Power penalties due to reflection and Rayleigh backscattering in a single frequency bidirectional coherent transmission system

Crosstalk penalties from a single reflection and Rayleigh backscattering (RB) are calculated and measured for a bidirectional coherent continuous-phase frequency-shift-keying (CPFSK) transmission system, having both transmitters operating at the same optical frequency. A 0.5 dB penalty occurs for -22 dB crosstalk/signal ratio for both types of crosstalk. The measured crosstalk penalties for RB fit very well with the predicted Gaussian behavior. The crosstalk penalties for a single reflection are always lower than those for an equal amount of RB.<
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