Experimental implementation of quantum-enhanced tapered fiber sensor for simultaneous measurement of curvature and temperature

Abstract

This work reports a proof-of-principle experimental demonstration of a quantum-enhanced tapered fiber sensor based on intensity-correlated pulse twin beams and a conventional tapered fiber structure, which is prepared by concatenating two tapers along a single-mode fiber. The sensing beam from pulse twin beams is coupled into this structure for simultaneous measurement of curvature and temperature, then it is jointly measured with the other reference beam, this measurement technique can effectively enhance signal-to-noise ratio (SNR) and sensitivity of the tapered fiber sensor, due to the existence of intensity correlation shared by pulse twin beams. If the reference beam is kept unchanged during the measurement process, this measurement is called as unbalanced measurement condition; otherwise it is called as balanced measurement condition. Under balanced measurement condition for curvature sensing (curvature range from 3.266 m−1 to 9.412 m−1), SNR is maximally enhanced by a factor of 1.10 dB with respect to equally classical strategy. Under unbalanced measurement condition for curvature sensing, SNR and sensitivity are maximally enhanced by the factors of 0.98 dB and 1.277 dB/m−1, respectively. Under balanced measurement condition for temperature sensing (temperature range from 35 °C to 60 °C), SNR is maximally enhanced by a factor of 1.14 dB. Under unbalanced measurement condition for temperature sensing, SNR is maximally enhanced by a factor of 0.64 dB. The present research opens a new avenue for quantum-enhanced sensing based on tapered fiber structure.