在色散补偿光纤上刻写光栅, 形成全光纤复合传感结构, 将干涉结构和光栅结构集成在同一段光纤内.分析了干涉包层模式和布拉格谐振峰对纵向拉力以及温度的响应机理.通过监测包层模式和布拉格谐振峰的波长漂移量, 建立矩阵方程, 实现对纵向拉力和温度双参量的同时测量.实验结果表明, 包层模式和布拉格谐振峰对温度的响应灵敏度分别为49.4 pm/℃和11.0 pm/℃, 包层模式对纵向拉力的响应灵敏度为1.05 pm/με, 布拉格谐振模式对纵向拉力的响应灵敏度为0.651 pm/με, 且这四个参数均表现出良好的线性度.该传感器结构采用低阶包层模式和纤芯基模模式, 对外界环境折射率不敏感, 能较好地应用于纵向拉力和温度的同时测量中.

A compound structure is fabricated by inscribing fiber Bragg gratings in dispersion compensation fiber, which is constituted by interferometer and fiber Bragg grating in a length of fiber. The strain and temperature response mechanisms of cladding mode and Bragg resonance are analyzed. The matrix equation is established through monitoring the cladding modes and Bragg resonance wavelength shift on the reflection spectrum, so that the simultaneous measurement of strain and temperature is achieved. The experimental results indicated that the temperature sensitivity of cladding mode and Bragg resonance are 49.4 pm/℃ and 11.0 pm/℃, respectively. The strain sensitivity of cladding modes is 1.05 pm/με and the strain sensitivity of Bragg resonance is 0.651 pm/με. The four parameters show good linearity. Since the compound structure has low-order cladding modes and core modes, it is insensitive to the environment and can play an important role in the field of strain and temperature simultaneous measurement.