Optical Fiber-Tip Fabry–Pérot Interferometric Pressure Sensor Based on an In Situ μ-Printed Air Cavity

In this paper, we present a miniature fiber-optic Fabry-Pérot interferometric pressure sensor based on an in situ printed fiber-top air cavity. With an in-house optical 3D μ-printing setup, a suspended SU-8 diaphragm with light scatter is directly printed on the end face of standard optical fiber to form a sealed Fabry-Pérot cavity. The fabricated Fabry-Pérot microinterferometer shows a linear response to the change of pressure with a sensitivity of 2.93 nm/MPa in the range of 0 ~ 700 kPa. The response of the sensor to the change of temperature in the range from 30 °C to 65 °C is measured to be ~38 pm/°C. Such an ultra-small fiber-optic pressure sensor has remote monitoring capability and is promising for a great number of measurement and testing applications ranging from miniature manometers to bioprobes.