Study Of Slow Light Delays Using Stimulated Brillouin Scattering In Photonic Crystal Fibers

Different from traditional fiber, photonic crystal fiber (PCF) possesses some excellent characteristics, such as high birefringence, high nonlinearity, chromatic dispersion controllable and endlessly single mode transmission, and it has unparalleled advantages in optical signal transmission and optical sensing. With the development of the application filed on PCF, the design, analysis and application of new type PCF become one of the hot research fields in recent years. Based on stimulated Brillouin scattering (SBS), the slow light effect in PCF is investigated systematically. The main research results are as follows:A liquid-core photonic crystal fiber (LCPCF) with excellent slow light characteristics was designed, which is filled with CS2 material. The basic characteristics of the LCPCF are analyzed by using the full vector finite element method. The influence of the structural parameters on the stimulated Brillouin effect threshold, Brillouin gain and time delay is analyzed by SBS slow light theory. From the numerical simulation, it is reasonable to adjust the structural parameters of the fiber so that the nonlinear coefficient ? can reach 15W-1 · m-1 at the wavelength ? =1.064?m. In addition, when the structural parameter A=1.2?m, d1=0.9?m, d2=0.5?m,the LCPCF with lm long can obtain 134.44ns of slow light at ?=1.064?m when the pump power is 65.8mW.A kind of mixed photonic crystal fiber with As2S3 material as the background material and As38Se62 material as the solid core is designed. The structure is made of all round holes, which is easy to be drawn. Due to the high refractive index of these two materials and the large difference in refractive index values, it is possible to obtain very high nonlinearity even in a relatively simple structure. The results show that the optimum structural parameters are ?=1?m, r2==0.3um, r1/?=0.3 at the wavelength of 1550nm by adjusting the pore spacing and the radius of the core hole of the cladding air hole. At the wavelength of 1550nm, the effective modulus of the structure is 0.572um2, the nonlinear coefficient reaches 78W-1 m-1, and the single mode is realized. At the same time, when the pump power is 5.2mW, the 1m long mixed photonic crystal fiber get 236ns maximum slow light delay.A photonic crystal fiber based on As2Se3 background material is designed. Four circular air holes were introduced into the core, and the air holes used in the whole structure were round and obtained by numerical simulation of the full vector finite element method. Under certain parameters, they were effective at the wavelength of 1.56?m, The module area reaches 0.49um2, and the nonlinear coefficient reaches 89.8W-1 · m-1. The optimal parameters are ?1=1.6um,d1=1.5um,?2=1um,d2=1um,and the slow delay time is linearly increased from Ons to 251ns with the increase of pump power,and the slope is 89.6 ns/mW,by changing the size of the pump optical power to achieve controllable time delay.