Thermo-Optic Mode-Selective Switch Based On Polymer Optical Waveguide Asymmetric Directional Coupler

Thanks to the improvement of science and technology,billions of smart devices are continuously connecting to networks and constantly exchanging information.As a result,the transmission capacity of standard single-mode fiber has closely approached theoretical limit.To deal with this challenge,new technologies have been developing to improve transmission capacity of optical networks,in which the most promising technology is Mode-division Multiplexing?MDM?.The reconfigurable Mode-division Multiplexing?RMDM?system could switch mode channel expediently to decline the blocking probability of the network and improve the utilization ratio of the network according to the requirement of the network traffic.In a RMDM system,mode-selective switch that provide more flexibility of optical network is necessary for signal routing.In this dissertation,we propose and demonstrate a simple and compact thermo-optic mode-selective switch based on an asymmetric polymer optical waveguide directional coupler?ADC?formed with a single-mode waveguide?SMW?and a two-mode waveguide?TMW?as well as two heaters located respectively on the top of the two waveguides.With such a configuration,the LP₀₁ mode in the SMW can be selectively coupled to the LP₀₁ mode or the LP_11a mode in the TMW just by applying suitable current across one or the other of the two heaters while the coupling between the modes in the two waveguides is almost impossible when the two heater states are off.Firstly,the principle of directional coupler is introduced simply.Then,the device structure and experimental results based on configuration one are analyzed.Next,we optimize design of mode-selective switch and propose another structure,i.e.the configuration two.The principle of and design of the configuration two are investigated.To effectively utilize the power of the two heaters and improve the temporal switching characteristics of our proposed mode-selective switch,we optimize the design of the heater.Then,we build physical model to carry out the joint simulation of thermal field and optical field with commercial software?COMSOL?.Finally,we get the relevant parameters to design the mask.The fabrication and test of the mode-selective switch are introduced in detail.