INVESTIGATION OF OPTICAL SPECTRAL REGIONS FOR SPACE COMMUNICATIONS
Abstract
A study was initiated on the problem of background interference and on communications systems components for the optical spectral region. Literature searches were necessary to determine (a) the problems of space missions, (b) spectral descriptions and categories of background interferences, and (c) the most recent developments in communications systems components. The principle power loss in space communications is in beam divergence. The compilation of data on radiation from the sun, planets, and stars made it possible to categorize background interference. Analysis showed that, while sun is the best continuous, noncoherent source, there is as yet no practical system for utilizing it in space communications; intermittent, noncoherent sources, have greater p ak spectral radiance than continuous sources but are limited in their modulation capabilities and thus have low information rate. Coherent sources (lasers) can be modulated externally, but so far laser capabilities are far short of theoretical predictions. Photoconductive detectors have a higher sensitivity and a narrower spectral response than thermal detectors. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1962
- Accession Number
- AD0278215
Entities
People
- R.a. Jr. Rollin
Organizations
- University of Michigan