All Single-Mode Fiber Mach–Zehnder Interferometer Based on Two Peanut-Shape Structures

Refractive index desensitized optical fiber temperature sensor

“…The cladding modes on the other hand, are directly exposed to the surrounding medium and changes in its refractive index (RI) can alter significantly their effective propagation constant [12,13].…”

“…a different behavior) depending on the RI of the surrounding medium. This scenario becomes more complicated in cases where the RI of the external medium changes as temperature changes [12,13].…”

“…Both the changes of temperature and strain contribute to the wavelength shifts, which mean that the MI can be used either as temperature or strain sensor [12].…”

Sensitivity-enhanced temperature sensor based on PDMS-coated long period fiber grating

“…Since characteristics of material has a strong dependence on temperature, it is essential to measure temperature in practical applications [2]. At present, various of temperature sensors based on optical fiber structure have been proposed and demonstrated, such as Sagnac [3,4], Fabry-Perot [5][6][7][8], fiber MachZehnder interferometers [9,10], fluid-filled photonic crystal fiber [11,12], etc.…”

Refractometer based on Mach–Zehnder interferometer with peanut-shape structure

“…The Peanut-Shape structure has been proved of high sensitivity to temperature before [10]. The Peanut-Shape structure could excite the high-order cladding modes and couple light between the core mode and the cladding modes [11]. In this paper, the PeanutShape structure is used to examine the sensitivity to refractive index, compared with refractometer fabricated with two cascaded LPGs [4], this sensor improves the sensitivity greatly.…”