Dual spherical single-mode-multimode-single-mode optical fiber temperature sensor based on a Mach–Zehnder interferometer

Abstract

A dual spherical single-mode-multimode-single-mode (DSSMS) optical fiber temperature sensor based on a Mach-Zehnder interferometer (MZI) was designed and implemented in this paper. Theoretical and experimental results indicated that the LP 01 mode in the core and the LP 09 mode excited by the spherical structure were maintained and transmitted via multimode fiber and interfered at the second spherical structure, resulting in the interference spectrum. An increase or decrease in temperature can cause significant red-shift or blue-shift of the spectrum, respectively. The linearity of the spectral shift due to the temperature change is ~0.999, the sensitivity at 30 °C-540 °C is ~37.372 pm °C−3 , and at −25 °C-25 °C is ~37.28 pm °C−1 . The reproducibility error of this all-fiber temperature sensor at 30 °C-540 °C is less than 0.15%. Compared with the optical fiber sensor with a tapered structure and fiber core offset structure, this MZI-based DSSMS optical fiber temperature sensor has higher mechanical strength. Moreover, benefiting from low-cost and environmentally friendly materials, it is expected to be a novel micro-nano all-fiber sensor.

Up-down Taper Based In-Fiber Mach-Zehnder Interferometer for Liquid Refractive Index Sensing

“…where ∆n = n co e f f − n cl e f f is the difference of the ERI between the core and cladding modes, and I 1 is the power of the core mode, I 2 is the power of the m-th cladding mode, L 1 is the length of PMF, λ is the wavelength of incident light, ∆ϕ = 2π ∆n λ •L 1 represents the phase difference between the fiber modes [28]. In Equation 1, the resulting value reaches to the minimum value when the phase difference ∆ϕ = 2π ∆n λ •L 1 = (2m + 1)π (m is an integer) [29].…”

High temperature and vector curvature sensor with high linearity and sensitivity based on asymmetric dual-core photonic crystal fiber

“…Based on the above analysis and our previous work, 28) the wavelength change of interference trough and the temperature sensing sensitivity of the DCPCF-based MZI can be given by…”

Optical fiber temperature sensor with insensitive refractive index and strain based on phase demodulation

“…The all‐fiber Mach‐Zehnder interferometer is a particularly simple device that interferes by recoupling two beams of light generated by splitting light from one light source. In recent years, many different types of MZI‐based fiber optic sensors have been developed and used for temperature sensing, such as mismatch structure, 12,13 single mode‐multimode‐single mode structure, 14 fiber tapers, 15 peanut structure, 16,17 and combination structures 18 . Recently, many special optical fibers have also been applied to the sensing field, such as PCF, 19 multi‐core fiber, 20,21 and thin‐core fiber 22 .…”