Connect public, paid and private patent data with Google Patents Public Datasets

Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch

Download PDF

Info

Publication number
US20100098406A1
US20100098406A1 US12620512 US62051209A US2010098406A1 US 20100098406 A1 US20100098406 A1 US 20100098406A1 US 12620512 US12620512 US 12620512 US 62051209 A US62051209 A US 62051209A US 2010098406 A1 US2010098406 A1 US 2010098406A1
Authority
US
Grant status
Application
Patent type
Prior art keywords
optical
transponders
wavelengths
wavelength
transponder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12620512
Inventor
Thomas Andrew Strasser
Paul Bonenfant
Per Bang Hansen
Torben N. Nielsen
Ken R. Roberts
Jefferson L. Wagener
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Meriton Networks U S Inc
Original Assignee
Meriton Networks U S 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
Family has litigation

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0278WDM optical network architectures
    • H04J14/0283WDM ring architectures
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/28Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293Optical 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
    • G02B6/29346Optical 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
    • G02B6/29361Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
    • G02B6/29362Serial cascade of filters or filtering operations, e.g. for a large number of channels
    • G02B6/29365Serial 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
    • G02B6/29367Zigzag path within a transparent optical block, e.g. filter deposited on an etalon, glass plate, wedge acting as a stable spacer
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/28Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293Optical 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
    • G02B6/29379Optical 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
    • G02B6/2938Optical 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 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/28Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293Optical 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
    • G02B6/29379Optical 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
    • G02B6/2938Optical 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 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G02B6/29382Optical 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 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM including at least adding or dropping a signal, i.e. passing the majority of signals
    • G02B6/29383Adding and dropping
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/28Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293Optical 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
    • G02B6/29379Optical 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
    • G02B6/29391Power equalisation of different channels, e.g. power flattening
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/28Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293Optical 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
    • G02B6/29379Optical 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
    • G02B6/29395Optical 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
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/354Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/356Switching arrangements, i.e. number of input/output ports and interconnection types in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0202Arrangements therefor
    • H04J14/0204Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0202Arrangements therefor
    • H04J14/0205Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0202Arrangements therefor
    • H04J14/021Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0202Arrangements therefor
    • H04J14/021Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
    • H04J14/0212Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM] using optical switches or wavelength selective switches [WSS]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0215Architecture aspects
    • H04J14/0217Multi-degree architectures, e.g. having a connection degree greater than two
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0215Architecture aspects
    • H04J14/022For interconnection of WDM optical networks
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0278WDM optical network architectures
    • H04J14/0286WDM hierarchical architectures
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00Data switching networks
    • H04L12/28Data switching networks characterised by path configuration, e.g. local area networks [LAN], wide area networks [WAN]
    • H04L12/42Loop networks
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005Switch and router aspects
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/351Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3512Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/354Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/35442D constellations, i.e. with switching elements and switched beams located in a plane
    • G02B6/35481xN switch, i.e. one input and a selectable single output of N possible outputs
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/3564Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/357Electrostatic force
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/3564Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/3578Piezoelectric force
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B6/00Light guides
    • G02B6/24Coupling light guides
    • G02B6/26Optical coupling means
    • G02B6/35Optical coupling means having switching means
    • G02B6/3564Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3582Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J14/00Optical multiplex systems
    • H04J14/02Wavelength-division multiplex systems
    • H04J14/0201Add-and-drop multiplexing
    • H04J14/0202Arrangements therefor
    • H04J14/0206Express channels arrangements
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00Data switching networks
    • H04L12/28Data switching networks characterised by path configuration, e.g. local area networks [LAN], wide area networks [WAN]
    • H04L12/42Loop networks
    • H04L2012/421Interconnected ring systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005Switch and router aspects
    • H04Q2011/0007Construction
    • H04Q2011/0016Construction using wavelength multiplexing or demultiplexing
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005Switch and router aspects
    • H04Q2011/0007Construction
    • H04Q2011/0024Construction using space switching
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005Switch and router aspects
    • H04Q2011/0007Construction
    • H04Q2011/0026Construction using free space propagation (e.g. lenses, mirrors)
    • H04Q2011/003Construction using free space propagation (e.g. lenses, mirrors) using switches based on microelectro-mechanical systems [MEMS]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0005Switch and router aspects
    • H04Q2011/0052Interconnection of switches
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062Network aspects
    • H04Q2011/0079Operation or maintenance aspects
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/0001Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062Network aspects
    • H04Q2011/009Topology aspects
    • H04Q2011/0092Ring

Abstract

In a WDM optical communication system that includes a plurality of nodes interconnected by communication links, a node is provided that includes a first plurality of transponders each generating and/or receiving an information-bearing optical signal at a different channel wavelength from one another. An optical coupling arrangement, which may include one or more reconfigurable optical switches, transfers the channel wavelengths between a link connected to the node and the first plurality of transponders. The arrangement is adaptable to reconfigure its operational state to selectively direct different ones of the channel wavelengths from the link to different ones of the transponders without disturbing the optical path through the node traversed by any other channel wavelengths. A communications and configuration arrangement is provided, which transfers data identifying the respective channel wavelengths at which the transponders operate from the transponders to the optical coupling arrangement. In response to the transferred data, the communications and configuration arrangement reconfigures the operational state of the optical coupling arrangement.

Description

    STATEMENT OF RELATED APPLICATION
  • [0001]
    This application is a continuation of U.S. patent application Ser. No. 10/099,890, filed Mar. 15, 2002, entitled “Method and Apparatus For Interconnecting A Plurality Of Optical Transducers With A Wavelength Division Multiplexed Optical Switch,” now U.S. Pat. No. 7,620,323, which claims the benefit of priority to U.S. Provisional Patent Application 60/276,310, filed Mar. 16, 2001, entitled “Reconfigurable Optical System.” Each of the prior applications is incorporated herein by reference in its entirety.
  • FIELD OF THE INVENTION
  • [0002]
    The invention relates generally to wavelength division multiplexed optical communication systems, and more particularly, to wavelength division multiplexed optical communication systems which include reconfigurable optical switches.
  • BACKGROUND OF THE INVENTION
  • [0003]
    Wavelength division multiplexing (WDM) has been explored as an approach for increasing the capacity of fiber optic networks to support the rapid growth in data and voice traffic applications. A WDM system employs plural optical signal channels, each channel being assigned a particular channel wavelength. In a WDM system, signal channels are generated, multiplexed, and transmitted over a single waveguide, and demultiplexed to individually route each channel wavelength to a designated receiver. Through the use of optical amplifiers, such as doped fiber amplifiers, plural optical channels are directly amplified simultaneously, facilitating the use of WDM systems in long-distance optical systems.
  • [0004]
    Proposed wavelength division multiplexed optical communication systems typically include multiplexer and demultiplexer switching elements which permit only a fixed number of optical channels to be used in the optical system. In one optical system configuration, for instance, the multiplexed signal is broken down into its constituent optical signals through the use of an integrated frequency router demultiplexer. The frequency router uses silicon optical bench technology in which plural phosphorus-doped silica waveguides are disposed on a silicon substrate. An optical star outputs to an array of N waveguides having adjacent optical path lengths which differ by q wavelengths; this array in turn feeds an output N×N star. Such a frequency router design for an optical communication system is described in Alexander et al., J. Lightwave Tech., Vol. 11, No. 5/6, May/June 1993, p. 714. Using a 1×N configuration at the input, a multiplexed optical signal containing light of different frequencies is separated into its component frequencies at each waveguide extending from the output N×N star. Although this configuration adequately separates light of different frequencies, the integrated optical design fixes both the number and the respective wavelengths of the optical channels. Additionally, each wavelength has a fixed relationship between a particular pair of input and output ports of the routing element.
  • [0005]
    The deployment and serviceability of the aforementioned switching elements becomes problematic as the number of channels, and hence the number of input and output ports, increases to support future DWDM networks, which may have anywhere from 256 to thousands of channels. Since each port is assigned a unique wavelength that cannot be changed, a field technician must ensure that the proper transmitter operating at the appropriate wavelength is connected to the proper port of the switching element. These connections are typically manually provisioned to the front bay of the switching element. Assuming fixed-wavelength transmitters are employed, the technician may be required to install thousands of different transmitters so that each transmitter is properly connected to its corresponding port. Accordingly, this installation procedure can be quite time consuming and prone to error, while also requiring that it be performed by a skilled technician.
  • [0006]
    Ideally, a so-called “plug and play” approach would be employed in which the technician connects any one of a series of transmitters to any of the ports of the switching element so that provisioning can be accomplished quickly and in a nearly error-free manner by a technician having minimal training.
  • SUMMARY OF THE INVENTION
  • [0007]
    In a WDM optical communication system that includes a plurality of nodes interconnected by communication links, the present invention provides a node that includes a first plurality of transponders each generating and/or receiving an information-bearing optical signal at a different channel wavelength from one another. An optical coupling arrangement transfers the channel wavelengths between a link connected to the node and the first plurality of transponders. The arrangement is adaptable to reconfigure its operational state to selectively direct different ones of the channel wavelengths from the link to different ones of the transponders without disturbing the optical path through the node traversed by any other channel wavelengths. A communications and configuration arrangement is provided, which transfers data identifying the respective channel wavelengths at which the transponders operate from the transponders to the optical coupling arrangement. In response to the transferred data, the communications and configuration arrangement reconfigures the operational state of the optical coupling arrangement.
  • [0008]
    In accordance with one aspect of the invention, the first plurality of transponders respectively include a plurality of receivers receiving the information-bearing optical signals. The communications and configuration arrangement reconfigures the operational state of at least the portion of the optical coupling arrangement transferring the channel wavelengths from the link to the first plurality of transponders so that the transponders can receive optical signals at the channel wavelengths at which they respectively operate.
  • [0009]
    In accordance with another aspect of the invention, the transponders each include an identifying element containing data identifying the respective channel wavelengths at which the transponders operate. Moreover, the optical coupling arrangement has a receiving element for obtaining the data contained in the identifying element.
  • [0010]
    In accordance with yet another aspect of the invention, the optical coupling arrangement includes a tunable coupling arrangement for selectively transferring the different ones of the channel wavelengths from the link to the first plurality of transponders. The optical coupling arrangement also includes a passive coupling arrangement for directing the channel wavelengths from the transponders to the link.
  • [0011]
    In accordance with another aspect of the invention, the optical coupling arrangement includes a reconfigurable optical switch having at least three ports. The reconfigurable optical switch is adaptable to reconfigure its operational state to receive at any of the ports any of the channel wavelengths at which the first plurality of transponders operate and direct the channel wavelengths to any of the other ports of the optical switch.
  • [0012]
    In accordance with another aspect of the invention, the optical coupling arrangement includes a reconfigurable optical switch having at least three ports. The reconfigurable optical switch is adaptable to reconfigure its operational state to receive at a plurality of the ports any of the channel wavelengths at which the first plurality of transmitters operate and direct the channel wavelengths to any remaining ones of the ports of the optical switch.
  • [0013]
    In accordance with another aspect of the invention, a second plurality of transponders is provided, which serve as backup transponders in the event of a failure in one or more of the transponders in the first plurality of transponders.
  • [0014]
    In accordance with another aspect of the invention, the optical coupling arrangement includes at least two reconfigurable optical switches each having at least three ports. A first of the reconfigurable optical switches is adaptable to reconfigure its operational state to drop channel wavelengths to the first plurality of transponders and to receive channel wavelengths from the second plurality of transponders. A second of the reconfigurable optical switches is adaptable to reconfigure its operational state to drop channel wavelengths to the second plurality of transponders and to receive channel wavelengths from the first plurality of transponders.
  • [0015]
    In accordance with yet another aspect of the invention, the first and second plurality of transponders are arranged in transponder pairs comprising transponders from each of the first and second plurality of transponders. The transponders in each of the transponder pairs may be located in adjacent slots in electrical connection with one another for transferring electrical data signals therebetween.
  • [0016]
    In accordance with another aspect of the invention, the optical coupling arrangement includes at least four reconfigurable optical switches. A first transponder in each of the transponder pairs transmits and receives channel wavelengths to first and second ones of the reconfigurable optical switches, respectively. A second transponder in each of the transponder pairs transmits and receives channel wavelengths to third and fourth ones of the reconfigurable optical switches, respectively.
  • [0017]
    In accordance with another aspect of the invention, the optical coupling arrangement includes at least two passive coupling arrangements and two reconfigurable optical switches each having a plurality of ports. A first transponder in each of the transponder pairs sends and receives channel wavelengths from a first of the passive coupling arrangements and a first of the optical switches associated therewith. A second transponder in each of the transponder pairs sends and receives channel wavelengths from a second of the passive coupling arrangements and a second of the optical switches associated therewith.
  • [0018]
    In accordance with another aspect of the invention, a method is provided for assigning channel wavelengths to a plurality of ports of an optical switch. The method begins by receiving a plurality of transmitters in the plurality of the ports of the optical switch. The transmitters are operable at distinct wavelengths from one another. Data is obtained from the transmitters identifying one or more operating characteristics of the transmitters, which characteristics include the distinct wavelengths at which the transmitters respectively operate. Based on the data obtained from the transmitters, the optical switch is configured so that the plurality of ports are assigned channel wavelengths respectively corresponding to the distinct wavelengths of the transmitters received in the plurality of ports.
  • [0019]
    In accordance with another aspect of the invention, the data may be manually input by a technician or read directly from the transmitter.
  • [0020]
    In accordance with another aspect of the invention, the plurality of transmitters are received in a plurality of transponder slots, each of which optically communicates with a predetermined one of the ports of the optical switch. The plurality of transponder slots may be optically coupled with the ports of the optical switch via an optical backplane.
  • [0021]
    In accordance with another aspect of the invention, a method is provided for automatically provisioning a service in an optical transmission system having a plurality of nodes, at least one of which includes at least one optical switch, The method begins by identifying a transponder coupled to a given port of an optical switch and which is associated with the service to be provisioned. The optical switch is configured so that the given port is assigned a channel wavelength based at least in part on the identification of the transponder.
  • [0022]
    In accordance with another aspect of the invention, a first protection scheme is provided for the service being provisioned. In some cases the first protection scheme may be selectively switched to a second protection scheme for the service being provisioned.
  • [0023]
    In accordance with another aspect of the invention, the first protection scheme is selected from the group consisting of a dedicated protection scheme, a shared protection scheme, a dual homing path protection, a dual ring interworking scheme, and a 1:N protection scheme.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0024]
    FIG. 1 is a schematic representation of a wavelength division multiplexed optical communication system in accordance with the present invention.
  • [0025]
    FIG. 2 is a schematic representation of an exemplary transponder in accordance with the present invention.
  • [0026]
    FIG. 3 shows an exemplary reconfigurable optical switch that may be employed in the present invention.
  • [0027]
    FIG. 4 shows an exemplary network node that provides protected services in the event of a fault.
  • [0028]
    FIG. 5 shows another network node that provides an additional degree of protection services in the event of a fault.
  • [0029]
    FIG. 6 shows a network node similar to that of FIG. 5 in which one of the optical switches is replaced with passive couplers.
  • [0030]
    FIG. 7 shows a network node similar to that of FIG. 6 in which another of the optical switches is replaced with a splitter followed by tunable bandpass filters.
  • [0031]
    FIG. 8 shows yet another network node configuration.
  • DETAILED DESCRIPTION
  • [0032]
    In accordance with the present invention, a WDM optical transmission system is provided which employs reconfigurable switching elements that can dynamically change the channel wavelength that is routed between any pair of input and output ports. By employing such switching elements, the present invention provides a “plug and play” arrangement in which any transmitter can be connected to any input port of the switching element, after which the switching element is reconfigured so that its input ports are assigned to the operating wavelengths of the transmitters respectively connected to those ports, thus allowing the wavelengths to be properly routed through the switching element.
  • [0033]
    Recently, switching elements that provide a degree of reconfigurability have become available. These reconfigurable optical elements can dynamically change the path along which a given wavelength is routed to effectively reconstruct the topology of the network as necessary to accommodate a change in demand or to restore services around a network failure. Examples of reconfigurable optical elements include optical Add/Drop Multiplexers (OADM) and Optical Cross-Connects (OXC). OADMs are used to separate or drop one or more wavelength components from a WDM signal, which is then directed onto a different path. In some cases the dropped wavelengths are directed onto a common fiber path and in other cases each dropped wavelength is directed onto its own fiber path. OXCs are more flexible devices than OADMs, which can redistribute in virtually any arrangement the components of multiple WDM input signals onto any number of output paths. Unfortunately, current OXC's generally employ optoelectronic regeneration at their network interfaces, thus requiring optical-to-electrical interfaces into and out of the cross-connect. Such an arrangement gives rise to a number of limitations, including a relatively high insertion loss because the optical signals must pass through three discrete components. In addition, the components are relatively expensive while still not providing a completely flexible switch that can transfer light between any two subsets of the ports. Finally, because of their high loss as well as the need to provide channels with equal power, such OXC's typically employ optoelectronic regenerators on at least their output side, and in many instances on their input side as well. While these regenerators overcome the problem of insertion loss and effectively allow wavelength conversion of the signal as it traverses the switch fabric, they substantially add to the cost of an already expensive switch fabric because a regenerator is required for each and every wavelength that is used in the network.
  • [0034]
    More flexible still are all-optical reconfigurable switches which have much lower insertion losses and are less expensive than the aforementioned OXC's. Various examples of all-optical reconfigurable optical switches are disclosed in U.S. patent application Ser. No. 09/571,833, which is hereby incorporated by reference in its entirety, and in particular FIGS. 2-4 of that reference. The switching elements disclosed therein can selectively direct any wavelength component from any input port to any output port, independent of the routing of the other wavelengths without the need for any electrical-to-optical conversion. Another all-optical reconfigurable optical switch that provides additional functionality is disclosed in U.S. patent application Ser. No. 09/691,812, which is hereby incorporated by reference in its entirety. This reference discloses an optical switching element in which each and every wavelength component can be directed from any given port to any other port without constraint. More specifically, unlike most optical switches, this switch is not limited to providing connections between a subset of input ports and a subset of output ports, or vice versa. Rather, this switch can also provide a connection between two ports within the same subset (either input or output). While the present invention may employ any of the aforementioned reconfigurable optical switches, the optical switch disclosed in U.S. patent application Ser. No. 09/691,812 will serve as an exemplary reconfigurable optical switch, and accordingly, additional details concerning this switch will be presented below.
  • [0035]
    Turning now to the drawings in detail in which like numerals indicate the same or similar elements, FIG. 1 schematically depicts a bi-directional wavelength division multiplexed (WDM) optical communication system 10 according to one embodiment of the present invention. Optical communication system 10 includes optical transmission paths 40 1 and 40 2 for transporting information in opposite directions, a first pair of optical switches 30 1 and 30 2, which are typically co-located in a common node, a second pair of optical switches 32 1 and 32 2, which are also typically co-located in a common node, and a plurality of optical transponders 20 1-20 6 and 60 1-60 6, e.g., transmitter/receiver pairs, respectively assigned to the first and second pair of optical switches 30 and 32. Each optical transponder emits and receives an information-bearing optical signal at an optical channel wavelength that differs from transmitter to transmitter. The expression “information-bearing optical signal,” as used herein, refers to an optical signal which has been coded with information, including, but not limited to, audio signals, video signals, and computer data. The WDM optical communication systems of the present invention include N channels, where N is a whole number greater than or equal to 2. Exemplary values for N are 4, 8, and 16 optical channels. In the optical system of FIG. 1, N is depicted as 6 for ease of illustration.
  • [0036]
    It should be noted at the outset that the present invention is not limited to WDM systems such as shown in FIG. 1, which have a point-to-point configuration consisting of end terminals or nodes spaced from each other by one or more segments of optical fiber. For example, in metropolitan areas, WDM systems having a ring or loop configuration are currently being developed. Such systems typically include a plurality of nodes located along the ring. At least one optical add/drop element, associated with each node, is typically connected to the ring with optical connectors. The optical add/drop element permits both addition and extraction of channels to and from the ring. One of the nodes, referred to as a hub or central office node, typically has a plurality of associated add/drop elements for transmitting and receiving a corresponding plurality of channels to/from other nodes along the ring. Of course, the present invention is equally applicable to other network topologies in addition to rings such as a mesh topology.
  • [0037]
    FIG. 2 shows an exemplary transponder 200 that may be employed as optical transponders 20 1-20 8 and 60 1-60 8 seen in FIG. 1. Transponder 200 includes a transmitter 250 and receiver 240. The receiver 240 generally detects the optical signal and converts it to an electrical signal, typically through the use of a photodiode device. The transmitter 250 generally includes a laser 220, such as a DFB semiconductor laser, a laser controller 210, and a modulator 230 for creation of an information-bearing optical signal. In an exemplary embodiment, the transmitter laser 220 is a DFB semiconductor diode laser, generally comprising one or more III-V semiconductor materials, commercially available from a wide variety of suppliers. The laser outputs an optical carrier signal at a particular wavelength assigned to its channel. The laser controller 210 provides the required laser bias current as well as thermal control of the laser 220. Using thermal control, the precise operating wavelength of the laser is maintained, typically to within a one-angstrom bandwidth or less.
  • [0038]
    The optical transmitter 250 typically includes a modulator 230 for imparting information to the optical carrier signal. An exemplary modulator is an external modulator, such as a Mach-Zehnder modulator, employing a waveguiding medium whose refractive index changes according to the applied electrical field, i.e., a material exhibiting an electro-optic effect. In the Mach-Zehnder configuration, two optical interferometer paths are provided. An incoming optical carrier signal is split between the two optical paths. At least one path of the interferometer is phase modulated. When the signal is recombined at the output, the light from the paths either constructively or destructively interferes, depending upon the electrical field applied to the surrounding electrodes during the travel time of the carrier. This recombination creates an amplitude-modulated output optical signal. The optical carrier signal can alternatively be directly modulated for some system applications. It is noted that while the above-described transmitters are exemplary, any transmitting elements capable of producing optical signals for use in an optical communication system can be employed in the WDM systems of the present invention.
  • [0039]
    Typically, the wavelengths emitted by the optical transmitters are selected to be within the 1500 nanometer range, the range in which the minimum signal attenuation occurs for silica-based fibers. More particularly, the wavelengths emitted by the optical transmitters are selected to be in the range from 1530 to 1560 nanometers. However, other wavelengths, such as those in the 1300-1500 nm range and the 1600 nm range, can also be employed in the WDM systems of the present invention. Optical transmitters may operate at a single fixed wavelength or they may be tunable to operate and any wavelength within a predefined range of wavelengths.
  • [0040]
    Each information-bearing optical signal produced by an optical transmitter constitutes a channel in optical system 10. In a WDM system, each channel is generally associated with a unique wavelength. As depicted in FIG. 1, six optical transponders 20 1-20 6 are provided to create a six-channel wavelength division multiplexed optical communication system along transmission path 40 1 and six optical transponders 60 1-60 6 are provided to create a six-channel wavelength division multiplexed optical communication system along transmission path 40 2. The optical transmitters located within transponders 20 1-20 6 operate at channel wavelengths of {circle around (2)}1-{circle around (2)}6, respectively. These optical signal channels are output from transponders 20 1-20 6 and are brought together in optical switch 30 1 for conveyance to optical waveguide 40 1 via output port 26 1 in the form of a multiplexed optical signal. Optical switch 30 1 has six input ports that are optically coupled to the six transponders 20 1-20 6 through optical waveguides 22 1-22 6. Likewise, the optical transmitters located within transponders 60 1-60 6 also operate at channel wavelengths of {circle around (2)}1-{circle around (2)}6, respectively. These optical signal channels are output from transponders 60 1-60 6 and are brought together in optical switch 32 2 for conveyance to optical waveguide 40 2 via output port 26 2. Optical transmission path 40 1 is typically an optical waveguide and is the principal transmission medium for the optical communication system. While the optical waveguide is generally selected from single-mode optical, any optical waveguiding medium which is capable of transporting multiple optical wavelengths can be employed as waveguide 40 1 in optical system 10. Similar to optical switch 30 1, optical switch 32 2 provides a multiplexed optical signal along optical transmission path 40 2. Following transmission and amplification of the multiplexed optical signals along waveguides 40 1 and 40 2, each channel must be demultiplexed and routed to the receiver located in the transponder designated for the particular optical signal channel.
  • [0041]
    Optionally, one or more optical amplifiers 50 are interposed along optical transmission paths 40 1 and 40 2. Optical amplifiers 50 are selected from any device which directly increases the strength of plural optical signals without the need for optical-to-electrical conversion. In general, optical amplifiers 50 are selected from optical waveguides doped with a material which can produce laser action in the waveguide. Such materials include rare earth dopants such as erbium, neodymium, praseodymium, ytterbium, or mixtures thereof. Pumping of the doped waveguide at a specific pump wavelength causes population inversion among the electron energy levels of the dopant, producing optical amplification of the wavelength division multiplexed optical signals. For doped fiber amplifiers employing erbium as the dopant, a wavelength band between approximately 1500 nm and approximately 1630 nm provides gain to optical signals when the doped fiber is pumped.
  • [0042]
    As previously mentioned, in a conventional WDM optical communication system optical switches 30 1-30 2 and 32 1-32 2 are generally based on multiplexers and demultiplexers that are fixed wavelength-dependent elements in which a given wavelength must be pre-assigned to a particular pair of input/output ports. As a result, each port must be connected to a different transponder that incorporates a transmitter operating at the wavelength associated with that port. As DWDM systems are implemented with an ever-increasing number of channels, installation of the transmitters becomes an increasingly complex task that is time-consuming and prone to error. However, in the present invention, this task is simplified by employing flexible optical switches instead of fixed-wavelength dependent switching elements. Such optical switches are reconfigurable elements that can dynamically change the channel wavelength that is assigned to its input and output ports.
  • [0043]
    As previously mentioned, for purposes of illustration only the present invention will be depicted in connection with the reconfigurable optical switch disclosed in the aforementioned U.S. application Ser. No. 09/691,812, which is shown in FIG. 3. Of course, those of ordinary skill in the art will recognize that the invention is equally applicable to a communication system that employs any reconfigurable optical switch in which any wavelength component received on any input port can be selectively directed to any output port, independent of the routing of the other wavelengths. In FIG. 3, the optical switch 300 comprises an optically transparent substrate 308, a plurality of dielectric thin film filters 301, 302, 303, and 304, a plurality of collimating lens pairs 321 1 and 321 2, 322 1 and 322 2, 323 1 and 323 2, 324 1 and 324 2, a plurality of tiltable mirrors 315, 316, 317, and 318 and a plurality of output ports 340 1, 340 2, . . . 340 n. A first filter array is composed of thin film filters 301 and 303 and a second filter array is composed of thin film filters 302 and 304. Individual ones of the collimating lens pairs 321-324 and tiltable mirrors 315-318 are associated with each of the thin film filters. Each thin film filter, along with its associated collimating lens pair and tiltable mirror effectively forms a narrow band, free space switch, i.e. a switch that routes individual wavelength components along different paths. The tiltable mirrors are micro mirrors such as the MEMS (microelectromechanical systems) mirrors. Alternatively, other mechanisms may be employed to control the position of the mirrors, such as piezoelectric actuators, for example.
  • [0044]
    In operation, a WDM optical signal composed of different wavelengths λ1, λ2, λ3 and λ4 is directed from the optical input port 312 to a collimator lens 314. The WDM signal traverses substrate 308 and is received by thin film filter 301. According to the characteristics of the thin film filter 301, the optical component with wavelength λ1 is transmitted through the thin film filter 301, while the other wavelength components are reflected and directed to thin film filter 302 via substrate 308. The wavelength component λ1 which is transmitted through the thin film filter 301, is converged by the collimating lens 321 1 onto the tiltable mirror 315. Tiltable mirror 315 is positioned so that wavelength component λ1 is reflected from the mirror to a selected one of the output ports 340 1-340 n via thin film filters 302-304, which all reflect wavelength component λ1. The particular output port that is selected to receive the wavelength component will determine the particular orientation of the mirror 315.
  • [0045]
    As mentioned, the remaining wavelength components λ2, λ3, and λ4 are reflected by thin film filter 301 through lens 321 2 back into substrate 308 and directed to thin film filter 302. Wavelength component λ2 is transmitted through thin film filter 302 and lens 322 1 and directed to a selected output port by tiltable mirror 316 via thin film filters 303-304, which all reflect wavelength component λ2. Similarly, all other wavelength components are separated in sequence by the thin film filters 303-304 and subsequently directed by tiltable mirrors 317-318 to selected output ports. By appropriate actuation of the tiltable mirrors, each wavelength component can be directed to an output port that is selected independently of all other wavelength components.
  • [0046]
    Returning to FIG. 1, if switching elements 30 1-30 2 and 32 1-32 2 are reconfigurable, then when installing a set of transmitters or transponders that have been pre-selected to operate at the various channel wavelengths of the switch, the field technician can, in principle, connect any transmitter or transponder to any of the switch input ports. Once the connections are made, the switching elements can be internally reconfigured so that their input ports correspond to the operating wavelengths of the transponders to which the respective input ports are connected. That is, the switching elements are configured to conform to the sequential arrangement of the transponders rather than requiring the sequential arrangement of the transponders to conform to the configuration of the switching element. In this way a “plug and play” approach is achieved in which the technician is able to connect any transponder to any input port of the optical switches.
  • [0047]
    In order to achieve the aforementioned plug and play interconnectability between the transponders and the optical switches, the switches must be able to detect when a transponder has been connected to one of its ports and to recognize the operating wavelength (or wavelengths in the case of a tunable transmitter) of the transmitter incorporated into that transponder. To provide this functionality, in accordance with the present invention, each transponder is associated with a memory module that identifies the operating wavelength of its transmitter. The memory modules incorporated into the transponders may be read only (ROM) or a rewritable memory such as RAM. For example, in some embodiments of the invention the memory module may be an EPROM that stores the operating wavelength or wavelengths of the transmitter located in the transponder. Further, the optical switch incorporates a controller that reads the memory module when the transponder is received by one of its input ports. In some embodiments of the invention the memory module and controller may be replaced by alternative identification mechanisms or even eliminated. For example, in some cases the technician may simply manually input an identification number such as a serial number or a model number into the switch controller.
  • [0048]
    Regardless of the mechanism by which the switch obtains the information it needs to properly configure its input ports so that they are assigned the same wavelengths as the transponders connected to those ports, the switch in turn provides this information to software resident in the transmission network. This software may reside in a network management element that operates at the highest level of network control. When a new service is to be provisioned between the switch and another node in the network, the software can compare the wavelengths that are available on the transmission path with the operating wavelengths of the transponders that have been installed in the switch. If there is a match, the software can establish the connection at the appropriate wavelength. This process is much less prone to error because it is controlled by software and is not dependent on manual provisioning by a technician. Moreover, when there is no match between the available wavelengths and the operating wavelengths of the transponders, the network software can alert the technician or the network operations center so that an unsuitable transponder can be replaced with an appropriate transponder operating at an appropriate wavelength. A transponder may be unsuitable for a variety of reasons, including, for example, because it operates at the wrong wavelength, transmission rate, or in the wrong transmission format. Additionally, a transmitter that has been installed in a switch may also be unsuitable because of a hardware failure or because of technician error during the installation process.
  • [0049]
    The aforementioned inventive plug and play arrangement for installing transponders is applicable not only to WDM communication systems of the type depicted in FIG. 1, but also to communication systems that employ more complex arrangements of transponders and switches for the purpose of providing varying degrees of redundancy to ensure that service will be maintained in the event of a failure in a component or the transmission path. Redundancy is typically provided in such systems for two failure scenarios. One is to provide protection from a transponder failure by providing a duplicate backup transponder on both ends of the service to transmit information should either of the first transponders fail. The second protects against a fiber cut by providing two diverse paths (fibers) over which a signal can travel between the source and destination, where the signal source may come from two transponders, or be switched between paths from a single transponder. In practice, the transponder failure impacts one wavelength (service) and occurs more frequently than a fiber cut, which will impact all the wavelengths in the fiber. Therefore since the network impact in these scenarios is different, the protection requirement for either of these options will depend on the type of services in the optical layer, and whether such services are protected at other layers in the network (i.e. via transmission protocol). The most reliable optical protection from a network equipment perspective is using a source pair of transponders that are simultaneously routed via different paths to a destination transponder pair. The signals are routed between each transponder via an electrical backplane, where upon failure of the signals along a working path the transponders will change the signal source to the protection path, thereby ensuring communication after a failure. The inventive plug and play arrangement advantageously facilitates the implementation of this type of redundancy because the protection transponders can always be inserted in adjacent slots, resulting in a less challenging backplane design because the degradation of high frequency electrical signals is reduced by minimizing the backplane interconnection lengths in this manner. Moreover, this plug and play arrangement may be used by the communication system to automatically restore service when a failure does arise without the need for manual reconfiguration. The forthcoming description of different protection types will be described for the purposes of this invention in the more reliable implementation, which uses redundant transponders to protect against transponder failures and fiber cuts. It should be understood that if only fiber cut protection is required, and not transponder protection, a single transponder with an optically switched path could be employed in the same geometry to reduce cost. FIGS. 4-5, which illustrate exemplary nodes incorporating such protection schemes, will be presented after the following discussion of various conventional protection schemes
  • [0050]
    A number of different well-known protection techniques may be used in connection with networks that employ nodes that incorporate backup transponders. For example, in a ring network a dedicated protection technique can be used in which two copies of the same information-bearing signal are transmitted in opposite directions around the ring. While both signals can be transmitted at the same or different wavelengths, it generally will be more efficient to use the same wavelength because this fully utilizes the ring's capacity at that wavelength while placing no restrictions on the use of other wavelengths because of wavelength blocking. While a dedicated protection technique is an extremely reliable and rapidly responsive form of protection, a disadvantage of dedicated protection is that it is extremely rare that the backup signal will ever be used, thus making it an inefficient and hence expensive form of protection. Accordingly, it is often desirable to share a backup channel path among many in-service channels since it is unlikely more than one in-service channel will fail at any one time. Such protection is referred to as shared protection and is typically implemented by reserving a single channel as a back-up channel to protect multiple channels traveling different paths on another wavelength. A disadvantage of shared protection is that restoration generally takes more time after a failure and requires more network signaling than dedicated protection because the backup channel is not already transmitting the signal at the time of failure. Since shared protection requires the backup transmitter and appropriate switches to be activated, it also has a greater probability of not restoring service because of a component failure during the restoration process. Because dedicated and shared protection schemes offer different advantages and disadvantages, different customers may prefer one over the other and thus service providers might ideally want to offer both schemes on the same network and even from the same transponder slot, if this could be arranged with minimal difficulty.
  • [0051]
    Traditional optical layer protection schemes such as the aforementioned dedicated and shared protection schemes, which employ multiple transponders to route light over diverse paths to a common destination, are fundamentally inefficient. This is particularly true because it is somewhat uncommon for the “primary” or “working” transponder to fail, and therefore the “spare” or “backup” transponder is rarely utilized. Since a network operator typically has more than one protected service at a given node, and multiple transponders are unlikely to fail at the same time, one way to leverage poor transponder utilization is to protect N different transponders with a smaller number of backup transponders. For example, in FIG. 1, one or more of the transponders 20 1-20 6 may serve as backup for the remaining transponders 20 1-20 6. Similarly, one or more of the transponders 60 1-60 6 may serve as backup for the remaining transponders 60 1-60 6. This arrangement can be called 1:N protection, where N working transponders are protected with 1 backup transponder. One problem with 1:N protection in more advanced optical networks is that the entire path through a wavelength-routed network must be reconfigured during the transition to the backup transponder unless the backup transponder can transmit at the same wavelength as the primary transponder it is replacing. Such a path reconfiguration is extremely undesirable because it requires network-wide communication and reconfiguration, which leads to an additional delay in service restoration. Moreover, if the backup transponder does not employ the same wavelength as the failed transponder, further inefficiencies arise because one or more additional wavelengths must be reserved along all potentially protected paths, thereby setting aside bandwidth which otherwise could be used for revenue generating services. For these reasons it would advantageous to protect N transponders operating at different wavelengths with a single backup transponder that is tunable so that its output can emit the same wavelength as any of the N primary transponders, should any of them fail.
  • [0052]
    The use of a reconfigurable switch with an 1:N protection scheme is highly desirable because the switch controls the coupling of both the working and protection transponders to the transmission system, which means that the switch can prevent the protection transponder from transmitting through the system until a protection state is activated. When this does occur, the switch can preferably only allow the appropriate wavelength to be coupled into the transmission system to replace the failed transponder, and this coupling can be provided at an insertion loss that is similar to original transponder. This functionality enables the working and protection transponders to offer similar optical transmission capabilities when their transmitters have the same output power, which means there could be only one code of transponder for either application. It also controls from the system perspective which transponder receives a given incoming wavelength. This arrangement isolates the remaining transponders from any errant power output arising from the working and/or protection transponders that participate in providing protection. Finally, it also allows all protection events and actions to be isolated to the individual node in which the transponder fails, which reduces the time needed to restore service and simplifies the controlling software needed to provide the restoration.
  • [0053]
    It is worth noting that a 1:N protection scheme as described above only protects against a transponder failure and not a fiber cut. That is, if all N outputs are traveling on a single fiber and the fiber is cut, all N services will be disconnected. However, it should also be noted that transponder failures generally occur much more frequently that fiber cuts, and therefore the 1:N protection scheme is a suitable solution for many applications, even without reserving bandwidth for a fiber cut. If the advantages of 1:N protection are desired while protecting for a fiber cut, a hybrid protection scheme could be employed with the present invention using 1:N transponder protection and shared protection against a fiber cut. In this embodiment, the shared protection would be implemented with a single transponder having a tunable wavelength output that circumvents fiber cuts by optically switching between two paths. Failure of the transponder would also be protected via conventional 1:N protection as described above, using a different wavelength tunable transponder. This form of protection would eliminate both the inefficiency of protection fiber paths that are rarely used, and also would eliminate the inefficiency from the need to require many backup transponders that are seldom used. The disadvantage of this approach would be a complex, longer protection switching time to configure all the switches and tunable transponders, and an inability to protect against multiple transponder failures that are sharing a single protection transponder.
  • [0054]
    Returning now to the discussion of exemplary inventive nodes incorporating various protection schemes, FIG. 4 shows a node that includes two sets of transponders 410 and 412. Each set 410 and 412 includes a series of transponders operational at the different wavelengths that correspond to the various channel wavelengths employed in the transmission system. Transponders 410 receive signal wavelengths from transmission path 400 1 via switch 414 and transmit signal wavelengths on transmission path 400 2 via switch 416 while transponders 412 receive signal wavelengths from transmission path 400 2 via switch 416 and transmit signal wavelengths on transmission path 400 1 via switch 414. By using the two transponder sets 410 and 412 instead of a single set of transponders, a degree of redundancy is provided to ensure that service will be maintained if, for example, a fiber cut occurs at a single point in either transmission path 400 1 or 400 2. For example, a fiber cut at point 420 on path 400 1 will disrupt service provided by transponders 410 but not transponders 412. Accordingly, in this situation transponders 412 can be used to maintain service. However, a fiber cut in both transmission paths 400 1 and 400 2 will disrupt service provided by both sets of transponders 410 and 412. Nevertheless, the configuration shown in FIG. 4 provides relatively high reliability because it is unlikely that there would be a simultaneous failure at multiple points in the transmission paths. Other types of failures, however, will cause all service to be interrupted. For example, should a failure occur in either of the switches 414 and 416, service provided by both sets of transponder sets 410 and 412 will be disrupted.
  • [0055]
    FIG. 5 shows another node configuration that provides an additional degree of protection relative to the configuration shown in FIG. 4. In contrast to the node in FIG. 4, which employs two switches 414 and 416, the node in FIG. 5 employs four switches 514, 516, 518 and 520. In this configuration service can be maintained even if there is a failure in one of the switches. As shown, the transponders are arranged in transponder pairs 522-527 located in adjacent slots. The individual transponders in each pair can serve as backup for the other in case of a failure. Similar to the configuration in FIG. 4, the transponders in each pair communicate with different switches. For example, in pair 522, transponder 522 1 receives and transmits via switches 514 and 516, respectively, while transponder 522 2 receives and transmits via switches 520 and 518, respectively. Since the two transponders in each pair transmit and receive on completely different switches, a failure in one switch need not disrupt service because the service provided by the impacted switch can be provided by the other transponder in the adjacent slot.
  • [0056]
    The present invention offers the requisite degree of flexibility to quickly and easily reconfigure a service to support a variety of different protection schemes such as the aforementioned dedicated, shared, or 1:N protection schemes or even other protection schemes such as Dual Ring Interworking (DRI) for example, which uses the Drop and Continue feature that is discussed later in connection with FIG. 8 to split a signal in the node so that it can be dropped at multiple locations for interconnection to network For example, referring again to FIG. 5, if transponder 522 2 is to serve as a backup for transponder 522 1, then the network software can provision the switches for either a dedicated or shared protection scheme, eliminating the need for a technician to manually reconfigure the network. Moreover, if transponder 522 2 incorporates a tunable transmitter, a dedicated protection channel may even be offered at the same wavelength as the in-service channel. The advantages that arise from the use of the inventive plug and play arrangement when reconfiguring a service for different protection schemes are similar to the advantages obtained when using the inventive arrangement to initially install transponders in a switch. However, its use in connection with services having various protection schemes is particularly advantageous because such a service installation procedure is particularly complex to perform manually. In addition, the combination of an optical backplane and the flexible switch enables any two adjacent slots to transmit on any wavelength, thereby enabling multiple protection schemes from the same configuration while minimizing the complexity of the optical interconnections at installation as well as the cost and complexity of the electrical backplane.
  • [0057]
    One disadvantage of the node configuration shown in FIG. 5 is that it is relatively expensive to implement because it requires four optical switches. In some embodiments of the invention a cost savings may be obtained by replacing one or both switches 518 and 516, which serve as add switches for adding wavelengths to the transmission system, with an arrangement of passive optical combiners such as couplers shown in FIG. 5, or alternatively, with 1×N star couplers for larger port count implementations. Each transponder may be connected to a passive coupler that in turn couples the wavelength to a series of one or more additional passive couplers that couple the resulting WDM signal to the transmission system. For instance, in FIG. 6 the add switch 518 of FIG. 5 is replaced with an arrangement of passive couplers 618. It is to be understood that FIG. 6 only shows a single transmission path 600 1 and thus does not illustrate switches 516 and 520, nor transponder pairs 522-527, which are shown in FIG. 5. In addition to its reduced cost, the use of a passive coupling arrangement is advantageous because it allows the wavelengths to pass through only a single wavelength selective element per node, which minimizes the effects of bandwidth narrowing that arise when the wavelengths pass through a series of filters, which do not, of course, exhibit ideal square filter functions. A disadvantage of this approach is that the passive coupler arrangement has a relatively large insertion loss that scales with the number of transponders connected to the arrangement. Other disadvantages are its inability to block errant wavelengths from entering the transmission system or to control the attenuation of the wavelengths when they are added to the transmission system so that the added channel power can be equalized with the other channels passing through the node. Accordingly, the arrangement shown in FIG. 6 is generally appropriate when cost is a major factor and there is an excess of transmitter power available.
  • [0058]
    While in FIG. 6 the add switch 518 of FIG. 5 is replaced with passive couplers 618, FIG. 7 shows another embodiment of the invention in which the drop switch 514 of FIG. 5 is replaced with a passive splitter 714 followed by tunable bandpass filters 715, each of which couple one of the dropped wavelengths to the appropriate transponder (not shown in FIG. 7). This all-passive configuration further reduces the cost of the node, although it may require additional optical amplifiers to accommodate the losses imparted by the passive splitters. One characteristic of this all-passive configuration is that not all the power in a dropped channel is in fact entirely dropped. Rather, because no filtering is performed, a portion of the dropped channel exits the node and continues along the transmission path. This characteristic can be advantageous when there is a need to create multiple copies of a signal or to broadcast a signal. Unfortunately, this characteristic also prevents wavelengths from being reused because crosstalk would arise between the portion of the dropped channel remaining on the transmission path and the added channel located at the same wavelength. However, the primary disadvantage of the configuration shown in FIG. 7 is that it is very bandwidth inefficient and thus unattractive unless the number of available wavelengths is greater than the total number of connections to be used in the network.
  • [0059]
    FIG. 8 shows another node that can perform the drop and continue functionality of the node in FIG. 7, but which also allows wavelengths to be reused. In this configuration two switches are employed along each transmission path. As shown, switches 816 and 818 serve as drop and add switches, respectively (see the discussion of switches 514 and 518 in FIG. 5). A passive coupler 820 preceding switch 816 splits the WDM signal traveling on transmission path 800 1 as it enters the node. One output of the passive coupler 820 is coupled to optical switch 816 and the other output of the passive coupler 820 is coupled to an input of switch 818. Switch 818 can therefore remove any wavelengths dropped by switch 816 that were not designated for multicast transmission. The capability to transmit multicast can be used in the communication network to broadcast to multiple locations from a single transponder, or to create a dual-homing diverse path for network protection of an optical signal. As discussed earlier, Dual Ring Interworking is an example of dual homing, wherein the diverse routing between two rings occurs at separate node-pairs.
  • [0060]
    The ability to reuse wavelengths within an optical network such as in FIG. 8 is one key means to improve overall network efficiency. Because there is an effective network cost to provide the facilities to transport a given wavelength, if that wavelength is used for multiple transport links within a ring or network, the cost of the wavelength is shared. Current technology requires filtering or removal of the dropped wavelength on the order of 99.9% if the wavelength is to be reused. This wavelength-dependent filtering is preferably performed while adding minimal loss to the adjacent wavelengths, which are typically only separated by 1 nm or less in current WDM systems. Technologies that are unable to meet this demanding filtering requirement with the wavelength filtering used in the drop path may also employ additional filtering to achieve the level required to reuse the same wavelength at other points in the network. The element providing this additional filtering is sometimes referred to as a clean up filter or a blocking filter. The blocking filter may be a distinct filter element or it may be integrated with the drop element itself. An example of a blocking filter with the latter configuration is shown, for example, in Duck et al, U.S. Pat. No. 5,920,411. The drop and continue configuration shown in FIG. 8 is one specific example of a blocking switch, where the passive coupler 820 does not block the wavelengths that will be dropped, and thus the second switch 818 must block the dropped wavelengths as well as adding wavelengths to the network.
  • [0061]
    Another situation addressed by the present invention arises when the transponders include tunable lasers. In this case it is important to multiplex any of the wavelengths generated by the tunable lasers onto the data stream of the network with a low and constant loss. In current systems this is accomplished with a multiplexer having ports that generally each offer low insertion loss at a single wavelength. Thus, the flexibility of the tunable laser is restricted by the multiplexer so that the laser can only be used at the single wavelength. One way to overcome this problem is by using a passive coupler that couples all wavelengths with the same insertion loss. Of course, this solution comes at the expense of higher insertion loss. The present invention, however, provides an alternative solution to this problem because the reconfigurable switch can serve as a low loss reconfigurable multiplexer. When used in cooperation with a tunable laser, any of the wavelengths generated by the laser can be multiplexed onto the data stream with low loss. This solution is particularly advantageous because it enables systems to operate in accordance with the same engineering rules for both fixed and tunable lasers, which is important in hybrid systems using fixed and tunable transponders.

Claims (43)

1. A node comprising:
a first plurality of transponders each generating and/or receiving an information-bearing optical signal at a different channel wavelength from one another;
an optical coupling arrangement transferring the channel wavelengths between a link connected to the node and the first plurality of transponders, said arrangement being adaptable to reconfigure its operational state to selectively direct different ones of the channel wavelengths from the link to different ones of the transponders without disturbing the optical path through the node traversed by any other channel wavelengths,
wherein said optical coupling arrangement includes a reconfigurable optical switch having at least three ports, said reconfigurable optical switch being adaptable to reconfigure its operational state to receive at a plurality of the ports any of the channel wavelengths at which the first plurality of transponders operate and direct said channel wavelengths to any remaining ones of the ports of the optical switch; and
a communications and configuration arrangement transferring data identifying the respective channel wavelengths at which the transponders operate from the transponders to the optical coupling arrangement and, in response to the transferred data, reconfiguring the operational state of the optical coupling arrangement.
2. The node of claim 1, wherein the first plurality of transponders respectively include a plurality of receivers receiving the information-bearing optical signals, and further wherein the communications and configuration arrangement reconfigures the operational state of at least the portion of the optical coupling arrangement transferring the channel wavelengths from the link to the first plurality of transponders so that the transponders can receive optical signals at the channel wavelengths at which they respectively operate.
3. The node of claim 1, wherein said transponders each include an identifying element containing data identifying the respective channel wavelengths at which the transponders operate, said optical coupling arrangement having a receiving element for obtaining the data contained in the identifying element.
4. The node of claim 1 wherein said optical coupling arrangement includes a tunable coupling arrangement for selectively transferring the different ones of the channel wavelengths from the link to the first plurality of transponders and a passive coupling arrangement for directing the channel wavelengths from transponders to the link.
5. The node of claim 1 wherein said reconfigurable optical switch is adaptable to reconfigure its operational state to receive at any of the ports any of the channel wavelengths at which the first plurality of transponders operate and direct said channel wavelengths to any of the other ports of the optical switch.
6. The node of claim 1, further comprising a second plurality of transponders serving as backup transponders in the event of a failure in one or more of the transponders in the first plurality of transponders.
7. The node of claim 1 wherein said optical coupling arrangement includes at least four reconfigurable optical switches, wherein a first transponder in each of the transponder pairs transmits and receives channel wavelengths to first and second ones of the reconfigurable optical switches, respectively, and a second transponder in each of the transponder pairs transmits and receives channel wavelengths to third and fourth ones of the reconfigurable optical switches, respectively.
8. The node of claim 1 wherein said optical coupling arrangement includes at least four reconfigurable optical switches, wherein a first transponder in each of the transponder pairs transmits and receives channel wavelengths to first and second ones of the reconfigurable optical switches, respectively, and a second transponder in each of the transponder pairs transmits and receives channel wavelengths to third and fourth ones of the reconfigurable optical switches, respectively.
9. A node comprising:
a first plurality of transponders each generating and/or receiving an information-bearing optical signal at a different channel wavelength from one another;
an optical coupling arrangement transferring the channel wavelengths between a link connected to the node and the first plurality of transponders, said arrangement being adaptable to reconfigure its operational state to selectively direct different ones of the channel wavelengths from the link to different ones of the transponders without disturbing the optical path through the node traversed by any other channel wavelengths;
a communications and configuration arrangement transferring data identifying the respective channel wavelengths at which the transponders operate from the transponders to the optical coupling arrangement and, in response to the transferred data, reconfiguring the operational state of the optical coupling arrangement; and
wherein said optical coupling arrangement includes at least one reconfigurable optical switch, said reconfigurable optical switch being adaptable to reconfigure its operational state to drop channel wavelengths to the first plurality of transponders.
10. The node of claim 9 further comprising at least a second transponder serving as a backup transponder in the event of a failure in one of the first plurality of transponders.
11. The node of claim 9 wherein said optical coupling arrangement includes at least one two reconfigurable optical switches each having at least three ports, a first of said reconfigurable optical switches being adaptable to reconfigure its operational state to drop channel wavelengths to the first plurality of transponders and receive channel wavelengths from the second transponder, a second of said reconfigurable optical switches being adaptable to reconfigure its operational state to drop channel wavelengths to the second transponder and receive channel wavelengths from the first plurality of transponders.
12. The node of claim 11, wherein the second transponder includes a second plurality of transponders and the first and second plurality of transponders are arranged in transponder pairs comprising transponders from each of the first and second plurality of transponders.
13. The node of claim 12, wherein the transponders in each of the transponder pairs are located in adjacent slots in electrical connection with one another for transferring electrical data signals therebetween.
14. The node of claim 12, wherein the transponders in each of the transponder pairs operate at a common channel wavelength.
15. The node of claim 12, wherein, the transponders in at least one of the transponder pairs are operable at either a common channel wavelength or a different channel wavelength.
16. The node of claim 1, further comprising a blocking filtering element for filtering from the link channel wavelengths dropped by the optical coupling arrangement.
17. The node of claim 3, wherein the identifying element is a serial or model number and the receiving element is an alphanumerical input through which the data is manually received.
18. The node of claim 3, wherein the identifying element is a memory module and the receiving element includes a processor for reading the data from the memory module when the transducer is coupled to the optical coupling arrangement.
19. The node of claim 1, wherein the first plurality of transponders are respectively located in a plurality of transponder slots each of which optically communicates with a predetermined one of the ports of the optical switch.
20. The node of claim 1, wherein the data identifying the respective channel wavelengths at which the transponders operate is the respective channel wavelengths themselves.
21. A method for assigning channel wavelengths to a plurality of ports of an optical switch, said method comprising the steps of:
receiving a plurality of transmitters in the plurality of the ports of the optical switch, said transmitters being operable at distinct wavelengths from one another, said reconfigurable optical switch being adaptable to reconfigure its operational state to receive at any of the ports any of the wavelengths at which the plurality of transponders operate and direct said wavelengths to any of the other ports of the optical switch;
obtaining data from the transmitters identifying one or more operating characteristics of the transmitters, said one or more operating characteristics including the respective distinct wavelengths at which the transmitters operate; and
based on the data obtained from the transmitters, configuring the optical switch so that the plurality of ports are assigned channel wavelengths respectively corresponding to the distinct wavelengths of the transmitters received in the plurality of ports.
22. The method of claim 21 wherein the step of obtaining the data includes the step of receiving data manually input by a technician.
23. The method of claim 21 wherein the step of obtaining data includes the step of reading the data directly from the transmitter.
24. The method of claim 23 wherein the data is read from a memory module.
25. The method of claim 24 wherein said memory module is a read-only memory.
26. The method of claim 24 wherein said memory module is a random-access memory.
27. The method of claim 24 wherein said memory module is an EPROM.
28. The method of claim 24 wherein said memory module is read by a controller located in the optical switch.
29. The method of claim 21 wherein said data is a serial or model number of the transmitter.
30. The method of claim 21 wherein at least one of the transmitters is incorporated in an optical transponder.
31. The method of claim 21 wherein at least one of said transmitters is a tunable transmitter tunable to a plurality of wavelengths respectively corresponding to a plurality of channel wavelengths employed by a transmission system in which the optical switch is incorporated.
32. The method of claim 21 further comprising the step of tuning a first of the transmitters to a first wavelength corresponding to a channel wavelength employed by a transmission system in which the optical switch is incorporated, wherein the step of configuring the optical switch includes assigning the first wavelength to the port of the optical switch in which said first transmitter is received.
33. The method of claim 32 wherein the tuning step includes the step of selecting the first wavelength corresponding to the channel wavelength, said selecting step being performed by a network element located in the transmission system.
34. The method of claim 21 further comprising the step of generating an alert if one or more of the operating characteristics of one of the transmitters does not correspond to a prescribed operating characteristic.
35. The method of claim 34 wherein a comparison between the operating characteristics of said one transmitter and the prescribed operating characteristic is performed by a network element located in a transmission system in which the optical switch is incorporated.
36. The method of claim 35 wherein the network element is a network management element operating at a highest level of network control.
37. The method of claim 36 wherein the network management element employs a routing and wavelength assignment algorithm.
38. The method of claim 21 further comprising the step of generating an alert if a fault is detected prior to completion of the step of configuring the optical switch.
39. The method of claim 21 wherein said at least one operating characteristic of the transmitters further includes a power level.
40. The method of claim 21 wherein said at least one operating characteristic of the transmitters further includes a transmission format.
41. The method of claim 21 wherein the receiving step includes the step of receiving the plurality of transmitters in a plurality of transponder slots each of which optically communicates with a predetermined one of the ports of the optical switch.
42. The method of claim 41 further comprising the step of optically coupling in a predetermined manner the plurality of transponder slots with the ports of the optical switch, said coupling step being performed by an optical backplane.
43. The method of claim 21 wherein the data obtained from the transmitters is the distinct wavelength at which the transmitters operate.
US12620512 2001-03-16 2009-11-17 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch Abandoned US20100098406A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US27631001 true 2001-03-16 2001-03-16
US10099890 US7620323B2 (en) 2001-03-16 2002-03-15 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch
US12620512 US20100098406A1 (en) 2001-03-16 2009-11-17 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12620512 US20100098406A1 (en) 2001-03-16 2009-11-17 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US10099890 Continuation US7620323B2 (en) 2001-03-16 2002-03-15 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch

Publications (1)

Publication Number Publication Date
US20100098406A1 true true US20100098406A1 (en) 2010-04-22

Family

ID=23056135

Family Applications (9)

Application Number Title Priority Date Filing Date
US10099888 Abandoned US20020145782A1 (en) 2001-03-16 2002-03-15 Method and apparatus for transferring WDM signals between different wavelength division multiplexed optical communications systems in an optically transparent manner
US10099890 Active 2023-12-28 US7620323B2 (en) 2001-03-16 2002-03-15 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch
US10098746 Active US6614953B2 (en) 2001-03-16 2002-03-15 Modular all-optical cross-connect
US10099891 Active 2028-10-09 US7676157B2 (en) 2001-03-16 2002-03-15 Method and apparatus for providing gain equalization to an optical signal in an optical communication system
US10632670 Active 2023-12-05 US7469080B2 (en) 2001-03-16 2003-08-01 Modular all-optical cross-connect
US12259946 Active 2024-01-01 US9258628B2 (en) 2001-03-16 2008-10-28 Method and apparatus for transferring WDM signals between different wavelength division multiplexed optical communications systems in an optically transparent manner
US12343422 Active US7738748B2 (en) 2001-03-16 2008-12-23 Modular all-optical cross-connect
US12620512 Abandoned US20100098406A1 (en) 2001-03-16 2009-11-17 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch
US15003037 Pending US20160142172A1 (en) 2001-03-16 2016-01-21 Ring network including at least one subtending ring originating and terminating at a central-office node

Family Applications Before (7)

Application Number Title Priority Date Filing Date
US10099888 Abandoned US20020145782A1 (en) 2001-03-16 2002-03-15 Method and apparatus for transferring WDM signals between different wavelength division multiplexed optical communications systems in an optically transparent manner
US10099890 Active 2023-12-28 US7620323B2 (en) 2001-03-16 2002-03-15 Method and apparatus for interconnecting a plurality of optical transducers with a wavelength division multiplexed optical switch
US10098746 Active US6614953B2 (en) 2001-03-16 2002-03-15 Modular all-optical cross-connect
US10099891 Active 2028-10-09 US7676157B2 (en) 2001-03-16 2002-03-15 Method and apparatus for providing gain equalization to an optical signal in an optical communication system
US10632670 Active 2023-12-05 US7469080B2 (en) 2001-03-16 2003-08-01 Modular all-optical cross-connect
US12259946 Active 2024-01-01 US9258628B2 (en) 2001-03-16 2008-10-28 Method and apparatus for transferring WDM signals between different wavelength division multiplexed optical communications systems in an optically transparent manner
US12343422 Active US7738748B2 (en) 2001-03-16 2008-12-23 Modular all-optical cross-connect

Family Applications After (1)

Application Number Title Priority Date Filing Date
US15003037 Pending US20160142172A1 (en) 2001-03-16 2016-01-21 Ring network including at least one subtending ring originating and terminating at a central-office node

Country Status (7)

Country Link
US (9) US20020145782A1 (en)
JP (3) JP2004536484A (en)
KR (5) KR20040052492A (en)
CN (4) CN1502183A (en)
CA (4) CA2441059A1 (en)
EP (3) EP1371162A4 (en)
WO (4) WO2002075369A3 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120148231A1 (en) * 2004-02-02 2012-06-14 Farley Joseph D Fiber optic multiplex modem
WO2013164044A1 (en) 2012-05-04 2013-11-07 Deutsche Telekom Ag Method and device for constructing and operating a modular, highly scalable, very simple, cost-efficient and sustainable transparent optically-routed network for network capacities of greater than 1 petabit(s)
US9882643B2 (en) 2012-05-04 2018-01-30 Deutsche Telekom Ag Method and device for setting up and operating a modular, highly scalable, very simple, cost-efficient and enduring transparent optically routed network for network capacities of greater than 1 Petabit/s

Families Citing this family (123)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6721508B1 (en) 1998-12-14 2004-04-13 Tellabs Operations Inc. Optical line terminal arrangement, apparatus and methods
US6618520B2 (en) * 1999-11-09 2003-09-09 Texas Instruments Incorporated Micromirror optical switch
US6922530B1 (en) 2000-04-06 2005-07-26 Fujitsu Limited Method and apparatus for optical channel switching in an optical add/drop multiplexer
US6633694B2 (en) * 2000-09-29 2003-10-14 Texas Instruments Incorporated Micromirror optical switch
WO2002075369A3 (en) * 2001-03-16 2003-05-01 Photuris Inc Modular all-optical cross-connect
US6941071B2 (en) * 2001-05-25 2005-09-06 International Business Machines Corporation Test method and apparatus for parallel optical transceivers using serial equipment
GB0121308D0 (en) 2001-09-03 2001-10-24 Thomas Swan & Company Ltd Optical processing
JP3693020B2 (en) * 2002-01-22 2005-09-07 日本電気株式会社 Communication system using wavelength division multiplexing optical transmission equipment and apparatus
GB0203037D0 (en) 2002-02-08 2002-03-27 Marconi Comm Ltd Telecommunications networks
US20030174935A1 (en) * 2002-03-14 2003-09-18 Miller Samuel Lee Channel balancer for WDM optical units
US7085242B2 (en) * 2002-03-22 2006-08-01 Telcordia Technologies, Inc. Virtual IP topology reconfiguration migration
US7116905B2 (en) * 2002-03-27 2006-10-03 Fujitsu Limited Method and system for control signaling in an open ring optical network
US7076163B2 (en) * 2002-03-27 2006-07-11 Fujitsu Limited Method and system for testing during operation of an open ring optical network
US7231148B2 (en) * 2002-03-28 2007-06-12 Fujitsu Limited Flexible open ring optical network and method
US7072584B1 (en) * 2002-04-22 2006-07-04 Atrica Israel Ltd. Network hub employing 1:N optical protection
US7283739B2 (en) * 2002-05-29 2007-10-16 Fujitsu Limited Multiple subnets in an optical ring network and method
US7184663B2 (en) 2002-05-29 2007-02-27 Fujitsu Limited Optical ring network with hub node and method
US7283740B2 (en) * 2002-05-29 2007-10-16 Fujitsu Limited Optical ring network with optical subnets and method
US7075712B2 (en) 2002-05-30 2006-07-11 Fujitsu Limited Combining and distributing amplifiers for optical network and method
US6842562B2 (en) * 2002-05-30 2005-01-11 Fujitsu Network Communications, Inc. Optical add/drop node and method
US7085496B2 (en) 2002-05-30 2006-08-01 Fujitsu Limited Passive add/drop amplifier for optical networks and method
US7813601B2 (en) * 2002-09-06 2010-10-12 Texas Instruments Incorporated Reconfigurable optical add/drop multiplexer
US20040052530A1 (en) * 2002-09-17 2004-03-18 Cechan Tian Optical network with distributed sub-band rejections
JP4183681B2 (en) * 2002-09-23 2008-11-19 ビーエーエスエフ ソシエタス・ヨーロピアBasf Se Thin films of oxide materials having a high dielectric constant
US7715713B1 (en) * 2002-09-30 2010-05-11 Meriton Networks Us Inc. Method and apparatus for providing multiple optical channel protection switching mechanisms in optical rings
US7321729B2 (en) * 2003-05-29 2008-01-22 Fujitsu Limited Optical ring network with selective signal regeneration and wavelength conversion
US20050019034A1 (en) * 2003-07-25 2005-01-27 Fujitsu Network Communications, Inc. System and method for communicating optical traffic between ring networks
US7483636B2 (en) * 2003-07-28 2009-01-27 Fujitsu Limited Optical network with sub-band rejection and bypass
DE10343615A1 (en) * 2003-09-20 2005-04-14 Marconi Communications Gmbh Network node for an optical communications network
US20050095001A1 (en) * 2003-10-29 2005-05-05 Fujitsu Limited Method and system for increasing network capacity in an optical network
US7483637B2 (en) 2003-11-26 2009-01-27 Fujitsu Limited Optical ring network with optical subnets and method
US20050175346A1 (en) * 2004-02-10 2005-08-11 Fujitsu Limited Upgraded flexible open ring optical network and method
US7369765B2 (en) * 2004-02-26 2008-05-06 Fujitsu Limited Optical network with selective mode switching
US20050196169A1 (en) * 2004-03-03 2005-09-08 Fujitsu Limited System and method for communicating traffic between optical rings
US20050232565A1 (en) * 2004-04-16 2005-10-20 Ross Heggestad Normal through optical panel
US7257288B1 (en) 2004-04-23 2007-08-14 Nistica, Inc. Tunable optical routing systems
US7408639B1 (en) 2004-04-23 2008-08-05 Nistica, Inc. Tunable optical routing systems
US20050286896A1 (en) * 2004-06-29 2005-12-29 Fujitsu Limited Hybrid optical ring network
US7450851B2 (en) * 2004-08-27 2008-11-11 Fujitsu Limited System and method for modularly scalable architecture for optical networks
US7639677B2 (en) * 2004-11-02 2009-12-29 Electronics And Telecommunications Research Institute Optical transponder having switching function
US7376322B2 (en) * 2004-11-03 2008-05-20 Adc Telecommunications, Inc. Fiber optic module and system including rear connectors
US7826743B2 (en) * 2004-11-22 2010-11-02 Fujitsu Limited Optical ring network for extended broadcasting
JP4593267B2 (en) * 2004-12-28 2010-12-08 富士通株式会社 Optical node and the optical add drop apparatus
US7120360B2 (en) * 2005-01-06 2006-10-10 Fujitsu Limited System and method for protecting traffic in a hubbed optical ring network
US7570844B2 (en) * 2005-01-18 2009-08-04 Doron Handelman Photonic integrated circuit device and elements thereof
US7412147B2 (en) * 2005-03-15 2008-08-12 Adc Telecommunications, Inc. Normal through optical panel
US7376323B2 (en) * 2005-05-25 2008-05-20 Adc Telecommunications, Inc. Fiber optic adapter module
US7400813B2 (en) 2005-05-25 2008-07-15 Adc Telecommunications, Inc. Fiber optic splitter module
US7636507B2 (en) * 2005-06-17 2009-12-22 Adc Telecommunications, Inc. Compact blind mateable optical splitter
US8428461B2 (en) * 2005-06-22 2013-04-23 Tellabs Operations, Inc. Apparatus for managing an optical signal
US7346254B2 (en) * 2005-08-29 2008-03-18 Adc Telecommunications, Inc. Fiber optic splitter module with connector access
JP4673712B2 (en) * 2005-09-28 2011-04-20 富士通株式会社 Network configuration device and network configuration method
US7526198B1 (en) * 2005-11-30 2009-04-28 At&T Corp. Methods of restoration in an ultra-long haul optical network
US7639946B2 (en) * 2006-01-06 2009-12-29 Fujitsu Limited Distribution node for an optical network
US7418181B2 (en) 2006-02-13 2008-08-26 Adc Telecommunications, Inc. Fiber optic splitter module
KR100819035B1 (en) 2006-09-29 2008-04-03 한국전자통신연구원 Photonic cross-connector system, wdm system using the same photonic cross-connector system and optical communication network based in the same wdm system
KR100833501B1 (en) * 2006-11-17 2008-05-29 한국전자통신연구원 Multi-degree cross-connector system, operating method and optical communication network using the same
US7391954B1 (en) 2007-05-30 2008-06-24 Corning Cable Systems Llc Attenuated optical splitter module
US20080298743A1 (en) * 2007-05-31 2008-12-04 Konstantinos Saravanos Microsplitter module for optical connectivity
US20080298748A1 (en) * 2007-05-31 2008-12-04 Terry Dean Cox Direct-connect optical splitter module
CN101355430B (en) * 2007-07-27 2012-02-29 华为技术有限公司 Exchange frame, cluster router
US8798427B2 (en) 2007-09-05 2014-08-05 Corning Cable Systems Llc Fiber optic terminal assembly
US7885505B2 (en) * 2007-10-22 2011-02-08 Adc Telecommunications, Inc. Wavelength division multiplexing module
US7536075B2 (en) * 2007-10-22 2009-05-19 Adc Telecommunications, Inc. Wavelength division multiplexing module
EP2071377B1 (en) * 2007-12-12 2012-04-18 JDS Uniphase Corporation Packaging a reconfigurable optical add-drop module
US8107816B2 (en) 2008-01-29 2012-01-31 Adc Telecommunications, Inc. Wavelength division multiplexing module
US8045854B2 (en) * 2008-02-07 2011-10-25 Jds Uniphase Corporation M×N wavelength selective optical switch
US8213794B2 (en) * 2008-02-12 2012-07-03 Nec Laboratories America, Inc. Programmable optical network architecture
EP2255542B1 (en) * 2008-03-05 2016-12-07 Tellabs Operations, Inc. Constructing large wavelength selective switches using parallelism
US8943509B2 (en) * 2008-03-21 2015-01-27 International Business Machines Corporation Method, apparatus, and computer program product for scheduling work in a stream-oriented computer system with configurable networks
US8125984B2 (en) * 2008-03-21 2012-02-28 International Business Machines Corporation Method, system, and computer program product for implementing stream processing using a reconfigurable optical switch
EP2335364A4 (en) 2008-08-08 2012-06-27 Hewlett Packard Development Co Methods and systems for implementing high-radix switch topologies on relatively lower-radix switch physical networks
US8031703B2 (en) 2008-08-14 2011-10-04 Dell Products, Lp System and method for dynamic maintenance of fabric subsets in a network
WO2010040256A1 (en) 2008-10-09 2010-04-15 Corning Cable Systems Llc Fiber optic terminal having adapter panel supporting both input and output fibers from an optical splitter
US8879882B2 (en) 2008-10-27 2014-11-04 Corning Cable Systems Llc Variably configurable and modular local convergence point
US8396366B2 (en) * 2008-11-10 2013-03-12 Cisco Technology, Inc. Optical safety implementation in protection switching modules
EP2380054A1 (en) * 2009-01-15 2011-10-26 ADC Telecommunications, INC. Fiber optic module, chassis and adapter
US8218969B2 (en) * 2009-03-18 2012-07-10 Cisco Technology, Inc. OFDM transponder interface with variable bit transfer rate in optical communications systems
EP2237091A1 (en) 2009-03-31 2010-10-06 Corning Cable Systems LLC Removably mountable fiber optic terminal
US8467651B2 (en) 2009-09-30 2013-06-18 Ccs Technology Inc. Fiber optic terminals configured to dispose a fiber optic connection panel(s) within an optical fiber perimeter and related methods
US9547144B2 (en) 2010-03-16 2017-01-17 Corning Optical Communications LLC Fiber optic distribution network for multiple dwelling units
US8792767B2 (en) 2010-04-16 2014-07-29 Ccs Technology, Inc. Distribution device
US20110262143A1 (en) * 2010-04-21 2011-10-27 Nec Laboratories America, Inc. Roadm systems and methods of operation
US8412042B2 (en) * 2010-04-21 2013-04-02 Cisco Technology, Inc. Innovative architecture for fully non blocking service aggregation without O-E-O conversion in a DWDM multiring interconnection node
EP2564250A4 (en) 2010-04-27 2013-11-13 Adc Comm Shanghai Co Ltd Fiber optic module and chassis
US8300995B2 (en) 2010-06-30 2012-10-30 Jds Uniphase Corporation M X N WSS with reduced optics size
US8547828B2 (en) * 2010-08-03 2013-10-01 Fujitsu Limited Method and system for implementing network element-level redundancy
US8553531B2 (en) * 2010-08-03 2013-10-08 Fujitsu Limited Method and system for implementing network element-level redundancy
JP5609463B2 (en) * 2010-09-14 2014-10-22 富士通株式会社 Transmission device and a control device, as well as erroneous signal line connection detection method
JP5617503B2 (en) * 2010-09-30 2014-11-05 富士通株式会社 Optical network relay device
WO2012054454A3 (en) 2010-10-19 2012-08-02 Corning Cable Systems Llc Transition box for multiple dwelling unit fiber optic distribution network
US9182563B2 (en) 2011-03-31 2015-11-10 Adc Telecommunications, Inc. Adapter plate for fiber optic module
US8768167B2 (en) * 2011-04-29 2014-07-01 Telcordia Technologies, Inc. System and method for automated provisioning of services using single step routing and wavelength assignment algorithm in DWDM networks
US8842947B2 (en) * 2011-06-03 2014-09-23 Futurewei Technologies, Inc. Method and apparatus for colorless add
US9417401B2 (en) 2011-09-06 2016-08-16 Commscope Technologies Llc Adapter for fiber optic module
EP2582152A1 (en) * 2011-10-12 2013-04-17 ADVA Optical Networking SE Remote node and network architecture and data transmission method for a fiber-optic network, especially for low bit-rate data transmission
US9219546B2 (en) 2011-12-12 2015-12-22 Corning Optical Communications LLC Extremely high frequency (EHF) distributed antenna systems, and related components and methods
CN102572621A (en) * 2012-02-02 2012-07-11 中兴通讯股份有限公司 Optical module and wavelength division multiplexing system
US8995832B2 (en) * 2012-04-02 2015-03-31 Nec Laboratories America, Inc. Transponder Aggregator-based optical loopback in a MD-ROADM
WO2013162567A1 (en) * 2012-04-26 2013-10-31 Hewlett-Packard Development Company, L.P. Optical slab
US9004778B2 (en) 2012-06-29 2015-04-14 Corning Cable Systems Llc Indexable optical fiber connectors and optical fiber connector arrays
JP6007983B2 (en) * 2012-07-02 2016-10-19 日本電気株式会社 Optical branching device and an optical branching METHOD
US9274299B2 (en) 2012-08-29 2016-03-01 International Business Machines Corporation Modular optical backplane and enclosure
US9049500B2 (en) 2012-08-31 2015-06-02 Corning Cable Systems Llc Fiber optic terminals, systems, and methods for network service management
US8768116B2 (en) * 2012-09-28 2014-07-01 Avago Technologies General Ip (Singapore) Pte. Ltd. Optical cross-connect assembly and method
US8909019B2 (en) 2012-10-11 2014-12-09 Ccs Technology, Inc. System comprising a plurality of distribution devices and distribution device
WO2014078940A1 (en) * 2012-11-26 2014-05-30 Viscore Technologies Inc. Methods and systems for passive optical switching
US9054955B2 (en) 2012-12-30 2015-06-09 Doron Handelman Apparatus and methods for enabling recovery from failures in optical networks
FR3002393B1 (en) * 2013-02-15 2016-06-24 Thales Sa Architecture for transmitting information including application avionics embarquee
US9497519B2 (en) * 2013-03-18 2016-11-15 Oplink Communications, Inc. Twin multicast switch
WO2015016841A1 (en) * 2013-07-30 2015-02-05 Hewlett-Packard Development Company, L.P. Two-dimensional torus topology
US9819436B2 (en) 2013-08-26 2017-11-14 Coriant Operations, Inc. Intranodal ROADM fiber management apparatuses, systems, and methods
US9344187B2 (en) * 2013-09-17 2016-05-17 Doron Handelman Apparatus and methods for enabling recovery in optical networks
US9301030B2 (en) 2013-11-11 2016-03-29 Commscope Technologies Llc Telecommunications module
CN105122681A (en) 2013-12-31 2015-12-02 华为技术有限公司 Optical transmitter, transmission method, optical receiver and reception method
US20160327746A1 (en) * 2014-01-25 2016-11-10 Hewlett-Packard Development Company, L.P. Bidirectional optical multiplexing employing a high contrast grating
US9699074B2 (en) * 2014-04-10 2017-07-04 Fujitsu Limited Efficient utilization of transceivers for shared restoration in flexible grid optical networks
US9395509B2 (en) 2014-06-23 2016-07-19 Commscope Technologies Llc Fiber cable fan-out assembly and method
US9429712B2 (en) 2014-07-23 2016-08-30 Ii-Vi Incorporated Dual-ganged optical switch
US20170230116A1 (en) * 2014-08-15 2017-08-10 Hewlett Packard Enterprise Development Lp Optical mode matching
WO2016037262A8 (en) * 2014-09-09 2016-04-21 Viscore Technologies Inc. Low latency optically distributed dynamic optical interconnection networks
JP2016161802A (en) * 2015-03-03 2016-09-05 富士通株式会社 A variable optical attenuator and the optical module
CN105572818A (en) * 2015-12-29 2016-05-11 江苏奥雷光电有限公司 Multichannel parallel light emitting device and multi-mode long-distance transmission system

Citations (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5267309A (en) * 1990-11-20 1993-11-30 Alcatel Network Systems, Inc. Telephone line unit having programmable read-only memory
US5555477A (en) * 1992-04-08 1996-09-10 Hitachi, Ltd. Optical transmission system constructing method and system
US5793909A (en) * 1996-09-09 1998-08-11 Lucent Technologies Inc. Optical monitoring and test access module
US5920414A (en) * 1995-03-22 1999-07-06 Kabushiki Kaisha Toshiba Wavelength division multiplexing optical transmission apparatus and optical repeater
US5953141A (en) * 1996-10-03 1999-09-14 International Business Machines Corporation Dynamic optical add-drop multiplexers and wavelength-routing networks with improved survivability and minimized spectral filtering
US5995256A (en) * 1997-09-30 1999-11-30 Mci Communications Corporation Method and system for managing optical subcarrier reception
US5999288A (en) * 1998-02-02 1999-12-07 Telcordia Technologies, Inc. Connection set-up and path assignment in wavelength division multiplexed ring networks
US6067389A (en) * 1998-07-27 2000-05-23 Lucent Technologies Inc. Wavelength-selective optical cross-connect
US6081359A (en) * 1997-01-28 2000-06-27 Nec Corporation Transmitting apparatus and receiving apparatus for wavelength-division-multiplex signal transmission
US6084694A (en) * 1997-08-27 2000-07-04 Nortel Networks Corporation WDM optical network with passive pass-through at each node
US6101011A (en) * 1997-05-29 2000-08-08 Ciena Corporation Modulation format adjusting optical transponders
US6108113A (en) * 1995-12-29 2000-08-22 Mci Communications Corporation Method and system for transporting ancillary network data
US6154728A (en) * 1998-04-27 2000-11-28 Lucent Technologies Inc. Apparatus, method and system for distributed and automatic inventory, status and database creation and control for remote communication sites
US6169994B1 (en) * 1998-04-02 2001-01-02 Lucent Technologies, Inc. Method for creating and modifying similar and dissimilar databases for use in hardware equipment configurations for telecommunication systems
US6195186B1 (en) * 1996-12-04 2001-02-27 Nec Corporation Optical WDM ring network
US6256125B1 (en) * 1997-04-30 2001-07-03 Nec Corporation WDM optical transmission system
US6272154B1 (en) * 1998-10-30 2001-08-07 Tellium Inc. Reconfigurable multiwavelength network elements
US6288811B1 (en) * 2000-10-17 2001-09-11 Seneca Networks WDM optical communication system with channels supporting multiple data formats
US6295149B1 (en) * 1997-01-15 2001-09-25 Pirelli Cavi E Sistemi S.P.A. System and method of telecommunication with wavelength division multiplexing comprising a demultiplexer
US6321255B1 (en) * 1998-04-10 2001-11-20 Cisco Technology, Inc. Extensible storage of network device identification information
US6411412B1 (en) * 2000-12-08 2002-06-25 Seneca Networks WDM optical communication network with data bridging plural optical channels between optical waveguides
US6414765B1 (en) * 2000-03-07 2002-07-02 Corning, Inc. Protection switch in a two-fiber optical channel shared protection ring
US6516105B1 (en) * 2000-10-10 2003-02-04 Teradyne, Inc. Optical backplane assembly and method of making same
US6587470B1 (en) * 1999-03-22 2003-07-01 Cisco Technology, Inc. Flexible cross-connect with data plane
US20030163555A1 (en) * 2001-02-28 2003-08-28 Abdella Battou Multi-tiered control architecture for adaptive optical networks, and methods and apparatus therefor
US6631222B1 (en) * 2000-05-16 2003-10-07 Photuris, Inc. Reconfigurable optical switch
US6697546B2 (en) * 2000-03-21 2004-02-24 Fujitsu Limited Optical node system and switched connection method
US20040085345A1 (en) * 1999-05-26 2004-05-06 Fujitsu Network Communications, Inc., A California Corporation Cross-connect management with display selectable by inputting endpoints
US6856594B1 (en) * 1999-08-09 2005-02-15 Fujitsu Limited ATM switching system and method for switchover between working channel and protection channel in an ATM network
US7136586B2 (en) * 2000-02-18 2006-11-14 Marconi Uk Intellectual Property Ltd. Optical communication system

Family Cites Families (45)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US615157A (en) * 1898-11-29 Traction-wheel
US5429803A (en) * 1991-04-18 1995-07-04 Lamina, Inc. Liquid specimen container and attachable testing modules
JPH08278523A (en) * 1995-04-05 1996-10-22 Hitachi Ltd Light amplifier
US5504609A (en) * 1995-05-11 1996-04-02 Ciena Corporation WDM optical communication system with remodulators
US5583683A (en) * 1995-06-15 1996-12-10 Optical Corporation Of America Optical multiplexing device
US5557439A (en) * 1995-07-25 1996-09-17 Ciena Corporation Expandable wavelength division multiplexed optical communications systems
US5712932A (en) * 1995-08-08 1998-01-27 Ciena Corporation Dynamically reconfigurable WDM optical communication systems with optical routing systems
US5870216A (en) * 1995-10-26 1999-02-09 Trw Inc. Splitterless optical broadcast switch
US6201909B1 (en) * 1996-10-25 2001-03-13 Arroyo Optics, Inc. Wavelength selective optical routers
US6005694A (en) * 1995-12-28 1999-12-21 Mci Worldcom, Inc. Method and system for detecting optical faults within the optical domain of a fiber communication network
US5608825A (en) * 1996-02-01 1997-03-04 Jds Fitel Inc. Multi-wavelength filtering device using optical fiber Bragg grating
US5774245A (en) * 1996-07-08 1998-06-30 Worldcom Network Services, Inc. Optical cross-connect module
US6005697A (en) * 1996-07-23 1999-12-21 Macro-Vision Communications, L.L.C. Multi-wavelength cross-connect optical network
US6288810B1 (en) * 1996-07-31 2001-09-11 Pirelli Cavi E Sistemi S.P.A. Device for adding and dropping optical signals
US5909295A (en) * 1996-11-06 1999-06-01 Li; Jinghui Hybrid bi-directional wavelength division multiplexing device
US5881199A (en) * 1996-12-02 1999-03-09 Lucent Technologies Inc. Optical branching device integrated with tunable attenuators for system gain/loss equalization
US6028689A (en) * 1997-01-24 2000-02-22 The United States Of America As Represented By The Secretary Of The Air Force Multi-motion micromirror
US6046833A (en) * 1997-02-10 2000-04-04 Optical Networks, Inc. Method and apparatus for operation, protection, and restoration of heterogeneous optical communication networks
US6154587A (en) * 1997-03-21 2000-11-28 Oki Electric Industry Co., Ltd. Optical cross connector apparatus
KR100265865B1 (en) * 1997-06-16 2000-09-15 윤덕용 All-fiber acousto-optic tunable filter
US6151157A (en) * 1997-06-30 2000-11-21 Uniphase Telecommunications Products, Inc. Dynamic optical amplifier
WO1999035522A1 (en) 1998-01-05 1999-07-15 Corning Incorporated Add/drop optical multiplexing device
JP3085274B2 (en) 1998-01-19 2000-09-04 日本電気株式会社 Optical transmitter
US6097859A (en) 1998-02-12 2000-08-01 The Regents Of The University Of California Multi-wavelength cross-connect optical switch
US6351581B1 (en) * 1998-03-17 2002-02-26 Agere Systems Optoelectronics Guardian Corp. Optical add-drop multiplexer having an interferometer structure
CN1179510C (en) * 1998-06-25 2004-12-08 艾利森电话股份有限公司 Method and wavelength selective switching for switching optical wavelengths
US6195187B1 (en) * 1998-07-07 2001-02-27 The United States Of America As Represented By The Secretary Of The Air Force Wavelength-division multiplexed M×N×M cross-connect switch using active microring resonators
US6212315B1 (en) * 1998-07-07 2001-04-03 Lucent Technologies Inc. Channel power equalizer for a wavelength division multiplexed system
US6449073B1 (en) * 1998-07-21 2002-09-10 Corvis Corporation Optical communication system
US6466341B1 (en) * 1998-08-03 2002-10-15 Agere Systems Guardian Corp. Add/drop filter for a multi-wavelength lightwave system
GB9823015D0 (en) * 1998-10-22 1998-12-16 Hewlett Packard Co Optical switching interfaces
US6256430B1 (en) * 1998-11-23 2001-07-03 Agere Systems Inc. Optical crossconnect system comprising reconfigurable light-reflecting devices
US6192782B1 (en) * 1998-12-31 2001-02-27 John W. Rogers Torque control means for hydraulic motor
US6263123B1 (en) * 1999-03-12 2001-07-17 Lucent Technologies Pixellated WDM optical components
US6947670B1 (en) * 1999-06-30 2005-09-20 Lucent Technologies Inc. Optical add/drop arrangement for ring networks employing wavelength division multiplexing
US6192172B1 (en) * 1999-08-09 2001-02-20 Lucent Technologies Inc. Optical wavelength-space cross-connect switch architecture
CA2285128C (en) * 1999-10-06 2008-02-26 Nortel Networks Corporation Switch for optical signals
US6501877B1 (en) * 1999-11-16 2002-12-31 Network Photonics, Inc. Wavelength router
US6192174B1 (en) 1999-12-21 2001-02-20 Dicon Fiberoptics, Inc. Wavelength selection switches for optical application
DE60028551T2 (en) * 2000-06-05 2006-09-28 Pirelli Cavi E Sistemi S.P.A. An optical wavelength division system of combined wavelength routing and routing of optical fibers
US6754174B1 (en) * 2000-09-15 2004-06-22 Ciena Corporation Interface for communications among network elements
US6678445B2 (en) * 2000-12-04 2004-01-13 Jds Uniphase Corporation Dynamic gain flattening filter
US6721509B2 (en) * 2000-12-05 2004-04-13 Avanex Corporation Self-adjusting optical add-drop multiplexer and optical networks using same
WO2002075369A3 (en) 2001-03-16 2003-05-01 Photuris Inc Modular all-optical cross-connect
JP3798642B2 (en) * 2001-03-26 2006-07-19 富士通株式会社 Management device of Wdm network

Patent Citations (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5267309A (en) * 1990-11-20 1993-11-30 Alcatel Network Systems, Inc. Telephone line unit having programmable read-only memory
US5555477A (en) * 1992-04-08 1996-09-10 Hitachi, Ltd. Optical transmission system constructing method and system
US5739932A (en) * 1992-04-08 1998-04-14 Hitachi, Ltd. Optical transmission system constructing method and system
US5920414A (en) * 1995-03-22 1999-07-06 Kabushiki Kaisha Toshiba Wavelength division multiplexing optical transmission apparatus and optical repeater
US6108113A (en) * 1995-12-29 2000-08-22 Mci Communications Corporation Method and system for transporting ancillary network data
US5793909A (en) * 1996-09-09 1998-08-11 Lucent Technologies Inc. Optical monitoring and test access module
US5953141A (en) * 1996-10-03 1999-09-14 International Business Machines Corporation Dynamic optical add-drop multiplexers and wavelength-routing networks with improved survivability and minimized spectral filtering
US6195186B1 (en) * 1996-12-04 2001-02-27 Nec Corporation Optical WDM ring network
US6295149B1 (en) * 1997-01-15 2001-09-25 Pirelli Cavi E Sistemi S.P.A. System and method of telecommunication with wavelength division multiplexing comprising a demultiplexer
US6081359A (en) * 1997-01-28 2000-06-27 Nec Corporation Transmitting apparatus and receiving apparatus for wavelength-division-multiplex signal transmission
US6256125B1 (en) * 1997-04-30 2001-07-03 Nec Corporation WDM optical transmission system
US6101011A (en) * 1997-05-29 2000-08-08 Ciena Corporation Modulation format adjusting optical transponders
US6084694A (en) * 1997-08-27 2000-07-04 Nortel Networks Corporation WDM optical network with passive pass-through at each node
US5995256A (en) * 1997-09-30 1999-11-30 Mci Communications Corporation Method and system for managing optical subcarrier reception
US5999288A (en) * 1998-02-02 1999-12-07 Telcordia Technologies, Inc. Connection set-up and path assignment in wavelength division multiplexed ring networks
US6169994B1 (en) * 1998-04-02 2001-01-02 Lucent Technologies, Inc. Method for creating and modifying similar and dissimilar databases for use in hardware equipment configurations for telecommunication systems
US6321255B1 (en) * 1998-04-10 2001-11-20 Cisco Technology, Inc. Extensible storage of network device identification information
US6154728A (en) * 1998-04-27 2000-11-28 Lucent Technologies Inc. Apparatus, method and system for distributed and automatic inventory, status and database creation and control for remote communication sites
US6067389A (en) * 1998-07-27 2000-05-23 Lucent Technologies Inc. Wavelength-selective optical cross-connect
US6272154B1 (en) * 1998-10-30 2001-08-07 Tellium Inc. Reconfigurable multiwavelength network elements
US6587470B1 (en) * 1999-03-22 2003-07-01 Cisco Technology, Inc. Flexible cross-connect with data plane
US20040085345A1 (en) * 1999-05-26 2004-05-06 Fujitsu Network Communications, Inc., A California Corporation Cross-connect management with display selectable by inputting endpoints
US6856594B1 (en) * 1999-08-09 2005-02-15 Fujitsu Limited ATM switching system and method for switchover between working channel and protection channel in an ATM network
US7136586B2 (en) * 2000-02-18 2006-11-14 Marconi Uk Intellectual Property Ltd. Optical communication system
US6414765B1 (en) * 2000-03-07 2002-07-02 Corning, Inc. Protection switch in a two-fiber optical channel shared protection ring
US6697546B2 (en) * 2000-03-21 2004-02-24 Fujitsu Limited Optical node system and switched connection method
US6631222B1 (en) * 2000-05-16 2003-10-07 Photuris, Inc. Reconfigurable optical switch
US6516105B1 (en) * 2000-10-10 2003-02-04 Teradyne, Inc. Optical backplane assembly and method of making same
US6288811B1 (en) * 2000-10-17 2001-09-11 Seneca Networks WDM optical communication system with channels supporting multiple data formats
US6411412B1 (en) * 2000-12-08 2002-06-25 Seneca Networks WDM optical communication network with data bridging plural optical channels between optical waveguides
US20030163555A1 (en) * 2001-02-28 2003-08-28 Abdella Battou Multi-tiered control architecture for adaptive optical networks, and methods and apparatus therefor

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120148231A1 (en) * 2004-02-02 2012-06-14 Farley Joseph D Fiber optic multiplex modem
US8503491B2 (en) * 2004-02-02 2013-08-06 Simplexgrinnell Lp Fiber optic multiplex modem
WO2013164044A1 (en) 2012-05-04 2013-11-07 Deutsche Telekom Ag Method and device for constructing and operating a modular, highly scalable, very simple, cost-efficient and sustainable transparent optically-routed network for network capacities of greater than 1 petabit(s)
US9882643B2 (en) 2012-05-04 2018-01-30 Deutsche Telekom Ag Method and device for setting up and operating a modular, highly scalable, very simple, cost-efficient and enduring transparent optically routed network for network capacities of greater than 1 Petabit/s

Also Published As

Publication number Publication date Type
US20090142060A1 (en) 2009-06-04 application
US20090196549A1 (en) 2009-08-06 application
JP2005502222A (en) 2005-01-20 application
US20020145779A1 (en) 2002-10-10 application
WO2002075369A2 (en) 2002-09-26 application
KR100993182B1 (en) 2010-11-10 grant
WO2002075403A1 (en) 2002-09-26 application
CA2441045A1 (en) 2002-09-26 application
EP1368923B1 (en) 2013-04-24 grant
JP2004536484A (en) 2004-12-02 application
CN1993915B (en) 2010-10-06 grant
JP2004536485A (en) 2004-12-02 application
US20160142172A1 (en) 2016-05-19 application
US9258628B2 (en) 2016-02-09 grant
EP1368924A1 (en) 2003-12-10 application
CA2441343A1 (en) 2002-09-26 application
KR20040052492A (en) 2004-06-23 application
CN1672351A (en) 2005-09-21 application
WO2002075999A2 (en) 2002-09-26 application
US20020145782A1 (en) 2002-10-10 application
KR20090106622A (en) 2009-10-09 application
WO2002075369A3 (en) 2003-05-01 application
WO2002075998A1 (en) 2002-09-26 application
CN1596517A (en) 2005-03-16 application
WO2002075999A3 (en) 2002-11-21 application
US6614953B2 (en) 2003-09-02 grant
KR20040000408A (en) 2004-01-03 application
KR20090107549A (en) 2009-10-13 application
CN1993915A (en) 2007-07-04 application
US7738748B2 (en) 2010-06-15 grant
CN1502183A (en) 2004-06-02 application
EP1368924A4 (en) 2010-01-06 application
CA2441303A1 (en) 2002-09-26 application
EP1371162A4 (en) 2010-01-06 application
KR20030083742A (en) 2003-10-30 application
US7620323B2 (en) 2009-11-17 grant
US20020146198A1 (en) 2002-10-10 application
EP1368923A2 (en) 2003-12-10 application
EP1371162A2 (en) 2003-12-17 application
CA2441059A1 (en) 2002-09-26 application
US7676157B2 (en) 2010-03-09 grant
US7469080B2 (en) 2008-12-23 grant
EP1368923A4 (en) 2010-01-06 application
US20080166087A1 (en) 2008-07-10 application
US20020159679A1 (en) 2002-10-31 application
KR100993500B1 (en) 2010-11-11 grant

Similar Documents

Publication Publication Date Title
US6426815B1 (en) WDM ring transmission system having two hubs
US6504963B1 (en) Optical fiber protection switch
US5550818A (en) System for wavelength division multiplexing/asynchronous transfer mode switching for network communication
US6023359A (en) Optical wavelength-division multiplex transmission equipment with a ring structure
US6477288B1 (en) Optical line switching system
US6532089B1 (en) Optical cross-connect, method of switching over optical path, optical ADM, and optical cross-connect network system
US6226111B1 (en) Inter-ring cross-connect for survivable multi-wavelength optical communication networks
US6195186B1 (en) Optical WDM ring network
US6288811B1 (en) WDM optical communication system with channels supporting multiple data formats
US6587235B1 (en) Method and apparatus for capacity-efficient restoration in an optical communication system
US6606427B1 (en) Switch for optical signals
US6735393B1 (en) All-optical network with passive wavelength routers
US5777761A (en) System and method for photonic facility and line protection switching using wavelength translation
US5610744A (en) Optical communications and interconnection networks having opto-electronic switches and direct optical routers
US20060013149A1 (en) Suprvisory channel in an optical network system
US6519064B1 (en) Scalable add/drop architecture for lightwave communication system
US5889600A (en) Cross-connect for an optical network
US20020054406A1 (en) Bidirectional WDM optical communication network with optical bridge between bidirectional optical waveguides
US5557439A (en) Expandable wavelength division multiplexed optical communications systems
US20030210870A1 (en) Switch for optical signals
US6333799B1 (en) Hybrid wavelength-interchanging cross-connect
US5930016A (en) Upgradable modular wavelength division multiplexer
US20030175029A1 (en) Method of seamless migration from scaleable OADM to a network switching node
EP0716521A2 (en) Ring network communication structure on an optical carrier and reconfigurable node for said structure
US6333798B1 (en) Bidirectional WDM optical communication network