高功率激光作用于汞原子产生三阶谐波

本文讨论了在金属蒸气中的光学三阶谐波的产生，首次在实验中使用波长为１．０６２５μｍ的高功率激光作用于汞（Ｈｇ）蒸气获得了三阶谐波（３５４．２ｎｍ）谱线。     

高功率激光作用于汞原子产生三阶谐波

本文讨论了在金属蒸气中的光学三阶谐波的产生，首次在实验中使用波长为１．０６２５μｍ的高功率激光作用于汞（Ｈｇ）蒸气获得了三阶谐波（３５４．２ｎｍ）谱线。     

低压MOCVD外延生长InGaAsP／InP应变量子阱材料与器件应用

本文报道用低压有机金属化合物化学气相淀积（ＬＰ－ＭＯＣＶＤ）外延生长ＩｎＧａＡｓＰ／ＩｎＰ应变量子阶材料，材料参数与外延条件的关系，量子阱器件的结构设计及其器件应用．用所生长的材料研制出宽接触阈值电流密度小于４００Ａ／ｃｍ２（腔长４００μｍ），ＤＣ－ＰＢＨ结构阈值７～１２ｍＡ的１．３μｍ量子阱激光器和宽接触阈值电流密度小于６００Ａ／ｃｍ２（腔长４００μｍ），ＤＣ－ＰＢＨ结构阈值９～１５ｍＡ的１．５５μｍ量子阶激光器以及高功率１．３μｍ量子阱发光二极管和ＩｎＧａＡｓＰＩＮ光电探测器．     

InGaAsP及其量子阱结构的LP－MOCVD

报道了用低压金属有机化学汽相淀积（ＬＰ－ＭＯＣＶＤ）技术在（１００）ＩｎＰ衬底上生长ＩｎＧａＡｓＰ体材料及ＩｎＧａＡｓＰ（１．３μｍ）／ＩｎＧａＡｓＰ（１．６μｍ）量子阱结构的生长条件和实验结果。比较了５５０℃和５８０℃两个生长温度下Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ体材料及相应量子阱结构的特性，表明在５８０℃生长条件下，晶体具有更好的质量和特性。     

LP－MOCVD制作InGaAs／InPPIN光电二极管

采用ＬＰ－ＭＯＣＶＤ制作了ＩｎＧａＡｓ／ＩｎＰ平面型ＰＩＮ光电二极管。器件光敏面直径为７５μｍ，采用Ｚｎ扩散形成ＰＮ结，－６Ｖ偏置下其暗电流低达８～１３ｎＡ；反向击穿电压为６０Ｖ（１μＡ）。在没有增透膜时，对１．３μｍ注入光响应度为０．５６Ａ／Ｗ，光谱响应范围为０．９０～１．７０μｍ。     

用LPE研制的室温连续工作的1．48μm单量子阱激光器

利用液相外延（ＬＰＥ）技术研制出室温连续工作的ＩｎＧａＡｓＰ／ＩｎＰ分别限制单量子阶（ＳＣＨ－ＳＱＷ）双沟平面掩埋（ＤＣ－ＰＢＨ）激光器。室温下，腔面未镀膜的激光器最低阈值电流为２３ｍＡ（激光器腔长为２００μｍ，ＣＷ，１３℃）。激射波长为１．４８μｍ，最高输出功率达１８．８ｍＷ（Ｌ＝２００μｍ．ＣＷ，１８℃）。脉冲输出峰值功率大于５０ｍＷ（脉冲宽度１μｓ、频率１ｋＨｚ），未见功率饱和。量子阱的阱宽为２０ｎｍ［１］．     

我量子点激光器研究获突破

我国科学家在Ｉｎ（Ｇａ）Ａｓ自组织量子点激光器研究中获得突破。目前已经获得室温下ＰＬ峰值在１．３μｍ的量子点材料,朝１．３μｍ激光器迈出了一大步。Ｉｎ（Ｇａ）Ａｓ／ＧａＡｓ量子点体系因其独特、优越的光电性质,成为替代目前ＩｎＰ基材料、制备光纤通讯用１、３μｍ长波激光器的热门材料之一,迄今已有美国德克萨斯大学、日本ＮＥＣ实验室、日本富士通实验室,及德国ＰＤＩ研究所和俄罗斯约飞研究所联合小组等几个研究小组成功制备了室温激射波长在１．３μｍ的量子点激光器。中国科学院半导体所是国内率先开展自组织量子点激…     

低衰减色散补偿光纤及其应用

本文介绍了用具有大的正常色散单模光纤作色散补偿光纤来抵消１．３μｍ零色散波长传输光纤的反常色散的设计原理。用ＶＡＤ法制作了Δ范围从１．６－３．５ 种ＣＤＦ，并检验了其性能。获得了最大Δ为３．５％的ＤＣＦ，其在１．５５μｍ波长处的最大色数为－１４０ｐｓ／（ｎｍ．ｋｍ）。随着Δ的增大，瑞利散射和缺陷衰减增加，致使传输衰减也增大。     

All Optical Wavelength Conversion from 1.3μm to 1.55μm Using Two-segment DFB Lasers

ＡｌＯｐｔｉｃａｌＷａｖｅｌｅｎｇｔｈＣｏｎｖｅｒｓｉｏｎｆｒｏｍ１．３μｍｔｏ１．５５μｍＵｓｉｎｇＴｗｏ－ｓｅｇｍｅｎｔＤＦＢＬａｓｅｒｓ①ＬＵＯＢｉｎ，ＬＵＨｏｎｇｃｈａｎｇ，ＣＨＥＮＪｉａｎｇｕｏ（ＳｏｕｔｈｗｅｓｔＪｉａｏｔｏｎｇＵｎｉｖｅ...     

硅基GaAs／GaAlAs平面光波导的研究

分析了金属有机化合物化学气相淀积（ＭＯＣＶＤ）ＧａＡｓ／ＧａＡｓＡｌ／ＧａＡｓ／Ｓｉ材料结构的性能，用ＭＯＣＶＤ法地硅衬底上生长了ＧａＡｓ／ＧａＡｓＡｌ／ＧａＡｓ材料，并用这种材料制备了平面光波导样品，测定了１．３μｍ，单模激光的传输损耗小于０．６５ｄＢ／ｃｍ。     

Frequency stabilization in FBG external cavity semiconductor laser based on acetylene absorption method

A frequency-stabilized 1.53 μm FBG external-cavity semiconductor laser by using acetylene absorption is presented and its basic principles are introduced. Graded refractive index fiber and pigtailed fiber are used in the absorption air chamber to enhance the coupling stability. The impact of the background power is eliminated by using the third-harmonic mode-locking technique. A lock-in amplifier is utilized to ensure that the output laser wavelength is locked at the C2H2 absorption line of 1530.37 nm. The frequency stability reaches 10^-8 within 24 h.     

基于CO2激光的AgGaSe2晶体中3次谐波产生

为了在AgGaSe2 晶体中产生3次谐波,利用自行研制的1台可调谐脉冲CO2激光器,在2次谐波中采用Ⅰ类匹配,并在3次谐波中采用Ⅱ类匹配的方法。实验中CO2激光输出波长为9.6m,在AgGaSe2 晶体中得到了波长为4.8m的2次谐波以及波长为3.2m的3次谐波,其峰值功率分别为88kW和4kW,并测量了相位匹配允许角。结果表明,在该AgGaSe2晶体实验中能有效地输出3次谐波,随着CO2激光功率的增大,输出2次谐波峰值功率和3次谐波峰值功率的级数都增加。     

水气含量对基于QEPAS甲烷气体探测性能的影响

由于气体的湿度对分子振动弛豫有着较大的影响,利用石英音叉增强型光声光谱(QEPAS)技术作为甲烷气体传感,在实际应用中,空气的水气浓度变化将会使光声测量气体浓度的信号强度发生变化。实验中采用鼓泡法结合湿度计来改变探测气体中的湿度,测量了常压下1.653μm波长处甲烷的二次谐波信号,系统地研究了探测气体中水气浓度的变化对石英音叉Q值、共振频率f0等参数的影响。实验结果表明,水气对基于QEPAS技术甲烷气体传感器的实际应用有着很大的影响,主要表现在甲烷分子振动弛豫和探测系统性能两个方面。当实际大气中绝对湿度为2.34%时,获得的系统最小可探测质量浓度为0.57mg/m3。     

Nonlinearities of GaAlAs lasers--Harmonic distortion

Narrow stripe lasers (2-6 mum) and transverse junction lasers exhibit excellent linearity. The dependence of relative second-and third-harmonic distortion is investigated as a function of modulation frequency and modulation current. Relative second- and third-harmonic distortion of -50 and -70 dB is observed for an optical signal of 4 mW p-p (f_{m} = 60MHz). Intermodulation products are compared with the harmonic distortion and good agreement is obtained between the two quantities when the relations for a simple nonlinearity without memory are used. The measured distortion is in agreement with distortion calculated from rate equations.     

1.78 μm应变InGaAs-InGaAsP-InP分布反馈量子阱激光器

采用低金属有机汽相外延(LP-MOVPE)生长大应变InGaAs/InGaAsP做有源区,研制了激射波长为1.78μm的脊波导分布反馈(DFB)激光器,对于解理腔长为900μm的激光器,室温时其激射的阈值电流为33mA,最大单面光输出功率/和单面外微分量子效率分别为8mW和7％;此外,激射光谱边模抑制比(SMSR)为27.5dB。     

Measurements of Atmospheric Water Vapor Above Mauna Kea Using an Infrared Radiometer

This paper presents the first results from a prototype infrared radiometer which has been developed to measure variations in atmospheric water vapor column abundance from high altitude sites. The performance of the infrared radiometer is compared and contrasted with that of a water vapor monitor operating at radio frequencies. Analysis shows that the infrared radiometer can measure variations at the level of ～ 1 μm precipitable water vapor (pwv) in an integration time of 1 s when the total column abundance is ～0.5 mm pwv. Since variations in atmospheric water vapor are the dominant source of phase noise in (sub)millimeter astronomical interferometry, an instrument capable of rapid and high sensitivity water vapor measurements has the potential to provide the necessary phase correction information for interferometric arrays.     

High growth rate metal‐organic molecular beam epitaxy for the fabrication of GaAs space solar cells

In this work, the epitaxial growth of GaAs photovoltaic devices using metalorganic molecular beam epitaxy (MOMBE) and chemical beam epitaxy (CBE) with growth rates in excess of 3 μm/h is undertaken. The performance of these preliminary devices offer encouraging evidence for MOMBE and CBE as possible alternatives to the more common metalorganic chemical vapor deposition (MOCVD) for the production of III‐V solar cells. Copyright © 2000 John Wiley & Sons, Ltd.     

W-band divide-by-3 frequency divider using 0.1 /spl mu/m InAlAs/InGaAs metamorphic HEMT technology

A W-band divide-by-3 frequency divider with wide bandwidth and low power dissipation is presented using harmonic injection-locking technique. A cascode FET is employed for a self-oscillating second-harmonic mixer which is injection-locked by third-harmonic input to obtain the division order of three. The fabricated frequency divider using 0.1 /spl mu/m GaAs metamorphic HEMT technology shows superior performance such as large bandwidth of 6.1 GHz around 83.1 GHz (7.3%) under small DC power consumption of 12 mW.     

Light and Strong SiC Networks

The directional freezing of microfiber suspensions is used to assemble highly porous (porosities ranging between 92% and 98%) SiC networks. These networks exhibit a unique hierarchical architecture in which thin layers with honeycomb‐like structure and internal strut length in the order of 1–10 μm in size are aligned with an interlayer spacing ranging between 15 and 50 μm. The resulting structures exhibit strengths (up to 3 MPa) and stiffness (up to 0.3 GPa) that are higher than aerogels of similar density and comparable to other ceramic microlattices fabricated by vapor deposition. Furthermore, this wet processing technique allows the fabrication of large‐size samples that are stable at high temperature, with acoustic impedance that can be manipulated over one order of magnitude (0.03–0.3 MRayl), electrically conductive and with very low thermal conductivity. The approach can be extended to other ceramic materials and opens new opportunities for the fabrication of ultralight structures with unique mechanical and functional properties in practical dimensions.     

808nm大功率连续半导体激光器研究

利用金属有机化学气相淀积(MOCVD)技术,生长了AlGaInAs/AlGaAs分别限制压应变单量子阱材料,利用该材料制成3mm宽、填充因子20%的半导体激光器阵列(版型100μm/500μm,6个发光单元),通过腔面反射率设计确定了最佳反射率,采用CS载体标准封装。在输入电流8A、水冷19℃条件下测试,输出功率达到8.4W,阈值电流为1.8A,斜率效率为1.26W/A,功率转换效率为59.4%,波长为805.7nm,光谱半宽为1.8nm;输入电流12A时,输出功率达到13W,斜率效率为1.22W/A,功率转换效率为58.9%,波长为807.9nm,光谱半宽为2.0nm。