Outage probability of WDM free‐space optical systems affected by turbulence‐accentuated interchannel crosstalk

Massive deployment of free space optical (FSO) communication systems in future optical access networks will use wavelength division multiplexing (WDM) technology to leverage extended reach and enhanced user capacity. An analytical framework for the estimation of outage probability in a turbulence‐affected WDM FSO system is presented in this study. The authors derive simplified expressions of the probability of outage in the presence of turbulence‐accentuated interchannel crosstalk, and show how design parameters such as the FSO link length, demultiplexer adjacent channel rejection and receiver aperture diameter affect the performance of the system. Numerical results show that the outage probability due to irradiance fluctuation is worsened in WDM FSO systems by the effects of turbulence‐affected interchannel crosstalk signals. Specifically, the average crosstalk power and the degree of irradiance fluctuations on the crosstalk set a limit on the outage probability performance of the system which appears in the form of outage floors.