Surface roughness

Physics

Diaphragm (acoustics)

Laser

Optics

Engineering

Loudspeaker

Composite material

Fiber optic sensor

Acoustics

Materials science

Optical fiber

Sapphire

Pressure sensor

Optoelectronics

Fiber

Mechanical engineering

Pressure measurement

Thermodynamics

Optics Express

In this paper, an all-sapphire fiber-optic Fabry-Perot (F-P) pressure sensor is proposed. The sapphire pressure-sensitive diaphragm with low surface roughness is fabricated by MEMS wet etching. The direct bonding process is adopted to bond the sapphire-sensitive diaphragm and substrate together. And the sapphire fiber is adopted to be the lead-in fiber to ensure the sensor's resistance to high temperature. The performance of the sensor is tested within a pressure range of 0.1∼5 MPa and within the temperature range from room temperature to 1200°C. Experimental results show that the sensor could work stably at the temperature of 1200°C. The pressure sensitivity reaches up to 15nm/MPa. The nonlinearity of the sensor is 0.96% FS (full scale), and the relative resolution reaches 0.12%FS. The all-sapphire F-P sensor could be used for high-pressure testing in a high-temperature environment.

All-sapphire fiber-optic pressure sensors for extreme harsh environments