The Study On The Theory & Experiment Of Fiber Optical Rotary Joint Using Dove Prism

Fiber optical rotary joint (FORJ), employed to transmit signals between two relatively rotating devices, has been playing a significant role in the technical field of digital information transmission. The optical properties of Dove prism was analyzed; meanwhile, the displacement error formula and angle error formula was carried out in this thesis. The paper not only discussed the alignment method of Dove prism and the impact of various errors on the loss and emergent ray, but designed experiments to verify the theoretical analysis as well. The results of these experiments agree with the theory analysis. On this basis, a FORJ design proposal was discussed.This work concentrates on:1. Based on the theory of matrices and vectors, image law and image rotation law of Dove prism are carried out. In the case of prism rotating, the quantitative error relationship between the incident ray and the emergent ray, caused by the errors between Dove prism, incident ray axis and mechanical rotary axis, has been carried out. Meanwhile we discussed the displacement error and angle error originated from the rotary error of prism, and the influence on image caused by the processing of prism has been assessed as well.2. In the case of rotating prism, resulted from the axis displacement and angle error, the track shift of exit rays, known as limacon of Pascal in mathematics, has been point out. The unique patterns of limacon of Pascal allows us to distinguish and measure the misalignment errors, which are utilized to assemble and regulate the FORJ. The influence on coupling loss has been analyzed when the rotary Dove prism system was introduced between two collimators.3. An experimental system is built based on rotary Dove prism. By simulating the displacement error and angle error between the different axes, the curves of track shift of exit rays and loss variation were obtained.4. By means of Dove prism and collimator, the overall plan of multi-channel fiber optic rotary joint was designed. We made a concrete analysis of the various errors and estimated the total loss of rotary joint.