设计了一种以As2S3玻璃为纤芯、碲酸盐玻璃为微结构包层的锥形光子晶体光纤.该结构光纤兼具阶跃折射率光纤和光子晶体光纤双重特性, 具有色散调制灵活性高且限制损耗低等优点.模拟结果表明：优化该光纤结构包层空气孔径、孔间距、纤芯直径等特征参量, 使参量之间及参量与椎区长度之间满足特定线性关系时, 该光纤在2～4.5 μm中红外波段呈现色散平坦渐减特性; 对该光纤微包层进行折射率~1.6的液体油填充处理, 色散曲线对称性及平坦性得到进一步优化.该光纤在超短脉冲压缩与展宽、色散波、光孤子及中红外平坦超连续谱产生等领域应用潜力巨大.

A photonic crystal fiber with As2S3 glass core and tellurite glass micro-cladding was designed. This design is a perfect conbination of both traditional step index fiber and photonic crystal fiber and own the characteristics of high dispersion adjustment flexibility and low confinement lose. Simulation results show that, by carefully optimizing the characteristic structure parameters such as the fiber cladding air holes diameter , air hole pitches and fiber core diameter of this fiber, and while letting the parameters above meet linear relationship with fiber length, the dispersion profile of this fiber will be flattened and decreasing with fiber length in mid-infrared region of 2～4.5 μm. In addition, we optimized the dispersion of this fiber by filling the air holes of micro-cladding with oil which linear index is around 1.6. Fiber with such novel dispersion property is rare and will be of great importance in applications of laser pulse compression and stretching, dispersive wave generation, soliton and mid-infrared super-continuum generation.