解析式表示外腔半导体激光器的特征参量

用射线法研究了强反馈可调谐外腔式半导体激光器的阈值行为，导出了ＥＣＬＤ被财在不同波长振荡所需的阈值载流子数密度外腔长度及阈值电流的解析表达式，也得到了不同电流ＥＣＬＤ的调谐输出功率及载流子密度的表达式。     

减反射膜与外腔半导体激光器调谐范围

由于镀了减反射膜的半导体激光二极管端面的反射曲线的谱宽有限，而且，增益峰值波长随载流子密度的变化，因而实际上起作用的反射率通常都比能测到的最低反射率高，在腔内可建立的载流子密度的上限比预期的低。在考虑了这些因素后，计算了用这种管子作外腔半导体激光器（ＥＣＬＤ）的增益介质时，ＥＣＬＤ的调谐范围。     

同时实现LD—CELP和EC的研究

本文提出了一种将回波抵消器（ＥＣ）作为ＬＤ－ＣＥＬＰ编解码器的部分工作的方法，将ＥＣ功能融入ＬＤ－ＣＥＬＰ编解码器之中，文中讨论了用两片ＴＭＳ３２０Ｃ３０实时实现ＬＤ－ＣＥＬＰ与ＥＣ于一个系统中的可能性。     

GaAs DCFL超高速集成电路研究

直接耦合场效应逻辑（ＤＣＦＬ）具有简单的结构、良好的速度／功耗性能，是ＧａＡｓＦＥＴＬＳＩ电路中一种重要的逻辑形式。传统Ｅ／Ｄ型ＤＣＦＬ电路具有较低的成品率和较差的温度特性，本文研究了改进的Ｅ／Ｅ型ＤＣＦＬ电路。对Ｅ／Ｄ、Ｅ／Ｅ型ＤＣＦＬ电路的直流、瞬态及温度特性进行了分析、模拟和比较，Ｅ／Ｅ逻辑具有良好的高温性能。经优化设计，最后制作出单门延迟约１００ｐｓ、单门功耗约１ｍＷ的Ｅ／Ｄ和Ｅ／Ｅ型ＤＣＦＬ电路，且Ｅ／Ｅ型电路较Ｅ／Ｄ型电路具有更高的成品率。     

深亚微米MOSFET二维数值模拟的若干结果

对溶亚微米器件，由于工作电压下降，要求重新确定ＬＤＤ和常规ＭＯＳＦＥＴ在ＶＬＳＩ中的作用。本文从基本器件数理方程发出，对深亚微米常规及ＬＤＤ ＭＯＳＦＥＴ的器件特性、热载流子效应及短沟道效应进行了二维稳态数值模拟，指出了常规和ＬＤＤ ＭＯＳＦＥＴ各自的局限性，明确了在深亚微米ＶＬＳＩ中，ＬＤＤ仍然起主要作用。     

SOI LDD MOSFET的栅电流的模拟

本文介绍一种采用载流子总量方法分析ＳＯＩ ＭＯＳＦＥＴ器件特性及热载流子效应的数值模型。使用专用模拟程序ＬＡＤＥＳ７联解器件内部二维泊松方程、电子和空穴的连续性方案。ＬＡＤＥＳ７可用于设计和预测不同工艺条件、几何结构对器件性能的影响。该模型直接将端点电流、端点电压与内部载流子的输运过程联系在一起，可准确地模拟ＳＯＩ ＭＯＳＦＥＴ器件的特性并给出清晰的内部物理图象。本文给出了ＬＡＤＥＳ７软件模拟的部     

PROTEL图形在CorelDraw软件中的处理及应用

文章通过对ＰＲＯＴＥＬ和ＣｏｒｅｌＤｒａｗ两个软件包的分析,提出了利用ＣｏｒｅｌＤｒａｗ作为工具,打印ＰＲＯＴＥＬ图形,以及插入ＷＯＲＤ文档中的方法。同时介绍了使用ＣｏｒｅｌＤｒａｗ处理ＰＲＯＴＥＬ图形的进一步应用,以及将ＰＲＯＴＥＬ图形插入ＷＯＲＤ文档中的实用技巧     

半导体光电子器件的研究进展

文章综述ＣＬＥＯ’９４及ＩＱＥＣ’９４会议报道的有关光电子器件的发展状况，叙述了大功率ＬＤ、蓝绿光ＬＤ、垂直腔面发射半导体激光器、可调谐ＬＤ及ＯＥＩＣ的最新研究进展。     

EL7512C升压变换器在DSL用户端电源的设计与应用

本文较详细介绍了 ＥＬ７５１２Ｃ ＤＣ／ＤＣ 升压转换器的性能以及在ＤＳＬ用户端（ＣＰＥ）电源设计与布线中要考 虑的要素。     

ADSL的操作和维护

阐述了ＡＤＳＬ中ＥＯＣ的功能，ＥＯＣ帧结构，ＥＯＣ命令，以及ＥＯＣ协议，对在ＡＤＳＬ数据帧中插入ＥＯＣ帧这一问题也进行了讨论。     

Small-signal admittance of BARITT diodes

Small-signal admittance and phasor diagrams for metal-semiconductor-metal microwave oscillator diodes (BARITT diodes) were calculated by taking previously neglected carrier diffusion and field dependence of carrier velocity into account. It was shown that the microwave performance greatly degrades with an increase of dc current density and of oscillation frequency.     

Large-signal dynamic behavior of distributed-feedback lasersincluding lateral effects

The large-signal behavior of DFB lasers is analyzed, including lateral as well as longitudinal variations in carrier density, photon density, and refractive index. The effective index method and other approximations are used to reduce the complex three-dimensional problem to one dimension. The coupled wave and carrier rate equations are then solved in a self-consistent manner. Lateral spatial carrier hole burning and lateral diffusion are found to affect the relaxation oscillation frequency and damping rate of DFB lasers, depending on their detailed structure. The effective time-averaged linewidth enhancement factor is also affected. In symmetric AR-coated λ/4 phase-shifted lasers the side mode suppression ratio can be deteriorated significantly by lateral spatial hole burning when kL is large     

Nonlinear dynamics of semiconductor laser emission under variablefeedback conditions

A study was made of the behavior of external cavity semiconductor lasers with tilted external cavity mirrors providing variable feedback. The appearance of intermittent breakdowns of the light intensity induced by the tilting of the external mirror is demonstrated. The rate of the breakdowns of the light intensity is directly related to the relaxation oscillation frequency of the external cavity semiconductor laser. The authors describe the experimental observations theoretically by the coupled rate equations for the electric field density and the carrier density     

Low-frequency intensity noise resonance in an external cavity GaAslaser for possible laser characterization

The dependence of the (low-frequency) resonance of light intensity noise in an external-cavity GaAs laser on cavity length and bias current, combined with the dependence of the threshold current on the magnitude of the light feedback, is used to determine simultaneously the carrier recombination lifetime, the carrier injection at transparency, and the optical loss. The key to this technique is understanding the correction term to the relaxation oscillation frequency due to finite carrier density at transparency and the influence of the long external cavity transit time on the photon lifetime in the three-mirror cavity. The technique uses commercial lasers without modifying them and does not require fast electronics     

射线法研究外腔半导体激光器的调谐范围

利用由射线法导出的广义两段式半导体激光器的输出光谱的表达式，讨论了外腔式半导体激光器（ＥＣＬＤ）的调谐范围，当ＥＣＬＤ调谐到半导体激光二极管的共振波长附近振荡时，可以重到ＥＣＬＤ的最大调谐范围；当激光器调谐到半导体激光二极管的反共振波长附近振荡时，可以获得ＥＣＬＤ的准连续调谐范围；同时，还求得了实现准连续调谐所需的面向外腔的半导体二极管端面的反射率。     

The effect of injecting contacts on avalanche diode performance

Metal-semiconductor contact injection on the junction side of diffused-mesa avalanche diodes has been found to have a significant effect on the performance of these diodes as oscillators. A minority carrier injection ratio of 6 percent reduces the efficiency of what would be 9 percent efficient diodes to less than 1 percent and increases the FM noise by a factor of 2 as tested in a 6-GHz oscillator circuit. The dependence of the minority carrier injection ratio of the metal-semiconductor barrier upon current density has been measured and quantitatively modeled. Calculated values of diode admittance, including the effects of injection at the contact, are shown to be in agreement with measured values of both small-signal diode admittance versus frequency and large-signal diode admittance versus RF voltage. Germanium avalanche diodes with low-minority carrier injection contacts have demonstrated CW oscillation efficiencies greater than 9 percent at 6 GHz. The realization of low-injection contacts is shown to be a requirement for achievement of high-efficiency avalanche oscillation.     

Improved strained HEMT characteristics using double-heterojunctionIn0.65Ga0.35As/In0.52Al0.48As design

The DC and microwave properties of strained In_0.65Ga _0.35As/In₀₅₂Al_0.48As HEMTs (high electron-mobility transistors) with double-heterojunction design are presented. The high sheet carrier density and good carrier confinement give rise to excellent device performance with very low output conductance. For 1×150-μm² long-gate HEMTs, the measured cutoff frequency f_T and maximum frequency of oscillation f_max are as high as 37 and 66 GHz, respectively     

A tractable above-threshold model, for the design of DFB andphase-shifted DFB lasers

A model, based on the transfer matrix method, and extended to above-threshold conditions in order to be used in the analysis and design of distributed feedback (DFB) structures, is presented. It provides the oscillation parameters as lasing frequency and net material gain, the linewidth estimation and output power, the photon density, carrier density, and effective refractive index profiles. This model can be used with or without facet reflectivities and with a number of symmetric or asymmetric phase shifts. It takes into account nonuniform envelope material gain and nonuniform index saturation. It is easily adaptable to any structure modifications     

Delta-doped AlGaN/AlN/GaN microwave HFETs grown by metalorganicchemical vapour deposition

The performance of an innovative delta-doped AlGaN/AlN/GaN heterojunction field-effect transistor (HFET) structure is reported. The epitaxial heterostructures were grown on semi-insulating SiC substrates by low-pressure metalorganic chemical vapour deposition. These structures exhibit a maximum carrier mobility of 1058 cm²/V s and a sheet carrier density of 2.35×10¹³ cm^-2 at room temperature, corresponding to a large n_s μ_n product of 2.49×10¹⁶ V s. HFET devices with 0.25 μm gate length were fabricated and exhibited a maximum current density as high as 1.5 A/mm (at V_G=+1 V) and a peak transconductance of g_m=240 mS/mm. High-frequency device measurements yielded a cutoff frequency of f_t≃50 GHz and maximum oscillation frequency f_max≃130 GHz     

Rabi oscillations for subpicosecond pulses in quantum-well optical amplifiers: interplay of carrier heating, nonlinear, and spectral effects

Using the Foreman effective mass Hamiltonian for strained In/sub x/Ga/sub 1-x/As--In/sub y/Ga/sub 1-y/As/sub z/P/sub 1-z/ quantum wells, the propagation of subpicosecond pulses in a 1.55-/spl mu/m optical amplifier was calculated. The multisubband carrier dynamics as well as the polarization dynamics were taken into account. Carrier heating and coherent light-carrier interactions as well as the interplay of these nonlinear processes and the amplifier dispersion are studied. Strong Rabi oscillations occur in the optical field of a propagated pulse, its frequency chirp, as well as in the carrier density and temperature. While the Rabi oscillation imposes negative frequency chirp and hence red-shifts the pulse spectrum, positive frequency chirp can occur due to the local gain dispersion, where the higher frequency components of the pulse have larger gain. Due to the Rabi oscillation, the spectrum of the amplified pulse is considerably distorted and sidebands emerge. For a linearly chirped input pulse, the spectrum of the output pulse can be either red-shifted or blue-shifted with respect to its center frequency, depending on its initial chirp. For strong pulse propagation, a pronounced pulse break up occurs when a 175-fs pulse propagates in the gain regime, while a significant pulse compression occurs when the pulse propagates at the transparency point.