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

In this paper, we present a miniature fiber-optic Fabry-Perot interferometric pressure sensor based on an in situ printed fiber-top air cavity. With an in-house optical 3D mu-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-Perot cavity. The fabricated Fabry-Perot microinterferometer shows a linear response to the change of pressure with a sensitivity of 2.93 nm/MPa in the range of similar to 700 kPa. The response of the sensor to the change of temperature in the range from 30 degrees C to 65 degrees C is measured to be similar to 38 pm/degrees 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.