Research On 1550 Nm Wavalength Filtering And Beam Splitter Device Based On Antiresonant Fiber

Anti-resonant fibers have the characteristics of low loss,low nonlinearity,high damage threshold,wide transmission frequency band,and flexible structural design,making photonic devices based on anti resonant fibers one of the current research hotspots in the field of all optical network communication systems.In order to solve the problems of low extinction ratio and narrow bandwidth based on anti resonant fiber polarization filter and polarization beam splitter,this paper,based on the light guide mechanism of planar optical waveguide,combined with the mode coupling theory and surface plasmon resonance principle,uses the finite element method to study the effects of substrate materials,filler metal and fiber structure on the optical properties,polarization filtering and beam splitting performance of anti resonant fiber.The main research content of the paper is as follows:Firstly,based on the principle of surface plasmon resonance and planar waveguide anti resonance,a polarization filter based on single core anti resonance fiber is designed.When the gold wire is introduced into the surface of individual cladding tubes,free electrons and photons in the metal will resonate,and a certain polarization mode in the fiber core will couple with the surface plasma mode,causing its transmitted light to not pass through the fiber,while another polarization mode will transmit through the fiber at low loss,thereby achieving the purpose of polarization filtering.The polarization filtering characteristics of gold wire filled anti resonant fiber were simulated using finite element method,and the results were obtained at 1.55 μm The polarization filtering effect with a bandwidth of 390 nm near achieves a low polarization loss and high filtering bandwidth anti resonant fiber polarization filter.Secondly,using quartz glass as the substrate material,a polarization beam splitter for dual hollow core anti resonant fibers based on coupling effect was designed,and the physical mechanism of introducing embedded sleeves in the cladding tube to reduce the dependence of coupling length on wavelength and increase bandwidth was explored.By adjusting the coupling channel between two fiber cores,the coupling length of odd and even modes can be changed.The finite element method was used to simulate the effects of fiber structure parameters on the bandwidth and splitting length of the polarization beam splitter,resulting in a polarization beam splitter designed at 1.55 μm.At the wavelength,a beam splitting length of 11.0 cm,a polarization extinction ratio of-39 d B,and a bandwidth of 410 nm were achieved.Finally,using tellurium glass as the substrate material,a polarization beam splitter for dual hollow core anti resonant fibers based on coupling effect was designed,and the influence of changing the substrate material on the coupling length between odd and even modes was studied.By comparing the polarization beam splitter with quartz glass of the same structure,it was found that the increase in the effective refractive index of the substrate material shortens the coupling length between odd and even modes.By optimizing the fiber structure parameters,a tellurium glass polarization beam splitter with broadband width and short length was achieved.