An All-Fiber MMI-Based Transmitter Head for Performance Improvement Over Turbulent FSO-FC Channels

This letter presents performance improvement in a free-space optical-fiber converged (FSO-FC) communication system under varying turbulence conditions using an all-fiber multimode interference head connected to a single mode fiber. The transmitter head is used for the generation of fundamental (LG00)-alike and first higher order Laguerre-Gaussian (LG01)-alike optical beams in free-space. The FSO channel is statistically characterized under different levels of turbulence, in terms of the probability density functions, for both the beams. We show that the transmitter head generatingLG01-alike optical beam shows average bit error rate improvement as compared toLG00-alike beam under similar operating conditions. This study demonstrates the feasibility and robustness of fiber based transmitter heads for performance enhancement of the FSO-FC communication systems under varying turbulence conditions.