Design Of Novel Photonic Crystal Fiber And Sensing Applications

Photonic Crystal Fiber(PCF) is a new type of optical fiber.Because of its unique optical properties such as high birefringence,single-polarization-single-mode.endless single mode,special dispersion characteristics,high nonlinearity,large mode area and so on. compared with conventional fibers,PCF has become more attractive in recent years. Specially,birefringence,which has potential in applications of optical fiber communications,fiber sensors,fiber laser, and fiber filters.has become one of the research focuses.This paper has introduce the concept, features,research background and current development of PCF.as well as the sensing applications of PCF.Three kinds of structures of PCF are designed and some basic characteristic of PCF.such as birefringence, confinement loss and so on,are numerical studied. The content of the original paper are listed as follow:Firstly,it has introduced the concept,features.research background and current development of PCF.Secondly.it showed the numerical simulation principle and calculation methodThirdly, a novel highly birefringent photonic crystal fiber with elliptical air holes in the fiber cladding and arrays of subwavelength double-hole units in the fiber core was proposed. Dispersion and birefringence property of the proposed PCFs was investigated. The curves between modal birefringence, and confinement loss of the proposed PCFs and the wavelength of the input light for different ellipticities,normalized areas,diameters of the two microholes, distances between the two microholes are reported in details. Simulation results showed that high birefringence and ultralow confinement loss are achieved.Fourth, a novel highly birefringent photonic crystal fiber is proposed based on a lattice structure of three-hole units.Properties such as the birefringence, the confinement loss and the mode area of the proposed PCF based three-hole units are investigated compared with the elliptical air hole PCF and the double-hole PCF. This part also studys the role to achieve the highest birefringence of the proposed PCF of the size of the central air hole of the three air holes.Fifth, a dual-core fiber with two fiber cores and an air hole in the cross-section is proposed for refractive index sensing. The coupled-mode theory if the dual-core fiber and its principle of refractive index sensing are introduced in detail.the sensing characteristics of the dual-core fiber are also studied.Finally.the conclusion and outlook are gived,show the mainly results in this paper and the future works.