Strain-insensitive high-sensitivity temperature sensing based on multimode interference in a square-core fiber

Abstract

A strain-insensitive high-sensitivity temperature sensor based on multimode interference in a specialty fiber with a square core is developed and experimentally investigated. A 25-cm-long square-core fiber is used as a multimode fiber (MMF) of a single-mode--multimode--single-mode structure and the temperature dependence of its transmitted spectrum is measured while the strain is applied continually from 0 to 500 με with steps of 100 με. The mean temperature sensitivity is -22.35 pm/°C, which is ∼3.5 times higher than that of a standard MMF, and it is almost independent of strain with a small standard deviation of 0.44 pm/°C.

Multimode optical fiber sensors: from conventional to machine learning-assisted

“…However, it is worth noting that MMF sensors are not limited to MMI-based designs. In fact, many different types of MMFs, including specialty fibers, such as microfiber [23,24], square-core fiber [25,26], and thin-core fiber [27], have been extensively developed and utilized in sensing applications. Recently, the blossom of machine learning methods, which can benefit the analysis of the MMI in MMFs, paves a new path to enhance the performance of MMF sensors and new applications like biosensors.…”

Temperature sensing based on multimode interference in polymer optical fibers: sensitivity enhancement by PC-APC connections

“…12) Many SMS-based configurations implementing silica optical fibers have been reported for various sensing scenarios. [13][14][15][16][17][18][19] In addition to silica optical fibers, polymer optical fibers (POFs) have also been used for sensing applications. [20][21][22][23] Although the optical attenuation of a POF is higher than that of silica optical fibers, its influence is sometimes negligible for a short POF.…”