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注入连续光实现锁模光纤激光器的波长稳定 总被引:2,自引:1,他引:2
提出了一种实现锁模光纤激光器波长稳定的方法,即向锁模激光器腔内注入连续光,使某一组纵模在注入连续光的基础上起振。这组纵模在对增益介质的竞争中可以稳定地占据优势,从而实现激光器输出光谱的稳定。理论分析发现注入连续光会使锁模激光器纵模线宽变大,而线宽的增大将会增加进入纵模的连续光功率。在实验中对基于掺铒光纤放大器(EDFA)的主动锁模光纤激光器进行波长稳定,激光器的调制频率为10.06 GHz,观察到了良好的稳定效果。为进一步检验波长稳定的效果,对锁模光纤激光器进行波长稳定后,将其输出的光信号经过一个法布里-珀罗(F-P)滤波器,稳定地滤出了功率较高的纵模。法布里-珀罗滤波器的自由光谱区(FSR)为40.24 GHz,透射峰3 dB带宽为40 MHz。实验结果证明纵模被稳定在法布里-珀罗滤波器的透射峰范围内,纵模波长的波动小于40 MHz。 相似文献
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报道了一种环形腔全光纤掺Yb3+光纤(YDF)激光器的中出现的多波长锁模现象。在腔内无任何选频元件或常规可饱和吸收体的情况下,仅靠YDF的非均匀加宽效应以及增益光纤未泵浦部分的等效可饱和吸收作用实现了稳定的多波长锁模输出,并进行了相关的分析。当泵浦功率为128mW时,得到了稳定的平均功率为1.5mW、重复频率为14.85MHz的基频锁模脉冲序列,边模抑制比为60dB。当泵浦功率逐步增加时,依然可以获得稳定的锁模脉冲,其光谱出现了多个波长峰值,中心波长在1 035nm左右,波长间隔平均为1.5nm,调整偏振控制器(PC),波长数和波长间隔会发生相应的改变。最大泵浦功率达到330mW时,可得到6个等间距的波长输出,平均输出功率为7.23mW。 相似文献
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单模光纤的偏振模色散 (PMD)是两个垂直的偏振模之间的差分群时延。它会引起数字通信系统中脉冲展宽与模拟系统中的信号失真 ,从而会限制光纤的传输距离与传输容量。本文介绍了测试非零色散位移单模光纤 PMD的波长扫描法以及在制造光缆过程中对光纤 PMD值的控制 ,最后 ,根据目前制造光纤、光缆的技术工艺水平与电信公司等对光缆 PMD的要求 ,探讨了光缆中继段上 PMD的标准 相似文献
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一种分析长周期光纤光栅谐振波长漂移的新方法 总被引:4,自引:3,他引:1
通过导模与包层模之间的有折射率差或谐振波长与光纤光栅周期的关系图,即可由图解法快速得到谐振波长在写入过程中的漂移特性。进而由几何关系给出了谐振波长漂移规律的解析表达式。 相似文献
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自2009年石墨烯(Graphene)材料被成功用于产生超短脉冲以来,出现了多种腔形、多种波长、多种脉冲特性的锁模激光器。利用石墨烯可饱和吸收特性制成的锁模器件具有稳定性好、响应波长广、恢复时间短、插入损耗小等多方面的优势,是目前超短脉冲领域的研究热点。重点对石墨烯被动锁模光纤激光器的研究进展进行了总结,并针对该领域面临的问题,指出其发展趋势。 相似文献
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在要求低漏电流的电子设备中使用的开关电源不能采用Y电容,但无Y电容的开关电源往往难以通过EMC测试。文中通过分析开关电源中造成电磁干扰问题的原因和解决方法,提出利用吸收电路来抑制无Y电容情况下开关电源的电磁干扰。测试表明,这种方法可以有效解决无Y电容的开关电源中EMI问题。 相似文献
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传统激光器由于封装键合工艺的要求,需要较大的芯片电极面积,限制了器件尺寸进一步小型化。量子尺寸的衍射效应使量子阱半导体激光器的垂直结平面发散角较大,不利于光束整形,限制了半导体激光器的直接应用。为解决这些问题,采用加入模式扩展层的光波导结构,将垂直发散角由40°减小到22°左右;采用p与n电极同面的脊波导结构,可将激光器同载体直接烧结,无需键合工艺,减小了电极面积,进而缩小了芯片尺寸。25℃,60mA注入电流下进行测试,阈值电流Ith≤10mA,输出功率P约为55mW。 相似文献
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《Solid-state electronics》1986,29(8):797-806
Enhancement and depletion mode n-channel MOSFETs are investigated with respect to short channel effects and hot carrier related instabilities. It is found that subthreshold characteristics of normally off type devices are improved by additional deep channel implants. However, long term stability of enhancement mode devices decreases with the deep channel implant dose. A similar behavior is observed for depletion mode devices. Significant improvement in device stability can be realized using buried channel conduction. However, short channel effects attain untolerable magnitudes in devices with deep buried channels. It is concluded in this paper, that the conventional approaches used for optimization of long term stability and d.c. characteristics of small size MOSFETs are technologically incompatible. In the outlook, device design requirements are discussed to circumvent these problems. 相似文献
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首次报道了一种稳定工作的二次模半导体激光器,该器件具有全新的远场特性.该器件的设计中采用了模式扩展层结构.利用模式扩展层抑制基模,加强二次模,并避免了模式不稳定的问题.使用常规的工艺手段成功制作了该器件,初步测试结果显示该器件的模式稳定,远场光斑为对称的三瓣结构,并且光功率与阈值电流均为正常水平.这种新器件的研制成功表明,这种特殊的器件结构能够造成半导体激光器的远场模式,而特殊的远场模式可能带来一些新的应用. 相似文献
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W. B. Cho J. H. Yim S. Y. Choi S. Lee A. Schmidt G. Steinmeyer U. Griebner V. Petrov D.‐I. Yeom K. Kim F. Rotermund 《Advanced functional materials》2010,20(12):1937-1943
Single‐walled carbon‐nanotube absorbers are experimentally demonstrated for laser mode‐locking. A saturable absorber device is used to mode‐lock three different bulk solid‐state lasers in a 500 nm‐wide wavelength interval. The devices exhibit a low saturation fluence of <10 µJ cm?2, low scattering losses, and an exceptionally rapid relaxation, with time constants reaching <100 fs. The latter two properties are explained by a decreased curling tendency and increased tube‐to‐tube interactions of the nanotubes, respectively. These properties are the result of an optimized manufacturing procedure in combination with the use of a starting material with a higher microscopic order. The decreased scattering enables universal use of these devices in bulk solid‐state lasers, which tend to be highly sensitive against non‐saturable device losses as caused by scattering. The favorable saturable absorption properties are experimentally verified by mode‐locking the three lasers, which all exhibit near transform‐limited performance with about 100 fs pulse duration. The complete and unconditional absence of Q‐switching side bands verifies the small saturation fluence of these devices. 相似文献
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有源相控阵天线一般通过设置延迟单元来实现宽带信号扫描。但是在宽带工作方式时,存在波束偏转的问题。在大扫描角条件下,这个问题尤其突出。在这种情况下,波束实际指向与预期值的偏差较大,不能满足应用需求。本文针对有源相控阵雷达天线宽带模式的设计现状和应用需求,提出了两种改进方法。首先分析了现有宽带模式设计的局限性,并对天线波瓣方向图进行了仿真,说明了存在的问题;然后针对这些问题,提出了两种改进方法,其中一种改进方案已经在课题上应用,证明了技术的有效性。 相似文献
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Packet switching over broadcast channels with random access schemes is of current interest for local distribution system and for satellite channels. This mode of operation is useful when the communicating devices are mobile and when the ratio of the peak to average data rate requirement of each device is high. Such systems have been analyzed for the case in which all communicating devices are within an effective transmission range of each other; either directly or through the satellite. In this paper, we address broadcast networks in which originating devices cannot directly reach the destination receiver. Thus, devices are introduced which receive these packets and repeat them to the destination. The capacity (maximum throughput) of such systems is determined, and design problems related to the number of repeating devices and the usefulness of directional antennas are resolved. 相似文献
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