Strain sensor based on a pair of single-mode-multimode-single-mode fiber structures in a ratiometric power measurement scheme

Abstract

The strain and temperature dependencies of a step-index single-mode-multimode-single-mode (SMS) fiber structure are investigated numerically and experimentally. For intensity-based strain measurement using a single SMS fiber structure, at a selected wavelength, it is found that there is a high strain dependence, but also a temperature dependence that will induce strain measurement error. To minimize the temperature-induced strain measurement error, two SMS fiber structures are proposed and demonstrated in a ratiometric power measurement scheme; one SMS structure acts as the strain sensor, and the other SMS structure acts as the temperature monitor. The extracted temperature information is used to determine a strain value based on a suitable calibration of strain responses with temperature variations. It is demonstrated that for strain measurement from 0 to 1000 με within the temperature range from 10°C to 40°C, the proposed configuration can provide a strain and temperature resolution of 0:34 με and 0:14°C, respectively, with a temperature-induced strain measurement error as low as 0:39 με.

Strain sensor based on gourd-shaped single-mode-multimode-single-mode hybrid optical fibre structure

“…In recent years, optical fibre strain sensors based on interferometers have become increasingly popular. Examples include the Sagnac interferometer [15], Mach-Zehnder interferometer (MZI) [16], Fabry-Perot interferometer (FPI) [17] and MMI [18,19]. Optical fibre strain sensors based on MMI offer the advantages of potentially lower fabrication cost, higher sensitivity while being more mechanically robust compared with the other interference based devices.…”

“…Optical fibre strain sensors based on MMI offer the advantages of potentially lower fabrication cost, higher sensitivity while being more mechanically robust compared with the other interference based devices. An SMS (using a step-index MMF) fibre structure strain sensor based on intensity variation monitoring has been proposed in [18], for which the measurement scheme is relatively complicated. Graded-index (GI) MMF has also been used to perform strain sensing and proved to have higher strain sensitivity [19].…”

Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror

“…FLMs made of highly birefringent fiber (HiBi-FLM) have several advantages, including input polarization independence and high extinction ratio. Besides the gyroscope application, various kinds of sensors based on FLMs have been realized [3], such as temperature sensors [2,4], strain sensors [5,6], pressure sensors, liquid level sensors [7], biochemical sensors, UV detection [8] and multiparameter measurement [9][10][11].…”

SMS fiber structure for temperature measurement using an OTDR

“…Multimode interference effects occurring in singlemode-multimode-singlemode (SMS) fiber structures have been investigated and utilized for both sensing and signal processing applications [1][2][3][4][5][6][7][8]. These optical devices offer an all-fiber solution with the advantages of easiness of fabrication, packaging, and interconnection over other optical fibers.…”