Exceptional-point-enhanced sensing in an all-fiber bending sensor
全光纤弯曲传感器中卓越的点增强传感
全ファイバ曲げセンサにおける優れた点強化センシング
전광섬유 커브 센서의 탁월한 점 강화 감지
Excelente detección de mejora de puntos en todos los sensores de flexión de fibra óptica
Excellente détection améliorée par points dans les capteurs de flexion à fibre optique
Превосходная точечная сенсорная чувствительность в полностью волоконно - оптических датчиках изгиба
Zheng Li 李铮 ¹, Jingxu Chen 陈敬旭 ¹, Lingzhi Li 李凌志 ¹, Jiejun Zhang 张杰君 ¹, Jianping Yao 姚建平 ¹ ²
¹ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
中国 广州 暨南大学光子技术研究院 广东省光纤传感与通信技术重点实验室
² Microwave Photonics Research Laboratory, School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6N5, Canada
An exceptional-point (EP) enhanced fiber-optic bending sensor is reported. The sensor is implemented based on parity-time (PT)-symmetry using two coupled Fabry-Perot (FP) resonators consisting of three cascaded fiber Bragg gratings (FBGs) inscribed in an erbium-ytterbium co-doped fiber (EYDF). The EP is achieved by controlling the pumping power to manipulate the gain and loss of the gain and loss FP resonators.
Once a bending force is applied to the gain FP resonator to make the operation of the system away from its EP, frequency splitting occurs, and the frequency spacing is a nonlinear function of the bending curvature, with an increased slope near the EP. Thus, by measuring the frequency spacing, the bending information is measured with increased sensitivity.
To achieve high-speed and high-resolution interrogation, the optical spectral response of the sensor is converted to the microwave domain by implementing a dual-passband microwave-photonic filter (MPF), with the spacing between the two passbands equal to that of the frequency splitting.
The proposed sensor is evaluated experimentally. A curvature sensing range from 0.28 to 2.74 m⁻¹ is achieved with an accuracy of 7.56×10⁻⁴ m⁻¹ and a sensitivity of 1.32 GHz/m⁻¹, which is more than 4 times higher than those reported previously.
