一种新的低非线性宽带色散补偿微结构光纤的设计

采用矢量光束传输法对空气孔包层呈正六边形分布的微结构光纤的色散和非线性特性进行了数值模拟。通过分别调节内三层空气孔的直径和包层空气孔节距,设计了一种低非线性宽带色散补偿微结构光纤。该光纤在波长1.55 μm处具有－3 235.8 ps/nm/km的大负色散,可在以1.55 μm为中心的100 nm宽带波长范围对相当于自身长度190倍的普通单模传输光纤进行宽带色散补偿(色散补偿率偏移在0.5%以内),同时该光纤可在此宽带波长范围内保持非线性系数低于5 W^-1·km^-1。

Design of a Novel Microstructure Fiber with Broadband Dispersion Compensation and Low Nonlinearity

The dispersion-induced broadening of the optical pulses and nonlinear effects are the adverse limitation in modern optical communications;moreover, high powers can be transmitted without and unwanted nonlinear effects in high-speed and long-haul optical systems. The advent of microstructure fiber affords a novel approach to address these difficulties. For compensating the positive dispersion of the single mode fiber over a wide wavelength range in wavelength division multiplexing systems, the microstructure fiber for broadband dispersion compensation have large negative dispersion magnitudes and proper negative dispersion slope while keeping low nonlinearity. The dispersive and nonlinear properties of the microstructure fiber with hexagonally distributed air-holes in the cladding are numerically simulated by using the vectorial beam propagation method. A microstructure fiber for broadband dispersion compensation with low nonlinearity was designed through separately adjusting the diameters of the inner three air-hole rings and the lattice pitch in the cladding. The proposed microstructure fiber has a large negative dispersion of -3 235.8 ps/nm/km at the wavelength of 1.55 μm, which can compensate (to within 0.5% of the dispersion compensation ratio) the dispersion of 190 times length of standard single mode fiber over the entire 100 wavelength range centered at 1.55 μm. Furthermore, the proposed fiber also can retain the nonlinear coefficient lower than 5 W~(-1)·km~(-1) over this wide wavelength range. The proposed microstructure fiber can be used as function of dispersion-compensating device in high-capacity and long-distance modern optical transmission systems.