Highly Sensitive Tapered Fiber Mach–Zehnder Interferometer for Liquid Level Sensing

A low cost, simple, and in-line liquid level sensor based on a dual-tapered fiber Mach-Zehnder interferometer (DTFMZI) is proposed. In this letter, the configuration, operation principle, experimental results, and discussion for the proposed fiber-optic liquid level sensor are investigated. Experimental results show that the proposed DTFMZI sensor is highly sensitive and linear in the response; a good sensitivity of ~2.8 nm/cm within the whole measurement range of 10 cm is achieved in this letter.