Generation of a full-rate optical duobinary signal using half-rate electrical binary signals

摘要

An optical transmitter that uses half-rate electrical signals, without multiplexing them to the full rate, to generate a full-rate optical duobinary signal. In one embodiment, an optical transmitter of the invention has a Mach-Zehnder modulator (MZM) driven by two half-rate electrical data streams. A first half-rate data stream is applied to drive a first arm of the MZM. A delay element misaligns a second half-rate data stream that is synchronized with the first data stream by one half of a bit period, and the resulting misaligned data stream is applied to drive a second arm of the MZM. The MZM is configured to (i) transmit substantially no light from the feeding laser when the applied data streams have the same binary value and (ii) have a maximum transmission when the applied data streams have different binary values, thereby generating a full-rate optical duobinary signal at its output.

主权项

1. A method of generating an optical duobinary signal, comprising:
applying a first data stream having a first bit rate to drive a first arm of an optical modulator; misaligning a second data stream with respect to the first data stream by one half of a bit period corresponding to the first bit rate to produce a misaligned data stream, wherein the second data stream is synchronized with the first data stream and has the first bit rate; and applying said misaligned data stream to drive a second arm of the optical modulator, wherein:
the optical modulator is adapted to modulate an optical beam based on said applied data streams to generate the optical duobinary signal; andthe step of misaligning comprises delaying the second data stream with respect to the first data stream by a delay time greater than a bit-period duration corresponding to the first bit rate.