scholarly journals Tapered Fiber-Optic Mach-Zehnder Interferometer for Ultra-High Sensitivity Measurement of Refractive Index

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1652 ◽  
Author(s):  
Vahid Ahsani ◽  
Farid Ahmed ◽  
Martin Jun ◽  
Colin Bradley

A Mach-Zehnder interferometer (MZI) based fiberoptic refractive index (RI) sensor is constructed by uniformly tapering standard single mode fiber (SMF) for RI measurement. A custom flame-based tapering machine is used to fabricate microfiber MZI sensors directly from SMFs. The fabricated MZI device does not require any splicing of fibers and shows excellent RI sensitivity. The sensor with a cladding diameter of 35.5 µm and length of 20 mm exhibits RI sensitivity of 415 nm/RIU for RI range of 1.332 to 1.384, 1103 nm/RIU for RI range of 1.384 to 1.4204 and 4234 nm/RIU for RI range of 1.4204 to 1.4408, respectively. The sensor reveals a temperature sensitivity of 0.0097 nm/°C, which is relatively low in comparison to its ultra-high RI sensitivity. The proposed inexpensive and highly sensitive optical fiber RI sensors have numerous applications in chemical and biochemical sensing fields.

A Mach-Zehnder interferometer (MZI) built using several concatenated different structures is proposed as a refractive index sensor. This sensor is comprised of a microbubble, a section of reduced cladding fiber (RCF) and a core-offset single-mode fiber (SMF). These structures are joined together through specialized arc fusion splicing procedures. The sensor is characterised by immersing it in Cargille oil with refractive index values ranging from 1.30 to 1.39. The sensor exhibits linearity in respect to the refractive index changes, with a good sensitivity of 144.42 nm/RIU. The proposed MZI has the advantages of cost effective, repeatable fabrication, compact size and high sensitivity, which make it a promising sensor.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5870
Author(s):  
Huitong Deng ◽  
Xiaoman Chen ◽  
Zhenlin Huang ◽  
Shiqi Kang ◽  
Weijia Zhang ◽  
...  

A 3-aminopropyl-triethoxysilane (APES) fiber-optic sensor based on a Mach–Zehnder interferometer (MZI) was demonstrated. The MZI was constructed with a core-offset fusion single mode fiber (SMF) structure with a length of 3.0 cm. As APES gradually attaches to the MZI, the external environment of the MZI changes, which in turn causes change in the MZI’s interference. That is the reason why we can obtain the relationships between the APES amount and resonance dip wavelength by measuring the transmission variations of the resonant dip wavelength of the MZI. The optimized amount of 1% APES for 3.0 cm MZI biosensors was 3 mL, whereas the optimized amount of 2% APES was 1.5 mL.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 258
Author(s):  
Weihao Yuan ◽  
Changyuan Yu

We report the ring core fiber spliced with single mode fiber and no core fiber which is used for temperature and refractive index (RI) sensing. The Mach-Zehnder interferometer (MZI) is formed with this kind of sandwich fiber structure and the maximum extinction ratio of the interference spectra reaches 27 dB with the free spectra range of 12 nm. The MZI fiber sensor is applied for temperature sensing with the sensitivity of 69 pm/°C and 0.051 dB/°C. The RI sensitivity reaches 182.07 dB/RIU and −31.44 nm/RIU with the RI ranging from 1.33 to 1.38. The RI value can be directly demodulated with the interference dip intensity which shows insensitivity to temperature. The demodulation of temperature can be achieved by using the linear equations between dip wavelength shift with the variation of temperature and RI.


2008 ◽  
Vol 20 (8) ◽  
pp. 626-628 ◽  
Author(s):  
Zhaobing Tian ◽  
Scott S.-H. Yam ◽  
Jack Barnes ◽  
Wojtek Bock ◽  
Patricia Greig ◽  
...  

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