School of Mechanical Engineering, Beijing Institute of Technology, 100081, China.
Sensors (Basel). 2011;11(1):54-61. doi: 10.3390/s110100054. Epub 2010 Dec 23.
During new fiber sensor development experiments, an easy-to-fabricate simple sensing structure with a trench and partially ablated fiber core is fabricated by using an 800 nm 35 fs 1 kHz laser. It is demonstrated that the structure forms a Mach-Zehnder interferometer (MZI) with the interference between the laser light passing through the air in the trench cavity and that in the remained fiber core. The fringe visibilities are all more than 25 dB. The transmission spectra vary with the femtosecond (fs) laser ablation scanning cycle. The free spectral range (FSR) decreases as the trench length increases. The MZI structure is of very high fabrication and sensing repeatability. The sensing mechanism is theoretically discussed, which is in agreement with experiments. The test sensitivity for acetone vapor is about 10(4) nm/RIU, and the temperature sensitivity is 51.5 pm/°C at 200 ∼ 875 °C with a step of 25 °C.
在新的光纤传感器开发实验中，通过使用 800nm、35fs、1kHz 的激光制作了一个易于制造的具有浅槽和部分烧蚀光纤芯的简单传感结构。结果表明，该结构形成了马赫-曾德尔干涉仪（MZI），激光光通过浅槽腔中的空气和剩余光纤芯中的光之间产生干涉。条纹可见度均大于 25dB。传输光谱随飞秒（fs）激光烧蚀扫描周期而变化。自由光谱范围（FSR）随浅槽长度的增加而减小。MZI 结构具有非常高的制造和传感重复性。从理论上讨论了传感机制，该机制与实验结果一致。对丙酮蒸气的测试灵敏度约为 10(4)nm/RIU，在 200∼875°C 范围内温度灵敏度为 51.5pm/°C，步长为 25°C。
