Method and system for optical time division multiplexed fiber communications with coherent detection
The present invention relates to a receiver for receiving a time division multiplexed (TDM) optical signal, which is formed of a plurality of interleaved optical pulse streams. Each optical pulse stream includes a plurality of optical pulses. The receiver includes a detector for detecting at least a first optical pulse stream of the optical signal and an optical hybrid for coherently mixing the first optical pulse stream with a reference pulse stream. The first optical pulse stream and the reference pulse stream impinge simultaneously upon the detector.
1. A time division multiplexed optical communication receiver for a received time division multiplexed optical signal, comprising:
a light sensitive detector for detecting at least a first optical pulse stream of the time division multiplexed optical signal; the time division multiplexed optical signal having a plurality of interleaved optical pulse streams, each optical pulse stream including a plurality of optical pulses;
an optical hybrid coupled to the light sensitive detector and configured to coherently mix the first optical pulse stream and a second optical pulse stream, pulses of the first optical signal and second optical pulse streams configured to simultaneously impinge upon the detector; wherein the first optical signal is a part of the time division multiplexed optical signal; and
wherein the optical hybrid and light sensitive detector are configured to provide the receiver with dual functions of, (i) first optical pulse stream selection and (ii) data recovery for first optical pulse stream, and
wherein the second optical pulse stream is a framing pulse stream of the time division multiplexed optical signal with a pulse period that is N times larger than a period of the received time division multiplexed optical signal, wherein N is the number of interleaved pulsed optical streams within the recived time division multiplexed signal.
2. The receiver of claim 1 , further comprising a synchronization device to synchronize pulses of the first optical pulse stream with pulses of the second optical pulse stream.
3. The receiver of claim 2 , wherein the synchronization device and the optical hybrid are configured to select the first optical pulse stream when pulses of the second pulse stream coincide with pulses of the first pulse stream, the pulses of the first pulse stream being a part of the received time division multiplexed optical signal with multiple interleaved pulsed optical streams.
4. The receiver of claim 1 , wherein the time division multiplexed optical signal is received from a first transmitter and the second optical pulse stream is received from a second transmitter.
5. The receiver of claim 4 , wherein the first transmitter is a remote transmitter, and the second transmitter is a local transmitter.
6. The receiver of claim 1 , wherein optical pulses of the time division multiplexed signal have a width of less than about 100 ps.
7. The receiver of claim 1 , wherein the optical pulses of the time division multiplexed signal comprise at least one of return-to-zero pulses, and short pulses.
8. The receiver of claim 1 , wherein the receiver is a balanced receiver with at least four balanced light detectors.
9. The receiver of claim 1 , wherein the receiver is a phase-diversity receiver.
10. The receiver of claim 1 , wherein the time division multiplexed signal is encoded with at least one of amplitude shift keying, phase shift keying, differential phase shift keying, and polarization shift keying.
11. The receiver of claim 1 , wherein the receiver is a phase-polarization diversity receiver.