20.500.12556/DKUM-99217 A fiber-optic differential pressure sensor and its application in liquid level measurement This paper reports an all-fiber, all-silica differential pressure sensor based on a Fabry–Pérot interferometer (FPI) with a pressure-sensitive diaphragm. Differential pressure sensing is achieved by a custom-designed single-mode fiber, that incorporates two capillaries that are placed in parallel with the fiber core. These capillaries connect the interior of the FPI cavity to the external environment through radially fabricated venting ports, allowing for the creation of a second pressure port. The sensor was characterized experimentally as a differential pressure sensor. The sensor demonstrated a high-pressure sensitivity of − 1311 nm/bar near zero pressure (quadratic fit: ΔOPL = 499.1P2 − 1311P, R2 = 0.999), and fast dynamic response with time constants as low as 1.4 s, which can be reduced further to the millisecond range by increasing the custom designed single-mode fiber diameter. When employed as a liquid level gauge, the sensor achieves a resolution of 1.1 mm with negligible hysteresis over the operating range of 0–800 mm. Owing to its compact design with a short FPI cavity, the sensor eliminates the need for temperature compensation. Its fully dielectric construction and low optical power requirement (≤150 µW) make it intrinsically safe and highly suitable for deployment in potentially explosive environments, such as fuel tanks. fiber-optic differential pressure sensor Fabry-Pérot sensor liquid level measurement micro-capillary venting micromachining optična vlakna optični senzorji senzorji true false true Elsevier Ltd. Angleški jezik Slovenski jezik https://www.sciencedirect.com/journal/optics-and-laser-technology © 2026 The Author(s). Članek v reviji 2026-08-07 12:07:57 2026-08-07 12:07:57 2026-08-08 03:08:39 0000-00-00 00:00:00 2026 0 0 11 str. Part B [article no.] 116103 Vol. 204 Dec. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2026-05-28 2026-08-03 2026-08-05 535 287247107 10.1016/j.optlastec.2026.116103 1879-2545 1-s2.0-S1568494626014213-main.pdf 1-s2.0-S1568494626014213-main.pdf 1 246F0C98D833BE56F3B6FAFA30B06942 97130b31f8c0a72298fdc9e7e2bbbb2ef2525cc6e916bc85d0549b0b39986499 e4f35c0b-9247-11f1-a6bf-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=209054 Fakulteta za elektrotehniko, računalništvo in informatiko 0 0 0