基于飞秒激光加工的马赫-曾德尔干涉氢气传感器

Mach-Zehnder Interference Hydrogen Sensor Based on Femtosecond Laser Processing

介绍了一种基于光纤微加工的氢气传感技术方案。利用波长为800nm的飞秒激光脉冲在普通单模光纤上加工马赫-曾德尔(M-Z)干涉腔,并采用磁控溅射方法在加工后的M-Z干涉微腔上溅射钯(Pd)膜,制备了一种新型的光纤氢气传感器。分析了加工工艺对微腔干涉效果的影响,选择合适的加工参数以及加工后对微腔进行后续处理,可使微腔的透射光谱的分辨率得到提高。实验研究了腔长为40μm的M-Z干涉传感器分别镀36nm、110nmPd膜后,对氢气的响应。结果表明,在不同的氢气浓度下,镀Pd膜的M-Z干涉传感器都表现出对氢气的敏感特性,随着氢气浓度的增大,透射光谱会向长波长方向偏移,其中Pd膜厚度为110nm比厚度为36nm的传感器对氢气有更好的灵敏度。

A kind of hydrogen sensing technologic solution is proposed based on optical fiber micromachining. The femtosecond laser with 800 nm wavelength is used to fabricate a Mach-Zehnder （M-Z） interference cavity in single- mode optical fiber, and the palladium（Pd） film is deposited in the M-Z interference cavity by magnetron sputtering processing to make novel optical fiber hydrogen gas sensor. The effect of micromachining process on microcavity interference is analyzed. The resolution of the transmission spectrum is improved by choosing the right processing parameters and the follow-up processing of the cavity. The response to hydrogen of M-Z interference sensor is experimentally studied with the cavity length of 40 ~m, the thickness of Pd film of 36 nm and 110 nm respectively. The results show that M-Z interference sensor with Pd film is sensive to hydrogen of different concentrations. The transmission spectrum will offset toward the direction of long wavelength along with the increase of hydrogen concentration, and the response to hydrogen of sensor with 110 nm Pd film is more sensitive than 36 nm Pd film.