Xinghu Fu

Investigation of a shape curve function for a special solid coupled optical taper

For a special solid coupled optical taper, a differential equation of its shape curve is deduced using the curvature-shape matching relationship, and the closed-form solution of the equation can be acquired by its concrete initial curvature and shape boundary condition. Since the physical formation process in different tapering conditions can be described conveniently by the solution, the variation relationships among the taper length, shape factor, large-end radius, small-end radius, and shape function are analyzed. The results show that the theoretical simulation is basically in accordance with the experimental data and the errors are also given. Thus, given the shape factor parameters of the special solid coupled optical taper, the solution can be properly used to predict the taper shape curve for any taper length, large-end radius, and small-end radius.

A novel receiving system based on optical taper applied to wireless optical communication

A novel optical receiver in wireless optical communication system is presented. The receiving method is demonstrated based on an optical taper. The taper is mounted near the focus spot of the receiving lens along the principal axis. The larger-area end of the taper receives the converging beam and the smaller-area end transmits optical power to detector or optical fiber. In this way, the immunity to light beam deviation in wireless optical communication system can be enhanced evidently. The theoretical and experimental results show that the system has a perfect performance and realizes a low loss of 4dB for the range of field of view within 1mrad.

The coupling efficiency for different shape curve of specialty optical taper

A specialty optical taper is proposed for receiving optical signal. According to the geometrical optics, the coupling efficiency for different shape curve is analyzed, such as piecewise function type, parabola type, and linear type. The relationship between the different large endface radius, small endface radius, taper length, refractive index and coupling efficiency is analyzed, respectively. By comparing the input and output light energy of specialty optical taper, the coupling efficiency can be analyzed in experiment. The experimental results are in good accordance with the theoretical data. For the ±1.5 mm radial displacement, the coupling efficiency can be more than 50% in different directions, respectively. Finally, the errors are also given.

Analyzing the receiving power of rectilinear mobile/free-space optical links by considering the effect of laser beam divergence and deflection angles

For rectilinear mobile/free-space optical (RM-FSO) links, laser beam divergence and deflection angles are key factors to get highly accurate receiving power. The effective receiving area of the receiving-lens (R-lens) is presented and used to investigate receiving power under different circumstances. By comparing the optical spot size on the receiving plane with the R-lens diameter, the effects of laser beam divergence and deflection angles on receiving power are analyzed. The results show that the theoretical simulation is basically consistent with the experimental data, and the errors are given. Thus, given different moving situations of RM-FSO links, the solution can be used to analyze the receiving power more effectively by considering the effect of laser beam divergence and deflection angles.

Investigation of the coupling efficiency for specialty solid coupled optical taper

A specialty solid coupled (SSC) optical taper was introduced into the receiving termination for the rectilinear mobile wireless optical communication. Based on the curvature-shape matching relationship, the profile curve equation for SSC optical taper has been deduced. According to ray-tracing method, the optical coupling efficiency can be analyzed by the comparing the input and output light energy based on Fresnel reflection loss principle. The variation relationships among the taper length, shape factor, large end radius, small end radius, radial displacement, incidence depth, and coupling loss are analyzed. The results show that the theoretical simulation is in good accordance with the experimental data. The errors were also given. The coupling loss was less than 10dB as the radial displacements vary within 1.5 mm in x and y directions, respectively. For this experimental system, the receiving performance of SSC optical taper can satisfy the communication.