Abstract

Several authors have theoretically studied the influence of laser phase noise on the performance of amplitude-shift-keying (ASK) heterodyne coherent detection.^1,2 They have established that a high ratio of the laser linewidth to bit rate (BR) causes a bit-error-rate (BER) floor and decreases receiver sensitivity. We have experimentally investigated the dependence of the BER on laser linewidth for two extreme cases; (a) two 1.55-μm DFB lasers which have 3-dB linewidths of ~50 MHz and (b) two external cavity lasers (ECL)^3,4 with linewidths of <50 kHz.

© 1986 Optical Society of America