S. Ovadia et al., MULTIPLE OPTICAL REFLECTIONS IN HYBRID AM 16-QAM MULTICHANNEL VIDEO LIGHTWAVE TRANSMISSION-SYSTEMS, IEEE photonics technology letters, 6(10), 1994, pp. 1261-1264
The effects of multiple optical reflections on bit-error-rate characte
ristics using a directly-modulated DFB laser transmitter and an extern
ally-modulated YAG laser transmitter are compared in hybrid multichann
el AM/16-QAM video light-wave transmission systems. The measured 16-QA
M bit-error-rate is increased from 10(-10) at reflections of -60 dB to
10(-1) at reflections of -20 dB for a 16-QAM modulation index of 0.22
% using the DFB laser transmitter (AM modulation index of 3.3%) with a
n analog CNR of 52 dB. In contrast, the observed 16-QAM bit-error-rate
is essentially unaffected by reflections using an externally-modulate
d YAG laser transmitter with the same AM modulation index and received
optical power.