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The effects of the onset of lasing on the I-V characteristics, the impedance characteristics and the light modulation characteristics of laser diodes have been discussed by introducing the rate equations which involve carrier diffusion process in the active layer interacting with the radiation field intensity. The static I-V characteristics exhibit a kink at lasing threshold current, reflecting the decrease of effective lifetime of carriers. Effective carrier lifetimes decrease with increasing light intensity, which results in a steep attenuation of injected carrier density in the active region. The impedance and light modulation characteristics are obtained in the small signal approximation. The small signal light modulation characteristics depend strongly on whether the laser diode is excited by the constant current modulation or the constant voltage modulation. The impedance is changed drastically by the onset of lasing and exhibits a resonance which coincides exactly with the optical modulation resonance frequency. 相似文献
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Mawatari H. Fukuda M. Kano F. Tohmori Y. Yoshikuni Y. Toba H. 《Lightwave Technology, Journal of》1999,17(5):918-923
Changes in the wavelength and lamp characteristics due to the degradation of distributed Bragg reflector (DBR) lasers are investigated and the lasers are confirmed to be reliable enough for application as the light sources in WDM systems. The change in wavelength characteristics is due to degradation of the DBR or phase control region and the change in lamp characteristics is due to the degradation of active region. These changes in the characteristics are caused by diminished recombination carrier lifetime. The wavelength stability is strongly correlated with the injected current density. The lamp characteristics is confirmed to be almost as stable as in conventional Fabry-Perot lasers. The applicability of DBR lasers as the light source for wavelength division multiplexing (WDM) systems is demonstrated for actual-use conditions 相似文献
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低压电力线信道噪声特性分析 总被引:1,自引:0,他引:1
主要研究了低压电力线信道噪声特性,首先,介绍了电力线通信(PLC),然后,针对不同种类的噪声进行了建模,测量并分析了电力线信道的噪声特性。通过实验和仿真,得出了低压电力线信道噪声波形及其特点。 相似文献
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ZnO材料的电子输运特性 总被引:4,自引:0,他引:4
用全带Monte Carlo方法模拟了纤锌矿Zn O材料电子的稳态和瞬态输运特性.稳态输运特性包括稳态平均漂移速度-电场特性、电子平均能量-电场特性和在不同电场下电子按能量的分布.在平均漂移速度-电场特性中发现了微分负阻效应.Zn O的瞬态输运特性包括平均漂移速度-位移关系曲线、渡越时间-位移关系曲线等.在平均漂移速度-位移关系曲线中发现了过冲现象,这种现象是电子从低能谷到高能谷跃迁过程中的弛豫时间产生的. 相似文献
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Performance Optimization of Microstrip Antenna with Different Slot Configurations and Various Dielectric Materials
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The probe-fed patch antennas were proposed by changing the parameters such as dielectric materials and dimensions of patch for detail investigation of changes in output characteristics. Four rectangular slots were introduced separately for optimizing the antenna design and characteristics. This study illustrated the changes of output characteristics of an antenna with respect to the number of introduced slots on the radiating patch in addition to the effect of various dielectric materials on antenna performances. The antenna performances were analyzed by plotting the observation of various dielectric materials. The changes of antenna characteristics were also observed by introducing four numbers of slots on each edge of the patch to improve radiation characteristics with a wider impedance bandwidth. 相似文献
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说明了集中武与分布式音频矩阵系统的特征,详细介绍了QSControl.Net系统的组成、特点以及在会议中心项目中的应用.最后总结了利用QSControl.Net系统配置的会议中心的多会议室扩声系统的特点。 相似文献
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复杂环境下的红外目标特性测量方法研究 总被引:1,自引:0,他引:1
在复杂环境下进行目标特性测量是一项极其复杂的工作。研究了红外波段复杂环境的构成因素及特点,系统分析了复杂环境对红外目标特性测量的影响,并提出了测量条件及要求。最后对复杂环境下目标红外特性的测量与研究方法进行了详细讨论。该研究结果对目标辐射特性的测量与研究具有一定的参考意义。 相似文献
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提出一种应变Si/SiGe UMOSFET结构,并与Si-UMOSFET器件的电流-电压特性进行比较;对SiGe区域在UMOSFET器件中的不同厚度值进行静态电学仿真。应变Si/SiGe异质结能够有效地提高沟道区载流子的迁移率,增大IDS,降低Vth及器件的Ron;且应变异质结与载流子有效传输沟道距离的大小,对器件的Vth、Isat、V(BR)DSS及电流-电压特性都有较大的影响。因此在满足击穿电压要求的基础上,应变Si/SiGe沟道异质结的UMOSFET相对Si-UMOSFET在I-V特性和Ron方面有较大的改进。 相似文献
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The characteristics of a conductivity-modulated transistor which can control AC current are presented. Measured characteristics of a fabricated device are shown and compared with calculated characteristics. Calculations are based on a physical, one-dimensional analytical model which has been, in part, derived from numerical analysis of the device. The proposed model gives relatively good qualitative agreement between calculated and measured characteristics. Potential applications of the device are discussed 相似文献
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纯切趾线性啁啾长周期光纤光栅的研究 总被引:1,自引:0,他引:1
为进一步拓宽长周期光纤光栅在光通信领域中的应用,在长周期光纤光栅中引入纯切趾包络和线性啁啾,构成光谱特性更为丰富的纯切趾线性啁啾长周期光纤光栅。采用耦合模理论,对纯切趾线性啁啾长周期光纤光栅中的模式耦合特性进行了研究,给出了纯切趾线性啁啾长周期光纤光栅的耦合系数和耦合模方程。在此基础上,详细研究了啁啾和切趾对长周期光纤光栅光谱特性的影响,讨论了纯切趾长周期光纤光栅用作色散补偿器的结构特性和色散补偿机制。最后,设计出一种采用两个相同光栅对称级联的基于纯切趾线性啁啾长周期光纤光栅的色散补偿器,该器件的3dB带宽为0.16nm,3dB带宽内的色散值约为-1954psnm,时延曲线偏离线性的波动幅度小于±2.5ps。 相似文献
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Camellia是NESSIE计划2003年公布的分组密码标准算法之一.本文对Camellia的差分迭代特征和线性迭代特征进行分析,发现了P置换及其逆置换对3轮和4轮迭代特征的影响,找到了到目前为止最优的3轮和4轮差分和线性迭代特征,并利用4轮最优差分和线性迭代特征,给出了r(6≤r≤18)轮Camellia变体的差分特征概率和线性偏差概率,其中18轮的差分特征概率为2-296,线性偏差概率为2-141.32,这些结果优于Eli Biham等人2001所得的结果. 相似文献