分布反馈式光纤激光器的动态特性  

Dynamical characteristics of distributed feedback fiber laser

作　　者：谭波[1,2] 黄俊斌[1] 何琳[2] 顾宏灿[1] 李日忠[1] 

机构地区：[1]海军工程大学兵器工程系,湖北武汉430033 [2]海军工程大学振动与噪声研究所,湖北武汉430033

出　　处：《光学精密工程》2009年第8期1832-1838,共7页Optics and Precision Engineering

基　　金：国家973安全重大基础研究发展规划资助项目

摘　　要：为了探明分布反馈式(DFB)光纤激光器用于水声探测时,所测得的声压灵敏度高于静压条件下计算所得的声压灵敏度,且动态响应曲线不平坦的原因及其机理,对DFB光纤激光器的动态特性进行了研究。对两端固定并分别置于空气和水介质中的DFB光纤激光器的振动模态进行了数值仿真分析;设计加工了实验夹具,分别对其进行了实验研究。实验测得数据显示,两端固定的裸纤在发生振动时的第一阶固有频率与其夹持长度有关,且随着该长度的增大,固有频率降低;当夹持长度分别为50、55和60mm时,在空气和水介质中DFB光纤激光器振动的第一阶固有频率分别约为250、200、125Hz以及200、160、120Hz,实测数据与仿真分析吻合。结果表明,当DFB光纤激光器受外界激励发生振动时,会引起激光器输出信号幅值的波动,导致其声压灵敏度出现起伏,第一阶固有频率对其具有很大的影响。When a Distributed Feedback（DFB） fiber laser is used in underwater acoustic detection, it is found that the acoustic pressure sensitivity of the DFB fiber laser is higher than that calculated under hydrostatic boundary conditions, and its frequency response curve is not smooth. To explore the reason and the mechanism of the above, the dynamical characteristics of the DFB fiber laser are investigated. Firstly, the vibration models of the DFB fiber laser whose both ends are fixed and placed in air and water respectively is analyzed numerically. And then, with specially designed testing assemblies, experimental study on it is also conducted. The results indicate that the first order natural frequency of the DFB fiber laser is related to the length of the optical fiber between the two fixed ends, and the frequency decreases with the length increases. When the length is set as 50, 55 and 60 mm respectively, the first order natural frequencies have been found to be about 250, 200 and 125 Hz in air, and 200, 160 and 120 Hz in water. These data show that when vibration takes place in the DFB fiber laser, its output will be changed to cause the fluctuation of acoustic pressure sensitivity, which shows the first natural frequency is an important factor for the underwater acoustic detection.

关 键 词：分布反馈光纤激光器 水听器 水声探测 动态特性 声压灵敏度 

分 类 号：TN248.8[电子电信—物理电子学]