Characteristics of nano-structured photonic crystal fibers with high birefringence

A kind of high birefringence and highly nonlinear nano-structured photonic crystal fibers (N-PCFs) is proposed. The birefringence, fundamental mode field, dispersion and nonlinear characteristics of the fiber have been studied by electromagnetic scattering theory of multipole. It is found that the birefringence becomes larger by increasing the dissymmetry level of fiber core and air holes in cladding, and the largest birefringence reaches up to 1.918 × 10^-2. With this type of high birefringence and highly nonlinear N-PCFs, the peak of birefringence can be moved to the required wavelength by adjusting the pitch value. The non-linear coefficient of N-PCF with pitch 400 nm reaches up to 0.2 m^-1 · W^-1 in the wavelength of 800 nm. Meanwhile, the birefringence value is also very large in the wavelength range of 750-1000 nm. A perfect combination of high birefringence and high nonlinearity is realized in N-PCF. It is useful for manufacturing new type of nano-photonic apparatus and development of integrated optics.