Author Affiliations
Abstract
1 Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, Guangzhou 510006, China
2 School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
Vortex optical communication has been a hot research field in recent years. A key step is mode recognition in the orbital angular momentum (OAM) free-space optical (FSO) communication system. In this article, we propose an OAM mode recognition method based on image recognition technology, which uses the interferogram between the vortex beam and the Gaussian beam to identify the OAM mode. In order to resist the influence of atmospheric turbulence on the recognition accuracy, we added a Gaussian smoothing filter into the recognition process. Moreover, we used random phase screens to generate interferogram sets at distances of 1 km and 2 km. The verification result shows that the proposed scheme produces high identification accuracy for the distorted optical field. The average accuracy can reach 100% and 87.78% under the conditions of medium- and strong-turbulence levels, respectively. It is anticipated that these results might be helpful for improving the reliability of the OAM-FSO communication system in the future.
Chinese Optics Letters
2022, 20(2): 020601
Author Affiliations
Abstract
Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China
A novel high sensitivity relative humidity (RH) sensor was proposed by using micro structure plastic optical fiber (POF) based on the surface plasmon resonance (SPR) effect and the evanescent wave (EW) loss. The micro structure was fabricated on the POF and coated with a gold layer and agarose, adopting the sputtering and dip-coating technique. These construction effects on the attenuation of power caused by the SPR effect and the EW loss were used to perform RH detections. The agarose’s different refractive indexes (RIs) caused fluctuations in the transmission power when the humidity increased. The demonstrated experimental results showed that the proposed sensor achieved a linear response from 20% RH to 80% RH with a high sensitivity of 0.595 μW/%. The proposed sensor had the advantages of fast response and recovery. Furthermore, the temperature dependence and the repeatability test of the sensor were also performed.
SPR evanescent wave loss agarose RH sensor Photonic Sensors
2021, 11(4): 392
Author Affiliations
Abstract
Key Laboratory of Instrumentation Science & Dynamic Measurement (North University of China), Ministry of Education, Taiyuan, 030051, China
The macro-bending induced optical fiber cladding modes frustrated total internal reflection effect is used to realize the liquid level probe with a simple structure of single macro-bend polymer optical fiber loop. The test results show that the extinction ratio reaches 1.06 dB. “First bath” phenomenon is not obvious (about 0.8%). The robustness of the sensor is better, and the ability of anti-pollution is stronger compared with the conventional sensors. The process of making this sensing probe is extremely easy, and the cost is very low.
Water leakage measurement polymer optical fiber frustrated total internal reflection Photonic Sensors
2016, 6(4): 312
Author Affiliations
Abstract
1 Science and Technology on Inertial Laboratory, Beihang University, Beijing 100191, China
2 Precision Opto-mechatronics Technology Key Laboratory of Education Ministry, Beihang University, Beijing 100191, China
3 Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, North University of China, Taiyuan 030051, China
4 Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
Preparation and characterization of a liquid level sensor based on macro-bending coupling of fibers are demonstrated in this Letter. The sensitive component can be obtained through a twisting and twining structure of transparent cladding plastic fibers. The difference in light power originating from the surrounding media in the fibers is tested. The light power loss for different tested media and the fiber bending magnitude are investigated. The sensing measurements show that the coupling light power in the passive fiber decreases in accordance with increasing liquid level, whereas it exhibits a steady tendency in the case of the active fiber.
060.2370 Fiber optics sensors 060.2400 Fiber properties 060.2270 Fiber characterization 040.1880 Detection Chinese Optics Letters
2015, 13(8): 080601
