共查询到19条相似文献,搜索用时 156 毫秒
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《物理学报》2017,(2)
少模光纤可以传输有限的正交模式,具有模间干涉小、模式易于控制等优点.基于少模光纤的布里渊散射传感器能够有效地减小多参量测量过程中的交叉敏感,实现多物理量的测量.本文基于波动光学理论对阶跃型少模光纤各个模式布里渊散射谱的频移、线宽、峰值增益等参数进行了分析.首先对少模光纤进行了模式分析,其次分析了少模光纤不同模式的频移、线宽、增益的数学模型,以及不同模式叠加的布里渊散射谱频移、线宽、增益.结果表明:少模光纤各模式布里渊散射谱的频移在10.19—10.23 GHz范围内,且随模式阶数的减小而增加;各模式布里渊散射谱的线宽在32—34 MHz,且随模式阶数的减小而增加;各模式布里渊散射增益谱相对幅度因为模式阶数的减小而增大.少模光纤中各个模式布里渊增益谱和多模式联运布里渊增益谱均符合洛伦兹曲线分布,多模式联运导致布里渊增益谱线宽展宽,且多模式联运布里渊增益谱相对振幅一般小于单个模式的布里渊相对振幅. 相似文献
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利用全矢量有限元法计算了少模光纤中模内和模间受激布里渊散射各模式布里渊频移和布里渊增益谱,模拟了泵浦功率、有效传输长度及脉冲宽度对各模式慢光时间延迟量、脉冲展宽因子的影响.模拟结果表明:少模光纤中不同传输模式产生的受激布里渊散射慢光特性不同,输入泵浦功率及有效传输长度越大,各模式的慢光时延量、展宽越大,且当输入泵浦功率相同时,模内的慢光时延量、展宽因子均大于模间的.优化参数可得,在输入泵浦功率为0.5W,光纤有效长度为1km的条件下,LP_(01)-LP_(01)、LP_(11)-LP_(11)及LP_(01)-LP_(11)模式的时间延迟量分别为643.7ns、362.6ns和213.2ns,其展宽因子分别为1.346、1.207和1.126. 相似文献
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《物理学报》2020,(11)
少模光纤的受激布里渊散射对于分布式温度/应变传感具有重要应用价值.本文提出一种纤芯折射率呈M型分布的少模光纤,详细研究了光学模式LP_(01)和LP_(11)模式内及模式间的布里渊增益谱.研究结果表明:LP_(01)-LP_(11)模式对的布里渊增益谱中,其相邻两个布里渊散射峰的频率间隔较宽、增益峰值较大且峰值相差较小.通过优化光纤结构参数,提高了基于LP_(01)-LP_(11)模式对布里渊增益谱的温度和应变传感性能,最小误差分别为0.23℃和5.67μe.该研究对探究少模光纤中模式内及模式间的受激布里渊散射特性具有一定的指导意义,对提升同时温度和应变传感测量的性能具有一定参考价值. 相似文献
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《物理学报》2021,(15)
受激布里渊散射在激光雷达海洋遥感领域具有广泛应用,而水体参数变化对其阈值及增益等关键特征参数影响的研究还很缺乏.本文利用分布式噪声模型及耦合波方程,理论分析了水的温度、压强和衰减系数对受激布里渊散射阈值和增益系数的影响.在理论分析基础上,设计了一种温度压强可控实验系统,采用平均衰减系数法实验测量了不同温度、压强及衰减系数下的阈值和增益系数.结果表明,受激布里渊散射阈值随压力和衰减系数的增大而增大,随温度的升高而减小,而增益系数则呈现与阈值相反的变化趋势.温度和衰减系数对阈值和增益系数的影响大于压力.研究结果对受激布里渊散射激光雷达海洋遥感探测具有重要意义. 相似文献
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针对多芯光纤完善了描述抽运光、信号光和Stokes信号的速率方程组.考虑了温差对受激布里渊散射的影响,利用有限元法求解温度分布方程组,分析了前向和后向抽运方式、对流系数、Stokes初始功率、光纤掺杂粒子密度和光纤长度对受激布里渊散射增益的影响.研究表明:后向抽运方式在抑制受激布里渊散射方面具有明显优势;减小对流系数有助于抑制受激布里渊散射;提高光纤掺杂密度能够加强抑制受激布里渊散射,同时也有助于提高光纤放大器的斜率效率.比较了在相同最佳光纤长度条件下,单芯和19芯光纤放大器的最高工作温度和受激布里渊散射
关键词:
光纤放大器
受激布里渊散射
大功率
有限元法 相似文献
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S波段光纤拉曼放大器中级联受激布里渊散射串扰的实验研究 总被引:2,自引:0,他引:2
研究了光纤激光器前向抽运的S波段分布式光纤拉曼放大器中级联的受激布里渊散射(SBS)串扰现象。用窄光谱带宽(<100MHz)的可调谐激光二极管作为信号源,通过S波段分布式光纤拉曼放大器,当被放大的信号功率超过单模光纤受激布里渊散射的阈值时,出现了前向受激布里渊散射,这是传导声波布里渊散射在光纤放大器中放大的现象。随着拉曼放大器抽运功率的提高,在斯托克斯区,出现了两阶受激布里渊散射线,在实验中观测到偶数阶的受激布里渊散射谱线功率大于奇数阶的布里渊一瑞利散射线。当进一步增加拉曼放大器的抽运功率,出现了前向级联的多阶受激布里渊散射现象,拉曼放大器的增益下降,被放大的信号功率转换为受激布里渊散射,噪声变大。受激布里渊散射的串扰破坏了拉曼放大器的特性,使拉曼放大器无法在密集波分复用光纤传输系统中使用,因此需要严格地控制入纤的信号功率和放大器的抽运功率。在实验中还观测到在光纤拉曼放大器中被放大的信号光和受激布里渊散射线两侧的伴线。 相似文献
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Investigation of Brillouin effects in small-core holey optical fiber: lasing and scattering 总被引:6,自引:0,他引:6
We demonstrate for what is believed to be the first time a Brillouin laser based on a holey fiber (HF). Using a simple Fabry-Perot resonator scheme containing a 73.5-m-long highly nonlinear HF with an effective area of 2.85 microm(2) , we obtain a threshold of 125 mW and a slope efficiency of ~70% . Stimulated and spontaneous Brillouin scattering effects are investigated in the HF, and we show that the high lasing threshold is due mainly to reduction of the effective gain coefficient caused by structural nonuniformity along the fiber length. 相似文献
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We have developed a theoretical approach to simulate stimulated Brillouin scattering (SBS) generation in photonic crystal fiber (PCF). The threshold condition for the SBS occurrence has been derived as a function of fiber parameters and input pump power. A particular emphasis is given to the influence of the input pump power and fiber length on the Brillouin gain in the PCF. To assess threshold pump power accurately, the pump depletion effect has been included by employing the 1% criterion. This simulation can anticipate the Brillouin threshold gain value precisely. The threshold gain varies from 14 to 18 depending on the PCF length. 相似文献
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Da-he Liu Jin-wei Shi Xu-dong Chen Min Ouyang Wen-ping Gong 《Frontiers of Physics in China》2010,5(1):82-106
The principle of a lidar based on Brillouin scattering is introduced. The basic physics of the Brillouin lidar is discussed.
The applications of the Brillouin lidar in remote sensing of the ocean, such as measurement of the sound speed and the bulk
viscosity of water and detecting submerged objects are investigated. An actual Brillouin lidar system is developed. Also,
several basic problems related to Brillouin lidar are studied in detail. The attenuation coefficient of a pulsed laser beam
with high pulsed energy in water is investigated; it is helpful to reveal the propagation property of a laser beam in water.
The investigations on the threshold value of SBS are made theoretically and experimentally. Finally, a novel phenomena is
investigated experimentally, in which Stimulated Raman scattering can be enhanced by stimulated Brillouin scattering. 相似文献
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Stimulated Brillouin scattering-induced phase noise in an interferometric fiber sensing system
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Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering. 相似文献
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We demonstrate a new and simple solution to suppress stimulated Brillouin scattering in fiber optical parametric amplifiers. Cumbersome PRBS or sinusoidal generators used to broaden the pump spectrum are replaced by a filtered microwave noise source. Stimulated Brillouin scattering threshold can be increased up to large values still keeping an excellent quality of amplification of nonreturn to zero signals. The simplicity and the performances of this setup open the way for a wide variety of applications for FOPAs. 相似文献
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Stimulated Brillouin scattering-induced phase noise in an interferometric fiber sensing system
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Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems.The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber.The phase noise structure is analyzed for an interferometric fiber sensing system,and an unbalanced Michelson interferometer with an optical path difference of 1 m,as well as the phase-generated carrier technique,is used to measure the phase noise.It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold,increases dramatically at first and then gradually becomes flat when the input power is above the threshold,which is similar to the variation in relative intensity noise.It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering,which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering. 相似文献
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We propose and investigate an accurate method for the experimental measurement of the stimulated Brillouin scattering gain coefficient in optical fiber. The gain is extracted from measuring the transmitted pump power at the threshold of stimulated Brillouin scattering (SBS) laser oscillation in a Fabry-Perot cavity formed by Fresnel reflection at the fiber ends. The method is free from a range of uncertainties and difficulties of commonly used approaches and is easy to implement. Experimental evidence of the variation of the SBS gain coefficient with numerical aperture of the fiber, first predicted in [Phys. Rev. Lett. 85, 1879 (2000)], is proven. 相似文献