All-fiber high-sensitivity pressure sensor with SiO_2 diaphragm

The design and fabrication of a miniature fiber Fabry–Perot pressure sensor with a diameter of 125??m are presented. The essential element in the process is a thin SiO2 diaphragm that is fusion spliced at the hollow end of an optical fiber. Good repeatability and high sensitivity of the sensor are achieved by on-line tuning of the diaphragm thickness during the sensor fabrication process. Various sensor prototypes were fabricated, demonstrating pressure ranges of from 0 to 40 kPa to 0 to 1 MPa. The maximum achieved sensitivity was 1.1?rad?40?kPa at 1550 nm, and a pressure resolution of 300 Pa was demonstrated in practice. The presented design and fabrication technique offers a means of simple and low-cost disposable pressure sensor production.