Direct detecting of optical PSK signals
AssigneeNorthern Telecom Limited
InventorJonathan P. King
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Abstract
A self homodyne direct detection optical transmission system includes a transmitter in which binary data signals are converted into double differential phase shift keyed (DDPSK) optical signals. The receiver includes a two-path optical interferometer, having a path unbalance optical delay substantially equal to 1 bit period, to which received DDPSK signals are applied. The interferometer output is converted into a plurality of balanced phase diversity outputs. From each of the phase diversity outputs a replica of the binary data signals is recovered and the replica signals are combined to form an output binary data signal.
Claims1
A self homodyne direct detection optical transmission system including at a transmitter means for converting binary data signals into double differentiated phase shift keyed optical signals, and at a receiver
- a 2.times.2 optical coupler to one input of which are applied the received double differentiated phase shift keyed optical signals,
- a 3.times.3 optical coupler two inputs of which are coupled to respective outputs of the 2.times.2 coupler to form a two-path optical interferometer, one of the paths including an optical delay substantially equal to 1 bit period, whereby the output of the 3.times.3 coupler forms 3 balanced phase diversity signals,
- separate means for recovering from each of the phase diversity signals a replica of the binary data signals, and
- means for combining the replica signals to form an output binary data signal.
Dependencies are inferred from the claim text.