Flexible-client, flexible-line interface transponder
Methods and systems for flexible-client, flexible-link optical transponders include electrical-to-optical transponders, which accept client data from a flow distributor, and a first multiplexing switch that connects modulated optical carriers from the transponders to line interfaces. The electrical-to-optical transponders each include a flexible optical transport unit (OTU) framer module that compresses multiple optical data units (ODUs) into a single ODU having a higher order than any of the input ODUs to form an optical transport network (OTN) frame. An electrical-to-optical modulator modulates OTN frames onto a carrier. The transponder includes a second multiplexing switch that accepts optical carriers from line interfaces and optical-to-electrical transponders that accept modulated optical carriers from the second multiplexing switch. Each optical-to-electrical transponder includes a photodetector to convert the modulated optical carriers to the electrical domain and a flexible OTU framer module that decompresses received ODUs in OTN frames into multiple ODUs to form a bit stream.
1. A transponder, comprising:
a first flow distributor configured to accept client data from a plurality of client interfaces;
a plurality of electrical-to-optical transponders configured to accept client data from the first flow distributor, each comprising:
a flexible optical transport unit (OTU) framer module configured to compress multiple optical data units into a single optical data unit having a higher order than any of the multiple optical data units to form an optical transport network (OTN) frame by adding and removing unused tributary slots of the formed OTN frame to avoid transmission of unnecessary data and to match a transmission rate between client and line interfaces without changing an OTN standard; and
an electrical-to-optical modulator configured to modulate OTN frames onto an optical carrier;
a first multiplexing switch configured to connect modulated optical carriers from the plurality of transponders to a plurality of line interfaces;
a second multiplexing switch configured to accept modulated optical carriers from a plurality of line interfaces;
a plurality of optical-to-electrical transponders configured to accept one or more modulated optical carriers from the second multiplexing switch, each comprising:
a photodetector configured to convert the modulated optical carriers from the optical domain to the electrical domain to produce optical transport network (OTN) frames; and
a flexible OTU framer module configured to decompress received optical data units in respective OTN frames into multiple optical data units, each having lower order than a respective received optical data unit to form a bit stream; and
a second flow distributor configured to distribute bit streams output by the plurality of optical-to-electrical transponders to a plurality of client interfaces.
2. The transponder of claim 1 , further comprising a controller configured to adapt a number of client interfaces for each of the first and second flow distributors and a number of line interfaces for each of the first and second multiplexing switches.
3. The transponder of claim 1 , wherein the first flow distributor is configured to aggregate client traffic headed to a same destination at a same electrical-to-optical transponder module.
4. The transponder of claim 1 , wherein the electrical-to-optical modulator of the electrical-to-optical transponders is further configured to enable and disable optical subcarriers in proportion to effective client traffic.
5. A method for transmitting optical data, comprising:
distributing client data from a plurality of client interfaces to a plurality of electrical-to-optical transponders;
compressing multiple optical data units of client data into a single optical data unit having a higher order than any of the multiple optical data units to form an optical transport network (OTN) frame, said compressing comprising adding and removing unused tributary slots of the formed OTN frame to avoid transmission of unnecessary data and to match a transmission rate between client and line interfaces without changing an OTN standard;
modulating OTN frames onto an optical carrier; and
connecting modulated optical carriers from the plurality of electrical-to-optical transponders to a plurality of line interfaces.
6. The method of claim 5 , wherein distributing client data comprises aggregating client traffic headed to a same destination at a same electrical-to-optical transponder module.
7. The method of claim 5 , wherein modulating comprises enabling and disabling optical subcarriers in proportion to effective client traffic.
8. A method for receiving optical data, comprising:
distributing received modulated optical carriers from a plurality of line interfaces to a plurality of optical-to-electrical transponders;
converting the modulated optical carriers from the optical domain to the electrical domain to produce optical transport network (OTN) frames;
decompressing received optical data units in respective OTN frames into multiple optical data units, each having lower order than a respective received optical data unit to form a bit stream; and
distributing bit streams output by the plurality of optical-to-electrical transponders to a plurality of client interfaces.