Demodulation method combining virtual reference interferometry and minimum mean square error for fiber-optic Fabry–Perot sensors

We propose a cavity length demodulation method that combines virtual reference interferometry(VRI) and minimum mean square error(MMSE) algorithm for fiber-optic Fabry–Perot(F-P) sensors. In contrast to the conventional demodulating method that uses fast Fourier transform(FFT) for cavity length estimation,our method employs the VRI technique to obtain a raw cavity length, which is further refined by the MMSE algorithm. As an experimental demonstration, a fiber-optic F-P sensor based on a sapphire wafer is fabricated for temperature sensing. The VRI-MMSE method is employed to interrogate cavity lengths of the sensor under different temperatures ranging from 28°C to 1000°C. It eliminates the "mode jumping" problem in the FFT-MMSE method and obtains a precision of 4.8 nm, corresponding to a temperature resolution of 2.0°C over a range of 1000°C. The experimental results reveal that the proposed method provides a promising, high precision alternative for demodulating fiber-optic F-P sensors.     

基于蓝宝石晶片的光纤法布里-珀罗高温传感器

提出并研制了一种基于蓝宝石晶片的光纤法布里-珀罗(法珀)高温传感器.该传感器采用斜端面蓝宝石光纤作传输波导,蓝宝石晶片作法珀干涉仪,"陶瓷插芯-陶瓷套管"结构做为传感器的固定结构.通过傅里叶变换-最小均方差联合算法解调传感器的反射光谱,实现了20℃~1 000℃范围内的温度测量,测试准确度为±2.5℃.该传感器具有体积小、成本低、制作简单以及重复性高的优点,可用于高温环境下稳定、精确的温度测量.