The Theoretical And Experiment Research On Dual-channel Fiber Optical Rotary Joint

With the rapid development of modern communications technology, thequantities and types of information has a big explosion, which makes a challenge totraditional communication media. In the field of rotatory optical signal transmission,it is urgent and necessary to employ the multi-channel fiber optic rotary joint (FORJ).In order to satisfy the application requirement of signal transmission, particularly forthe passive multi-channel FORJ, both an on-axis and a hollow dual-channel FORJ arestudied in this paper. The on-axis dual-channel FORJ based on lens group andmagnetic coupling technique is proposed; a hollow cone annular optical device whichcan be applied to constructing a hollow dual-channel FORJ is also proposed. Finally，the optics principle and properties of optical components are analyzed in detail.The major achievements in this thesis are as follows:1、A new dual-channel FORJ based on the lens group and magnetic couplingtechnique is designed. Theoretical analyses of the optical principle for this FORJ arecarried out in detail. The influence of collimator’s point accuracy to the assembly ofFORJ is pointed out by simulating. In order to obtain the alignment error tolerance ofthe central channel, the coupling loss of the collimator is analyzed; and the keymechanical structures and adjusting structure of FORJ are designed.2、The dual-channel fiber optic rotary joint system is set up and adjusted, Boththe insertion loss and rotation changes of the dual-channel FORJ are measured;Besides, the return loss of dual-channel FORJ is tested by building the return losstest system.3、The annular transmission light principle of cone annular optical device isanalyzed. The disadvantage of the solid cone annular optical device are pointed out,and two kind of improvement structures are proposed, the optical input and outputstructures are designed for the hollow cone annular optical device; Theoreticalanalysis is conducted on the relationships of the parameters of the annular opticaldevice, a set of parameters of cone annular optical device are obtained，a new hollowFORJ is designed and fabricated.4、The hollow cone annular optical device is simulated by the optical designsoftware of LightTools to verify the model of optical component. The simulationresults are in well agreement with theoretical analysis and prove that the designedoptical component can be used to transmit the rotary optical signals.