Pressure sensitivity of dual resonant long-period gratings written in boron co-doped optical fiber

Abstract

The paper presents a pressure sensor based on a long-period grating (LPG) written in boron co-doped photosensitive fiber and operating at the phase-matching turning point. It is shown that the pressure sensitivity can be tuned by varying the UV exposure time during the LPG fabrication process. The achieved pressure sensitivity can reach over 1 nm·bar -1 , and is at least four times higher than for previously presented gratings working away from the double-resonance regime. In terms of intensity-based measurement, the sensitivity at the turning point can reach 0.212 dB·bar -1 .