为改善分布反馈式(DFB)光纤激光器水声探测性能, 利用有限元软件ANSYS, 以相对加速度灵敏度为目标函数, 结构尺寸参数为设计变量, 结构第一阶固有频率和探头声压灵敏度为状态变量, 对夹层式封装结构进行了优化设计, 对其声压探测及抗加速度机理进行了分析。分析表明, 基于优化结果设计的探头在采用100 m非平衡干涉仪时, 其声压灵敏度约为-135.1 dB, 相对加速度灵敏度可达到-19.6 dB。结果表明, 基于封装结构敏感部分分别承受声压激励和加速度激励时的不同响应机理, 对夹层式封装结构关键部位尺寸进行优化设计后, 通过合理选择承压梁与中间变形梁的厚度以及上下连接点的位置, 封装制得的光纤激光水听器具有较高的声压灵敏度和良好的抗加速度性能。

To improve the underwater acoustic detecting capability of DFB fiber laser, the optimization design and mechanism analysis of a sandwich-type encapsulated structure were carried out using FEA software ANSYS, by setting the relative acceleration sensitivity as objective function, the structural dimension parameters as design variables, and the structural first-order inherent frequency and sound pressure sensitivity of the probe as state variables. The analysis results show that when a 100 m unbalanced interferometer is used, the sound pressure sensitivity of the designed probe can achieves about -135.1 dB, and the relative acceleration sensitivity -19.6 dB. It is shown that by properly setting the thicknesses of the beams and arranging the connection joints, the DFB fiber laser hydrophone with the optimized encapsulated structure has high sound pressure sensitivity and improved anti-acceleration performance.