Abstract—We present a miniature fiber-optic pressure sensor
with a diameter of only 125 m. The sensor works as an extrinsic
Fabry–Pérot interferometer and the cavity length can be controlled
with a resolution of about several nanometers. Also the
sensor sensitivity can be easily adjusted by controlling the sensor
gauge length. A passive temperature compensation scheme was
used to reduce most of the sensor’s temperature dependence. Since
the sensor is composed entirely of fused silica, it is reliable, biocompatible,
corrosion resistant, and immune to electromagnetic
interference and has high-temperature capability.