光纤麦克风传感探头设计的理论分析

鉴于光纤传感器具有体积小、结构简单、灵敏度高、抗电磁干扰且光纤本身的低损耗、耐腐蚀和安全可靠等优良特性，将光纤传感器应用到麦克风中可使麦克风的体积显著降低而灵敏度和抗电磁干扰性显著提高。提出一种新型反射式光纤麦克风的设计方法,采用Y形单根多模反射式光纤传感探头结构形式,给出了光纤麦克风的系统框图。由光纤出射光场分布理论出发，给出弹性膜片在声场作用下，中心形变大小h与出射光光强调制函数I(Z″)的关系。根据实际应用中有关参数的取值，用Matlab软件模拟出膜片形变后变形量h与光强调制函数I(Z″)的关系曲线。

Theoretical analysis of sensing probe in fiber microphone

Because of the fiber sensor's excellent characteristics,such as small volume,simply structure,high sensitivity,low loss,resistance to electromagnet interference and corrosion resistance,it is used in a microphone to reduce the size of the microphone,and improve its sensitivity and electromagnetic immunity performance. A new design for a reflective fiber microphone is proposed. The Y type reflective multimode fiber sensing probe is adopted. The block diagram of the fiber microphone system is given. Based on the theory of the optic field distribution of the exit light from a fiber,the relationship between the off-centering quantity h and the optical intensity modulate function I (Z＂) is presented for the deformed film in sound field.