基于FBG啁啾效应的强度解调型光纤热式风速计

Intensity interrogated optical fiber thermal anemometer based on the chirp effect of FBG

针对现有的波长解调型光纤布喇格光栅(FBG)风速计系统成本高、操作不方便等问题,提出一种基于FBG啁啾效应的强度解调型光纤热式风速计。使用泵浦激光对长度为15 mm的FBG进行非均匀加热后,使其产生明显的啁啾效应,利用啁啾化FBG在风速作用下温度梯度降低导致啁啾程度减弱,其反射光功率也随之减小的原理,成功实现了强度解调型的FBG风速测量。实验结果表明:风速计的测量范围达0~11 m/s,在风速为0.1 m/s时风速计的灵敏度高达-28.60μW/(m·s^(-1)),其动态响应时间小于1 s(低风速到高风速约为0.3 s,高风速到低风速为0.9 s)。

Aiming at the high cost and inconvenient operation of the wavelength demodulation fiber Bragg grating(FBG)anemometer system,an intensity interrogated optical fiber thermal anemometer based on the chirp effect of FBG is proposed.After using a pump laser to heat the 15 mm FBG non-uniformly,it produces a noticeable chirp effect.Under the airflow,the chirp effect of the chirped FBG weakens as its temperature gradient decreases,resulting in reflected optical power decline.Based on this principle,the FBG wind speed measurement with intensity demodulation is successfully realized.The experimental results show that the measurement range of the anemometer is 0~11 m/s,and the sensitivity is up to-28.60μW/(m·s^(-1))when the wind speed is 0.1 m/s.In addition,the dynamic response time is less than 1 s(about 0.3 s for low to high wind speed,and 0.9 s for high to low wind speed).