Research On Polarization-independent Triplexer Based On Polymer Material

Driven by increasing demand for broadband services and access network,Fiber-To-The-House (FTTH) has been intensively investigated for its unlimited bandwidth.With the develop of FTTH,the ultimate goal is to realize the union of CATV,telephone and internet,so triplexer is one of the key components in FTTH.This theisis suggests a novel structure for triplexer, which is more integrated compared to traditional ones.In addition,based on the birefringence material PPESK,polarization dependence problem is effectively solved.First,the basic theories of optical waveguides are thoroughly investigated.The waveguide propagation condition for three-layer symmetric and asymmetric slab waveguides is deduced from Maxwell's equations.Especially,the effective index method for channel waveguides is introduced.In addition,the frequently used numerical simulation method for waveguides——Finite-Difference-Beam-Propagation Method(FD-BPM).All of the work above can shed light on the design and analysis for the triplexer.Then the design and analyze of low insertion Y-branch waveguide based on polymer material PSQ-L is followed.The two important structure parameters(transition length and branch height) are simulated respectively by FD-BPM.The results provide a useful reference for designing and fabricating the Y-branch waveguide.At last,the thesis designs detailed structure of the asymmetric Y-branch triplexer,which includes the theory of the triplexer and the design of the unitary structure.In detail,it includes the design of the asymmetric waveguide,the height and width of the cross section of the waveguide,the length and the angle of the Y-branch waveguide.The effect of the angle and the length of the Y-branch on the insertion loss and crosstalk is analyzed by the combination of effective index method and waveguide simulation software BeamPROP^TM.Polarization dependence is a large problem lying in this structure.Based on the birefringence material, polarization dependence problem is effectively solved.Based on these analyses,the whole structure of the triplexer based on the polymer material PPESK is developed.The simulation result shows that this proposed triplexer can be used in FTTH application with low insertion loss,low crosstalk and polarization-independent.