Abstract

To reject the optical background radiation in free space laser communication, we have designed and built a direct detection building to building optical communication system that uses a Faraday Anomalous Dispersion Optical Filter (FADOF) in the receiver. The FADOF is a narrow bandpass optical filter, which can provide a background noise rejection of 10⁵ while transmitting the signal with up to 80% efficiency. The FADOF has a signal bandwidth that is variable between 0.5 GHz and 5 GHz, a field-of view that is flat over ±20° and excellent imaging qualities.

© 1994 Optical Society of America