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.
L. Zhao et al., "A High-Quality Mach-Zehnder Interferometer Fiber Sensor by Femtosecond Laser One-Step Processing," Sensors, vol. 11, no. 1, pp. 54-61, MDPI, Dec 2010.
The definitive version is available at https://doi.org/10.3390/s110100054
Mechanical and Aerospace Engineering
Electrical and Computer Engineering
Keywords and Phrases
Femtosecond Laser; Fiber Sensors; Mach-Zehnder Interferometer
International Standard Serial Number (ISSN)
Article - Journal
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23 Dec 2010