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A kind of fiber Bragg grating sensor with protecting equipment for the determination of leaking oil is designed and assembled through mechanical location limiting principle. During detection, the sensor can effectively prevent fiber-optic grating from cracking due to intense stress and eliminate signal crosstalk of the distributed fiber-optic grating sensing system by confining the expanding length of the sensitive material. The sensing system also displays fast response(less than 4 min) 采用机械限位原理,设计和组装了一种有保护装置的光纤Bragg光栅漏油传感器。该传感器在检测过程中,通过限制敏感材料的膨胀长度能有效防止光纤光栅因承受较大的应力而断裂,同时,能克服分布式光纤光栅漏油检测系统中相邻信号之间的串扰,并具有较短的响应时间,其漏油报警响应时间小于4min。 The influence of residual facet reflection on the high-frequency response of distributed feedback semiconductor laser(DFB-LD)/electroabsorption(EA) modulator integrated light sources and its suppression are studied.To explain the peaks observed in the low frequency range of the modulation response of the integrated light sources,we measured the relative intensity noise spectra of the DFB LD and the modulation response of the EA modulator at different reverse biases.It is found that the key factor influencing... The influence of residual facet reflection on the high-frequency response of distributed feedback semiconductor laser(DFB-LD)/electroabsorption(EA) modulator integrated light sources and its suppression are studied.To explain the peaks observed in the low frequency range of the modulation response of the integrated light sources,we measured the relative intensity noise spectra of the DFB LD and the modulation response of the EA modulator at different reverse biases.It is found that the key factor influencing the modulation response of integrated light sources comes from the residual reflection at the EA facet rather than the microwave signal crosstalk.In order to suppress the facet reflection,improved anti-reflection coating was applied to EA modulator facet,and efficient improvement in high-frequency performance has been demonstrated. 研究了分布反馈型半导体激光器(DFB-LD)与电吸收(EA)调制器集成光源中调制器端面残余反射对器件高频特性的影响及其消除。针对在DFB-LD/EA集成光源小信号调制响应曲线低频段观察到的异常起伏,测量了DFB-LD的强度噪声谱,比较了不同反向偏压下EA调制器的调制响应。实验结果表明,对集成器件调制响应的干扰主要是来自于EA调制器端面的残余反射而不是微波调制信号的串扰。为了抑制调制器端面的光反射,优化了抗反镀膜工艺,基本消除了调制响应的异常起伏,有效改善了集成器件的高频调制特性。 By analyzing the signal characteristics of the millimeter wave active/passive combined detector,a fast algorithm of eliminating pulse-modulated signal crosstalk to the passive signal based on shift step prediction is proposed in this paper.Emulation analysis and experiment results show that this method can be used to improve the SNR of the passive channel remarkably.This method has favorable performances,such as high speed,low cost and high realizability. 以毫米波主被动复合探测器为工程应用背景,通过分析信号的特点,提出一种基于移步预测思想的快速算法来消除脉冲调制信号对被动通道信号的串扰。仿真分析和实验结果表明,该方法对改善信噪比效果明显,而且具有成本低、速度快和易于工程化实现的优点。
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