基于光学频率梳与超声脉冲之间的声光效应, 提出了一种海水声速直接测量的方法。根据光学频率梳模间拍频的相位测量了超声脉冲的飞行距离,根据脉冲声光效应引起的零级光的强度变化测量了超声脉冲的飞行时间。搭建了基于马赫-曾德尔干涉仪的测量装置。实验结果表明,该方法可以在实验室条件下实现高精度的海水声速测量,测量不确定度优于5 cm/s。

Based on the acousto-optic effect between the optical frequency comb and the ultrasonic pulse, we propose a method for direct measurement of seawater sound velocity. We measure the flight distance of the ultrasonic pulse according to the phase of the beat frequency between the optical frequency combs, and measure the flight time of the ultrasonic pulse based on the intensity variation of the zero-order light caused by the pulse acousto-optic effect. A measuring device based on Mach-Zehnder interferometer is built. The experimental results show that this method can achieve high precision seawater sound velocity measurement in lab, and the measurement uncertainty is better than 5 cm/s.