Accession Number : ADA141090

Title :   Optical Adaptive Filter. Frequency Domain Implementation.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Newman,J L

PDF Url : ADA141090

Report Date : Dec 1983

Pagination or Media Count : 201

Abstract : This report presents the results of a feasibility test on an optical adaptive filter, implemented in the frequency domain. The OAFFI is the follow-on to the optical adaptive filter, which was implemented in the time domain. The theory of OAFFI is based on adaptive linear predictions using correlation cancellation loops and optical signal processing (OSP) using Fourier optics (lenses) and acousto-optics (Bragg cells). A few optical architectures, which form the fundamental building blocks of OAFFI, were built and examined prior to the OAFFI architectures. These fundamental architectures included an Optical Spectrum Analyzer, Optical Excisor (two versions) and a Liquid Crystal Light Valve. The Optical Excisor used heterodyning principles which in an OSP sense usually involves an interferometer (MZI) and common path interferometer (CPI). OAFFI(MZI) exhibited phase stability problems in the optical output. To overcome these phase stability problems, the common path interferometer version of OAFFI was built. OAFFI(CPI) overcame the phase stability problems of OAFFI(MZI). However, stability problems resulting from positive feedback at various frequencies were observed in OAFFI(CPI). Nevertheless, OAFFI(CPI) also demonstrated some positive results that should stimulate further investigations.

Descriptors :   *Optical filters, *Adaptive filters, *Feasibility studies, Frequency, Mathematical prediction, Installation, State of the art, Optical interferometers, Optical processing, Signal processing, Architecture, Theses

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE