. A focusing lens 16 receives the modulated discrete wavelength signal components 74 from each row of the two-dimensional mirror structure 88, and focuses all modulated discrete wavelength signal components 74 into an optical fibre 17.
Referring now to Figure 7, illustrated therein is a WDM receiver apparatus 100 made in accordance with the present invention which receives and detects data information, from each individual wavelength signal component within a wavelength division multiplexed (WDM) signal. The WDM signal is coupled from an optical fibre 126 to a collimating lens system 104. A wavelength separation device 128 receives the collimated WDM signal from the lens system 104 and spatially separates the WDM signal into a two-dimensional array of modulated discrete wavelength signal components. A focusing lens 108 couples the two-dimensional array of modulated wavelength signal components onto a two-dimensional array of photodetectors 122, where the photodetector array 122 detects data from each received discrete wavelength signal component. High speed interconnect cables 140 connect the detected data to an information data source 150.
Figure 8 shows an optical repeater apparatus 200 made in accordance with the present invention, which regenerates data information carried by the WDM signal. Optical repeater apparatus 200 comprises a WDM receiver 205, electrical processing device 209 and WDM signal generating apparatus 207. An optical lens system 203, 204 couples a WDM signal received from an optical fiber 226 to a wavelength separation device 228. The wavelength separation device 228 spatially separates the WDM signal into a two-dimensional array of modulated discrete wavelength signal components. A focusing lens 208 couples the two-dimensional array of modulated wavelength signal components onto a two-dimensional array of photodetectors 222, where the photodetector array 222 detects data from each received discrete wavelength signal component. High speed interconnect cables 240 connect the detected data to an electrical processing device 250. The electrical processing device 250 regenerates data received from each discrete wavelength signal component. High speed electrical interconnect cables 242 connect the regenerated data to the apparatus 207 generating a WDM signal for re-transmission over the optical fiber. An optical source 112 produces a broadband optical signal 113 comprising a plurality of wavelength signal components. A collimating lens system 114 couples the broadband optical signal 113 to a wavelength separation device 129, wherein the wavelength separation device 129 generates a two- dimensional array of discrete wavelength signal components. A focusing lens 118 concentrates the array of discrete wavelength signal components onto a two-dimensional optical modulator array 123. Each modulator 132 intensity modulates each focused discrete wavelength signal component with regenerated data received from the electrical processing device 250. An optical focusing device 116 couples the modulated discrete wavelength signal components 115 generated by the optical modulator array 123 back into an optical medium such as an optical fiber 117.
The wavelength separation devices made in accordance with the current invention offer an increased spatial resolution over that of prior art devices. Resolving the broadband optical signal into multiple channels across two dimensions offers a significant advantage in comparison to spatial wavelength separation achieved by using a single dispersive element within the wavelength separation device. The two dimensional approach to creating wavelength channels enables the current invention to have up to 20 times the channel capacity of existing prior art.
It should be understood that various modifications can be made to the preferred and alternative embodiments described and illustrated herein, without departing from the present invention, the scope of which is defined in the appended claims.

Claims

I CLAIM:
1. Apparatus for generating a wavelength division multiplexed optical signal for optical fiber systems, the apparatus comprising:
(a) an input optical coupling device for receiving an incident broadband optical signal;
(b) a wavelength separation device for spatially separating the incident optical signal into a two-dimensional array of discrete wavelength signal components;
(c) an array of optical modulators for modulating the discrete wavelength signal components, wherein each individual modulator is arranged to receive and modulate one of the discrete wavelength signal components so as to generate a discrete optically modulated wavelength signal component; and (d) an output optical coupling device for coupling the optically modulated two-dimensional array of discrete wavelength signal components to an optical waveguide.
2. The apparatus defined in claim 1, wherein the input optical coupling device comprises an optical lens system for collimating the incident optical signal.
3. The apparatus defined in claim 1, wherein the wavelength separation device comprises a two dimensional array of optical filter elements, each filter element being capable of transmitting a single discrete wavelength signal component .
4. The apparatus defined in claim 1, wherein the wavelength separation device comprises a first dispersion device having a first output plane of angular dispersion and a second dispersion device having a second output plane of angular dispersion, wherein the orientation of the two devices is such that second plane of angular dispersion is perpendicular to the first plane of angular dispersion.
5. The apparatus defined in claim 1, wherein the wavelength separation device comprises a first dispersion device and a second dispersion device, and the first dispersion device and second dispersion device are oriented so as to generate a two-dimensional array of discrete wavelength signal components.
6. The apparatus defined in claim 5, wherein the first dispersion device comprises a prism for spatially dispersing the incident optical signal into discrete wavelength signal components, and the second dispersion device comprises a diffraction grating for spatially dispersing collective discrete wavelength signal components received from the prism.
7. The apparatus defined in claim 5, wherein the first dispersion device comprises a first diffraction grating for spatially dispersing the output of the incident optical signal into discrete wavelength signal components, and the second dispersion device comprises a second diffraction grating for spatially dispersing collective discrete wavelength signal components received from the first diffraction grating.
8. The apparatus defined in claim 1, wherein the wavelength separation device comprises:
(a) a prism, for spatially dispersing the incident optical signal into discrete wavelength signal components; and (b) a two-dimensional array of wavelength selective mirrors, wherein each row of mirrors within the array, spatially separates each discrete wavelength signal component received from the prism, generating a two-dimensional array of discrete wavelength signal components.
9. The apparatus defined in claim 8, wherein the two dimensional array of wavelength selective mirrors comprise linear arrays of wavelength selective mirrors for each row.
10. The apparatus defined in claim 9, wherein the linear array of wavelength selective mirrors comprises a linear array of dichroic mirrors.
11. The apparatus defined in claim 10, wherein each dichroic mirror within the linear array of mirrors reflects a single wavelength signal component and transmits the remaining wavelength signal components.
12. The apparatus defined in claim 1, further comprising a device operable to optically couple the array of discrete wavelength components from the wavelength separating device to the optical modulator array.
13. The apparatus defined in claim 1, wherein the modulator array comprises an array of transparent modulators, wherein each modulator within the modulator array intensity modulates a discrete wavelength signal component so as to generate an array of intensity modulated discrete wavelength signal components.
14. The apparatus defined in claim 1, wherein the output coupling devicecomprises a focusing lens system.
15. Apparatus for generating a wavelength division multiplexed signal, the apparatus comprising: (a) an input optical coupling device for receiving an incident broadband optical signal;
(b) a wavelength separation device comprising a linear array of wavelength selective mirrors, wherein each mirror is arranged within the linear array so as to reflect a selected wavelength signal component, and transmit the remaining wavelength signal components;
(c) an array of optical modulators for modulating the discrete wavelength signal components, wherein each modulator is arranged to receive and modulate one of the discrete wavelength signal components so as to generate a discrete optically modulated wavelength signal component; and
(d) an output optical coupling device for coupling the optically modulated discrete wavelength signal components to an optical waveguide.
16. The apparatus defined in claim 15, wherein the output optical coupling device comprises:
(a) a linear array of wavelength selective mirrors, wherein each mirror selectively reflects a modulated wavelength signal component and transmits the remaining wavelength signal components; and
(b) an optical focusing device for focusing the modulated wavelength signal components into the optical waveguide.
17. Apparatus for receiving and spatially separating wavelength division multiplexed signals into individual modulated channels for optical detection, the apparatus comprising:
(a) a coupling device, for receiving a wavelength division multiplexed signal received from an optical medium;
(b) a wavelength separation device, for spatially separating the wavelength division multiplexed signal received from the coupling device, into a two dimensional array of modulated discrete wavelength signal components; (c) a matrix of photodetectors, for detecting data from the two dimensional array of modulated discrete wavelength signal components, wherein each photodetector detects data from a discrete wavelength component.
18. An optical repeater apparatus for receiving, regenerating and transmitting wavelength division multiplexed signals, the apparatus comprising:
(a) signal receiving apparatus for receiving and spatially separating wavelength division multiplexed signals into a two-dimensional array of modulated discrete wavelength signal components;
(b) signal generating apparatus for generating a wavelength division multiplexed optical signal for optical fiber systems, the apparatus comprising a wavelength separation device for spatially separating a broadband incident optical signal into a two-dimensional array of discrete wavelength signal components, and an array of optical modulators for modulating the discrete wavelength signal components, wherein each individual modulator generates a discrete optically modulated wavelength signal component; and
(c) an electrical processing device for receiving the modulated discrete wavelength signal components from the signal receiving apparatus and for generating input signals for driving the array of optical modulators of the signal generating apparatus.
19. The apparatus defined in 18, wherein the signal receiving apparatus comprises: (a) a coupling device for coupling wavelength division multiplexed signals received from the optical medium; (b) a wavelength separation device, for spatially separating the wavelength division multiplexed signal received from the coupling device, into a two dimensional array of modulated discrete wavelength components; and (c) a matrix of photodetectors, for detecting data from the two dimensional array of modulated discrete wavelength components, wherein each photodetector detects data from a discrete wavelength signal component, and generates an output data signal indicative thereof.
PCT/CA2001/000471 2000-04-05 2001-04-05 An information compressor for fiber-optic lines WO2001078281A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001248186A AU2001248186A1 (en) 2000-04-05 2001-04-05 An information compressor for fiber-optic lines

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US54357800A 2000-04-05 2000-04-05
US09/543,578 2000-04-05

Publications (2)

Publication Number Publication Date
WO2001078281A2 true WO2001078281A2 (en) 2001-10-18
WO2001078281A3 WO2001078281A3 (en) 2002-01-24

Family

ID=24168615

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA2001/000471 WO2001078281A2 (en) 2000-04-05 2001-04-05 An information compressor for fiber-optic lines

Country Status (2)

Country Link
AU (1) AU2001248186A1 (en)
WO (1) WO2001078281A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019219215A1 (en) * 2018-05-18 2019-11-21 Telefonaktiebolaget Lm Ericsson (Publ) Optical filtering module and method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0397372A1 (en) * 1989-05-08 1990-11-14 AT&T Corp. Network topology for reduced blocking and photonic system implementation thereof
US5099114A (en) * 1989-04-28 1992-03-24 Nippon Telegraph & Telephone Corporation Optical wavelength demultiplexer
US5315423A (en) * 1992-02-18 1994-05-24 Rockwell International Corporation Wavelength multiplexed two dimensional image transmission through single mode optical fiber

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5099114A (en) * 1989-04-28 1992-03-24 Nippon Telegraph & Telephone Corporation Optical wavelength demultiplexer
EP0397372A1 (en) * 1989-05-08 1990-11-14 AT&T Corp. Network topology for reduced blocking and photonic system implementation thereof
US5315423A (en) * 1992-02-18 1994-05-24 Rockwell International Corporation Wavelength multiplexed two dimensional image transmission through single mode optical fiber

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019219215A1 (en) * 2018-05-18 2019-11-21 Telefonaktiebolaget Lm Ericsson (Publ) Optical filtering module and method
US11128938B2 (en) 2018-05-18 2021-09-21 Telefonaktiebolaget Lm Ericsson (Publ) Optical filtering module and method

Also Published As

Publication number Publication date
AU2001248186A1 (en) 2001-10-23
WO2001078281A3 (en) 2002-01-24

Similar Documents

Publication Publication Date Title
US5777763A (en) In-line optical wavelength reference and control module
US5315423A (en) Wavelength multiplexed two dimensional image transmission through single mode optical fiber
US5936752A (en) WDM source for access applications
US5838848A (en) N×N wavelength router, optical routing method and associated communication network
US6016212A (en) Optical receiver and demultiplexer for free-space wavelength division multiplexing communications systems
US6339663B1 (en) Bidirectional WDM optical communication system with bidirectional optical service channels
US6281997B1 (en) Dense WDM optical multiplexer and demultiplexer
EP0295857B1 (en) Optical multiplexing
JPS61173537A (en) Optical fiber circuit network
JP2000089057A (en) Optical device, terminal apparatus and system for wavelength division multiplex
JPS59210413A (en) Device for optical multiplex communication
US6243175B1 (en) WDM optical communication system having reduced loss and cross-talk
US4957339A (en) Optical communication system, particularly in the subscriber area
WO2001078281A2 (en) An information compressor for fiber-optic lines
US6829096B1 (en) Bi-directional wavelength division multiplexing/demultiplexing devices
KR100444077B1 (en) A Wireless optical communication apparatus using multiple wavelength laser beams
US7286764B1 (en) Reconfigurable modulator-based optical add-and-drop multiplexer
JP3308148B2 (en) Optical submarine cable branching device for WDM communication system and WDM optical submarine cable network using the same
JPH11289317A (en) Wavelength multiplex optical interconnection device
WO2002089378A1 (en) Optical communications system and method for transmitting point-to-point and broadcast signals
US20030091276A1 (en) Grating-based MUX/DMUX with expanded waveguides
JPH04119023A (en) Optical transmission system
US20040071466A1 (en) Controlled optical splitter using a diffractive optical element and optical demultiplexer incorporating same
US6563616B1 (en) Optical demultiplexer
EP0571132A1 (en) Optical tunable receiver

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
AK Designated states

Kind code of ref document: A3

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP