Highly birefringent microstructured optical fiber for distributed hydrostatic pressure sensing with sub-bar resolution

We demonstrate distributed optical fiber-based pressure measurements with subbar pressure resolution and 1 m spatial resolution over a similar to 100 m distance using a phase-sensitive optical time-domain reflectometry technique. To do so, we have designed a novel highly birefringent microstructured optical fiber that features a high pressure to temperature sensitivity ratio, a high birefringence and a mode field diameter that is comparable to that of conventional step-index single mode fibers. Our experiments with two fibers fabricated according to the design confirm the high polarimetric pressure sensitivities (-62.4 radxMPa(-1)xm(-1) and -40.1 radxMPa(-1)xm(-1)) and simultaneously low polarimetric temperature sensitivities (0.09 radxK(-1)xm(-1) and 0.2 radxK(-1)xm(-1)), at a wavelength of 1550 nm. The fiber features a sufficiently uniform birefringence over its entire length (2.17x10(-4) +/- 7.65x10(-6)) and low propagation loss (similar to 3 dB/km), which allows envisaging pressure measurements along distances up to several kilometers. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement