A novel fiber-optic hydrophone based on a dual-polarization, short-cavity fiber grating laser as the sensing element is described. Wet chemical etching was used to fabricate a thinned fiber sensor to extend its frequency response as well as spatial resolution. The lateral beam profile at the focal plane of a 40-MHz lens-focused lithium niobate (LiNbO3) transducer was measured with the fiber sensor, and a tomographic technique was used to compute the transducer profile, which is compared with that obtained by a PVDF hydrophone. The fiber hydrophone has a sensitivity of approximately −259 dB re 1V/µPa up to 40 MHz, which is higher than that of a commercial PVDF hydrophone. Moreover, it is capable of accurately characterizing the beam generated by high-frequency transducer.
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机译：描述了一种基于双偏振，短腔光纤光栅激光器作为传感元件的新型光纤水听器。湿法化学蚀刻用于制造细化的光纤传感器，以扩展其频率响应以及空间分辨率。使用光纤传感器测量了40 MHz透镜聚焦铌酸锂（LiNbO3）传感器焦平面处的横向光束轮廓，并使用层析成像技术计算了该传感器轮廓，并将其与PVDF进行了比较水听器。光纤水听器在40 MHz以下的灵敏度约为-259 dB re 1V / µPa，最高40 MHz，高于商用PVDF水听器。而且，它能够准确地表征由高频换能器产生的光束。
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