光子晶体光纤色散特性的研究

Dispersion Characteristics of Photonic Crystal Fiber

基于标量近似理论,使用有效折射率方法对光子晶体光纤的群速度色散特性进行了详尽研究。由于光子晶体光纤是由单一材料制成,光纤的总色散便由波导色散决定,将群速度色散分为材料色散和波导色散,在分析光纤结构参数与波导色散关系的同时还讨论了剖面色散对总色散的影响。研究表明:调节光子晶体光纤包层空气柱的节距及其有效芯径,可以实现在很宽的波长范围内的单模传输,可以设计零色散光子晶体光纤和在较宽的波长段接近零色散的色散平坦光纤,以及具有较大正常色散的色散补偿光纤,尤其在零色散光纤设计时必须考虑剖面色散的影响。

Based on a scalar approximation, the group-velocity-dispersion properties of photonic crystal fiber (PCF) were investigated in detail by equivalent-index model, the PCF discussed here is made of a single material, the total dispersion is governed by waveguide dispersion, so the total dispersion has been divided into waveguide dispersion and material dispersion. The dependence of waveguide dispersion on structure parameters is investigated as well as discussion of the effect of section dispersion on the total dispersion of PCF. It is found that PCF can be single-mode transmission over a very broad spectral range by changing the pitch of PCF cladding air holes and its effective core diameter. PCF with zero dispersion, dispersion flattened fiber with nearly zero dispersion over a very broad spectral range and dispersion compensation fiber with a large normal dispersion can be designed. Designing the PCF with zero dispersion, the effect of the section dispersion must be taken into account.