Spatial Mode Discriminator Based On Leaky Waveguides

With the development of the Internet,people are increasingly demanding transmission capacity and information speed.The optical waveguide represented by the optical fiber also becomes the main carrier of information transmission.Optical information including frequency,polarization,spatial modal distribution,and the like is encoded into various channel information,and the signals are transmitted through the optical waveguide.It is important to extract the resolution of the spatial modal distribution and optimize the efficiency of the mode resolution.The most common mode resolution methods are terminal cut detection and mode multiplexing,but the first method blocks the transmission of light and the second method reduces the optical mode.The pattern discriminator of the leaky-mode waveguide we designed can solve the above problems.In the second chapter,based on the background of finite element research and the principle of algorithm,the specific solving steps of the finite element problem in the two-dimensional solution domain are introduced.Then simulate the leak mode in the COMSOL software.In the third chapter,the eigenmode solution of the w-type leaky mode waveguide is derived by using MATLAB software,and the consistency between the analytical solution and the simulation solution is proved.According to the leakage mode characteristic of the w-type leakage mode waveguide,a mode discriminator composed of two bound mode waveguides,a leakage mode waveguide and a detector array is designed.For leak modes with different propagation constants,the detector can be used to detect the associated leakage angle;for degenerate modes with the same propagation constant,the detector can be used to detect the distribution of leakage energy.The device can realize on-line extraction and accurate analysis of modal signals in the optical waveguide without impairing the integrity of the initial signal,and plays an important role in promoting the development of optical communication.