High-precision optical fiber pressure sensor using frequency-modulated continuous-wave laser interference

Abstract

This work presents a high-precision fiber optic pressure sensor based on frequency-modulated continuous-wave (FMCW) laser interference. The pressure sensor is primarily composed of a diaphragm-type Fabry–Pérot (F–P) cavity, with the diaphragm fabricated using high-elasticity SUS631 stainless steel. The external air pressure causes the center of the elastic diaphragm to deform, and this deformation results in a change in the F–P cavity length. The FMCW laser-interference method was used to demodulate the change in the length of the cavity and realize high-precision pressure measurements. The experimental results showed that when the pressure measurement is in the range of 0 kPa–600 kPa, an accuracy of 3.8 Pa can be obtained. In addition, the sensor had very good linearity with pressure change (R2 = 0.999 94), repeatability, and stability.

Development of the design and technology for manufacturing a combined fiber-optic sensor used for extreme operating conditions

“…The article [4] describes studies of the FOS design based on optoacoustic wave processes. The disadvantages of this method and design are the presence of discharges and shutdowns in conditions of vibrations and significant temperatures.…”

“…The paper [4] presents the results of research and the design of a two-channel pressure sensor in which the laser beam is modulated by a mirror reflecting surface of a pressure-sensing membrane. The main disadvantage of the sensor and its manufacturing technology is the separation of the laser beam supply channels and the measuring channel, which does not allow organizing another channel for a physical parameter other than pressure.…”