A fiber Bragg grating （FBG） hydrophone with enhanced sensitivity is demonstrated. A novel piston-like diaphragm with a hard core fixed at the center is used as the sensing element. Theoretical analysis shows that th...A fiber Bragg grating （FBG） hydrophone with enhanced sensitivity is demonstrated. A novel piston-like diaphragm with a hard core fixed at the center is used as the sensing element. Theoretical analysis shows that the Young＇s modulus of the diaphragm and the radius of the hard core have significant effect on the pressure sensitivity. Experiments are carried out to test this effect and the performance of the hydrophone. The static measure- ment result is in good agreement with the theoretical result and an acoustic sensitivity of 7 nm/MPa has been achieved.展开更多
Fiber-optic hydrophone (FOH) is a significant type of acoustic sensor, which can be used in both military and civilian fields such as underwater target detection, oil and natural gas prospecting, and earthquake inspec...Fiber-optic hydrophone (FOH) is a significant type of acoustic sensor, which can be used in both military and civilian fields such as underwater target detection, oil and natural gas prospecting, and earthquake inspection. The recent progress of FOH is introduced from five aspects, including large-scale FOH array, very-low-frequency detection, fiber-optic vector hydrophone (FOVH), towed linear array, and deep-sea and long-haul transmission. The above five aspects indicate the future development trends in the FOH research field, and they also provide a guideline for the practical applications of FOH as well as its array.展开更多
A fiber Bragg grating （FBG） hydrophone with high sensitivity was demonstrated. This hydrophone used a rubber diaphragm and a copper hard core as the sensing element. To compensate the hydrostatic pressure, a capilla...A fiber Bragg grating （FBG） hydrophone with high sensitivity was demonstrated. This hydrophone used a rubber diaphragm and a copper hard core as the sensing element. To compensate the hydrostatic pressure, a capillary tube was fixed at the end of the hydrophone. Theoretical analysis of the acoustic pressure sensitivity was given in this letter. Experiments were carried out to test the frequency response of the hydrophone. The result shows that when the Young＇s modulus of the diaphragm is higher, a flatter frequency response will be obtained.展开更多
通信中的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术具有频带利用率高、抗多径衰落强等优点,但是OFDM通信存在高峰值平均功率比(Peak to Average Power Ratio,PAPR)的问题,如果不加抑制,在输出时会导致信号失...通信中的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术具有频带利用率高、抗多径衰落强等优点,但是OFDM通信存在高峰值平均功率比(Peak to Average Power Ratio,PAPR)的问题,如果不加抑制,在输出时会导致信号失真,降低通信效率。提出了一种通过给OFDM符号不同信道的导频和信号添加固定相位偏移因子来抑制发射信号PAPR的方法。首先介绍了信道相位偏移因子的添加方法和解调过程,其次仿真分析表明随机产生的相位偏移因子可以将任意传输信号的PAPR抑制在小于11 dB的水平。此技术不需要消耗额外带宽和计算资源,且对系统的误码率几乎没有影响。最后采样低成本的功放和声源作为发射换能器,用光纤水听器作为接收换能器进行实际通信试验,验证了该方法的有效性。展开更多
基金supported by the National 863 Program under Grant No. 2007AA03Z415.
文摘A fiber Bragg grating （FBG） hydrophone with enhanced sensitivity is demonstrated. A novel piston-like diaphragm with a hard core fixed at the center is used as the sensing element. Theoretical analysis shows that the Young＇s modulus of the diaphragm and the radius of the hard core have significant effect on the pressure sensitivity. Experiments are carried out to test this effect and the performance of the hydrophone. The static measure- ment result is in good agreement with the theoretical result and an acoustic sensitivity of 7 nm/MPa has been achieved.
基金The authors would like to acknowledge the support of the National Natural Science Foundation of China(Grant Nos.61775238,61705263,and 61705262).
文摘Fiber-optic hydrophone (FOH) is a significant type of acoustic sensor, which can be used in both military and civilian fields such as underwater target detection, oil and natural gas prospecting, and earthquake inspection. The recent progress of FOH is introduced from five aspects, including large-scale FOH array, very-low-frequency detection, fiber-optic vector hydrophone (FOVH), towed linear array, and deep-sea and long-haul transmission. The above five aspects indicate the future development trends in the FOH research field, and they also provide a guideline for the practical applications of FOH as well as its array.
基金Key Projects Program of Chinese Acadelny of Sciences under Grant No.CXJJ-177.
文摘A fiber Bragg grating （FBG） hydrophone with high sensitivity was demonstrated. This hydrophone used a rubber diaphragm and a copper hard core as the sensing element. To compensate the hydrostatic pressure, a capillary tube was fixed at the end of the hydrophone. Theoretical analysis of the acoustic pressure sensitivity was given in this letter. Experiments were carried out to test the frequency response of the hydrophone. The result shows that when the Young＇s modulus of the diaphragm is higher, a flatter frequency response will be obtained.
基金Acknowledgment This work was financially supported by the National Natural Science Foundation of China （No. 60317101）, Key Research and Development Plan of Shandong Province （No. 2015GSF11500）, and Natural Science Foundation of Shandong Province （No. ZR2013FL029）.
文摘纤维激光水中听音器由于唯一的优点和宽广申请前景得到了普遍担心。在这篇论文，研究八元素的多路的纤维激光结果声学的压力数组和讯问系统被介绍，包含的低噪音的分布式的反馈纤维激光(DFB-FL ) 制造，包装的敏感改进，和 interferometric 表明解调。系统的频率反应范围是 10Hz-10kHz，声学的压力敏感到达的激光频率 115 dB re Hz/Pa，和声学的压力是的相等的噪音不到 60Pa/Hz <sup>1/2</sup> 。系统的动态范围比 120 dB 大。
基金This work is supported by Shandong Key Research and Development Projects （No. 2015GSF 115006）, National Nature Science Foundation （No. 61605102）, and Young Science Foundation of Shandong Academy of Sciences （No. 2016QN002）.
文摘一个短洞分布式的反馈(DFB ) 纤维激光被用于低频率声学的信号察觉。有不同中央波长的三 DFB 纤维激光一起被锁住与合适的敏感改进设计做三元素的向量水中听音器，它有广泛、重要的应用到为国家防卫的在水下的声学的监视，油，煤气的探索等等。由波长阶段解调，在不同频率信号下面的放射激光的波长变化能被解释，并且敏感被测试大约 33 dB re pm/g。频率反应范围从 5 Hz 是相当扁平的到 300 Hz。
文摘通信中的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术具有频带利用率高、抗多径衰落强等优点,但是OFDM通信存在高峰值平均功率比(Peak to Average Power Ratio,PAPR)的问题,如果不加抑制,在输出时会导致信号失真,降低通信效率。提出了一种通过给OFDM符号不同信道的导频和信号添加固定相位偏移因子来抑制发射信号PAPR的方法。首先介绍了信道相位偏移因子的添加方法和解调过程,其次仿真分析表明随机产生的相位偏移因子可以将任意传输信号的PAPR抑制在小于11 dB的水平。此技术不需要消耗额外带宽和计算资源,且对系统的误码率几乎没有影响。最后采样低成本的功放和声源作为发射换能器,用光纤水听器作为接收换能器进行实际通信试验,验证了该方法的有效性。
