A High-Quality Mach-Zehnder Interferometer Fiber Sensor by Femtosecond Laser One-Step Processing

Sensors

Longjiang Zhao³  Lan Jiang³  Sumei Wang³  Hai Xiao²  Yongfeng Lu¹ 

[1] Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; E-Mail:;Department of Electrical and Computer Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA; E-Mail:;School of Mechanical Engineering, Beijing Institute of Technology, 100081, China; E-Mails:

关键词: femtosecond laser;    fiber sensors;    Mach-Zehnder interferometer;   

DOI  :  10.3390/s110100054

来源: mdpi

【 摘 要 】

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 10⁴ nm/RIU, and the temperature sensitivity is 51.5 pm/°C at 200 ∼ 875 °C with a step of 25 °C.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.