非对称补偿条形复合腔半导体激光器列阵

本文描述了一种新结构半导体激光器阵列——非对称补偿条形复合腔半导体激光器阵列.这种列阵是由7个或9个非对称半腔长交叉错开的条形电极形成7个或9个复合腔结构,光束在腔中以交叉的方式耦合.从该结构列阵得到了直到1.6I_(th)、发散角仅为3～4°的单瓣远场图样.     

用于波导阵列——光纤阵列自动对接的多目标演化算法的研究

开发设计了一种新的列阵自动对接方法,该方法将多目标演化法导入光纤—光波导列阵—光纤列阵的自动对接,并行操作次数较常规遗传法大幅减少.数值仿真表明,对于模场非对称因子为0.4%的单模波导列阵与光纤列阵的双芯对接,能实现0.04 dB的平均端面耦合损耗.用于1×8波导分支耦合器与通道间距误差在0.35 μm以内的光纤列阵对接,自动耦合仿真达到了小于0.1 dB的平均端面耦合损耗,最大值与最小值的差小于0.06 dB.     

三种不同端面光纤列阵和半导体激光列阵耦合的(数值)模拟

半导体激光列阵的输出光束有较大的发散角和较强的不对称性，极大地限制了其在各领域中的应用。为了改善半导体激光列阵输出光束的质量，必须采用特殊的光学系统进行光束整形。一种简单有效的方法是利用光纤列阵实现光束由线性排列到圆形排列的转换。对三种特殊制备的光纤列阵和半导体激光列阵的耦合特性进行了数值模拟研究。结果显示，相对于球形端面光纤列阵和锥形端面光纤列阵，球顶锥形端面光纤列阵和半导体激光列阵有着更高的耦合效率(90％以上)。此外，利用球顶锥形端面光纤列阵还可以进一步压缩输出光束的发散角，从而获得更高质量的输出光束。     

超大功率二维半导体激光列阵并路自适应稳模技术

半导体列阵量子效率高,输出波长范围涵盖570～1600nm,工作寿命可达数百万小时,叠层列阵可提供超高功率激光输出,在工业、医学等很多领域具有非常广阔的应用前景。但列阵在自由运行时,各发光单元发出的光是不相干的,输出质量差,采用1/4Talbot外腔镜耦合技术,列阵实现了空间锁相最高阶超模,然而唯有基超模远场分布是中心单瓣结构,输出接近衍射极限。为得到最小谱宽、最小发散角、最大功率密度输出,必须将外腔镜倾斜β=λ/2d(λ为工作波长,d为列阵周期),这使得仅有基超模光能成像于发光单元内而被允许振荡。应用此技术于超大功率二维半导体列阵相干锁相时,尽管冷却子系统保障了持续出光,但一段时间后,残余热效应等将导致外腔镜发生随机形变,使β漂移超过阈值使基超模失配,非基超模振荡使远场为非中心单瓣结构,极大地恶化了输出质量。可见,必须适时补偿β漂移,为此,在列阵超模选择稳定性分析基础上,研发了并路自适应稳模技术,并由置于特定结构中的传感探测光源、微透镜等构成的传感探测子系统、补偿子系统实现。试验结果显示,β漂移被及时感知补偿,基超模光稳定占优地成像于发光单元内,使输出光质量高,列阵性能被有效增进,在满足有高品质需求的应用上意义重大。     

刻蚀光纤布拉格反射器特性的理论分析

从理论上研究了波导耦合型刻蚀光纤布拉格反射器的特性。采用正交模式耦合理论描述其中的光栅辅助正反向模式耦合，用非正交模式耦合理论描述输入输出接口的模式激发，给出了分析耦合波导布格瓣反射器的角析表达式，分析表明刻光张布拉格反应器中存在三种布拉格反应，在频谱中表现为六个分立的反射峰，与实验结果相符，其反射率不仅决定事系数，还与其结构参数，尤其是Ａｌ２Ｏ３层的厚度，Ａｌ２Ｏ３层与光纤芯的距离以及匹配层折射     

各向异性聚合物薄膜参数的测量与计算

讨论了用单侧漏模法测量薄膜共振漏模的耦合角、计算漏模的有效折射率并由相应的模方程来确定各向异性聚合物薄膜折射率ｎ０、ｎｅ及厚度ｄ的方法。对ＰＴ－ＰＥＫ－ｃ（酞酸铅－聚醚醚酮）膜，测量与计算结果为：ｎｏ＝１．６５２５±０．００１４，ｎｅ＝１．６４３９±０．００１９，ｄ＝２．３３±０．３２μｍ。     

化学氧碘激光器中的角立方反射器的研制

分别利用电子束蒸发和离子束溅射手段在单晶硅基底上制备了54.7°入射1315nm和632.8nm双波长高反射薄膜,并对两种手段所镀制薄膜地性能进行了比较;然后对离子束溅射所镀制的反射镜进行了胶合,得到了高精度的角立方反射器。最后,将所制备的角立方反射器实际用于化学氧碘激光谐振腔后,获得了近衍射极限的激光输出。     

光学测试 光学元件测试与设备

TB96 2005053880 简易修正角误差的回复反射器CIL测试系统=Retro-re- flector CIL testing system based on facilly amending angle error[刊,中]／徐欣锋(中科院长春光机所．吉林,长春 (130031)),冯毅…∥光电子·激光．-2005,16(2)．- 175-178 介绍了一种单探头式汽车回复反射器发光强度系数 (CIL)检测的基本原理、系统结构和实测过程。为了实现 对检测系统中转台角误差的快速修正,提出一种简捷修正     

应用于无线传感器的声表面波反射型延迟线的耦合模分析

基于耦合模理论对一种应用于无线传感器的声表面波(SAW)反射型延迟线的性能进行了优化模拟分析。结合混合等效电路模型推导出评价这种器件性能的时域反射系数S₁₁。典型的SAW反射型延迟线包含置于压电基片之上的一个换能器与沿声波传播方向设置的多个反射器。讨论了器件性能的各种结构性影响因素如换能器结构以及反射器类型等,并以此获得优化的器件设计参数。在理论优化分析的基础上,以41°YX LiNbO₃为压电基片,结合铝电极试验制作了采用单向单相换能器(SPUDT)与3个短路栅反射器的440 MHz SAW反射型延迟线器件,并与理论分析结果予以对比与评价分析。      

带有锥度结构的同轴开槽布拉格反射器研究

本文提出在Kα波段圆柱过模结构绕射辐射器件(RDG)中引入一种带有锥度结构的同轴内开槽布拉格反射器.采用复功率守恒技术(CCPT)对该反射器的频率响应特性进行分析.研究了相位匹配段长度,波纹槽深及锥度对反射器频率响应特性的影响,分析了波纹初始相位对反射器选模特性的影响,发现该反射器具有良好的模式选择特性.本文的研究工作为同轴Bragg反射器结构的研究提供了重要的理论分析手段. 关键词： 同轴Bragg反射器 频率响应特性 复功率守恒 绕射辐射振荡器     

Facet-embedded thin-film III-V edge-emitting lasers integrated with SU-8 waveguides on silicon

A thin-film InGaAs/GaAs edge-emitting single-quantum-well laser has been integrated with a tapered multimode SU-8 waveguide onto an Si substrate. The SU-8 waveguide is passively aligned to the laser using mask-based photolithography, mimicking electrical interconnection in Si complementary metal-oxide semiconductor, and overlaps one facet of the thin-film laser for coupling power from the laser to the waveguide. Injected threshold current densities of 260A/cm(2) are measured with the reduced reflectivity of the embedded laser facet while improving single mode coupling efficiency, which is theoretically simulated to be 77%.     

角锥棱镜阵列谐振腔的输出特性

 角锥棱镜阵列具有溯源反射和准相位共轭两大特点,可在一定程度上补偿高平均功率固体激光器的热畸变。但由于这种角锥棱镜阵列自身的缺陷和由它构成的谐振腔输出激光模式众多的特点,限制了其在谐振腔中的应用。分析了角锥棱镜阵列谐振腔产生多模输出的原因,提出了采用腔内滤波的方法实现单模输出。理论模拟和实验研究结果表明：利用该方法可较好地改善阵列角锥棱镜谐振腔的输出特性,获得了近5倍衍射极限的输出。     

A low-finesse Fabry–Pérot interferometer for use in displacement measurements with applications in absolute gravimetry

A low-finesse Fabry–Pérot interferometer is used to determine long and fast displacements. Two corner cube reflectors form the traveling-wave cavity and one beam splitter couples the input collimated laser beam. Given the retro-directive property of corner cube reflectors, the cavity operates at the edge of stability over an extended scanning range. The in-line scheme with a single fixed optical component makes the proposed interferometer robust and easy to align and use. These characteristics are particularly useful in applications running in noisy environments, such as in on-field absolute gravimetry. Experimental data showing the performances reached in a transportable ballistic gravimeter are also presented.     

Single mode lasers based on monolithic integration of ridge waveguides with 2D photonic crystal waveguides

The monolithic combination of active light sources with photonic crystal (PC) waveguide components is a key building block for future highly integrated photonic circuits. We demonstrate the coupling of light from an InGaAs/AlGaAs ridge waveguide laser to a monolithically integrated 2D PC waveguide. The PC guide is formed by removing three or five rows in a triangular lattice of air rods etched into the semiconductor. A tapered ridge waveguide geometry is demonstrated to improve coupling efficiency, so that maximum output powers of up to 10 mW from the PC waveguide are achieved. The resulting coupled cavity laser shows single mode emission with side mode suppression ratios > 35 dB over a broad range of injection currents.     

Novel hybrid construction of a visible surface-emitting laser and its two-dimensional arrays

A novel hybrid surface-emitting laser and two-dimensional laser array is reported. The device consists of rectangular GaAs reflectors and edge-emitting single laser or one-dimensional laser arrays which are fabricated separately. The devices are mounted upside-down on a copper heat sink, allowing for good heat conduction. The CW operation and the reflectivity characteristics of this surface-emitting laser have been investigated.     

Fiber Optic Coupling of CW Linear Laser Diode Array

Based on a set of microoptics the output radiation from a continuous wave (CW) linear laser diode array is coupled into a multi-mode optical fiber of 400 μm diameter.The CW linear laser diode array is a 1 cm laser diode bar with 19 stripes with 100 μm aperture spaced on 500 μm centers.The coupling system contains packaged laser diode bar,fast axis collimator,slow axis collimation array,beam transformation system and focusing system.The high brightness,high power density and single fiber output of a laser diode bar is achieved.The coupling efficiency is 65% and the power density is up to 1.03×104 W/cm2.     

Controlling spontaneous emission and threshold-less laser oscillation with optical microcavities

We describe the alteration of spontaneous emission of materials in optical microcavities having dimensions on the order of the emitted wavelength. Particular attention is paid to one-dimensional optical confinement structures with pairs of planar reflectors (planar microcavities). The presence of the cavity causes great modifications in the emission spectrum and spatial emission intensity distribution accompanied by changes in the spontaneous emission lifetime. Experimental results are shown for planar microcavities containing GaAs quantum wells or organic dye-embedded Langmuir-Brodgett films as light emitting layers. Also discussed are the laser oscillation properties of microcavities. A remarkable increase in the spontaneous emission coupling into the laser oscillation mode is expected in microcavity lasers. A rate equation analysis shows that increasing the coupling of spontaneous emission into the cavity mode causes the disappearance of the lasing threshold in the input-output curve. Experimentally verification is presented using planar optical microcavities confining an organic dye solution. The coupling ratio of spontaneous emission into a laser mode increases to be as large as 0.2 for a cavity having a half wavelength distance between a pair of mirrors. At this point, the threshold becomes quite fuzzy. Differences between the spontaneous emission dominant regime and the stimulated emission dominant regime are examined with emission spectra and emission lifetime analyses.     

Mathematical modeling of a relativistic effect that arises during laser ranging of artificial Earth satellites

A mathematical model of a relativistic effect that arises in the process of laser ranging of artificial Earth satellites (AESs) from the surface of the Earth is constructed. A numerical calculation algorithm is developed and the amplitude of this effect is calculated as a function of the AES orbital position. It is shown that this effect may be measured in the process of ranging of current Russian AESs equipped with laser corner reflectors.     

Fiber Optic Coupling of CW Linear Laser Diode Array

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PN1B微小卫星激光反射器设计及激光测距试验

大气密度探测实验卫星PN1B于2015年9月在太原卫星发射中心成功发射,为了实现对该卫星星载GPS定轨数据提供检核标准及高精度测轨应用要求,依据卫星无法提供阵列结构激光反射器所需要的安装面积的限制,首次采用通光口径为10 mm的微小激光反射器按照不同的指向分布在卫星的棱边。利用TROS1000流动人卫激光测距系统对该卫星进行追踪和激光测距试验,测量结果表明激光回波数据充足,每秒平均激光回波光子数达173个,标志着此类微小激光反射器的应用将会在卫星轨道精密定轨方面发挥重要作用。