Power-Referenced and Temperature-Calibrated Optical Fiber Refractometer

A novel technique for simultaneous measurement of refractive index and temperature based on power level detection of a weakly tilted fiber Bragg grating (TFBG) is proposed and experimentally demonstrated. Surrounding refractive index (RI) and temperature can be unambiguously determined by the TFBG transmitted and reflected power, respectively, avoiding complex wavelength interrogation. An accuracy approaching 1 x 10
^-4
in terms of the RI as well as temperature self-calibration is shown for this robust and cost-effective refractometer.