Miniature Fabry-Perot pressure sensor created by using UV-molding process with an optical fiber based mold

We present a miniature Fabry-Perot pressure sensor fabricated at the tip of an optical fiber with a pre-written Bragg grating by using UV-molding polymer process. The mold is constructed by integrating an optical fiber of 80 μm diameter with a zirconia ferrule. The optical fiber based mold makes it possible to use optical aligning method to monitor the coupled intensity between the mold-side and replica-side fibers, rendering a maskless alignment process with a submicrometer accuracy. A polymer-metal composite thin diaphragm is employed as the pressure transducer. The overall sensor size is around 200 μm in diameter. Experimental study shows that the sensor exhibits a good linearity over a pressure range of 1.9-7.9 psi, with a sensitivity of 0.0106 μm/psi. The fiber Bragg grating is exploited for simultaneous temperature measurements or compensation for temperature effects in pressure readings. The sensor is expected to benefit many fronts that require miniature and inexpensive sensors for reliable pressure measurement, especially biomedical applications.