CERTAIN DEMANDS ON THE OPTICAL FREQUENCY RECEIVERS IN COMMUNICATION SYSTEMS USING COHERENT LIGHT,
Abstract
The development of the laser as a coherent, excellent monochromatic and highly directional optical signal source has led to its possible application in optical communication. The object of this paper is to set forth some special requirements of light demodulators for coherent light optical communication. Light demodulators operate in a manner similar to radio receivers, except that they require the conversion of light input to photocurrent and their noise has strong quantum characteristics. General requirements for light demodulators are high sensitivity and a high signal to noise ratio. In an optical communication system, the preferred modulation frequencies and band widths are in the infra-red range and higher. Some semiconductors are promising for use in demodulators operating in the infra-red range, but they do not completely fulfill the other requirements. Among light detection methods that can be used, optical heterodyning appears to be of particular importance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 16, 1967
- Accession Number
- AD0674349
Entities
People
- Ch'en Heng
Organizations
- National Air and Space Intelligence Center