Study On Polymeric Waveguide Optical Attenuator

Integrated optics emerges with the development of modern information process system. It can offer integrated optical circuit with different functions to meet the new requirements for optical process system. Optical attenuator is a kind of widely used passive optical component. Recently material used to fabricate waveguide components has achieved considerable development. Among them, polymer has attracted great attention due to its superior characteristics such as low power consumption and easy to fabricate, etc. In this thesis, focusing on polymeric variable optical attenuator, the main content is as follows:Firstly, the development of integrated waveguide components and its fabrication method was introduced, and the function of attenuator was also described. Secondly, the principles of different kinds of optical attenuator were introduced , including type of mechanical-shift,optical attenuator glasses, liquid crystal, micro-electro-mechanical systems(MEMS) and thermo-optical waveguide. Then the basis of thermo-optical attenuator—thermo-optic effect and heat conduction was specially discussed.Thirdly, FD-BPM(Finite Difference-Beam Propagation Method),the method to simulate the variable optical attenuator was introduced. The reliability and its TBC(Transparent Boundary Condition) were also concerned. EIM(Efficient Index Method) was then analyzed which is used to transfer a 3-D waveguide to 2-D waveguide and simplify the simulation.Fourthly, a detailed process to design and optimize a variable optical attenuator was researched. Based on the theory of heat conduction, the heater thermal field was calculated to determine the most efficient position of heater. And the parameters of heater and asymmetric Y branch were decided using FD-BPM method. After the design and optimization, the polarization dependence and wavelength dependence of the attenuator were researched.Finally, the effect of spin coating polymer film error to the attenuator was simulated. Three kinds of errors were considered, which were film thickness, waveguides width and angle of Y branch. This thesis put forward a method to design and simulate a kind of waveguide component and will help to design other integrated waveguide components.