Design Of Photonic Crystal Fiber Polarization Device And Experimental Study On Femtosecond Laser Transmission

Compared with the traditional silica optical fibers,photonic crystal fibers have many properties,such as highly adjustable dispersion characteristics,no cut-off single mode transmission characteristics,high birefringence characteristics and flexible nonlinear control.Material filling is a technology for post-processing photonic crystal fibers,which can enhance and expand the performance of PCFs by filling metal,liquid crystal or other optical functional meterials.In this paper,two kinds of gold-coated photonic crystal fibers are designed,and their polarization splitting or polarization filtering properties are numerically studied.The experimental platform is designed and the basic characteristics of photonic crystal fiber are experimentally tested.The details are as follows:Firstly,the research background of photonic crystal fiber is introduced,and the main theoretical research methods of photonic crystal fiber are summarized.The theoretical basis of surface plasmonic photonic crystal fiber is given.Secondly,a new double core photonic crystal fiber polarization beam splitter is designed.The finite element method is used to simulate the beam splitting characteristics.The polarization splitting characteristics of the optical fiber in the optical communication band are studied by adjusting the structural parameters and the thickness of the gold film.Again,a photonic crystal fiber filter with a rectangular stomatal array containing elliptical pores was designed and simulated.The effect of gold and gold on its transmission characteristics,as well as the thickness of metal layer and the effect of air holes around the core,were studied.And explores the trend of its loss with wavelength.As the polarization filter operating wavelength can be transferred to the 1.55?m optical communication window.Finally,build the the experimental platform to test the laboratory homemade fiber by femtosecond laser experiment.The optical fiber is used to grind the end face of the optical fiber.Then,the single-modefiber and the photonic crystal fiber are welded by the fiber splicing machine,and the optical path is further built.The transmission spectrum and the nonlinear effect of the photonic crystal fiber are studied experimentally.The measured fiber has a very strong nonlinear effect,the energy from 180 nm to infrared band occurred in thetransfer.