Design, Construction, and Analysis of an Ultra-Low Expansion Quartz Resonant Cavity Passive Ring Resonator Laser Gyroscope

摘要

The purpose of this research is to design and build a Passive Ring Resonator Laser Gyroscope (PRLG) that is small in size, constructed from a thermally stable material, and utilizes a laser cavity--resonant cavity mode match design. The small size design is dominated by the physical size of the available components; consequently, the small design is as small as physically possible with these components. The dimensions of the PRLG are as follows: (1) the perimeter of the reson ant cavity is 45.2 cm., (2) the laser cavity is 22 cm. long, and (3) the distance from the center of the laser cavity to the input mirror of the resonant cavity is 49.664 cm. The thermally stable material obtained for the PRLG is a block of Ultra-Low Expansion Quartz (ULE Quartz). The coefficient of thermal expansion for ULE Quartz is 0.55 x 10 to the minus 6th power cm./cm./C, thus making this material a very thermally stable material. Due to the configuration and size of this ULE Quartz block, only the resonant cavity portion of the PRLG is formed using the ULE Quartz block. The laser cavity--resonant cavity mode matching design is accomplished in three steps. First, the spot size of the resonant cavity beam is determined at some point outside the resonant cavity. Second, the laser is designed such that its spot size is identical to the spot size of the resonant cavity beam at that same point. Third, the radius of curvature of the external corner mirror required to change the radius of curvature of the laser cavity beam into the radius of curvature of the resonant cavity beam is determined.