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A method of measuring vibration by using fiber Bragg grating (FBG) and demodulating the spectrum by blazed grating is introduced. The sensor system is made of a simple supported beam with a FBG adhered to its upper surface. A blazed grating is used to demodulate the changing spectrum that is got from the sensor system, and a line charge-coupled device (CCD) is used to accept the diffraction spectrum. Through analyzing the number of the CCD's pixels, we can get the amplitude of vibration and the change of the temperature. The experimental results show that the vibration amplitude of the exciter matches the detected signal under the stable frequency. The temperature shift and vibration signal are also successfully separated. 相似文献
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A method of measuring vibration by using fiber Bragg grating (FBG) and demodulating the spectrum by blazed grating is introduced. The sensor system is made of a simple supported beam with a FBG adhered to its upper surface. A blazed grating is used to demodulate the changing spectrum that is got from the sensor system, and a line charge-coupled device (CCD) is used to accept the diffraction spectrum.Through analyzing the number of the CCD's pixels, we can get the amplitude of vibration and the change of the temperature. The experimental results show that the vibration amplitude of the exciter matches the detected signal under the stable frequency. The temperature shift and vibration signal are also successfully separated. 相似文献
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聚合物光纤辐照特性的实验研究 总被引:3,自引:1,他引:2
分析了聚合物受辐照后发生物理化学变化的机理,实验研究了聚苯乙烯(PS)、聚碳酸脂(PC)、聚甲级丙烯酸甲脂(PMMA)三种聚合物光纤在不同辐照剂量下光传输性能的变化以及其恢复特性.在各种辐照剂量下,光透过率有不同程度的下降,经过一段时间后也有不同程度的回复,并且恢复主要发生在停止辐照后的较短时间内.在102 Gy以下,辐照造成的光损伤经过一段时间基本可以恢复,在更高剂量的辐照下(超过5*103 Gy),辐照对光纤造成了永久损伤,经过很长时间也只能恢复一部分.实验结果表明,PS光纤的抗辐照特性最好,PC光纤优于PMMA光纤. 相似文献
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提出了一种噪声下非重复瞬态弱信号感知灵敏度增强方法。在双相干光频率梳(OFC)频谱克隆接收系统的基础上,利用声光频移器和光耦合器分别对本振OFC和信号OFC进行多路复制,使得瞬态弱信号频谱被分割的子信道成倍增加。在接收端灵敏度范围内,各子信道频谱被下变频至同一中频,并在频域中同步累加,累加后瞬态信号的感知信噪比(SNR)以倍数增加。利用梳齿个数为9的频谱克隆接收机对带宽为18 GHz的瞬态噪声信号进行感知,当本振OFC和信号OFC进行1、2、3路复制时,瞬态信号的感知灵敏度增益分别提升至12.63 dB、14.04 dB、15.43 dB。与双相干OFC频谱克隆接收结果相比,所提结构的SNR提升了3.0 dB、4.5 dB、5.9 dB,并进一步讨论了分路损耗对SNR改善比的影响。所提方案基本上不增加OFC生成模块的复杂度和频谱覆盖范围,实现了SNR倍增式增强。 相似文献
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