Flexible-client, flexible-line interface transponder

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.