Fringe locking subsystem and methods of making and using the same

摘要

A fringe locking subsystem for an optical sensing cavity is provided. The subsystem comprises one or more photo detectors that detect a reference signal and a cavity signal; a first amplifier that generates a calculated differential between the reference signal and the cavity signal; a lock-in amplifier that generates a modulation signal based on the calculated differential; and a controller that adjusts a distance within the cavity based on the modulation signal.