Nonlinearity As Well As Applications Of Optical Fiber With Cladding Made Of Uniaxial Crystal Materials

Besides dispersion and loss of fiber,nonlinearity plays an important role in high-bit-rate and large capacity long-haul optical communication system.Fiber nonlinearity depends on optical and geometrical parameters,thus the nonlinearity can be effectively modified by tailoring the parameters of fibers so that it will be more efficient to serve the next generation optical fiber communication system and optical device design.In this work,the integral expressions of effective mode area and nonlinearity of the optical fiber with cladding made of uniaxial anisotropic crystal material are derived and simulated theoretically.The nonlinearity as well as its applications of this kind of optical fiber is investigated and the main achievements are as follows.1.The ratio of the extraordinary to the ordinary ray index kcl has significant impacts on the optical field distribution.Effective mode area increases as kcl decreases.when kcl <1,at the long wavelength(?>1.3?m),the optical fiber has the more scattering optical mode field and larger effective mode area than those of conventional fibers,resulting in a lower light power density,which can solve the problems of thermal damage and poor light beam quality effectively.2.At the long wavelength(?>1.3?m),the larger kcl is,the higher the nonlinearity is.It indicates nonlinear effects can be minimized if the optical fiber cladding is made of uniaxial anisotropic crystal material with the much smaller kcl(kcl<1).In the optical fiber with the much larger kcl(kcl>1),nonlinear effects is stronger than those of conventional fibers,which provides basis theory for designing nonlinear optical communication components and optical sensors.3.At a given wavelength,such as ?=1.55?m,nonlinearity can be effectively modified by tailoring kcl and changing the fiber core radius,the refractive index of fiber core or relative core-cladding index difference.Results indicate that optimal nonlinearity can be obtained through tailoring kcl together with adjusting fiber parameters.4.When the fiber cladding is made of electro-optic materials LiNbO3 or elasto-optic materials KDP and is applied voltage or strain,continuously tunable nonlinearity can be achieved due to the electro-optic effect of LiNbO3 or elasto-optic effect of KDP.