利用WDM光纤耦合器的光纤光栅传感解调技术

Demodulation of fiber Bragg grating sensing system based on WDM fiber coupler

根据 WDM 光纤耦合器波长解调方案的工作原理、偏振特性以及影响系统波长分辨力的因素,提出一种改进的利用 WDM 光纤耦合器的光纤光栅传感解调技术。该技术在原技术的基础上,采用偏振控制器控制入射光偏振状态,提高了解调的精度和稳定性。对 WDM 光纤耦合器的多次波长扫描结果表明,采用偏振控制器后,其波长误差可减小到 5pm 左右。实验采用 1540/1560nm的 WDM 光纤耦合器对单点光纤光栅应变传感器进行静态解调,结果表明:按此技术开发的解调系统具有 0.01nm 波长分辨力和 10nm 的波长线性解调范围。

An improved demodulation technique of fiber Bragg grating sensing system is proposed based on the operating principle of wavelength demodulation scheme of WDM fiber coupler, polarization character and the factors affecting wavelength resolution of the system. The polarization state of incident light is controlled by a polarization controller to improve the accuracy and stability of demodulation on the basis of original technique. Results of wavelength scanning with WDM fiber coupler show that wavelength error can be reduced to about 5 pm due to applying polarization controller. In experiments, static demodulation for single point fiber Bragg grating strain sensor is carried out by use of 1540/1560 nm WDM fiber coupler. The result shows that the demodulation system developed with this technique has a wavelength resolution of 0.01 nm and a linear wavelength demodulation range of 10 nm.