| 摘要 |
<p>An optical communication system for communicating information. The system includes a source of continuous wave laser light (30) and one or more acoustic beams (51) which are frequency or amplitude modulated by data. The laser light beam and the acoustic beams are input to an acousto-optical modulator (50) for producing an undiffracted laser light beam and one or more diffracted laser light beams (52). The diffracted laser light beams are frequency shifted from the undiffracted laser light beam and contain the data to be transmitted. The diffracted and undiffracted beams are combined (60), and transmitted over an optical fiber (16) for demodulation at a distant location by a receiver. The receiver includes a photodiode (70) which heterodynes the diffracted and undiffracted beams and produces signals having the frequencies of the acoustic beams. Tuning circuitry (74) separates the signals and demodulators (80) reconstruct the data transmitted. By using two such communication systems with a single optical fiber and by allocating the available bandwidth, simultaneous, bidirectional multi-channel communications are achieved.</p> |
