Enhanced axial strain and vector magnetic field sensitivity in MZI utilizing dual cascaded air bubbles with tapered fiber

In this study, we believe this is a novel and compact fiber optic sensor for measuring strain and vector magnetic fields that has been proposed and examined. The sensor is comprised of a sequence of two bubbles and a tapered fiber with a diameter of 31µm, offering a maximum strain sensitivity of -44.5 pm/µɛ. A susceptible magnetic field sensing structure can be achieved by simply bonding the strain device to a magnetostrictive material. Results demonstrate that the sensor exhibits a magnetic field sensitivity of -0.7838 nm/mT, with a linear fit of 0.9931 within the 8 to 28 mT. The direction sensitivity is calculated to be 230.85 pm/° for a magnetic field of 24 mT. This work demonstrates the device's great mechanical strength, low cross-sensitivity to temperature, ease of manufacture, and versatility in measuring strain and vector magnetic fields, making it suitable for use in civil engineering, aerospace, and other industrial fields.