Bi-Directional Optical Transmission System for RF Electrical Energy.
Patent, Filed 31 Jul 90, patented 19 Nov 91,
DEPARTMENT OF THE NAVY WASHINGTON DC
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A bi-directional optical transmission system for radio frequency electrical energy includes first and second transmitterreceiver stations which transmit and receive light signals along an optical path there between. Each station includes a laser transmitter for transmitting a carrier light beam which is intensity modulated by a synchronization of an input radio frequency electrical signal. A photodetector at each station detects the intensity variations of the carrier light beam from the other station and outputs a respective radio frequency electrical signal which is synchronized with the radio frequency electrical input signal of the other station. A beam splitter is provided between the optical path at both the laser transmitter and photodetector to split the light beams incident thereon into a pass portion and angularly reflected portion. An isolator device also is provided between the laser transmitter and beam splitter to isolate the laser transmitter from back reflections. Preferably, the isolator is a Faraday isolator, and additionally or alternatively the laser transmitters transmit at widely separate wavelengths. The optical path can either be free space or a main optical fiber, and the synchronization of the input radio frequency electrical energy can either be phase synchronization or time synchronization.
- Electrical and Electronic Equipment