Bidirectional optical data communications system

Abstract

A system and method are disclosed for optically communicating data between two data handling units where one of the data units supplies all of the optical power needed for the optical communications between the two data units. In a preferred embodiment a first data unit comprises a first data source, first and second optical sources of optical energy, and a first optical detector, while a second data unit comprises a second data source, a second optical detector and an optical modulator. In a first mode of operation, a first stream of digital data from the first data source pulse modulates the first optical source on and off causing the first optical source to transmit optical pulses to the second optical detector. These optical pulses are converted by the second optical detector back into a representation of the first stream of digital data for use by the second data unit. In a second mode of operation unmodulated optical energy is transmitted from the second optical source in the first data unit to the optical modulator in the second data unit. A second stream of digital data from the second data source is applied to the optical modulator to accordingly modulate the received unmodulated optical energy. Modulated optical pulses from the optical modulator are therefore reflected to the first optical detector. These reflected modulated optical pulses are converted by the first optical detector back into a representation of the second stream of digital data for use by the first data unit.