HIGH ACCURACY RING LASER INTERFEROMETER BASED ON EXTERNAL CAVITY RING LASER

摘要

To output the two part of the opposite directions proceeding the beam in the ring laser through the ring laser mirror Using this external reflector to thereby introduced into the re-create the ring laser cavity in the rear traveling wave (back travelling wave) lock-in zone (lock-in zone) wide, and at the same time the distance between the external reflector and the ring laser, that is the length (optical path length) of the two opposite direction traveling wave beam intensity (intensity) and phase change (phase change) of the varied by controlling by a measured amount of the optical path ring laser interferometer according to the measured interferogram (interference fringe) can change (variation) of using it for measuring the measured quantity and a method using the same. Placing an attenuator between the outer reflector and the ring laser is to operate only in the lock-in zone to zone, ring laser by enabling to adjust the intensity of the backward traveling wave on the outside.; Displacement (displacement), the length (length), the location (position), temperature (temperature), a refractive index (refractive index), can be the amount of the various physical quantities to be measured (physical quantity) such as a pressure (pressure). The output of the interferometer of the present invention is the rate of change of the two opposite direction traveling wave interference pattern by output sum and difference and phase difference between the beam intensity (phase difference) of the applied Some of these are negative feedback (negative feedback) variations in the voltage, and other to suppress or cancel the ring laser output beam intensity, and frequency change caused by the external influence, thereby enabling a high degree of measurement. In addition, because the ring laser operating in lock-zone effects the fine movement of the ring laser on the measured amount can also be minimized.