Multichannel image-rejection coherent detection system

An analysis is made of and data is presented from a prototype of an image channel rejection systems for the coherent detection of densely packed wavelength division multiplexed (WDM) channels. The system can simultaneously process a number of channels with a single-local laser diode and can extract the feedback control signals required to adjust critical system parameters. Although the system operates most simply for frequency shift keying (FSK) and phase-shift keying (PSK), it also operates for all the usual modulation schemes with minor adjustments. The control system aspects of the system are not affected by laser-diode phase noise.<
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