Single Step Process for Optical Microfiber In-Line Mach-Zehnder Interferometers Fabrication

Based on a novel modulated arc-discharge technique, a single step process for taper-functionalized optical microfiber in-line Mach-Zehnder interferometers (MZIs) fabrication is presented. By this process, microfiber and its added down-tapers are fabricated exploiting an amplitude modulated arc-discharge heating in one-step. In this letter, included short-time arc OFF switches during an arc-assisted microfiber fabrication process result in the formation of miniature down-tapers along the microfiber being pulled. The arrangement and time duration of these arc OFF pulses determine the functionality of the resultant microfiber structure. The first single step taper-functionalized microfiber in-line MZI exhibits an extremely high interference dip (~29 dB) with low full width at half maximum (~5 nm) and high external refractive index (RI) sensitivity of 1840 nm per RI unit around 1.368.