高斯腔模的稳定性

假设注入带球面镜的单向环形腔的电场为高斯光束TEM_(10)模,在单横模假设模型范围内讨论了定态及纯吸收情况下的稳定性问题,结果表明可能出现失稳。     

外腔半导体激光器动态模稳定性的研究

为了研究调谐过程中外腔半导体激光器的模稳定性,采用多光束干涉理论推导Littrow结构外腔半导体激光器的腔增益,并模拟其模结构。分析了光栅面和转臂不在同一平面的情形下,在光栅转动调谐时,通过匹配光栅的反馈波长变化率与外腔波长变化率,推导出最佳的初始外腔长度,并研究了动态模稳定（无跳模调谐）的范围;采用严格的耦合理论和光线变换矩阵分析了准直（耦合）透镜的位置对系统后向耦合效率的影响。结果表明,系统后向耦合效率最大可达99%,极大地压窄了中心波长为780nm半导体激光器的线宽,外腔半导体激光器的理论线宽为未加外腔时的0.96%,动态模稳定范围可达6.8nm。     

易于开启和维持自锁模的适度失谐腔克尔介质自锁模激光器

提出工作于谐振腔适度失谐时的克尔介质自锁模激光器易于开启和维持自锁模的理论。根据克尔镜锁模原理和动态可饱和高斯增益特性，利用激光传输矩阵理论，对系统进行了数值模拟计算，确证了最佳腔镜失谐角的存在．结论与已有的实验结果相符，并对它们赋予了新的合理解释。     

反馈光注入半导体激光器复合腔模的稳定性

利用渐进稳定性分析的方法研究了小注入电流条件下反馈光注入半导体激光器的复合腔模(ECM)的稳定性,并提出对应于所有的复合腔模在相空间内存在一个模式稳定区域,复合腔模出现在该模式稳定区域内的概率远大于出现在该模式稳定区域外.通过求解复合腔模的鞍结分岔及霍普夫分岔边界条件并计算载流子浓度的庞加莱截图,验证了模式稳定区域的存在.数值计算的半导体激光器载流子浓度的分岔图验证了在小注入电流条件下渐进分析的可靠性.     

在高斯腔模中失稳性的出现

本文研究了高斯腔膜中的光学双稳问题及失稳 范围。文章首先从Maxwell-Bloch方程出发,导出了高斯光束驱动的含均匀展宽介质的环行腔中场振幅的时间演化方程及定态方程。其次在入射场和     

可调腔锁模激光器

1987年4月27日至5月1日在美国巴尔的摩举行的激光和电光学讨论会(CLEO'87)上,激光应用股份有限公司展出一台新的100MHz锁模连续波Nd:YAG激光器.     

非线性耦合腔锁模激光器

本文综述了近几年非线性耦合腔锁模技术(NCCM)的发展。阐述了其现状,简述了其物理机制和实现的方法,分析了腔参量变化对激光器性能的影响,展望了其发展前景。     

位相共轭光腔与高斯光束基模

本文讨论了不同数学模式的位相共轭反射镜与普通反射镜所构成的光腔的基膜特征及其稳定性。     

长波长垂直腔面发射激光器开关及双稳特性

为了研究垂直腔面发射激光器偏振转换特性,基于自旋反转模型,数值研究了正交光注入下1550nm垂直腔面发射激光器频率诱导偏振开关及双稳特性。结果表明,在正交光注入下,连续改变注入光与激光器光场内x线性极化模的频率失谐可诱导产生两类偏振开关和偏振双稳现象,且注入光强与偏振电流的变化都显著影响双稳宽度和激光器的输出特性;合理选择操作条件,可实现对1550nm垂直腔面发射激光器频率诱导偏振开关及双稳的控制。这一结果对垂直腔面发射激光器在全光开关和全光存储等领域的应用具有参考价值。     

两段式半导体激光器的双稳条件

对Ｋｕｚｎｅｔｓｏｖ采用的速率方程加以修正，考虑了俄歇效应的影响，载流子寿命不再作为常数处理，而写成载流子浓度的函数。由此导出了两段式半导体激光器存在双稳的必要条件，计算结果表明，吸收区偏置电流对双稳条件影响极大，对具体器件而言，若增益区和吸收区隔离电阻不够大，几个ｍＡ的偏置电流泄露到吸收区就使器件难以产生双稳。     

Modulation response of multiple transverse modes in vertical-cavitysurface-emitting lasers

The small-signal modulation response of multiple transverse modes in a vertical-cavity surface-emitting laser was studied numerically. The overlap between the modal distribution of the field and the carrier distribution in the active region is fundamental to determining the modulation response, According to the injection current level, the modulation response curve in several configurations and parameters used can display peaks and notches that may impair the frequency response of the device. These features reflect the competition of carrier by the operating modes in a way that can be described as interference. Therefore, the total modulation response curve cannot be evaluated from the modulation response of the individual modes     

Selection mechanisms of transverse modes in semiconductor injection lasers

A discussion of the transverse mode selection in the conventional double-heterostructure injection lasers is given. The mechanisms considered as responsible for mode selection are 1) the nonnormal incidence in the plane perpendicular to the junction of the EM waves at the end faces; and 2) an uneven gain distribution across the active region. By using a multilayer waveguide model, results are presented that show the regions of preference of each of the modes as determined by each mechanism both in isolation and simultaneously. Hence, the regions of dominance of each mechanism are determined.     

Selection and modulation of high-order transverse modes invertical-cavity surface-emitting lasers

A theoretical proposal to double the pulse repetition frequency by alternating current modulation of two orthogonal high-order transverse modes of a vertical-cavity surface-emitting laser (VCSEL) is presented. Static and dynamic characteristics of weakly index-guided VCSELs in a multitransverse mode regime are analyzed. An efficient model that takes into account all the transverse modes supported by the waveguide is developed. Mode partition noise in a current modulated VCSEL is studied, taking into account the azimuthal degree of freedom. Different transverse modes can be excited with a probability that is numerically calculated. For high injection currents, modes that are not favored in the steady state can be excited with higher probability. The excitation probability is similar for azimuthally orthogonal modes. This symmetry can be broken by selecting a particular high-order transverse mode by using azimuthal-dependent current profiling. This selection can be achieved over current ranges as wide as ten times the threshold current. Current modulation of this transverse mode is then analyzed. Alternate current modulation of two orthogonal high-order transverse modes is also studied. Alternating modulation of these modes can double the pulse repetition frequency obtained by modulating just one high-order transverse mode, without increasing injected current density levels. This current-induced spatial switching leads to high-frequency beam steering in the laser azimuthal direction     

Suppression of higher-order transverse modes in vertical-cavity lasers by impurity-induced disordering

Etched pillar, bottom emitting vertical cavity surface emitting lasers (VCSELs) employing a zinc diffused and disordered spatial mode filter are fabricated and tested. The filters successfully suppress lasing of higher order transverse modes in VCSELs with diameters greater than 11 /spl mu/m, while obtaining output powers of up to 1.5 mW with threshold currents as low as 2.7 mA. Emission is entirely single mode, with mode suppression ratio greater than 25 dB up to the highest output power levels.     

Picosecond pulse generation in detuned distributed feedback lasers

The effect of detuning the Bragg wavelength for picosecond pulse generation in GaInAsP distributed feedback (DFB) lasers is investigated using the gain switching method. The authors have observed that the pulse width is reduced in a detuned DFB laser, in which the differential gain is enhanced through detuning the Bragg wavelength λ_B from the gain peak to a shorter wavelength by 100 Å. This result demonstrates the significance of the differential gain for short pulse generation     

Dynamics of longitudinal and transverse modes along the junction plane in GaAlAs stripe lasers

Observations of the transient excitation of higher order transverse modes along the junction plane in DH GaAlAs stripe lasers during subnanosecond pulse modulation is reported. These modes are strongly excited at the onset of the light pulse, they decay during 200 ps, and reappear after 400-600 ps. The width of the longitudinal mode spectrum decays from 40 to 10 Å during 0.5-1 ns.     

Increasing the power of broad-waveguide lasers by additional selection of transverse modes

A new method is proposed for transverse mode selection in high-power, broad-waveguide, separate-confinement, heterostructure quantum-well lasers by orienting the front mirror at an angle other than normal to the direction of radiation propagation. The dependence of the mode reflection coefficients on the laser mirror parameters is investigated. Optimal values are found for the mirror inclination angles and the thicknesses and refractive indices of the dielectric coating at which the fundamental guide mode dominates. The possibility of a 1.2-fold increase in the output power of a broad-waveguide, separate-confinement, heterostructure quantum-well diode laser is demonstrated. Fiz. Tekh. Poluprovodn. 33, 752–758 (June 1999)     

深扩Zn平面条形激光器的横模稳定性

实验发现扩Zn较深的平面条形激光器的横模比较稳定,提出了一个解释深扩Zn平面条形激光器能获得稳定横模工作的简单等效线路模型.分析表明,不掺杂作用层P-n-N型深扩Zn平面条形激光器,增益波导变窄是其横模稳定的主要原因.