Alkali etched fiber Mach-Zehnder interferometer with compact sensor head.

ABSTRACT

We demonstrate a scheme for fabricating compact fiber Mach-Zehnder interferometer (MZI). A section of Ge-doped fiber (GDF) is sandwiched between two single-mode fibers. The sandwich structure is side polished to make the core of GDF exposed to the surroundings. Alkali solution is utilized to etch the core of GDF. A compact fiber MZI is achieved when about half of the core is etched. Compared with the traditional ones, our scheme for fabricating fiber MZI has the characteristics of low cost, environmentally friendly, and regular transmission spectrum. This fiber MZI not only reduces the consumption of the sample, but also brings forth a good potential for micro-scale detection of refractive index.