Microbubble based fiber-optic Fabry–Perot interferometer formed by fusion splicing single-mode fibers for strain measurement

Abstract

We demonstrate an all-fiber optical Fabry-Perot interferometer (FPI) strain sensor whose cavity is a microscopic air bubble. The bubble is formed by fusion splicing together two sections of single-mode fibers (SMFs) with cleaved flat tip and arc fusion induced hemispherical tip, respectively. The fabricated interferometers are with bubble diameters of typically ~100 μm. Strain and temperature sensitivities of fabricated interferometers are studied experimentally; a strain sensitivity of over 4 Pm/με and a thermal sensitivity of less than 0.9 Pm/°C is obtained.

Hollow Core Fiber Based Interferometer for High-Temperature (1000 °C) Measurement

“…In FPI based sensors there is a need to very precisely control the size of the microcavity in the order of micrometers, as small variations in the cavity length will result in significant changes to the actual spectrum achieved by comparison to the intended spectrum. Moreover, most of the air gap FPI based temperature sensors have a very limited temperature sensitivity (~1 pm/°C) [22][23][24] and contamination from dust and other pollutants is a significant issue for the long term stability of the sensor, due to a structure that is typically open to the environment [11]. Recently, functionalized HCF based interferometer structures has been reported for use as a biosensor, a magnetic field sensor, a humidity sensor and a displacement sensor [25][26][27][28].…”

High-sensitivity strain sensor based on in-fiber rectangular air bubble

“…In addition, the cross-sensitivity between strain and temperature was hardly overcome in these sensor schemes. Recently, Fabry-Perot interferometers (FPIs) based on an in-fiber air cavity were proved to be outstanding in lots of sensing applications, such as strain measurements1213141516171819, refractive index (RI) measurements2021 and pressure measurements2223, due to the advantages of simple configuration, high sensitivity, compact size, and low temperature cross-sensitivity. However, it is very difficult to directly create an air cavity in the fiber.…”

A Micro Bubble Structure Based Fabry–Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost Characteristics

“…The FPI strain sensor of the air bubble was fabricated by two standard SMF and formed by arc fusion splicing; Chongqing University’s experimental results showed the strain sensitivity to be ~4 pm/με [15]. Shenzhen University reported a high-sensitivity of up to 6.0 pm/με [16], and then they improved the technique to create a rectangular air bubble based FPI with a cavity length of about 61 μm; the wavelength of 1550 nm exhibits a high strain sensitivity of 43.0 pm/με [17].…”