Simulation Research On Photonic Devices Based On Photonic Crystal Fiber Filled With Functional Materials

Photonic crystal fiber(PCF)is a special optical fiber with periodic or quasi periodic arrangement of air holes that can run through the entire length.Optical functional material is a kind of material of which the optical properties may be changed or modulated by the action of force,sound,heat,electricity,magnetism or light.The porous properties of PCF provide a new opportunity for the preparation of material filled fiber.The filling of PCF with functional materials is expected to greatly expand the performance and application range of optical fiber,so as to facilitate the realization of the new type of photonic devices.In this paper,metal,temperature-sensitive liquid,magnetic fluid and soft glass are selectively or fully filled into the pores of PCF,various types of PCF polarization devices and sensors are designed.Firstly,the PCF filled with metal wire or coated with metal film is designed,and many kinds of polarization filters are realized.When the optical fiber mode and the surface plasmon mode satisfy the phase matching condition,the coupling of the two modes can happen,a part of the energy of the core mode is coupled to the metal surface resulting in a rapid attenuation of the energy of a polarization mode in the fiber,and then the filtering effect is achieved.The drift of resonance wavelength is observed by changing the optical fiber parameters,polarization filtering can be realized at 1.31 ?m and 1.55 ?m simultaneously by optimizing the fiber parameters,and the tunable polarization filter is realized by filling high-index liquid in air hole selectively.Secondly,the polarization beam splitter of metal and soft glass selectively filling dualcore PCF is designed,the effects of optical fiber parameters,metal and soft glass on the coupling length and coupling length ratio of the dual-core PCF are observed,the insertion loss and beam splitting performance of the polarization beam splitter of the PCF are studied under the optimized parameters.There is a certain error in the optical fiber parameters between the drawn PCF and the theoretically designed fiber.Therefore,we consider the influence of the fluctuation of optical fiber parameters on the performance of the polarization splitting.The birefringence of the PCF filled and unfilled metal is compared,the results show that the birefringence of the PCF is improved by the metal and the performance of polarization beam splitting is achieved.Thirdly,the temperature-sensitive liquid selectivity and full filled PCF temperature sensors were designed.The temperature-sensitive liquid is filled in the central air hole of the six-core fiber,and the temperature field is detected by the coupling of the optical fiber mode and the liquid core mode.It also proved that the temperature-sensitive liquid filling in the central air hole coated with the metal film for the six-core optical fiber can improve the sensitivity.The liquid-core mode can be formed by filling high refractive index temperaturesensitive liquid in optical fiber,and the sensitivity of the sensor is further improved by using liquid-core mode and surface plasmon mode resonance coupling.Through the full filling of the temperature-sensitive liquid in the PCF air holes,the ultra high sensitivity temperature sensor is realized by using the Sagnac interferometer.Finally,a magnetic fluid filled PCF Sagnac interferometric magnetic field sensor is designed.The light emitted by the light source is divided into two beams through a coupler,a beam of light travels along the clockwise direction,the other one travels along the counterclockwise direction.The two beams with phase difference finally form a beam through the coupler and generate interference.A high sensitivity magnetic field sensor is realized by using a high birefringent fiber filled with magnetic fluid.A defect core is formed by introducing small air hole in the fiber core,because the defect core itself contains magnetic fluid,the external magnetic field has a greater impact on the optical fiber mode,the sensitivity of the magnetic field sensor is further improved.