Multiplexed transmission of optical signals

摘要

Optical signals in an optical communication system are transmitted as a train of optical pulses which are multiplexed to provide a large number of channels. Error correction coding is applied to data carried by the channels using both interchannel coding and serial coding of individual channels. When multiplexed by wavelength division multiplexing, a waveguide array is used as a dispersive device having a characteristic of frequency selectivity which is locked by a monitoring and control system to a set of spectral lines from the single pulsed laser which generates the pulses. In the receiver, clock signals are generated by extracting clock signals from the earliest and latest received channel signals and performing interpolation to obtain clock signals for the remaining channels. When multiplexed using a spectral modulation technique, individual channels are represented by distinct sinusoidal modulations in frequency space which are then detected in the receiver by Mach-Zehnder filters.