Research On Microfluidic Waveguide Optical Switch Based On Total Reflection

The basic function of the optical switch is to enable optical signals to be selectively switched-on and-off or switched from one channel to another.With the development of all-optical communication networks,optical cross-connect(OXC)technology plays an increasingly important role.And the optical switch is a key component in OXC.The optical switch can realize functions such as dynamic optical path management,optical network fault protection and dynamic wavelength allocation.The optical switch is also used in some optoelectronic subsystems besides in optical communication.Common optical switches include MEMS(Micro Electro Mechanical System)switch,electro-optical switch,acousto-optic switch and liquid crystal optical switch.MEMS optical switch is large in size,which is not conducive to integration and array design,and its performance is affected by the mechanical moving parts due to mechanical wear.Other optical switches are easily affected by temperature or environment,and have low performance stability,high insertion loss and polarization-related loss.Miniaturization and integration optical switch with good performance is the future development direction.As an emerging discipline,microfluidic optics has the advantages of small size,easy integration and flexible adjustment.Microfluidic optics can provide new solutions for optical communication technology.In this paper,by combining microfluidic optics and optical communication technology and using evanescent wave and optical waveguide theory,a microfluidic waveguide optical switch based on total reflection is proposed.The proposed optical switch utilizes a small amount of liquid and compressible air to realize channel switch.It has no mechanical moving parts,simple structure,small vol?me and can be integrated.Also,it can be directly connected to an optical fiber so as to reduce coupling loss,and has no polarization-related loss,small insertion loss and wavelength-related loss.In addition,it can be designed as a switch array.The research work in this paper has solved some of the existing problems of optical switch,and can provide a new idea for miniaturization,integration and good performance optical switch.The main research contents of this paper include: based on a large n?mber of investigations on microfluidic optics,optical waveguide theory and optical switch technology,the basic structure of a microfluidic waveguide optical switch based on total reflection is proposed;then it are designed as1×2,2×2 and 1×3 optical switches,and the working principle and preparation process are given.Since most optical switches work in single mode,this paper takes the designed 2×2 and 1×3 optical switches as examples to focus on the single mode transmission characteristics of optical switches.Because few-mode optical switches are rarely reported,the few-mode transmission characteristics of the designed 1×2 optical switch is studied in this paper.In Chapter 3,using the finite difference method and FDTD Solutions software,the single-mode transmission characteristics of the 2×2 and1×3 optical switches are researched,the influence of the microchannel and optical waveguide structure on the optical switch performance is discussed,and the structure is optimized.After optimized,at two output ports of the 2×2 optical switch,the insertion losses are respectively 0.52 d B and 0.26 d B,and the crosstalks are respectively-27.62 d B and-50.35 d B.At three output ports of 1×3 optical switch,the insertion losses are 0.44 d B,0.20 d B and 0.47 d B respectively,and the crosstalks are all lower than-25 d B.The insertion losses and crosstalks of the two optical switches are low;Then the comsol software is used to simulate and analyze the flow field characteristics in the microchannel of the control unit of the optical switch,and the response time of the optical switch is measured to be about 400 us;In addition,combined with the mode degeneracy theory,the optical characteristic of 1×2 few-mode waveguide optical switch is studied in chapter 4.When the wavelength is 1550 nm,under two mode(LP01 and LP11)operation,the insertion losses of two output ports are 0.54 d B and 0.42 d B,and the crosstalks are-20.4 d B and-48.0 d B;under the four-mode(LP01,LP11,LP02 and LP21)operation,the insertion losses of two output ports are below 0.6 d B,and the crosstalks are below-20 d B.