Design And Characteristics Of Photonic Crystal Fiber Polarizers

Photonic crystal fiber(PCF)is a microstructured fiber with excellent properties such as flat,near-zero dispersion,real-time detection,and high birefringence.In recent years,PCF devices based on the surface plasmon resonance(SPR)effect have been paid close attention by researchers,showing great potential in biosensors,filters,couplers,and optical instruments.With the rapid development of optical communication technology,higher requirements are put forward for high-performance polarization filters and beam splitters.In this paper,the structure of optical communication filters and beam splitters is designed and explored,and two splitters with different functions are designed respectively.A beam filter and a filter are used to deeply investigate the influence of structural parameters on filtering characteristics and beam splitting characteristics and their changing laws,and provide theoretical guidance for their application in the field of optical communication.(1)An ultra-short polarization beam splitter based on the SPR effect is designed,which realizes the polarization beam splitting of light waves at 1.31 μm and 1.55 μm.When the communication wavelength is 1.31 μm,the optimal fiber length,extinction ratio and bandwidth are 14.52 μm,114.02 d B and 257 nm,respectively.When the communication wavelength is 1.55 μm,the optimal fiber length,extinction ratio and bandwidth of the beam splitter are 11.02 μm,111.86 d B and 177 nm,respectively(2)A multifunctional dual-core photonic crystal fiber polarization beam splitter is proposed.At λ = 1.31 μm,the fiber length is 14.55 μm,and the bandwidths of the x and y polarization modes are 257 and 238 nm,respectively.In the case of λ = 1.55 μm,the fiber length is 10.86 μm,and the bandwidths of the x and y polarization modes are 239 and 174 nm,respectively.(3)A single-channel photonic crystal fiber polarization filter based on rhombus structure was designed,using silica as the base material and gold as the filling material.The numerical simulation results show that at the communication wavelength of 1.31 μm,the loss peak in the y-polarization direction is 2305.72 d B/cm,and the x-polarization loss is as low as 75.86 d B/cm.When the fiber length is 1000 μm,the crosstalk reaches 1936.83 d B,the bandwidth can reach more than 800 nm,and it has excellent filtering characteristics.