基于双 AWG 的新型 FBG 连续解调方法研究

为了实现基于阵列波导光栅(arrayed waveguide grating, AWG)的光纤布拉格光栅(fiber Bragg gratin, FBG)的连续解调, 提出了一种使用两个 AWG 联合解调的方法。 在一个 AWG 相邻两通道光谱中间插入另一个 AWG 对应通道的光谱,组成最小 的光谱周期;每次测量均从三通道中选择光强度最强的两个通道,利用相对光强解调算法,根据其波长—功率关系对 FBG 中心 波长进行精确测量。 使用两个 100 GHz 的 AWG 搭建了实验平台,并对温度传感器的解调进行研究。 实验表明,在 0. 8 nm 的系 统最小动态范围周期内,实现了对 FBG 的连续精确解调,系统的解调线性度达 0. 999 1,波长精度达±4 pm。 对数据和实验结果 进行数学分析,可以将 C 波段范围分成多个波长周期,系统可以实现在 C 波段 40 nm 全周期范围内对单个 FBG 的连续解调。 该方法不但可以实现在 C 波段范围内基于 AWG 对 FBG 的连续解调,使得运用 FBG 可以连续感测外界物理量变化,提高了系 统的实用性。 而且,该方法能够准确解调出波长信息,为实现对 FBG 的连续精确解调提供了借鉴信息,有利于进一步扩大 FBG 的应用领域。

Research on a novel method of continuous FBG interrogation based on double AWGs

To achieve continuous interrogation of fiber Bragg grating (FBG) based on arrayed waveguide grating (AWG), a method of joint interrogation using two AWGs is proposed. The insertion of the spectrum of the corresponding channel of another AWG in the middle of the spectra of two adjacent channels of one AWG, forming the minimum spectral period. Each measurement selected the two channels with the strongest light intensity from the three channels, and used the relative light intensity interrogation algorithm to accurately measure the FBG center wavelength based on its wavelength-power relationship. The experimental platform was built by using two 100 GHz AWGs, and the interrogation of the temperature sensors was investigated. The experimental results show that the continuous and accurate interrogation of FBG is achieved within the 0. 8 nm minimum dynamic range period of the system, and the interrogation linearity of the system reaches 0. 999 1 and the wavelength accuracy reaches ±4 pm. The C-band range can be divided into multiple wavelength cycles by mathematically analyzing the data and experimental results, and the system can achieve continuous interrogation of a single FBG in the C-band 40 nm full-cycle range. The method not only realizes continuous interrogation of FBG based on AWG in the C-band range, which makes it possible to continuously sense the external physical quantity changes using FBG and improves the practicality of the system. Moreover, the method can accurately interrogate the wavelength information, which provides reference information for the realization of continuous and accurate interrogation of FBG and is conducive to the further expansion of the application field of FBG.