Effect of Mesa Size on Thermal Characteristics of Vertical-cavity Surface-emitting Lasers

The effect of mesa size on the thermal characteristics of etched mesa vertical-cavity surfaceemitting lasers(VCSELs) is studied. The numerical results show that the mesa size of the top mirror strongly influences the temperature distribution inside the etched mesa VCSEL. Under a certain driving voltage, with decreasing mesa size, the location of the maximal temperature moves towards the p-contact metal, the temperature in the core region of the active layer rises greatly, and the thermal characteristics of the etched mesa VCSELs will deteriorate.

电光腔倒空激光二极管抽运Nd∶YAG锁模激光器

设计了一个简单的直腔,将电光腔倒空与激光二极管端面抽运Nd∶YAG半导体可饱和吸收镜锁模激光器结合,实现了锁模脉冲的产生、放大和输出。在连续抽运功率5 W的条件下,获得了脉冲宽度为11 ps的锁模单脉冲输出和脉冲宽度为200 ns的调Q脉冲输出,腔倒空单脉冲能量为30 nJ,重复频率为10 Hz。连续锁模运转时单个锁模脉冲的能量约为2 nJ,利用腔倒空将单脉冲的能量提高了15 倍左右。文章详细讨论了腔倒空脉冲及调Q脉冲的产生机理,并分析了加在电光晶体上的高压电脉冲以及偏振片的偏振度对腔倒空脉冲及调Q脉冲的影响。

激光二极管侧面抽运Nd∶YAG锁模激光器的研究

利用谐振腔的稳定条件对激光二极管侧面抽运的Nd∶YAG锁模直腔的稳区特性和谐振腔内的光斑分布进行了分析。根据对腔参量的分析，选取合适的腔参量设计了一个简单的侧面抽运直腔，该谐振腔腔形简单，没有像散，振荡光模式好，有利于激光器的锁模运转。实验中采用国内自行研制的半导体可饱和吸收镜，实现了激光二极管侧面抽运半导体可饱和吸收镜锁模Nd∶YAG激光器的连续锁模运转，平均输出功率为2 W，锁模脉冲宽度为10 ps,重复频率为100 MHz。结合实验结果进一步讨论了半导体可饱和吸收镜的一些参量如饱和恢复时间、调制深度等对实现稳定连续锁模的影响。

用表面态型半导体可饱和吸收镜实现Yb∶YAG激光器被动调Q锁模

制作了一种新型的半导体可饱和吸收镜--表面态型半导体可饱和吸收镜.用表面态型半导体可饱和吸收镜作为被动锁模吸收体实现了半导体端面泵浦Yb∶YAG激光器被动调Q锁模.在泵浦功率仅有1.4 W的情况下,获得了调Q锁模脉冲序列,锁模平均输出功率1 mW,锁模脉冲重复频率200 MHz.

连续波500 W全固态Nd∶YAG激光器研究

研制了全国产化全固态半导体激光器(LD)抽运模块，Nd∶YAG激光输出功率达500 W。介绍了优化抽运模块结构参数的程度。从增益分布特性等方面，介绍了研究其输入-输出功率特性的实验装置，随着抽运功率的增加，Nd∶YAG激光输出以斜率效率47%线性增加，最大输出功率达到575 W，光-光转换效率达26.1%。采用He-Ne激光探测法实验测量了该抽运模块中的热透镜效应。通过测量热焦距，分析了其热透镜效应

Passive Q-switching of diode-pumped Yb:YAG microchip laser with ion-implanted GaAs

We reported a passive Q-switched diode laser pumped Yb:YAG microchip laser with an ion-implanted semi-insulating GaAs wafer. The wafer was implanted with 400-keV As^(+) in the concentration of 10^(16) ions/cm^(2). To decrease the non-saturable loss, we annealed the ion-implanted GaAs at 500 oC for 5 minutes and coated both sides of the ion-implanted GaAs with antireflection (AR) and highreflection (HR) films, respectively. Using GaAs wafer as an absorber and an output coupler, we obtained 52-ns pulse duration of single pulse.

Passively Mode Locked Diode-End-Pumped Nd∶YAG Laser with In0.25 Ga0.75 As as Output Coupler

A novel InGaAs(LT-In0.25 Ga0.75 As) absorber grown by metal organic chemical vapor deposition at low temperature is presented.Using it as well as an output coupler,passive mode locking,which produces pulses as short as several hundred picoseconds for diode-end-pumped Nd∶YAG laser at 1.06μm,is realized.The pulse frequency is 150MHz.

表面态型半导体可饱和吸收镜实现Yb:YAG激光器被动锁模

制作了一种新型的半导体可饱和吸收镜:表面态型半导体可饱和吸收镜.用表面态型半导体可饱和吸收镜作为被动锁模吸收体,实现了半导体端面泵浦Yb:YAG激光器被动连续锁模.在泵浦功率为10W时,获得了连续锁模脉冲序列,重复频率200MHz,锁模脉冲平均输出功率为70mW.在未加任何色散补偿的情况下,脉冲宽度为4.35ps.

Monolithic Integration of Electro-Absorption Modulators and DFB Lasers by Modified Double Stack Active Layer Approach

Monolithic electro-absorption modulated distributed-feedback(DFB) lasers are proposed and fabricated by using a modified double stack active layer.The 38mA threshold,9dB extinction ratio (from 0.5V to 3.0V),and about 5mW output power at the 100mA operation current are achieved.Compared with other reported results (only 1.5mW at the same operation current) of the traditional stack active structure,the proposed structure improves the output power of devices.

1.78 μm Strained InGaAs-InGaAsP-InP Distributed Feedback Quantum Well Lasers

Ridge-waveguide distributed-feedback(DFB) lasers with highly strained InGaAs/InGaAsP active regions,emitting at 1.78 μm were fabricated by low pressure metal-organic vapor phase epitaxy(LP-MOVPE) and tested.The lasers exhibited threshold current of 33 mA for 900 μm long cavities at room temperature.A maximum light output power of 8 mW from one facet and an external differential quantum efficiency of 7% were also obtained.In oddition,the side mode suppression ratio (SMSR) is 27.5 dB.

表面态型半导体可饱和吸收镜实现Nd:YAG激光器被动锁模

砷化镓半导体材料与空气接触的表面存在密度很高的电子表面态,砷化镓材料内部的电子可以通过这种表面进行驰豫,驰豫时间估计在ps量级.依此原理,制作了一种新型的表面态型半导体可饱和吸收镜,用其作为被动锁模吸收体,实现了半导体端面泵浦Nd:YAG激光器被动连续锁模.在泵浦功率为4 W的情况下,获得了连续锁模脉冲序列,重复频率150 MHz,锁模脉冲平均输出功率为300 mW,脉冲宽度为10 ps.

半导体可饱和吸收镜被动锁模Nd:YAG激光器的研究

利用自行研制的半导体可饱和吸收镜(SESAM),在5 W光纤耦合半导体激光器端面抽运的Nd:YAG激光中,实现了半导体可饱和吸收镜被动锁模,获得了稳定的皮秒锁模激光输出.经自相关仪测量,其锁模激光脉冲宽度小于10 ps.实验采用直腔结构的谐振腔,该腔结构简单,易于调整,实现可饱和半导体吸收镜稳定锁模时,光-光转换效率达到19%.

Stable mode-locking in an Yb:YAG laser with a fast SESAM

Stable mode-locking in a diode-pumped Yb:YAG laser was obtained with a very fast semiconductor saturable absorber mirror (SESAM). The pulse width was measured to be 4 ps at the central wavelength of 1047 nm. The average power was 200 mW and the repetition rate was 200 MHz.

半导体可饱和吸收镜自启动的Kerr锁模Cr~(4+)∶YAG激光器

采用传统的X型像散腔,利用一块精心设计的半导体可饱和吸收镜(SESAM)做启动元件,实现了自启动的Kerr锁模Cr4+∶YAG激光器.输出脉冲的最窄脉宽小于80 fs,脉冲重复频率为120 MHz,脉冲峰值功率可以达到100 W以上.

掺铒nc-Si/SiO_2薄膜中nc-Si和Er~(3+)与非辐射复合缺陷间相互作用对薄膜发光特性的影响

对nc-Si/SiO_2薄膜中纳米硅(nc-Si)、Er~(3+)和非辐射复合缺陷三者间的关系作了研究.在514.5 nm光激发下,nc-Si/SiO_2薄膜在750nm和1.54μm处存在较强的发光,前者与薄膜中的nc-Si有关,后者对应于Er~(3+)从第一激发态4I13/2到基态4I15/2的辐射跃迁.随薄膜中Er3+含量的提高,1.54μm处的发光强度明显增强,750 nm处的发光强度却降低.H处理可以明显增强薄膜的发光强度,但是对不同退火温度样品,处理效果却有所不同.根据以上实验结果,可得如下结论:在nc-Si颗粒附近的Er~(3+)和其他的缺陷组成了nc-Si颗粒内产生的束缚激子的非辐射复合中心,束缚激子通过Er~(3+)的非辐射复合,激发Er~(3+)产生1.54μm处的发光,同时降低了750nm处的发光强度.nc-Si颗粒附近其他非辐射复合中心的存在会降低Er~(3+)被激发的概率,引起1.54μm处的发光强度降低.