AVALANCHE MODE PHOTODIODES FOR HETERODYNE TECHNIQUES AT 1.06 MICRONS.
Abstract
The objective of the program was the development of a high speed and highly sensitive optical detector which could be utilized in a laser radar operating at a wavelength of 1.06 microns. The detector quantum efficiency was to be greater than that of presently available photocathodes. The detector was to be adaptable to optical heterodyne techniques, and to have a frequency response extending into the one to two gigahertz range. The approach chosen utilized a germanium semiconductor photodiode because of its high quantum efficiency at the wavelength of interest. It was decided to operate the diode in an avalanche mode so that it could provide signal gain. This mode of operation would provide quantum noise limited sensitivity without the need of a high power optical local oscillator. A junction width of a few microns was maintained to provide the gigahertz frequency response capabilities. The detector packaging was designed to pass the frequency spectrum of interest. Experimental results indicated that the germanium photodiode successfully demonstrated coherent detection and responded to frequencies from 400 MHz to 2 GHz without carrier transit time reduction. A signal gain of 15 db by avalanche multiplication was sufficient to provide an increased detector sensitivity which was within 10 db of that limited by quantum noise. The successful demonstration of this detector fulfilled the program objectives and advanced the state-of-the-art in receiver technology. The utilization of this sensitive detector in a high power laser system can form the nucleus of future long range coherent optical surveillance systems. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1967
- Accession Number
- AD0822684
Entities
People
- Harry Kroger
Organizations
- Sperry Corporation