scholarly journals Dual Demodulation of Temperature and Refractive Index Using Ring Core Fiber Based Mach-Zehnder Interferometer

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.

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5440 ◽  
Author(s):  
Xiaopeng Han ◽  
Chunyu Liu ◽  
Shengxu Jiang ◽  
Shuo Leng ◽  
Jiuru Yang

A novel in-fiber Mach-Zehnder interferometer based on cascaded up-down-taper (UDT) structure is proposed by sandwiching a piece of polarization maintaining fiber between two single-mode fibers (SMF) and by utilizing over-fusion splicing method. The dual up tapers respectively act as fiber splitter/combiner, the down taper acts as an optical attenuator. The structure parameters are analyzed and optimized. A larger interference fringe extinction ratio ~15 dB is obtained to achieve refractive index (RI) sensing based on intensity demodulation. The experimental results show that the RI sensitivity is −310.40 dB/RIU with the linearity is improved to 0.99 in the range of 1.3164–1.3444. The corresponding resolution can reach 3.22 × 10−5 RIU, which is 6.8 times higher than wavelength demodulation. The cross sensitivity which caused by temperature fluctuation is less than 1.4 × 10−4.


2014 ◽  
Vol 635-637 ◽  
pp. 856-859 ◽  
Author(s):  
Ying Wu Zhou ◽  
Sheng Yu Chen

A novel in-line fiber temperature sensor by splicing a piece of single mode fiber between two thermally expanded core fibers at their core-expanded ends is proposed and demonstrated. This structure forms an all fiber Mach–Zehnder interferometer due to the interference between the core mode and the cladding modes of the single mode fiber. The fabricated sensor is applied to measure temperature changes. The temperature sensitivity of the sensor at a length of 6.3cm is about 65.3 pm/°C. The proposed sensor is low cost, easily fabricated, and may be useful for detection of temperature.


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

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Jun Huang ◽  
Bowen Wang ◽  
Kai Ni

A novel humidity sensor based on Mach-Zehnder interferometer (MZI) with the single-mode fiber (SMF) coated with methylcellulose (MC) is proposed and experimentally demonstrated. The MZI consists of two waist enlarged structures. Such an all-fiber MZI incorporates an intermodal interference between the core mode and cladding modes. The MC is coated on the surface of the SMF. External humidity changes the refractive index of MC, causing the intensity changes of the interference pattern. The proposed sensor is linearly responsive to refractive humidity (RH) within the range from 45% to 85% RH, with sensitivity of 0.094 dB/%RH. Moreover the insensitivity of the fiber to the temperature makes this structure more suitable for practical measurement.


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