Objective: Optical fiber communications technology has greatly improved the information transmission speed and capacity

and it has become a major information transmission technology. Fiber optical rotary joint technologies could be used in some occasion to transmit signals continuously from rotary platform to stationary platform. Fiber optic rotary joint with large transmission capacity

small size

light weight and good performance in electromagnetic compatibility has been widely studied and applied. Method: A novel multi-channel optical rotary joint using square-cylinder de-rotating prism was proposed based on analyzing principle of the de-rotating prism multi-channel Fiber optical rotary joint. Result: The results of analysis of coupling characteristic of this optical rotary joint indicate that its insert loss mainly comes from the mechanical inaccuracy and the spherical aberration of de-rotating prism. The insert loss is below 2.0 dB according to the results of numerical simulation. Conclusion: This entirely meets the requirement of military equipment such as radar system

and has widespread application prospect.