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

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.

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.