Summary: | 碩士 === 國立中山大學 === 光電工程學系研究所 === 106 === Optical Mach-Zehnder interferometer (MZI) fiber sensors have several advantages, such as small size, high sensitivity, and immunity to electromagnetic interference. Several kinds of MZI-based fiber sensors formed by the collapse splicing have been proposed in recent year due to their simple fabrication process and strong structures. We can get a single-MZI-based fiber sensor by collapse splicing a section of HCF between two SMFs. The double-MZI-based fiber sensor we propose is fabricated by collapsed the middle region of the single-MZI-based fiber sensor by a suitable fusion parameter. Compared to the interference spectrum of single-MZI-based fiber sensors, double MZI-based fiber sensors have larger FSR and deeper extinction ratio.
The double-MZI-based fiber sensors we proposed have been applied to environment sensing. The experiment results show the sensitivities of refractive index, temperature, strain, and pushing distance of the double-MZI-based fiber sensor are 218.84 nm/RIU, 14.32 pm/℃, 5.143×10-4 dB/με, and -0.214 dB/mm, respectively. According to the experiment results, the double-MZI-based fiber sensor which fabricated by collapsed the middle region of the single-MZI-based fiber sensor has higher sensitivity in RI and temperature sensing. Otherwise, the double-MZI-based fiber sensor can also improve the measurement range and accuracy.
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