窗口型极小孔激光器的研制

报道了一种窗口型的用于高分辨率近场光学存储领域的极小孔激光器.这种窗口结构的引入解决了出射端面处由于金属膜的存在而导致的pn结短路问题,同时一定程度上抑制了激光器腔面处的COD效应.简化了极小孔激光器的工艺,降低了制备难度,提高了激光器的输出特性.通过FIB设备制备出了小孔大小为400nm,工作电流在31mA时的出光功率约0.3mW的极小孔激光器.     

纳米孔径垂直腔面发射激光器的制备及特性

在850 nm波长垂直腔面发射激光器的基础上制备了纳米孔径垂直腔面发射激光器.当小孔尺寸为400 nm×400 nm时,在25 mA驱动电流下,其最大输出光功率达到了0.3 mW,功率密度约为2 mW/μm2.文中介绍了纳米孔径垂直腔面发射激光器的制备工艺,并对它的光谱特性和寿命特性进行了分析.     

纳米孔径垂直腔面发射激光器的制备及特性

在850 nm波长垂直腔面发射激光器的基础上制备了纳米孔径垂直腔面发射激光器.当小孔尺寸为400 nm×400 nm时,在25 mA驱动电流下,其最大输出光功率达到了0.3 mW,功率密度约为2 mW/μm2.文中介绍了纳米孔径垂直腔面发射激光器的制备工艺,并对它的光谱特性和寿命特性进行了分析.     

离子束刻蚀法制备大功率高效率650nm AlGaInP可见光激光器

用纯Ar离子束刻蚀方法制备出大功率高效率6 5 0 nm实折射率Al Ga In P压应变量子阱激光器.对偏角衬底,干法刻蚀可得到湿法腐蚀不能得到的高垂直度和对称台面.制备的激光器条宽腔长分别为4 μm和6 0 0 μm,前后端面镀膜条件为10 % / 90 % .室温下阈值电流的典型值为4 6 m A,输出功率为4 0 m W时仍可保持基横模.10 m W,4 0 m W时的斜率效率分别为1.4 W/ A和1.1W/ A.     

1.55μm AlGaInAs/InP小发散角量子阱激光器的仿真和制备（英文）

理论仿真和实验制备了AlGaInAs/InP材料1. 55μm小发散角量子阱激光器.为了扩展近场光场并减小内损耗,将一个非对称模式扩展层插入到外延结构的下盖层当中.仿真结果表明,该模式扩展层除了少量增加激光器阈值电流以外,在不影响激光器其它性能的情况下能显著减小激光器的垂直远场发散角.实验结果与理论仿真高度吻合.成功制备出脊宽4μm,腔长1000μm的脊波导小发散角激光器.在端面未镀膜的情况下,该激光器阈值电流为56 mA,输出功率为17. 38 mw@120 mA,斜率效率可以达到0. 272 W/A.实验测得垂直远场发散角为29. 6°,相比较传统激光器减小了约35. 3%.     

带有非吸收窗口的大功率915 nm半导体激光器

为了实现大功率输出,应用无杂质空位诱导量子阱混合(IFVD)方法制备带有非吸收窗口结构的915 nm半导体激光器单管.通过实验确定促进和抑制量子阱混合的Si02和SiaN4薄膜的厚度分别为300和500 nm,退火条件为800℃,90 s.最终制备出的带有非吸收窗口的激光器,与普通激光器的阈值电流和斜率效率几乎一样.但普通激光器在电流为10 A时发生灾变性光学损伤(COD)并失效,而带有非吸收窗口的激光器在电流达到13A时仍然可以正常工作,相比普通激光器其最大输出功率增加了15％.每种器件各20个在20℃,电流为9A时进行直流老化试验,普通激光器在老化时间达到100 h时全部失效,而带非吸收窗口器件在老化200 h时仅有两个失效,这表明非吸收窗口结构显著提高了器件的抗COD能力.     

MOCVD生长InGaAs/InGaAsP多量子阱光泵微碟激光器

用 MOCVD方法生长了 In Ga As/ In Ga As P多量子阱微碟激光器外延片 ,用光刻、干法刻蚀和湿法刻蚀等现代化的微加工技术制备出直径 9.5μm的 In Ga As/ In Ga As P微碟激光器 ,并详细介绍了整个制备工艺过程 .在液氮温度下用氩离子激光器泵浦方式实现了低阈值光泵激射 ,测出单个微碟激光器的阈值光功率为 15 0μW,激射波长约为 1.6μm,品质因数 Q=80 0 ,激射光谱线宽为 2 nm,同时指出微碟激光器激射线宽比 F- P普通激光器宽很多是由于其品质因数很高造成的     

键合法制备硅基1.55μm InP-InGaAsP量子阱激光器

在硅基上成功地制备出了1.55μm InP-InGaAsP量子阱激光器.设计并生长了适合于键合的量子阱激光器结构材料,通过直接键合技术,将Si衬底与InP-InGaAsP外延片键合到一起.剥离去掉InP衬底后,在5～6μm的薄膜上制备出20μm条形边发射激光器.室温下,阈值电流160mA(电流密度为2.7kA/cm2),功率可达10mW以上(在约350mA电流下),实现了1.55μm长波长边发射激光器与Si的集成.目前,该结果国际上还未见报道.     

键合法制备硅基1.55μm InP-InGaAsP量子阱激光器

在硅基上成功地制备出了1.55μm InP-InGaAsP量子阱激光器.设计并生长了适合于键合的量子阱激光器结构材料,通过直接键合技术,将Si衬底与InP-InGaAsP外延片键合到一起.剥离去掉InP衬底后,在5～6μm的薄膜上制备出20μm条形边发射激光器.室温下,阈值电流160mA(电流密度为2.7kA/cm2),功率可达10mW以上(在约350mA电流下),实现了1.55μm长波长边发射激光器与Si的集成.目前,该结果国际上还未见报道.     

全息光刻制备LC-DFB及光栅刻蚀优化（英文）

成功制备出室温激射波长为2μm的Ga Sb基侧向耦合分布反馈量子阱激光器.采用全息曝光及电感耦合等离子体刻蚀技术制备二阶布拉格光栅.优化了光栅制备的刻蚀条件,并获得室温2μm单纵模激射.激光器输出光功率超过5 m W,最大边模抑制比达到24 d B.     

二维非线性时域有限差分法分析微孔激光器出射光的近场特性

微孔激光器(VSAL)作为应用于近场光存储系统中的一种新型光源,它的出射光斑的近场特性对于近场光存储是十分重要的。运用二维非线性时域有限差分法(2D-NL-FDTD)分析VSAL出射端即微孔金属膜的近场光学性质,模拟计算了不同参数的微孔金属膜的光强近场分布,对所得结果加以分析,从光学性质的角度,讨论其在近场光存储中的应用,并给出反映其近场光学特性的相关数据。     

大口径激光二极管阵列端面抽运耦合系统设计模拟

根据光线追迹原理,研究用于端面抽运的大面阵激光二极管(LD)抽运源的耦合系统设计。结合当前大口径激光二极管阵列常用的空心导管型耦合系统,分别从耦合效率、抽运强度分布、抽运光传输等方面,讨论大口径激光二极管阵列耦合系统的一般设计准则,提出了将激光二极管阵列单元平面排布改为球面排布的办法。针对100 kW激光二极管阵列,将子阵列作球面排布后,仅用一空心导管来汇聚抽运光,这种设计获得了传输性能优良的大区域均匀分布的抽运场,抽运场起伏小于5%,抽运强度大于20 kW/cm2,耦合效率98%,有效抽运区域内效率达90%。     

Nonlinear dynamics of vertical-cavity surface-emitting lasers

The dependence of the transient response of a vertical-cavity surface-emitting laser (VCSEL) on its aperture size is investigated subject to direct current modulation and external optical feedback. It is shown that lasers with small aperture size suppress higher order bifurcations and chaos even under large-signal modulation and external optical feedback. Furthermore, the noise characteristics of VCSELs under the influence of external optical feedback are studied via the calculation of relative intensity noise. It is found that the level of external optical feedback for the onset of coherence collapse is high for devices with small aperture size. On the other hand, the small-signal response of lasers is also analyzed through the calculation of third-order harmonic distortion. It is shown that harmonic distortion is minimized in small devices. Therefore, VCSELs with small aperture size have better immunity to irregular response under direct current modulation and external optical feedback     

光子带隙加窗技术在功率放大器中的应用

利用光子带隙的带阻特性,抑制功率放大器的二次谐波分量,可提高功率放大器的输出性能的特点,制作了加窗光子带隙电路并进行了测量.结果与传统光子带隙结构相比,有效改善了在通带内射频传输特性的平坦度.     

A phase-space beam summation formulation for ultrawide-band radiation

A new discrete phase space Gaussian beam (GB) summation representation for ultrawide-band (UWB) radiation from an aperture source distribution is presented. The formulation is based on the theory of the windowed Fourier transform (WFT) frames, wherein we introduce a novel relation between the frequency and the frame overcompleteness. With this procedure, the discrete lattice of beams that are emitted by the aperture satisfies the main requirement of being frequency independent, so that only a single set of beams needs to be traced through the medium for all the frequencies in the band. It is also shown that a properly tuned class of iso-diffracting (ID) Gaussian-windows provides the "snuggest" frame representation for all frequencies, thus generating stable and localized expansion coefficients. Furthermore, due to the ID property, the resulting GBs propagators are fully described by frequency independent matrices whose calculation in the ambient environment need to be done only once for all frequencies. Consequently, the theory may also be expressed directly in the time-domain as will be presented elsewhere. The localization implied by the new formulation is demonstrated numerically for an UWB focused aperture. It is shown that the algorithm extracts the local radiation properties of the aperture source and enhances only those beams that conform with these properties, i.e., those residing near the phase space Lagrange manifold. Further localization is due to the fact the algorithm accounts only for beams that pass within a few beamwidths vicinity of the observation point. It is thus shown that the total number of beams is much smaller than the Landau Pollak bound on the aperture's degrees of freedom.     

受光阑限制离轴高斯光束的解析传输

激光束的传输特性在激光技术应用中有着重要的意义。光束的解析传输问题是激光光学中的难点之一。从Collins公式出发，详细研究了离轴高斯光束(OAGB)通过有光阑近轴ABCD光学系统的传输特性，推导出了受硬边光阑、高斯光阑或余弦光阑限制的离轴高斯光束通过近轴ABCD光学系统的解析传输公式，并讨论了硬边光阑、高斯光阑或余弦光阑之间的关系。数值计算证明了所得公式的正确性和优点。分析了求解受多光阑限制的激光束通过近轴ABCD光学系统的解析传输公式的困难性，结果表明，其困难性在于受单光阑限制激光束的解析传输公式中含有误差函数。     

高功率垂直腔底发射激光器的偏振特性

在垂直腔面发射激光器(VCSEL)作为显示光源的应用中,为了获得高功率的偏振激光,研究了980nm大口径底发射VCSEL的偏振特性。通过刻蚀矩形台面和矩形出光口径,制备矩形VCSEL。在连续条件下,出光口径为550μm×300μm的底发射矩形VCSEL最大输出功率为660mW,微分电阻为0.09Ω。实验中,矩形VCSEL在工作电流下,同时存在稳定的水平偏振光和竖直偏振光,并且沿着矩形长边出射的水平偏振光一直占据主导地位。而圆形VCSEL在水平和竖直方向的激射情况几乎相同。水平偏振光的激射光谱相对于竖直偏振光出现蓝移,并且用对称三层波导模型解释了蓝移现象。研究了矩形VCSEL的正交偏振比与矩形口径长宽比的关系。实验结果表明,矩形柱结构能够有效地稳定VCSEL的偏振方向,使大口径器件激射高功率的偏振激光。     

Uniform wafer-bonded oxide-confined bottom-emitting 850-nm VCSELarrays on sapphire substrates

Uniform bottom-emitting 850-nm vertical-cavity surface-emitting laser (VCSEL) arrays on sapphire substrates have been demonstrated using wafer bonding technology to transfer the epitaxially-grown VCSEL structures from GaAs substrates onto sapphire substrates. The uniformity of the VCSEL arrays were improved by placing thin oxide aperture at the standing wave node to reduce scattering loss for small aperture devices. The averaged threshold current of a 5×5 VCSEL array is as low as 346 μA, while the averaged external quantum efficiency approaches 57%. The maximum wall-plug efficiency is 25% and the single-mode output power is more than 2 mW under continuous-wave current excitation at room temperature. We have also demonstrated a large (10×20) VCSEL array with variations of threshold current and external quantum efficiency less than 4% and 2%, respectively     

一种合成孔径激光雷达激光器带宽测量新方法

提出一种合成孔径激光雷达(SAL)调频激光器带宽测量的新方法。使用法布里-珀罗(F-P)扫描共焦腔,对调频He-Ne激光器的带宽进行测量,结果表明,在测量激光器的调频带宽时不受调频速率的限制,可以实现对SAL系统调频激光器的带宽测量。