增大光场与气体的作用范围是提高光子晶体光纤(PCF)气体传感灵敏度的主要途径之一。首先, 利用多极方法模拟了空芯光子晶体光纤中的功率分数随波长的变化关系, 研究发现带隙型光子晶体光纤纤芯中光功率分数随波长变化是不连续的, 其最大值可达90%, 最小值不到5%。纤芯中光功率分数随波长的分布还与光子晶体光纤包层的空气填充率有关。其次, 通过平面波展开方法计算了相应光子晶体光纤周期性包层所导致的光子带隙, 研究发现纤芯中的功率分数与光子晶体光纤周期性包层光子带隙的特征有着密切的联系。只要被检测气体的特征波段落入空芯光子晶体光纤的光子带隙中, 纤芯中的光功率分数就会远大于实芯光子晶体光纤倏逝波吸收传感时气孔中的功率分数。

Increasing the effect of the light field and gases is one of the major ways to improve the photonic crystal fiber (PCF) gases sensing sensitivity. The power fraction in the hollow-core PCF (HC-PCF) changing with the wavelength is simulated by the multi-pole method. The power fraction in the HC-PCF changing with the wavelength is discontiguous, the maximum is more than 90% and the minimum is less than 5%.The power fraction in the HC-PCF changing with the wavelength is also relation to the air filling rate of the envelope. The photonic band gap is calculated by the plane-wave expansion method, the power fraction is relation to the photonic band gap character of PCF. As long as the characteristic wavelength of the detected gases is in the photonic band gap, the power fraction in the HC-PCF will be much bigger than the fraction of power which is made for the evanescent wave of solid-core PCF absorption.