Crosstalk and prefiltering in a two-channel ASK heterodyne detection system without the effect of laser phase noise

Abstract

We present an experimental and theoretical study on the crosstalk in a two-channel ASK heterodyne detection system where the effect of laser phase noise is negligible. Three r d t s are described: 1) the dependence of the crosstalk penalty on thQratb of chandel separation to bit rate and on the optical power level of the image band, 2) comparison of the measured crosstalk penalties with the ones obtained from a simple model, and 3) the effect of electrical preiiltering on the crosstalk penalty. The main conclusions are: 1) the ChaMel separation can he as low as four times the bit rate without incurring any crosstalk penalty as long as the optical power of the image band is comparable to the optical power of the desired channel and 2) electrical premtering of the trammitted signals significantly reduces the crosstalk penalty in multichannel ASK heterodyne systems where the effed of laser phase noise is negligible.

Crosstalk penalty in multichannel ASK heterodyne lightwave systems

“…Since this case is relatively simple and useful for understanding several important concepts, we concentrate on it in this section. The results obtained here are applicable to a) the experiments in which only two channels are used to study the effect of interchannel crosstalk [3], [7], b) the boundary channels of a multichannel system, and c) the intermediate channel of a multichannel system whose nearest neighbor is inactive (not used for data transmission).…”