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理论分析了隔离器在高功率多模激光入射时的自退偏特性.结果表明:线性双折射致退偏与圆双折射致退偏均与入射光功率的平方成正比,线性双折射致退偏与光斑大小无关,而圆双折射致退偏随光斑半径的增大而减小.当光斑半径与旋转晶体半径相比很小时(R0/r0≥80)圆双折射引起的退偏大于线性双折射引起的退偏,当光斑半径接近旋转晶体半径(R0/r0≤3)时,与线性双折射引起的退偏相比,圆双折射引起的退偏可以忽略.对比单模激光入射,在同种条件下,多模入射使得线性双折射致退偏减小了0.4倍, 最小圆双折射致退偏减小为0.05倍. 相似文献
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We propose a third-order intermodulation distortion (IMD3) compensation scheme based on the bidirec- tional modulation of 2-Ch phase modulator (PM). We realize the destructive combination of IMD3 by using different modulation efficiencies and appropriately adjusting the input optical power ratio to satisfy a fixed relationship with modulation efficiency. The primary advantage of this scheme is that out-of-phase IMD3 is introduced using only one 2-Ch PM, thereby resulting in the cancellation of IMD3. Up to 27-dB suppression in IMD3 is experimentally demonstrated--a feature that will be useful in low-distortion analog or)tical transrni~sirm. 相似文献
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Novel enabling technologies from physical layer to Medium Access Control (MAC) layer are proposed to provide energy efficient Radio-over-Fiber (RoF) Distributed Antenna System (DAS) based Wireless Sensor Networks (WSN). The power consumption performance of the network is evaluated in terms of the total network power consumption based on the proposed power consumption models from the physical layer. The results illustrate that for a given power consumption value, the tradeoff among the number of Remote Acces... 相似文献
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We present the design and optimization of evanescently coupled waveguide photodiodes (EC-WPDs) based on the coupling modes theory and the beam propagation method. Efficient focalization of the optical power in the absorber is achieved by an appropriate choice of index matching layers of EC-WPDs. Numerical simulation shows that high-speed (40 GHz), high quantum efficiency (81%) and high linearity photodiodes can be achieved, and EC-WPDs are promising devices for future optical communication systems. 相似文献
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This paper investigates the Medium Access Control (MAC) protocol performance in the IEEE 802.11g-over-fiber network for different payloads and fiber lengths using Direct Sequence Spread Spectrum-Orthogonal Frequency Division Multiplexing (DSSS- OFDM) and Extended Rate Physicals- Orthogonal Frequency Division Multiplexing (ERP-OFDM) physical layers using basic ac-cess mode, Request to Send/Clear to Send (RTS/CTS) and CTS-to-self mechanisms. The results show that IEEE 802.11g-over-fiber network employing the ERP-OFDM physical layer is much more efficient than that em-ploying the DSSS-OFDM physical layer, with regards to both throughput and delay. For a given maximum throughput/minimum delay, the tradeoff among the access mechanism, the fiber length, and the payload size must be considered. Our quantified results give a se-lection basis for the operators to quickly select suitable IEEE 802.11g physical layers and the different access mechanisms, and accurately predict the data throughput and delay given the specific parameters. 相似文献
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U型槽的干法刻蚀工艺是GaN垂直沟槽型金属-氧化物-半导体场效应晶体管(MOSFET)器件关键的工艺步骤,干法刻蚀后GaN的侧壁状况直接影响GaN MOS结构中的界面态特性和器件的沟道电子输运.本文通过改变感应耦合等离子体干法刻蚀工艺中的射频功率和刻蚀掩模,研究了GaN垂直沟槽型MOSFET电学特性的工艺依赖性.研究结果表明,适当降低射频功率,在保证侧壁陡直的前提下可以改善沟道电子迁移率,从35.7 cm^2/(V·s)提高到48.1 cm^2/(V·s),并提高器件的工作电流.沟道处的界面态密度可以通过亚阈值摆幅提取,射频功率在50 W时界面态密度降低到1.90×10^12 cm^-2·eV^-1,比135 W条件下降低了一半.采用SiO2硬刻蚀掩模代替光刻胶掩模可以提高沟槽底部的刻蚀均匀性.较薄的SiO2掩模具有更小的侧壁面积,高能离子的反射作用更弱,过刻蚀现象明显改善,制备出的GaN垂直沟槽型MOSFET沟道场效应迁移率更高,界面态密度更低. 相似文献
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利用软件Maxwell对中国聚变工程实验堆(CFETR)高场侧的水冷陶瓷增殖(WCCB)包层进行电磁分析,得到了包层在等离子体电流线性36ms衰减工况下产生的电磁载荷.采用载荷传递耦合法,结合软件ANSYS可得包层中产生的形变位移和等效应力.分析结果表明,WCCB包层中产生的最大等效应力符合设计要求,且形变位移均在许用... 相似文献
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