A high-performance fiber optic interferometric hydrophone based on a push–pull mandrel structure, with high sensitivity and wide-frequency response, is designed and developed. Each arm of the Michelson interferometer is a fiber coil wrapped onto a separate but concentric thin elastic tube as the sensing arm to detect acoustic pressure wave. The fiber optic hydrophone is fabricated and examined experimentally, demonstrating its capacity to detect very low-frequency underwater acoustic pressure variation. The theoretical design is validated experimentally, with results showing that the push–pull fiber optic hydrophone has an average sensitivity of −134.39 dB re rad/ μ\mu Pa within the frequency range of 1 Hz–2 kHz, which is 5.67 dB higher than that of the analogous one-sensing-arm fiber optic interferometric mandrel hydrophone that we made for comparison. The push–pull fiber optic hydrophone has a minimum detectable pressure (MDP) of 25.37 μPa/Hz−−−√\mu {\mathrm {Pa}}/\sqrt {{\mathrm {Hz}}} at 1 kHz, about 15 dB lower than the deep-sea state zero (DSS0) level. At 10 Hz, the MDP is ~1.71 mPa/ Hz−−−√\sqrt {{\mathrm {Hz}}} , which is nearly 7 dB lower than the acoustic ambient noise in the ocean at low frequency. The sensitivity and the MDP of the push–pull fiber optic hydrophone have been doubled and improved by about 20% at 1 kHz, respectively, compared to other state-of-the-art flat response fiber optic hydrophones.

中文翻译：

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基于推全结构的高性能光纤干涉水听器


设计开发了一种基于推拉心轴结构、高灵敏度、宽频响应的高性能光纤干涉水听器。迈克尔逊干涉仪的每个臂都是一个光纤线圈，缠绕在一个单独但同心的薄弹性管上，作为检测声压波的传感臂。光纤水听器的制造和实验检验表明其检测极低频水下声压变化的能力。实验验证了理论设计，结果表明推挽式光纤水听器在1 Hz~2 kHz频率范围内的平均灵敏度为-134.39 dB re rad/ μμ Pa，比传统推挽式光纤水听器提高了5.67 dB。我们为进行比较而制作的类似单传感臂光纤干涉心轴水听器。推挽式光纤水听器在 1 kHz 时的最小可检测压力（MDP）为 25.37 μPa/Hz−−−√\mu {\mathrm {Pa}}/\sqrt {{\mathrm {Hz}}}，大约比深海状态零（DSS0）水平低15 dB。在 10 Hz 时，MDP 约为 1.71 mPa/ Hz−−−√\sqrt {{\mathrm {Hz}}} ，比低频海洋中的声学环境噪声低近 7 dB。与其他最先进的平坦响应光纤水听器相比，推挽式光纤水听器的灵敏度和 MDP 在 1 kHz 下分别提高了一倍和约 20%。