An Optical Fiber Fabry–Pérot Pressure Sensor Using an SU-8 Structure and Angle Polished Fiber

In this letter, a novel pressure sensor using an SU-8 structure and angle polished fiber is proposed. There are two different Fabry-Pérot cavities in the design, and the cavity lengths can be demodulated at the same time to realize temperature compensation. SU-8 photoresist is suited for forming a high-aspect-ratio structure and the thickness can be controlled precisely. The fabrication process is described and the lithography technology is employed. The characteristics of both pressure and temperature are tested. Experimental results show that the sensor has a good linearity over the pressure range of 0-0.1 MPa. The R-square is 0.998. The sensitivity (change in cavity/loaded pressure) is 60.9 μm/MPa.