High-pressure and high-temperature characteristics of a Fabry–Perot interferometer based on photonic crystal fiber

Abstract

A fiber-optic Fabry-Perot interferometer was constructed by splicing a short length of photonic crystal fiber to a standard single-mode fiber. The photonic crystal fiber functions as a Fabry-Perot cavity and serves as a direct sensing probe without any additional components. Its pressure and temperature responses in the range of 0-40 MPa and 25°C-700°C were experimentally studied. The proposed sensor is easy to fabricate, potentially lowcost, and compact in size, which makes it very attractive for high-pressure and high-temperature sensing applications. . These advantages make them very suitable for deployment in space-limited harsh environments such as turbine engines and power plants and in the oil and gas industry, where pressure and temperature are the two most common measurands [3][4][5][6][7]. Many methods have been developed to fabricate fiberoptic FPIs. These include using conventional hollow-core fiber [3][4][5], chemical etching [7,8], and laser micromachining [9,10]. Recently, FPIs made from hollow-core photonic bandgap fiber [11] and solid-core photonic crystal fiber (PCF) [12] by simply cleaving and splicing have been demonstrated as strain and temperature sensors. The former needs a coating film onto the fiber endface, thereby increasing the complexity of the fabrication process. The latter as a temperature sensor is not stable, because the air holes are exposed to external environment [13].In this Letter, we report a fiber-optic FPI constructed by splicing a solid-core PCF to a standard single-mode fiber (SMF), and the other end of the PCF was collapsed with arc discharge using a fusion splicer. The entire fabrication process was performed using a commercially available fusion splicer. The principle of the FPI sensor is also presented here. We experimentally investigated the high-pressure and high-temperature characteristics of the proposed FPI sensor. Measurements of pressure up to 40 MPa and temperature up to 700°C were carried out. The pressure and temperature coefficients of the FPI sensor were measured to be −5:8 pm=MPa and ∼13 pm=°C, respectively. The experimental results agree well with the theoretical analysis. Figure 1(a) illustrates the experimental setup of our measurement. A broadband source (BBS) centered at 1530 nm is used to illuminate the FPI through an optical circulator. The reflection spectrum of the FPI is observed by an optical spectrum analyzer (OSA). Figures 1(b) and 1(c) show the schematic diagram and photograph of the fabricated FPI. A short length of a solid-core PCF (PM-1550-01 by Blaze Photonics) was first spliced to a standard SMF using the technique reported in [14]. Because of the small difference in refractive index between the SMF and the PCF, a mirror with relatively low reflectivity was formed at the fiber interface. The PCF was then cleaved to a length of several millimeters. A second lowreflection mirror at the end of the solid core was formed due to Frésnel reflection. As a result, a relatively weak FPI was constructed with an intensity contrast of ∼6 dB as sh...

Photonic Crystal Fiber–Based Interferometric Sensors

“…A SC-PCF was spliced to one end to a SMF and hole collapse was carried out at the other end, to improve the reflectivity of the second mirror. The pressure and temperature sensitivities were À5.8 and~13 pm/ C, respectively [19]. PCF based IFPIs may also have potential use in photonic integrated circuits [20].…”

A fiber optic temperature sensor based on the combination of epoxy and glass particles with different thermo-optic coefficients

“…Other sensors utilize Bragg gratings [7][8][9] or the temperature-dependent fluorescence intensity of certain materials [10] to measure the temperature. Another way is to analyze the Raman scattering in a glass fiber [11] or to analyze the temperature with a Fabry-Pérot interferometer (FPI) [12,13] or with a Mach-Zehnder interferometer [14] integrated into an optic fiber. Also stimulated Brillouin scattering can be used for distributed temperature measurement [15,16] whereby the scattered frequency depends on the temperature of the fiber.…”

Compressible fiber optic micro-Fabry-Pérot cavity with ultra-high pressure sensitivity

“…Various types of fiber optic pressure sensors have been demonstrated to fulfill specific pressure applications, including fiber Bragg gratings (FBGs) [1], photonic crystal fiber (PCF) devices [2] and interferometers [3,4], and the pressure sensitivity achieved is typically on the order of −10 pm/Mpa. Among above mentioned configurations, the pressure sensors that are based on Fabry-Pérot (FP) interferometer have shown promising results for static and dynamic pressure measurements [5,6], as well as other physical and chemical parameter detections such as temperature [7], strain [8,9] and refractive index [10].…”

“…Among above mentioned configurations, the pressure sensors that are based on Fabry-Pérot (FP) interferometer have shown promising results for static and dynamic pressure measurements [5,6], as well as other physical and chemical parameter detections such as temperature [7], strain [8,9] and refractive index [10]. The FP interferometers can achieve extremely high sensitivity and flexibly demodulated in the wavelength domain [3,4] and frequency domain [6,8], or simply use light intensity detection [11].…”