Effect of misalignment on rotating coupling efficiency of Dove Prism

摘要

In the optical rotary joints, the Dove Prism is employed to rotate an image about the optical axis and compensate optical path of optical signals so that the optical signals can be transferred across the rotating interface. However, manufacturing errors and assembling errors of Dove Prism will affect the coupling efficiency of Dove Prism. In this paper, the analytical expressions for errors of the rotating coupling efficiency are presented when the prism is manufactured with errors in its base angle and pyramidal angle. The analytical result showed that the coupling losses that arise from manufacturing errors would increase as the base angles deviate from the traditional value of 45° and the pyramidal angle increase. At the same time, the influence of assembling errors on coupling efficiency is also analyzed using the method of light ray tracing. The assembling errors of Dove Prism included angular tilt misalignment, height misalignment, and inclining misalignment. The results indicated that these misalignments cause the coupling efficiency of Dove Prism decreased. The coupling efficiency is more sensitive to the height misalignment and angular tilt misalignment than the inclining misalignment.