Single-lobed Near Diffraction-limited Beam from 1W Laser Diode Array with an External Cavity

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电光晶体调谐的外腔反馈半导体激光器

报道一种用电光晶体实现快速调谐和凋制激光频率的方法.在Littrow型外腔反馈半导体激光中插入LiNbO3晶体,利用LiNbO3晶体的电光效应,通过改变晶体电压来调节激光器的有效腔长,可以对激光频率进行快速的调谐和调制.采用该方法,自制外腔反馈半导体激光器的调谐频率可达到2 kHz,它的调谐范围为350 MHz,激光频率调谐系数约为1.06 MHz/V,用饱和吸收光谱观测频率调谐的效果.快速激光频率调制可以应用在稳频技术上,将外腔反馈半导体激光器调制在5～100 kHz频率下,均获得了87Rb原子D2线的饱和吸收光谱的色散信号,并实现了激光频率在饱和吸收峰上的长期稳定.     

Beam Profile Improvement of a LD Array by an External Cavity with Photorefractive Phase Conjugate Mirror

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基于降温技术的宽范围外腔光栅可调谐半导体激光器

使用半导体制冷块,通过优化设计两级制冷系统,并结合隔离、密封等措施,将LD的温度冷却到-20 ℃,使室温下输出波长为789 nm的激光器工作在780 nm附近,改变了约9 nm.结合外腔光栅反馈技术,可以使激光器的输出波长稳定在Rb原子的D2线上.自制了一个简单的电路,能够以适当的比例同时调谐光栅压电陶瓷的电压和激光器的驱动电流,使激光器可以连续调谐1O GHz以上而不跳模.     

Wavelength Tuning Characteristics of a Vertival Cavity Surface Emitting Laser Diode with an External Short Cavity

The characteristics of a wavelength tunable vertical cavity surface emitting laser diode (VCSEL) with an external short cavity are analyzed, in which the oscillation wavelength can be changed over several tens of nanometers with a nearly constant optical power by slightly altering the external cavity length. Analysis is based on rate equations for the optical power and carrier density, taking the effect of carrier-induced refractive index change into consideration, together with the study of behaviors of a complex resonator. The reflection coefficient r₂ of a laser facet facing the external mirror is shown to affect notably the characteristics of wavelength tuning, optical power and carrier density for a change of the external cavity length. It is also noticed that the wavelength change for this length becomes slower with relatively larger r₂ due to an increasing contribution of the effect of carrier-induced refractive index change, within the optical gain spectrum of the laser diode.     

基于外腔反馈二极管线阵列的smile效应测量方法

采用外建激光谐振腔,在低于原芯片阈值的电流激励下对LDA的每个发光点进行单独测量,从而分析整个半导体激光阵列(LDA)的smile效应。实验中利用镀膜反射率大于半导体前腔面的外腔镜形成外腔半导体激光器。在外腔中插入曲面平行于p-n结的柱面镜,使只在光轴上的发光点与外腔镜形成外腔激光器,降低该发光点的激光阈值,从而使其在正常的阈值以下的电流激励下输出激光,在平行于p-n结的方向移动柱面镜,可以逐个对半导体激光器中的发光点进行选择测量,从而获得LDA smile效应的测量值。测量中的低电流激励产生的热量对芯片寿命没有影响,对LDA的发光点的单个测量也避免了其他发光点对CCD的影响。     

首批系列化国产外腔半导体激光器

就首批系列化国产外腔半导体激光器的设计,关键技术和生产等多方面进行了介绍,对一些特性参数进行了说明,给出了一些实物的图片。长期稳定性实验表明,产品的一致性和稳定性都达到了设计要求,生产流程和生产工艺相对简单,各项性能指标完全达到了国外同类产品的性能和指标。     

基于组合模理论设计的激光二极管阵列外腔

针对激光二极管阵列提出了“组合模”慨念,计算了组合模的远场分布,每个组合模在远场的空间分布呈双瓣结构,基于激光二极管阵列组合模的远场分布特征,设计了离轴外腔反馈的激光二极管阵列,运用此装置所获得激光二极管阵列的远场分布有了明显变化,与自由运转的激光二极管阵列相比,离轴外腔反馈的激光二极管阵列远场宽度减少了4.3倍,在抽运电流为16 A时,测得输出激光的功率1.82W,这相当于相同电流下自由运转激光器输出功率的79％.组合模理论不仅可以用来指导设计一维离轴外腔反馈激光二极管阵列,而且也可以用于设计二维离轴外腔反馈激光二极管阵列.二维离轴外腔反馈激光二极管阵列可以产生高功率,高光束质量输出的激光.     

利用自相位延迟方法测量单块腔反馈半导体外腔激光器的线宽

提出了采用单块折叠法布里-珀罗(F-P)腔作为外腔反馈元件实现窄线宽半导体激光器,采用单块腔的光学反馈来锁定外腔激光器,使用自相位延迟法测量该窄线宽激光器的线宽。实验结果表明,激光器线宽小于35kHz。实验还观测到由于单块腔耦合面上各耦合点的几何量和物理量误差不一样,随着折叠面兼输入输出耦合面上的耦合点的变化,外腔激光器的线宽发生改变。     

基于组合模理论设计的激光二极管阵列外腔

针对激光二极管阵列提出了"组合模"概念,计算了组合模的远场分布.每个组合模在远场的空间分布呈双瓣结构.基于激光二极管阵列组合模的远场分布特征,设计了离轴外腔反馈的激光二极管阵列.运用此装置所获得激光二极管阵列的远场分布有了明显变化.与自由运转的激光二极管阵列相比,离轴外腔反馈的激光二极管阵列远场宽度减少了4.3倍.在抽运电流为16 A时,测得输出激光的功率1.82 W,这相当于相同电流下自由运转激光器输出功率的79%.组合模理论不仅可以用来指导设计一维离轴外腔反馈激光二极管阵列,而且也可以用于设计二维离轴外腔反馈激光二极管阵列.二维离轴外腔反馈激光二极管阵列可以产生高功率,高光束质量输出的激光.     

A Tunable External Cavity Laser Diode Possessing a Stable Wavelength

In this work we describe a simple external-cavity laser diode equipped with a feedback control system, in which a high-resolution position-sensitive detector detects the slight misalignment of the light within the cavity. Our system not only provides a stable wavelength that can be tuned within a maximum scanning range of 1.87 nm, but also allows for faster scanning, through precise control of the reflection angle within the cavity. The simultaneous controls on the rotation-angle of the external mirror and the injection current enabled us to realize continuous wavelength-tuning.     

Single-Mode Operation of Broad-Area Diode Laser at 670 nm by External Cavity Configuration with a Diffraction Grating

We demonstrate the single mode operation of a broad-area diode laser at 670 nm by means of an external cavity configuration using a diffraction grating. The output power of 150 mW is obtained with a spectral width of 40 MHz.     

激光引信中阵列激光二极管光束参数的测量方法

根据激光引信中激光器的脉冲功率高、发散角大的特殊测量要求,比较了ISO 11146标准文件对激光束的3种测量方法,以二阶矩法为基础,运用机械扫描法测量光束截面的功率密度,进而再现出光斑图形。采用光能量降为最大强度的1/e2来定义光束束宽,通过等强线求出了宽度和远场发散角。     

大功率激光二极管的微片棱镜堆光束整形和光纤耦合输出

提出用微片棱镜推实现大功率激光二极管线列阵器件的光束整形,进而实现光纤耦合输出。利用这一技术得到了直径为６００μｍ的光纤耦合输出的大功率半导体激光,总效率大于５０％。它具有易于制造、调整简便、结构简单的优点。文中从理论、计算机模拟以及实验三个方面对微片棱镜堆的整形进行了分析讨论。     

Continuous Wavelength Sweep of External Cavity 630 nm Laser Diode without Antireflection Coating on Output Facet

We developed a simple method of continuous wavelength sweep using a commercial laser diode (LD) without antireflection (AR) coating. A 630 nm AlGalnP LD was installed in a Littrow-type external cavity. In this cavity, the LD has the same effect as an etalon, and its free spectral range can be controlled easily by the LD drive current. By scanning the grating angle of the external cavity and LD drive current simultaneously, we obtained single-mode oscillation and continuous wavelength sweep of over 22 GHz without mode hopping. This technique is simple and inexpensive because it does not need AR coating on its output facet, and does not use a servo system which requires apparatuses such as a lock-in amplifier and local oscillator.     

用于全光波长转换的外腔半导体激光器的注入电流选择

实验研究了注入光对光纤光栅外腔半导体激光器阈值电流的影响,给出了可同时获得高消光比和高转换速率的注入电流范围。采用载流子消耗机抽对实验结果进行了实性分析。     

Micromechanical Photonics: Microresonator Displacement Measurement by an Extremely-Short-Length External Cavity Laser Diode

A composite cavity laser diode was used to monitor the displacement of the external cavity microresonator from the phase difference in the near field. The carrier-to-noise ratio was very high (more than 45 dB) because of the lack of mode hopping noise due to the extremely short (less than 3 μm) external cavity length and strong optical feedback. The small distance (near field) allows a lensless system, making it easier to integrate on a gallium arsenide (GaAs) substrate.     

基于微蒸发腔制冷的大功率激光二极管制冷组件

利用节流的高压冷却介质在微蒸发腔内相变吸热,设计了一种用于大功率激光二极管制冷的封装组件。该组件采用高热导的无氧铜,用精密线切割、化学腐蚀等技术制作微蒸发腔,再通过自制的焊接设备完成制冷组件的封装。按照大功率激光二极管条的发热模型,理论上对微蒸发腔制冷组件的温度分布进行了数值模拟,结果与60 W激光二极管条的散热实验符合较好,得到制冷剂流量为23 m L/min时的热阻为0.289℃/W。     

面对光栅的激光二极管端面上耦合问题的研究

从理论和实验上研究了面对长外腔（光栅作外反射镜）的激光二极管端面上的耦合问题，首次求出了耦合系数η的解析表达式，它是高斯函数。η可以分成η１和η２两部分，η描述的是由于经光栅的反射模和腔模之间不交叠引起的损耗。η２则是经光栅的反射光小矢的变化造成的。实验结果与理论预期符合得很好。     

强反馈光纤光栅外腔半导体激光器

在理论上对强外腔反馈情形的半导体激光器线宽压窄效应进行了分析，对消反膜剩余反射率，外腔反射率，外腔腔长对线宽压缩的影响进行了研究，在实验上采用光纤光栅作为反馈元件，与一端镀有消反膜的１．５μｍ波段的常规多纵模交导体激光器耦合，构成强反馈光纤光栅外腔半导体激光器，得到单频窄线宽的激光输出，静态下边模抑制比大于３０ｄＢ，线宽小于１２０ｋＨｚ。