High sensitivity liquid surface deformation sensor based on cascaded Bowknot Type Tapers

ABSTRACT

A liquid surface deformation sensor with high sensitivity based on a Mach–Zehnder interferometer (MZI) was demonstrated. The MZI was constructed by cascading two Bowknot Type Tapers (BTTs) with an interval of 1.0 cm. As the liquid surface changes gradually from the position higher than the optical fibre to a position lower than the optical fibre, the external environment of the optical fibre changes gradually from the liquid to air, this will result in a change of the interference of the MZI. By measuring the intensity variations of the resonant wavelength, the liquid surface deformation in the range from 0 to 5.22 mm can be determined with a high sensitivity of 0.99 dB/mm.

KEYWORDS:

• Liquid surface deformation sensor
• Mach–Zehnder interferometer
• Bowknot-type taper

ORCID

Tingting Lang http://orcid.org/0000-0002-7037-2163

Additional information

Funding

This work was supported in part by National Natural Science Foundation of China [grant number 11874332], National major scientific research instrument development project of Natural Science Foundation of China [grant number 61727816], National Natural Science Foundation of China [grant numbers 61875251, 61775202], National Key R&D Program of China [grant numbers 2017YFF0209703, 2017YFC0805905, 2018YFF0215104], Public project of Zhejiang province [grant number LGG18F050003] and Natural Science Foundation of Zhejiang Province China [grant number LY17F050010].