Optical path length sensor

Abstract

An optical path length sensor for sensing a physical quantity of an external source includes a plurality of lasers, each having an optical resonator and a gain medium to produce a laser beam in the optical resonator. At least one of the optical resonators is configured to modulate the optical frequency of the laser beam when exposed to the external source. The sensor further includes a common carrier, in which the optical resonators are arranged, and a device configured to receive light from the plurality of lasers and to determine a difference between the optical frequencies of the laser beams. In another aspect the optical path length sensor includes a plurality of interferometers, each being an asymmetric Mach-Zehnder or an asymmetric Michelson interferometer, at least two of the plurality of interferometers having a different optical path length imbalance.

Dependencies are inferred from the claim text.