Demodulators for optical fiber interferometers with [3.times.3] outputs

Abstract

A highly sensitive optical fiber interferometer sensor comprising a laser light source, a [2.times.2] optical fiber coupler to split the beam in two, a differential transducer which converts a signal of interest into optical phase shift in the laser light transmitted through the two optical fibers in the interferometer and a [3.times.3] optical fiber complex which recombines the two beams, producing interference which can be electronically detected. The use of the [3.times.3] coupler permits Passive Homodyne demodulation of the phase-modulated signals provided by the interferometer without feedback control or modulation of the laser itself and without requiring the use of electronics within the interferometer.

Dependencies are inferred from the claim text.