Time-domain based composite modulation for spectrally efficient optical networks
View Patent ↗Methods, systems, and apparatuses for time-based composite modulation of an optical carrier signal are provided. Time-based composite modulation includes determining a plurality of fixed time slots for the optical carrier signal, wherein the plurality of fixed time slots comprise a time-division-multiplexing frame. Determining a modulation format for each fixed time slot of the time-division-multiplexing frame, wherein a transport spectral efficiency of the modulation format determined for a first fixed time slot is different from a transport spectral efficiency of the modulation format determined for a second fixed time slot, and determining a number of binary bits for each fixed time slot of the time-division-multiplexing frame, wherein the number of binary bits for a fixed time slot is based on the modulation format determined for the fixed time slot.
1. A method comprising:
receiving by an optical receiver an optical carrier signal;
determining a plurality of fixed time slots defining a time-division-multiplexing frame for the optical carrier signal;
determining a modulation format for each fixed time slot of the time-division-multiplexing frame;
determining a number of binary bits for each fixed time slot of the time-division-multiplexing frame; and
generating a frame sync marker for the time-division-multiplexing frame based on a determined modulation format.
2. The method of claim 1 , wherein the modulation format determined for a fixed time slot is one of a PDM-4QAM, PDM-8QAM, PDM-16QAM, PDM-32QAM and PDM-64QAM modulation format.
3. The method of claim 1 , wherein one or more time-division-multiplexing frames define a packet.
4. The method of claim 1 , wherein a transport spectral efficiency of the modulation format determined for a first fixed time slot is different from a transport spectral efficiency of the modulation format determined for a second fixed time slot.
5. The method of claim 1 , wherein the number of binary bits for a fixed time slot is based on the modulation format determined for the fixed time slot.
6. An apparatus comprising:
a processing module;
a non-transitory computer-readable medium storing computer program instructions for generating a compositely-modulated digital signal, which, when executed on the processing module, cause the processing module to perform operations comprising:
determining a plurality of fixed time slots defining a time-division-multiplexing frame for an optical carrier signal;
determining a modulation format for each fixed time slot of the time-division-multiplexing frame, wherein one or more time-division-multiplexing frames define a packet;
determining a number of binary bits for each fixed time slot of the time-division-multiplexing frame based on the modulation format determined for the fixed time slot to generate a compositely modulated digital signal;
a digital-to-analog converter, having a digital signal input coupled to an output of the processing module and providing an analog signal output, for converting the compositely-modulated digital signal into a compositely-modulated analog signal; and
an optical modulator, having an analog signal input coupled to the analog signal output of the digital-to-analog converter and providing an optical signal output, for generating a compositely-modulated optical signal based on the compositely-modulated analog signal.
7. The apparatus of claim 6 , wherein the modulation format determined for a fixed time slot is one of a PDM-4QAM, PDM-8QAM, PDM-16QAM, PDM-32QAM and PDM-64QAM modulation format.
8. The apparatus of claim 6 , further comprising computer program instructions causing the processing module to perform an operation for generating a frame sync marker for the time-division-multiplexing frame, wherein the frame sync marker indicates the modulation format determined for a fixed time slot of the time-division-multiplexing frame.
9. The apparatus of claim 6 , wherein the processing module is implemented by a CMOS-based digital signal processing chip.
10. The apparatus of claim 6 , wherein the processing module and the digital-to-analog converter are integrated on a CMOS-based chip.
11. A non-transitory computer-readable medium storing computer program instructions for generating a compositely-modulated digital signal, which, when executed on a processor, cause the processor to perform operations comprising:
receiving with an optical receiver an optical carrier signal;
determining a plurality of fixed time slots defining a time-division-multiplexing frame for an optical carrier signal;
determining a modulation format for each fixed time slot of the time-division-multiplexing frame;
determining a number of binary bits for each fixed time slot of the time-division-multiplexing frame; and
generating a frame sync marker for the time-division-multiplexing frame based on a determined modulation format.
12. The non-transitory computer-readable medium of claim 11 wherein the modulation format determined for a fixed time slot is one of a PDM-4QAM, PDM-8QAM, PDM-16QAM, PDM-32QAM and PDM-64QAM modulation format.
13. The non-transitory computer-readable medium of claim 11 , wherein one or more time-division-multiplexing frames define a packet.
14. The non-transitory computer-readable medium of claim 11 , wherein a transport spectral efficiency of the modulation format determined for a first fixed time slot is different from a transport spectral efficiency of the modulation format determined for a second fixed time slot.
15. The non-transitory computer-readable medium of claim 11 , wherein the number of binary bits for a fixed time slot is based on the modulation format determined for the fixed time slot.