Paper
15 December 2022 Fiber ring cavity laser based on cascading two peanut-shape structures for liquid level measurement
Author Affiliations +
Proceedings Volume 12478, Thirteenth International Conference on Information Optics and Photonics (CIOP 2022); 124782R (2022) https://doi.org/10.1117/12.2654771
Event: Thirteenth International Conference on Information Optics and Photonics (CIOP 2022), 2022, Xi'an, China
Abstract
In this letter, a new method for liquid level measurement based on in-line Mach Zehnder interferometer (MZI) in fiber ring laser cavity is proposed and experimentally demonstrated. Two cascaded peanut-shaped fiber structures are designed to implement MZI with a length of 25 mm. At the beginning, the broadband light source was used to demonstrate the possibility of MZI as a liquid level sensor. The experimental results show that the liquid level sensitivity of -1.057 nm/cm can be achieved in the detection range of 0-20 mm. However, using broadband light sources to build a sensing system has a large 3-dB spectral bandwidth and low signal-to-noise ratio in the available wavelength range. Therefore, these sensing systems may have poor resolution, low accuracy monitoring and limited detection distance. Therefore, the experiment further uses the fiber ring laser (FRL) cavity to replace the broadband light source to realize the liquid level monitoring. Thanks to narrow laser linewidth and high signal-to-noise ratio, higher detection accuracy can be obtained. MZI acts as a filter and a sensor at the same time. When the liquid level changes, the interference peak shift plays the role of filtering and wavelength selection. The results showed that the detection sensitivity was as high as -1.348 nm/cm. Accompanied by a signal-to-noise ratio of up to 50 dB and a 3-dB linewidth of less than 0.2 nm. Besides, the fiber ring laser cavity can theoretically extend the length of single-mode fiber infinitely in the cavity. Hence, the sensor designed is exemplary and representative for liquid level monitoring in unconventional areas in the far field such as: extreme geological landforms, high temperature and high-pressure regions and anaerobic areas.
© (2022) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Weihao Lin, Siming Sun, Fang Zhao, Jie Hu, Shuaiqi Liu, Feihong Yu, and Liyang Shao "Fiber ring cavity laser based on cascading two peanut-shape structures for liquid level measurement", Proc. SPIE 12478, Thirteenth International Conference on Information Optics and Photonics (CIOP 2022), 124782R (15 December 2022); https://doi.org/10.1117/12.2654771
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KEYWORDS
Liquids

Fiber lasers

Sensors

Light sources

Structured optical fibers

Signal to noise ratio

Optical fibers

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