Design Of Surface Plasmon Microstructure Optice Fiber Polarization Beam Splitter

With the development of communication technology,the traditional optoelectronic communication system is gradually transforming into all-optical communication system.All-optical communication system requires the high-performance optical devices,and the polarization beam splitter has the function of splitting into two polarization states of a beam of light,which is one of the indispensable devices in the all-optical communication system.Microstructure optical fibers have been widely studied because of their adjustable structures and unique optical properties,and have a wide range of applications in the field of optical devices.Filling the metals into microstructure optical fibers can produce surface plasmon resonance effect,a special physical phenomenon formed between the light and metal,which makes this kind of microstructure optical fiber have better properties compared to the traditional microstructure optical fiber.Therefore,the surface plasmon microstructure optical fiber polarization beam splitter has excellent performance,so it is the development direction in the future.Based on the theory of the two-core coupling mode of microstructure optical fiber and surface plasmon resonance effect,two new polarization beam splitters are designed in this paper.With the finite element method,the beam splitting characteristics of the polarizing beam splitter are studied.The specific research contents and results are summarized as follows:An ultra-short polarization beam splitter based on a dual-core microstructure optical fiber with pure sillica substrate is designed,and the birefeingence is enhanced by introducing the elliptical air holes.The elliptical air hole is filled with the gold rod,and the surface plasmon polaritons mode excited by the gold rods is coupled with the core mode,which increases the beam splitting properties of the device.By numerical simulation analysis,the influence of each structural parameter on the performance of the polarization beam splitter is studied,the optimal parameter combination is obtained,and the device length is 62.5 μm is achieved,which reduces the space ratio of the device.An ultra-wideband polarization beam splitter based on dual-core microstructure optical fiber with a sulfur-based glass substrate is designed.The small air holes arranged in V shape are introduced into the cladding region,and the elliptical air holes are introduced into the fiber core region to increase the birefringence.The elliptical air hole is filled with the gold rod,and the surface plasmon polaritons mode excited by the gold rods is coupled with the core mode,enhancing the beam splitting characteristics.The influence of its structural parameters on the performance of the polarization beam splitter is studied,the optimal parameter combination is obtained,and the working bandwidth can be up to 350 nm,covering the E+S+C+L+U band.According to the theory related to microstructure optical fiber,two kinds of of microstructure optical fiber polarization beam splitter are studied numerically.The device length and working bandwidth are obviously improved by introducing the elliptical holes and filling the gold material.These achievements can promote the fabrication and practical application of microstructure optical fiber polarization beam splitter,and provide an important reference for the development of microstructure optical fiber devices.