Microbubble-based fiber-optic Fabry–Perot pressure sensor for high-temperature application

Abstract

Using arc discharge technology, we fabricated a fiber-optic Fabry-Perot (FP) pressure sensor with a very low temperature coefficient based on a microbubble that can be applied in a high-temperature environment. The thin-walled microbubble can be fabricated by heating the gas-pressurized hollow silica tube (HST) using a commercial fusion splicer. Then, the well-cut single-mode fiber (SMF) was inserted into the microbubble, and they were fused together. Thus, the FP cavity can be formed between the end of the SMF and the inner surface of the microbubble. The diameter of the microbubble can be up to 360 μm with the thickness of the wall being approximately 0.5 μm. Experimental results show that such a sensor has a linear sensitivity of approximately -6.382 nm/MPa, -5.912 nm/MPa at 20°C, and 600°C within the pressure range of 1 MPa. Due to the thermal expansion coefficient of the SMF being slightly larger than that of silica, we can fuse the SMF and the HST with different lengths; thus, the sensor has a very low temperature coefficient of approximately 0.17 pm/°C.

Optical fibre Fabry-Pérot interferometer based on inline microcavities for salinity and temperature sensing

“…Although these structures consist of hollow cavities within the fibres, they are mechanically strong, being resistant to lateral loads 17 and strain 16 . These type of sensors can also withstand high temperatures since no film or polymer integrate the sensors structure 18 .…”

All-SiC Fiber-Optic Sensor Based on Direct Wafer Bonding for High Temperature Pressure Sensing

“…Compared with the electrical sensors, fiber-optic pressure sensors are tolerant to extreme temperature and can offer immunity to electromagnetic interference (EMI), high sensitivity, electrical passivity, and good long-term stability [13][14][15][16][17][18]. Among them, diaphragm-based extrinsic Fabry-Perot interferometer (EFPI) sensors have been widely investigated for their high resolution and precision, ease of manufacture, and excellent survivability in harsh environments [19][20][21][22][23][24]. Pulliam et al [25] proposed an all-SiC pressure sensor fabricated by a deposited SiC diaphragm and a single-crystal SiC substrate.…”

Influence of Temperature on All-Silica Fabry-Pérot Pressure Sensor

“…Compared with IFPIs, EFPIs have advantages of low temperature cross-sensitivity, high tolerable temperature, etc. Plenty of methods were carried out to fabricate high-temperature pressure EFPIs, such as arc discharge technology [12] [13], diaphragm-coated technology [14] [15], chemical or femtosecond (fs) laser etched technology [16][17][18], etc. However, all these methods mentioned above need several steps to get thin diaphragms, either physical polishing, chemical or fs laser processing, which would make the sensor fabrication sophisticated.…”