实验技术与管理2026，Vol.43Issue(2)：148-154,7.DOI:10.16791/j.cnki.sjg.2026.02.017
光纤温湿度双参量传感器开发及呼吸监测应用
Development of a dual-parameter optical-fiber sensor for temperature and humidity and its application in respiratory monitoring
摘要
Abstract
[Objective]To meet the growing demand for high-precision temperature and relative humidity(RH)sensing in fields such as environmental monitoring and healthcare,a dual-parameter optical fiber sensor based on agarose-coated cascaded fiber Bragg gratings(FBGs)is developed and experimentally validated.[Methods]Two FBGs were inscribed in a single-mode fiber using a deep-ultraviolet laser phase mask technique.Both gratings had identical periods of 535.6 nm and lengths of 10 mm,separated by 15 mm.The initial center wavelength of FBG1 was 1 550.41 nm,while that of FBG2 shifted to 1 548.50 nm after coating.The hygroscopic coating material was prepared by dissolving agarose powder(Sigma-Aldrich)in deionized water at a concentration of 1%under a 90℃water bath.FBG2 was carefully straightened and fixed within a 3-mm-diameter plastic sleeve,which was then filled with the prepared agarose solution to completely immerse the grating region.After a controlled deposition period of 5 min,the excess solution was systematically drained,and the sensor was air-dried for 24-48 h under well-ventilated conditions at room temperature to facilitate uniform film formation.High-resolution microscopic examination confirmed the final structural parameters,showing a coated fiber diameter of approximately 501.6 μm,which corresponds to a consistent agarose film thickness of about 188.3 μm covering the grating region.The sensing mechanism operates on a differential response principle.The agarose-coated FBG2 responds to both humidity and temperature variations:moisture absorption induces hydrogel expansion,generating strain on the optical fiber and consequently shifting the Bragg wavelength.The same grating exhibits enhanced temperature sensitivity due to the thermo-optic effect and thermal expansion of the agarose material.In contrast,the uncoated FBG1 remains exclusively sensitive to temperature changes.This strategic differential response enables effective discrimination between humidity and temperature through established matrix methods.[Results]Comprehensive experimental characterization demonstrated outstanding sensor performance.The device achieved a remarkable humidity sensitivity of 84 pm/%RH within the 40%-79%RH range,significantly higher than that of many conventional humidity sensors.Temperature sensitivity measurements in the 24-42℃range showed distinct responses of 8 pm/℃for the uncoated FBG1 and-108 pm/℃for the agarose-coated FBG2,with the negative coefficient indicating dominant thermal expansion effects in the composite structure.A sensitivity coefficient matrix was subsequently constructed and validated for accurate parameter decoupling,demonstrating minimal cross-sensitivity in simultaneous measurement scenarios.Practical applications in human respiratory monitoring further verified the sensor's reliability and dynamic response.The sensor successfully detected respiratory rates across various modes,including normal,deep,and rapid breathing,and accurately captured transitions between different modes in real time,demonstrating its potential for biomedical monitoring applications.[Conclusions]This research demonstrates the development of a high-performance,cost-effective dual-parameter sensor utilizing functionalized cascaded FBGs with an agarose coating.The sensor exhibits superior sensitivity,simple structure,minimal cross-talk,and excellent anti-interference characteristics,rendering it suitable for diverse applications in environmental monitoring,healthcare diagnostics,and wearable devices.关键词
光纤温湿度传感器/光纤布拉格光栅/琼脂糖/双参量解调/呼吸监测Key words
fiber humidity and temperature sensor/fiber Bragg grating/agarose/dual-parameter demodulation/respiratory monitoring分类
信息技术与安全科学引用本文复制引用
黄秋萍,张敬红,朱晓帅,凌强,陈海云..光纤温湿度双参量传感器开发及呼吸监测应用[J].实验技术与管理,2026,43(2):148-154,7.基金项目
浙江省基础公益研究计划项目(LY19F050015) （LY19F050015）
教育部产学合作协同育人项目(231002116220149,231004730194026) （231002116220149,231004730194026）
