Optically implemented wideband complex correlator using a multi-mode imaging device
US6404535B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1998 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Nov 30, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06E3/005
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An optically implemented wide bandwidth correlation system (10) that employs a multi-mode imaging device (42) and a particular modulation format to provide both in-phase and quadrature phase correlation components in a single correlation process. The correlation system (10) includes an optical source (12) that generates a laser beam (14) that is split into a first beam path (18) and a second beam path (20). The first split beam and a first electrical signal are applied to a first modulator (22) in the first path (18) and the second split beam and the second electrical signal are applied to a second modulator (24) in the second path (20). The modulated beams are then applied to the optical imaging device (42) that causes the beams to interfere with each other within an optical cavity (48). Four optical outputs are connected to the optical cavity (48) at strategic locations to provide a zero phase output and a &pgr; phase output that represent the in-phase correlation component, and a &pgr;/2 quadrature phase output and a 3&pgr;/2 quadrature phase output that represent the quadrature phase correlation component. A photodetector (60-66) detects each of the output signals from the imag…
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