M-Z optical fiber liquid level sensor based on two cascaded spherical-shape structures

An MZI for measurement of liquid level is proposed and demonstrated, which consists of two cascaded spherical-shape structures. Two interferometers with different lengths of 34mm and 40mm are manufactured with their sensing characteristics studied. By measuring wavelength shifts of the dip in the interference spectrum, we can measurement liquid level. Experimental results show that the sensor (34mm) has a higher sensitivity of liquid level compared to the sensor (40mm). A higher liquid level sensitivity of -1.172nm/cm is obtained.