Bit-Error Rate Monitor for Laser Communications

摘要

This equipment grant has made it possible to perform the research on award FA9950-07-1-0310. A semiconductor based laser source, fiber coupled to a modulator and fiber amplifier were purchased. The system was fiber coupled to a beam director, with the possibility to launch four beams in parallel to reduce scintillation noise. A range between 10 m to 22 km can be tested with this system. The equipment grant has made it possible to train our graduate students for the first time with modern digital oscilloscopes. Real time BER estimator has been attempted using artificial neural network approach. After programming, the neural network outputs a continuous signal proportional to the bit error rate. This error level matched the reading of the bit error analyzer, only when the level of optical signal transmitted was kept at the same constant value used for the programming, and the whole optical link was bypassed. Considerable more parameters would have to be entered to the neural network program for a practical implementation to be possible.