高双折射纳米结构光子晶体光纤特性研究

Characteristics of nano-structured photonic crystal fibers with high birefringence

设计了一种高双折射高非线性纳米结构光子晶体光纤,利用电磁场散射的多极理论研究了这种光纤的双折射、基模模场、色散以及非线性特性.数值研究发现,加大纤芯及包层空气孔的非对称程度,可使双折射变大,其双折射最大值可达1.918×10-2.通过调节孔节距大小,可将双折射最大值调至所需波长处,孔节距为400nm的纳米光子晶体光纤在800nm波长处非线性系数高达0.2m-1.W-1,同时在750—1000nm的波段有较大的双折射值,高双折射和高非线性在纳米结构光子晶体光纤中实现了完美的结合.对新型纳米光子器件的研制和集成光学的发展具有重要意义.

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.