Study On Coupling System Of Off-axis Fiber Optic Rotary Joint

Fiber Optic Rotary Joint(FORJ)is a passive fiber optic connector for military radar,robotics,medical CT scanners,etc.,to realize optical signal rotation coupling transmission.The core mechanism of fiber optic rotary connector is optical signal coupling theory,which includes the rotation coupling of optical signal on the relative rotating platform and the coupling of optical signal at the input and output ports.How to improve the coupling efficiency of optical signal is the core problem of fiber optic rotary connector,and the coupling efficiency directly determines the performance of optical fiber rotary connector.Thus,this paper is worth researching.Compared with coaxial FORJ,optical signal coupling of off-axis FORJ is much more difficult,because it is not only necessary to achieve optical signal rotation coupling in hollow situation,but also to achieve signal output coupling in bypass output,which is the key constraint of off-axis FORJ implementation.Based on the realization of optical signal rotation coupling in the original hollow situation of the laboratory,this paper establishes a model of optical signal coupling in the off-axis FORJ output channel,analyzes the factors affecting the coupling of bypass optical signals,gives the method of bypass optical signal transmission steering,designs the coupling lens group of output signal and receiving optical fiber,and simulates the feasibility of the method and calculates the coupling efficiency of the coupling system.The main work of this paper:1.Study on the characteristics of the beam emitted by the plane-cone reflection structure: Because the ejection beam and the rotating axis are angled and the beams of different moments are different from each other,it is a difficult problem to study how to turn this complex beam into a beam parallel to the rotating axis.According to the characteristic conditions of the emitting beam,the structural parameters of the planecone reflection structure can be analyzed.2.A design of the beam steering of the ejection signal according to the principle of Evolvent and Involute Surface: By the nature of Evolvent,the steering effect of Evolvent for signal beam horizontal component can be analyzed;drawing the fade-out line as an upright fade-on face,the vertically open-faced signal beam steering can be discussed.;tilting the vertical fade-out face into an oblique fade-out surface,the effectiveness of the tilted fade-out face turning to the out-of-shot signal beam can be clarified.For steering signal beam equivalent,the lens group lens parameters can be determined and the lens group be designed according to the fiber coupling conditions.3.Modeling and optical simulation of the main components of the coupling system:It mainly includes plane-cone reflection structure modeling and optical simulation,surface substrate modeling and simulation,lens group-fiber coupling efficiency simulation,along with the theoretical computational efficiency and simulation efficiency of the components of the coupling system,and the coupling efficiency theory calculation and simulation of the whole coupling system.