Phase-shift formed in a tapered long period fiber grating and its application to simultaneous measurements of temperature and refractive-index

摘要

A novel approach to calibrate a phase-shift formed in a long-period fiber grating (LPG) is proposed and successfully demonstrated, which is based on the use of either a power- or a wavelength-interrogation technique to the loss-peak existed in the transmission spectrum of the phase-shifted LPG. Moreover, in this study, by tapering a LPG with CO_2 laser, phase-shift is successfully created at central part of the LPG. Finally, base on the use of this kind of phase-shifted LPG, a simultaneous measurement for the temperature and the surrounding refractive index has been proposed and experimentally demonstrated.