Method of fiber interferometry zero fringe shift referencing using passive optical couplers

摘要

A method and apparatus for zero fringe shift referencing has unique application in an optical fiber interferometer gyroscope. Passive optical couplers introduce pulsed laser energy into the interferometer's main loop and a much smaller loop encircling a negligible area. An output signal from the smaller loop is representative of a zero rotation rate while the output signal from the much larger main interferometer loop is representative of an unknown rotation rate. The zero rotation rate and unknown rotation rate signals are compared and referenced so that there can be compensation for the response variation of the photodetectors or the source of laser energy to enable more accurate responsive readouts.