High dynamic range free-space optical communication receiver

摘要

A free-space optical communications system and method in which a transmitter transmits a free-space optical communication beam to an optical receiver. The receiver includes an optical detector, an optical input level sensor and an optical attenuation device. The optical detector detects the optical communication beam, while the optical input level sensor senses an optical input level of the optical communication beam at the optical detector and outputs a control signal corresponding to the sensed optical input level. The optical attenuation device is responsive to the control signal by attenuating the optical input level of the optical communication beam to be less than a predetermined input level. The optical input level sensor includes a detector optical level sensor, a comparator circuit and a controller. The detector bias level sensor senses an optical level of the optical detector. The comparator circuit is coupled to the detector bias level sensor and compares the sensed optical level of the optical detector to predetermined threshold levels. The comparator circuit outputs a code signal relating a magnitude of the sensed optical level of the optical detector to the predetermined thresholds. The controller is responsive to the code signal by outputting the control signal.