Quantum-Enhanced Fiber Curvature Sensor Exploiting Intensity-Correlated Pulse Twin Beams

A quantum-enhanced fiber curvature sensor based on single-mode fiber (SMF) taper exploiting intensity-correlated pulse twin beams has been proposed and experimentally realized. The curvature can be measured by intensity difference noise power and degree of intensity difference squeezing which are tailored by the bending-induced loss of one beam’s SMF taper. In addition, the three different waist diameters of SMF tapers, i. e.,
$52.12~ \boldsymbol {\mu }\text{m}$
,
$61.68~ \boldsymbol {\mu }\text{m}$
, and 67.54
$\boldsymbol {\mu }\text{m}$
respectively have been prepared using a fusion splicer. Finally, the maximum measured sensitivity enhancement of 4.42 dB/m
⁻¹
and signal-to-noise ratio enhancement of 2.0 dB have been experimentally implemented through intensity difference measurement technique compared with the corresponding classical counterpart (double-channel light source). In contrast to other curvature sensors, this proposal has the advantages of high sensitivity, ease of fabrication, simple structure, and low cost.