Transponder and related network node for an optical transmission network
View Patent ↗In order to reduce power consumption in network equipment for optical transmission networks, it is proposed by reducing E/O conversion and signal processing in optical networks when not needed. A network node has two or more line cards. Each line card contains a receive side transponder section with a network side optical receiver, a first electrical section, and a client side optical transmitter and a transmit side transponder section with a network side optical transmitter, a second electrical section, and a client side optical receiver. The first electrical section has at least one intermediate electrical output the second electrical section has at least one intermediate electrical input. The intermediate electrical outputs and inputs lead to an electrical switch matrix, which controllably interconnects the intermediate electrical outputs and inputs. Preferably, the transponders can additionally contain second intermediate electrical outputs and inputs additionally bypassing a Forward-Error-Correction processing function in the line cards.
1. An optical network node comprising two or more line cards, each line card comprising a receive side optical transponder section comprising a network side optical receiver for single wavelength optical signals, a first electrical section, and a client side optical transmitter and a transmit side optical transponder section comprising a network side optical transmitter for single wavelength optical signals, a second electrical section, and a client side optical receiver, wherein said first electrical section comprises at least one intermediate electrical output and wherein said second electrical section comprises at least one intermediate electrical input; said optical network node further comprising an electrical switch matrix for controllably interconnecting one of said at least one intermediate electrical output of a first line card and one of said at least one intermediate electrical input of said first line card or a second line card;
wherein said first electrical section comprises a first Forward Error Correction processor and second electrical section comprises a second Forward Error Correction processor and wherein said at least one intermediate electrical output comprises a first electrical output connected between said first Forward Error Correction processor and said client side optical transmitter, and a second electrical output connected between said network side optical receiver and said first Forward Error Correction processor, and wherein said at least one intermediate electrical input comprises a first electrical input connected between said client side optical receiver and said second Forward Error Correction processor, and a second electrical input connected between said second Forward Error Correction processor and said network side optical transmitter; further comprising a controller adapted to implement a regenerator function by configuring said electrical switch matrix to activate either a bypass connection between said first electrical output and said first electrical input or a bypass connection between said second electrical output and said second electrical input, depending on a signal condition of a received optical signal.
2. An optical network node according to claim 1 , wherein said controller is adapted for deactivating said client side optical transmitter and said client side optical receiver if a bypass connection between said first intermediate electrical output and said first intermediate electrical input is activated.
3. An optical network node according to claim 1 , wherein when a bypass connection between said second intermediate electrical output and said second intermediate electrical input is activated, said controller is adapted to deactivate said client side optical transmitter, said client side optical receiver, and said first and second Forward Error Corrections processors.
4. A method of regenerating a single wavelength optical signal using two optical transponders each having an optical receiver, an electrical section for processing and/or reshaping said electrical signal, and an optical transmitter, the method comprising:
receiving said single wavelength optical signal at a first optical transponder comprising a network side optical receiver, a first electrical section having an intermediate electrical output, and a client side optical transmitter;
converting within said first optical transponder said optical signal to an electrical signal;
bypassing said electrical signal through said intermediate electrical output to an intermediate electrical input of a second optical transponder, the second optical transponder having a network side optical transmitter, a second electrical section with said intermediate electrical input, and a client side optical receiver;
converting at said second optical transponder said electrical signal to a single wavelength optical signal for onwards transmission; and
selecting between configuring a first bypass bypassing an electro-optical conversion in said first optical transponder and an opto-electrical conversion in said second optical transponder and configuring a second bypass further bypassing a Forward-Error-Correction processing function in said first and second optical transponders, depending on a signal condition of the received optical signal.