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In-fiber Mach–Zehnder interferometer based on polarization-maintaining fiber for displacement and temperature sensing

Cheng Jun-Ni, Jiang Xiao-Yan

Optica Applicata

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2023

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Vol. 53, nr 1

21--33

EN

A displacement sensor based on polarization-maintaining fiber has been proposed and proved in experiment. The polarization-maintaining fiber (PMF) is sandwiched with two graded-index multimode fibers (GI MMF), which form the Mach–Zehnder interferometer (MZI) sensor. Graded-index multimode fiber serve as an optical coupler for modes conversion. The results show that with the increase of displacement, the spectrum moves to the long wavelength direction, but when temperature increases, the spectrum has a red shift, which means that the displacement and temperature can be measured separately according to the wavelength drift direction. The sensor consists of 4 mm GI MMF and 14 mm PMF, which can exhibit the displacement sensitivity of –9.275 pm/μm in the range of 0–600 μm. In addition, temperature will also affect the sensitivity of displacement measurement, so the sensitivity of the sensor to temperature is also measured. The results show that the selected monitoring dip provides a better temperature sensitivity of 33.605 pm/°C in the range of 35–75°C. The sensor is easy to fabricate and does not has any functional coating, which make it become a good candidate in the industrial field.

2

Dual-resonance long-period grating in fiber loop mirror structure for liquid refractive index measurement

Zawisza R., Eftimov T., Mikulic P., Chinifooroshan Y., Celebańska A., Bock W. J., Jaroszewicz L. R.

Opto-Electronics Review

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2018

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Vol. 26, No. 1

24--28

EN

An interferometric structure based on a Dual-Resonance Long-Period Grating (DRLPG) within a Fiber Loop Mirror (FLM) is presented in this paper. Its purpose is to measure the refractive index (RI) of liquid analytes. The grating is the RI sensing probe, while the FLM serves as a band-pass filter. Due to the high extinction ratio of the FLM, amplitude measurements can be obtained, allowing implementation of the differential interrogation method to establish the sensitivity of the device. The use of a polarization controller makes it possible to fine-tune the interferometric peaks with respect to the two notches of the DRLPG. Precisely aligned configuration produces a maximum sensitivity of 3871.5 dB/RIU within the RI range of 1.3333 up to 1.3419 with linear sensor response.

3

Sensitivity and dynamic phase response to thermal radiation of a polarization-maintaining fiber

Kyselak M., Dvorak F., Maschke J., Vlcek C.

Optica Applicata

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2018

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Vol. 48, nr 2

249--261

EN

This paper deals with the phase shift development between two polarization modes in birefringent fiber, caused by body heat transfer of different temperatures. The aim is to analyze sensitivity and dynamic behaviors, which are significant when optical fiber is used as a sensor of temperature field disturbance. The analysis is based on the values measured during thermal exposure of a section of type PANDA birefringent optical fiber to heat emitted by an exposure body of chosen temperature, placed at a defined distance. The effect of heat transfer through conduction and convection is suppressed by shielding with plastic wraps. The analyzed results, the Stokes parameters and subsequent phase shift, are measured by the polarimeter. The paper follows up on previously published measurement results.