Study of the sensitivity of gas sensing by use of index-guiding photonic crystal fibers.
We demonstrate an absorption transmission spectrum of CH(4) in a 16.9 cm long index-guiding photonic crystal fiber (PCF) fabricated in our laboratory. One of the main factors to improve the sensitivity is to increase the fraction of power in PCF cladding air holes. We study the fraction of power in PCF cladding air holes as a function of the index-guiding PCF parameters. We found that a PCF with small spacing and a large air-filling ratio has a higher fraction of power in its cladding air holes. At the same time the mode area in this PCF is small and would generate strong nonlinear effects in the fiber. If we use a PCF in which the core is formed by missing seven air holes, it is immediately obvious that the PCF used as a sensor has higher sensitivity and a larger mode area.
Li
Shu-Guang
SG
College of Science and Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China. shuguangli@ysu.edu.cn
Liu
Si-Ying
SY
Song
Zhao-Yuan
ZY
Han
Yin
Y
Cheng
Tong-Lei
TL
Zhou
Gui-Yao
GY
Hou
Lan-Tian
LT