Effect of a waist diameter of a polarization-maintaining fiber on ambient index sensitivity

Abstract

We investigate the effect of a waist diameter of a polarization-maintaining fiber (PMF) on ambient index and temperature sensitivities by configuring a Sagnac loop interferometer. To make the PMF sensitive to external index change, a micro-tapering technique is exploited to fabricate the tapered PMF. The Sagnac loop interfoermeter is fabricated by using the tapered PMF with various waist diameters. The reduction of the PMF diameter results in the enhancement of the ambient index sensitivity of the tapered-PMF-based Sagnac interferometer. However, the temperature sensitivities of the proposed Sagnac interferometers are not changed by reducing the waist diameters of the PMFs.