共查询到19条相似文献,搜索用时 156 毫秒
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双波长激光器腔内模式竞争激烈,因此输出模式的稳定性是双波长激光器的关键参数。从降低双波长激光器中两个主模之间的功率差、提高边模抑制比出发,设计了集成反射区的两段式双波长分布反馈半导体激光器。利用传输矩阵法对激光器的光栅结构进行仿真,分析了反射区光栅对激光器的阈值、主模功率差等参数的影响。根据仿真优化的结果,制作了单片集成两段式双波长分布反馈半导体激光器芯片并进行了测试。测试结果表明两段式结构能够提高双波长激光器的稳定性和边模抑制比,减小两个主模的功率差。在稳定工作的情况下,两个主模功率差可达0.3 dB,边模抑制比大于35 dB。 相似文献
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弱耦合光纤光栅外腔半导体激光器 总被引:2,自引:0,他引:2
报道作者对单频窄宽光纤光栅外腔半导体激光器的一些研究结果。理论上分析了外腔的引入对激光器的阈值增益和光谱线宽的影响,实验上用自行研制的光纤布拉格反射滤波器(FBR)与普通多纵模半导体激光耦合,在1.55μm波段,得到边模抑制比大于25dB,线宽小于60kHz的激光输出。 相似文献
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基于半导体可饱和吸收镜(SESAM)的负克尔效应,对含SESAM的五镜腔进行了理论计算和分析.结果表明,由于SESAM的负克尔效应,与没有SESAM的相比,锁模激光器的稳区在上稳区的内边缘有明显扩展,这使得激光器锁模启动的工作点更加靠近直流运转时的稳区边缘,从而获得更大的非线性因子.这说明SESAM的可饱和吸收机理具有锁模自启动效应外,其负克尔效应也有助于锁模的自启动.
关键词:
半导体可饱和吸收镜
负克尔效应
五镜腔 相似文献
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980nm单模运转未镀增透膜光纤光栅激光器 总被引:1,自引:0,他引:1
提出了一种工艺简单的980nm未镀增透膜的光纤光栅外腔半导体激光器。首先从理论上分析了边模抑制比(SMSR)与激光二极管前表面反射率R2、外腔长Lext和激光二极管一光纤耦合效率之间的关系,得出边模抑制比随R2和Lext的增大而减小,而随着激光二极管一光纤的耦合效率的提高而增大。从计算结果中还可以看出,即使半导体激光器不镀增透膜(R2=0.3时)。在其它参量合适的情况下,边模抑制比仍可大于40dB。然后,对其进行实验验证。在半导体激光器未镀模的情况下,选择光纤光栅发射率为0.5,外腔长为12.5cm,输人电流为28.8mA(约为阈值电流的2.4倍)时,通过仔细调节恒温、恒流电路,实现了边模抑制比高于40dB的稳定的单纵模输出,外腔激光器的线宽优于1.6MHz。 相似文献
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The dependence of the intrinsic random intensity noise spectrum of the radiation from CW DH GaAIAs diode multimode lasers on optical wavelength has been investigated for the first time in a wide frequency range 30 MHz to 3 GHz. It was generally observed, that a lasing mode which is optically isolated from the rest of the radiation, shows much stronger intensity fluctuations as compared to the fluctuations of the total output, particularly in the frequency range below the intrinsic natural resonance frequency of the laser. The magnitude of the fluctuations decreases when the number of modes in the detected radiation increases. Our experimental results are compared to computer solutions which were obtained with a simple, analytical laser noise model. Good qualitative agreement between theory and experiment is demonstrated. 相似文献
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Y. I. Balkarey A. S. Cohen B. B. Elenkrig M. G. Evtikhov O. A. Pashko S. V. Tverdow 《Optical and Quantum Electronics》1991,23(8):1067-1076
The dynamics of optical filaments in broad aperture semiconductor lasers was studied. We use the model where one longitudinal mode is taken into account. The spectrum and the instabilities of lateral modes joined with the above mentioned longitudinal mode were investigated. The structures arise due to instability of various number of lateral modes. On the background of these modes we found a new type of modulation with a frequency depending on the laser aperture width. This frequency is smaller than the electron-photon resonance one. The existence of the modulation was confirmed by experimental investigations of broad aperture laser noise spectra. 相似文献
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Polarization switching in a quasi-isotropic microchip Nd:YAG laser induced by optical feedback 下载免费PDF全文
This paper demonstrates the influence of external optical
feedback on the polarization state of longitudinal modes in
quasi-isotropic microchip Nd:YAG lasers. Under optical feedback, the
polarization state of longitudinal modes in quasi-isotropic lasers
relies strongly on the intracavity anisotropy loss and mode
competition. When the intracavity anisotropy loss is small, external
optical feedback can cause polarization switching and strong mode
competition between two orthogonal linearly polarized eigenstates of
one laser longitudinal mode, which leads to the distortion of laser
intensity modulation waveform. The polarization switching is
independent of the initial external cavity length. By increasing the
intracavity anisotropy loss, one polarization eigenstate can be
suppressed and the laser works in single-polarization state. A
theoretical analysis based on the compound cavity model is
presented, which is in good agreement with the experimental results.
The results offer guidance to the development of laser feedback
interferometers. 相似文献
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One distributed feedback (DFB) laser diode with main and multiple side modes injection-locked is proposed and demonstrated. DFB laser diode can be successfully injection-locked not only in the main mode but also in the side modes. The side mode suppression ratio (SMSR) value of each injection-locked mode is enhanced, thereby, it can be a promising candidate for the use of multiple optical sources. Our proposed scheme has the potential to be used as optical sources for radio-on-wavelength division multiplexing (WDM) transport systems to provide multiple services. 相似文献
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R. Engelbrecht B. Lins P. Zinn R. Buchtal B. Schmauss 《Applied physics. B, Lasers and optics》2012,109(3):441-452
Laser diode line widths and line shapes are experimentally investigated in dependence on the diode current and on back reflections from an optical system. Four distributed-feedback (DFB)-type diode lasers and two vertical-cavity surface-emitting lasers (VCSELs) have been tested within the same optical setup and using the same fitting methods. System back reflection ratios of light reflected back to the laser have been varied between ?1?dB and ?45?dB and were below ?60?dB when all reflections were blocked. The background of this investigation is the evaluation of different laser types with respect to their suitability for sensor applications in which optical back reflections may occur, for example tunable diode-laser spectroscopy (TDLS). While DFB-type lasers showed almost pure Lorentzian line shapes and line widths of a few MHz, the tested VCSELs had a strong Gaussian contribution to the line shape, indicating stronger 1/f noise, which was also observed in the relative intensity noise of these particular lasers. System reflection ratios above ?25?dB had strong effects on the line width in both DFB diode lasers and VCSELs, while some influences have been observed at even lower reflection ratios for DFB diode lasers. As much smaller reflection ratios are typically required in TDLS systems to avoid etalon-like fringes and self-mixing interference effects, we conclude that the influence on the line width is not the most important reason to minimize back reflections in practical TDLS systems or to choose one type of diode laser over the other. 相似文献
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M. Fukuda S. Ooyama A. Utsumi Y. Kondo T. Kurosaki T. Masuda 《Applied physics. B, Lasers and optics》2008,90(2):269-272
The effect of optical feedback noise of a laser diode on the stability of gas-absorption spectra was investigated by monitoring
the optical absorption of CO2 gas. Lasing longitudinal mode instability greatly degraded the shape of the absorption spectra, and coherence collapse in
the laser diode greatly broadened the spectra. The correlation between the optical feedback noise of the laser diode and the
shape of the gas-absorption spectra was clarified on the basis of these spectral behaviors.
PACS 42.62.Fi; 42.55.Px; 42.68.Ca 相似文献
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The properties of V-shaped optical dielectric waveguides are investigated in detail using a vectorial finite element method. The fundamental modes exhibit extremely tight, heart shaped near field patterns. The maximum intensity of the fundamental mode is found to be vertically shifted with respect to the geometrical center of the waveguide. Fundamental and higher order mode properties are extensively studied, including mode patterns, dispersion curves and polarization properties. The local mode polarization of the two fundamental modes varies from a horizontal (vertical) orientation at the groove center to TM (or TE respectively) far in the side wings. The optimal design of waveguides for GaAs/AlGaAs quantum wire diode lasers and Quantum Confined Stark Effect modulators grown on V-grooved substrates is discussed. 相似文献
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We present investigations on the influence of mode matching on the efficiency of longitudinally pumped solid state lasers. In a theoretical part we enhance an existing model for four level lasers from idealized cylindrical modes to arbitary pump and laser modes in a random relative position thereby neglecting beam deformation due to thermal effects. The theoretical predictions were confirmed experimentally with an end-pumped Nd:YAG rod operated at 1064 nm. To investigate the effect of misalignment on the efficiency we used a Ti-Sapphire pump laser which was displaced relative to the laser beam. To establish the influence of arbitary pump modes on laser performance a diode laser equipped with coupling optics served as pump source for the same resonator. The resulting decrease in slope efficiency compared to the Ti-Sapphire pumped system could be explained in terms of limited mode overlap due to the characteristic pump field distribution produced by the diode coupling optics. 相似文献
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微片固体激光器具有体积小、寿命长等优点,是精密测量仪器的重要光源。构建了平-平、半外腔的Nd:YAG和Nd:YVO4微片激光器,通过控制压电陶瓷伸缩改变激光器的谐振腔长,同时使用F-P扫描干涉仪和波长计观察纵模和波长。研究了这2种微片固体激光器的腔调谐特性,包括腔长与光功率的关系,激光纵模扫过出光带宽过程的光功率和单、双纵模变化的规律。实验结果表明:腔调谐过程中单、双纵模交替出现,腔长和泵浦电流共同影响激光器的输出模式和光功率。 相似文献