Optical fiber bi-directional strain sensor based on coreless fiber.

An optical fiber bi-directional strain sensor principled on Mach–Zenhder interferometer is fabricated and demonstrated, a sensing segment no-core fiber of 125 μm diameter both ends fused with a couple of single-mode fibers then bi-directionally strained, the achieved sensitivity was around 16.37 pm με⁻¹, the sensor is excellently repeatable with a very good mechanical toughness; to the best of our knowledge, this is the best strain sensitivity reported in no-core fiber strain sensors. The sensor can be employed in a wide variety of opto-mechanical monitoring applications in different industrial facilities. [ABSTRACT FROM AUTHOR]