HIGH ACCURACY RING LASER INTERFEROMETER USING EXTERNAL CAVITY TYPE RING LASER

摘要

PURPOSE: A high accuracy ring laser interferometer using an external cavity type ring laser is provided to high accurately measure by straining or offsetting the change of the applied voltage and output beam strength and change of frequency of a ring laser. CONSTITUTION: In an optical sensing device for being used in an interferometer measuring measured amount by using a ring laser, the optical sensing includes a ring laser cavity and at least one or more external reflex mirrors(187), the ring laser cavity includes a plurality of inner reflex mirrors(219,220,223,224) and two laser beams having equal wavelength and transmitting in opposite direction, the part of the opposite directional traveling beams is penetrated through the plurality of inner reflex mirrors, the external reflex mirror respectively selects one penetrated beam from the two inner reflex mirrors different from each other so that two penetrated beams are in opposite direction and reflects the selected beams for making backward traveling waves and injects the backward traveling waves into the ring laser cavity through the different inner reflex mirrors, and an optical path from two inner reflex mirrors to the corresponding external reflex mirrors is changeable according to the measured amount.