THE OUTPUT OPTICAL FIELD INTENSITY DISTRIBUTION FORMED BY AN OPTICAL FIBER END

ＴＨＥＯＵＴＰＵＴＯＰＴＩＣＡＬＦＩＥＬＤＩＮＴＥＮＳＩＴＹＤＩＳＴＲＩＢＵＴＩＯＮＦＯＲＭＥＤＢＹＡＮＯＰＴＩＣＡＬＦＩＢＥＲＥＮＤ￥ＹＵＡＮＬｉ－Ｂｏ（Ｄｅｐａｒｔｍｅｎｔｏｆｐｈｙｓｉｃｓ，ＨａｒｂｉｎＥｎｇｉｎｅｅｒｉｎｇＵｎｉｖｅｒｓｉｔｙ...     

密集型波分复用系统概要(4)

４．１０．４．２光信噪比（ＯＳＮＲ）及其对应ＢＥＲ计算用于计算ＯＳＮＲ的光路示于图４８。在计算中考虑到了各级ＥＤＦＡ的不同。注意：为了Ｑ值有一定裕量,ＥＤＦＡ线放Ⅰ和Ⅱ的ＮＦ均假定为５ｄＢ,而ＥＤＦＡ预放的ＮＦ假定为４．５ｄＢ。Ａ点（ＥＤＦＡ功放输入...     

OPTICAL FIBER-MOBILE COMMUNICATION

ＯＰＴＩＣＡＬＦＩＢＥＲ－ＭＯＢＩＬＥＣＯＭＭＵＮＩＣＡＴＩＯＮ￥ＦＥＮＧＸｉ－Ｙｕ；ＳＵＮＴｉｅ－Ｃｈｅｎｇ（ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙＤａｌｉａｎ１１６０２３）Ａｂｓｔｒａｃｔ：Ｔｈｅｔｅｃｈｎｉｑｕｅｏｆｍｏｂｉｌ...     

ROHM公司CD／CDROM用集成电路一览表

ＲＯＨＭ公司ＣＤ／ＣＤＲＯＭ用集成电路一览表ＣＤ信号处理品名电源电压（Ｖ）功能特点封装ＢＡ６３７６Ｋ３．１～３．８ＲＦ·ＴＥ·ＦＥ生成、探伤、ＡＰＣ适应电压输出拾波、可在低电压下工作、内设自动聚焦ＱＦＰ３２ＢＡ６３７７Ｋ３．１～５．５ＲＦ·ＴＥ·Ｆ...     

初识接单生产（BTO）

一、ＢＴＯ概念介绍在生产模式中有所谓预测生产（ＢＵＩＬＤＴＯＦＯＲＥＣＡＳＴ）及接单生产（ＢＵＩＬＤＴＯＯＲＤＥＲ，简称ＢＴＯ），电脑大厂商最近为提高竞争力而采用的方式即为ＢＴＯ。一般工厂在预测生产的运作下，必须提前预测未来一段期间市场的需求量，并考...     

柏林异步传送模式局域网互连—ATM环境及多媒体业务

本文介绍了ＤｅＴｅＢｅｒＫｏｍ，ＧＭＤ－ＦＯＫＵＳ公司和柏林理工大学在柏林建立的地区性异步传送模式（ＡＴＭ）试验床ＢＡＬＩ。它用于由ＢＥＲＫＯＭ和ＤＦＮ投资的一个大型项目，以试验ＡＴＭ技术和取得利用ＡＴＭ的多媒体远程服务和应用的运用经验。提出了ＢＥＲＫＯＭ远程业务多媒体信箱和多媒体合作。     

五品牌手机生产日期轻松辨

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关于光纤用户传输网的研究（续）

关于光纤用户传输网的研究（续）解金山，赵玉兰，桂厚义，杨邦湘（武汉邮电科学研究院４３Ｏ０７４）ＳＴＵＤＹＯＮＦＩＢＥＲＯＰＴＩＣＳＵＢＳＣＲＩＢＥＲＮＥＴＷＯＲＫ（Ｃｏｎｔｉｎｕｅｄ）￥ＸＩＥＪｉｎ－Ｓｈａｎ；ＺＨＡＯＹｕ－Ｌａｎ；ＧＵＩＨｏｕｙｉ；...     

FoxBASE^＋多用户环境下的碰撞处理

ＦｏｘＢＡＳＥ~＋多用户环境下的碰撞处理李树新，杨天佑（陕西电视台７１００６８）ＦＯＸＢＡＳＥ“是一个功能很强的数据库管理系统，它能够运行在ＤＯＳ、ＵＮＩＸ／ＸＥＮＩＸ等不同的操作系统下，并且有较强的上网能力。但是在ＵＮＩＸ／ＸＥＮＩＸ及ＤＯＳ网络环?..     

有线电视系统设计中EDFA的影响

有线电视系统设计中ＥＤＦＡ的影响□刘铮（深圳飞通光电子技术有限公司器件部５１８０４９）摘要：本文详细描述了带有ＥＤＦＡ的ＣＡＴＶ系统的ＣＮＲ的计算模型，讨论了ＥＤＦＡ对系统ＣＳＯ与ＣＴＢ的影响以及如何克服ＳＢＳ带来的问题。１前言我国有线电视事业正处于...     

Er3+-Yb3+ and Er3+ doped fiberlasers

Single-mode fiber lasers operating at ~1.57 μm are described. Output powers of >2 mW are reported for laser diode pumped operation. Direct comparison is made between fiber lasers using sensitized erbium (Er³⁺ and Yb³⁺) and erbium on its own. The performance of Er³⁺-Yb³⁺ fiber lasers is analyzed in more detail as a function of fiber length. Both CW and Q-switched operations are studied and the results obtained demonstrate that practical sources at 1.5 μm are available from diode pumped Er³⁺ -Yb³⁺ systems     

An In0.52Al0.48As/n+-In0.53Ga0.47As MISFET with a modulation-doped channel

A heterostructure metal-insulator-semiconductor field-effect transistor (MISFET) with a modulation-doped channel is proposed. In this device, a very thin undoped subchannel is located between the undoped wide-bandgap insulator and a thin heavily doped channel. In the depletion mode of operation, electron transport takes place along the heavily doped channel. When the device enters the accumulation mode of operation, electrons pile up against the heterointerface in the high-mobility undoped subchannel. This results in markedly improved transport characteristics at the onset of accumulation. The concept is demonstrated in the In_0.52Al_0.48As/In_0.53 Ga_0.47As system on InP. A 1.5-μm-gate-length MISFET shows a unity current-gain cutoff frequency of 37 GHz     

Optimum design of Er3+-Yb3+ codoped fibersfor large-signal high-pump-power applications

A comprehensive numerical fiber amplifier model has been used to optimize Er³⁺-Yb³⁺ codoped active fiber for maximum gain and quantum conversion efficiency (QCE) at large signal operation. The optimum cutoff wavelength of the LP₁₁ mode has been found to increase from 800 mm at low pump powers (≈50 mW) to 1400 mn at pump powers higher than 500 mW. While at low pump powers fibers with higher numerical aperture give higher QCE, at high pump levels better large signal performance is achieved with fibers having lower numerical aperture     

Effect of i-layer parameters on the performance of Sin+-i-n+ homojunction far-infrared detectors

A unified formalism, including space-charge-limited (SCL) conduction, tunneling, and the multiple-image-force effect, is developed to perform a complete analysis of Si n⁺-i-n⁺ homojunction interfacial workfunction internal photoemission (HIWIP) FIR detectors. It is shown that due to the space-charge effect, the detector performance, such as cutoff wavelength (λ_c), quantum efficiency (η), dark current (I_d), noise equivalent power (NEP), etc., is strongly influenced by the i-layer thickness (W_i ) and compensating acceptor concentration (N_ai) in addition to the emitter layer parameters. As a result, the optimum operating conditions of detectors also depend on W and N_ai. The background limited performance (BLIP) is evaluated, and a critical W _i value is found for BLIP operation     

Tunable solid-state laser action in Ce3+:LiSrAlF6

Continuously tunable UV laser operation of cerium-doped LiSrAlF ₆ (Ce³⁺:LiSAF) between 285 and 297 nm is demonstrated. At the peak operating wavelength of 290 nm, output energies of 1.3 mJ with slope efficiencies of 17% have been obtained     

The N2+waveguide laser experiment and theory

The operation of an N+2ion waveguide laser (4278 Å) excited by charge transfer from He+2created in a capacitively coupled self-sustained discharge is described. In addition, the results of an experimental diagnostic program and a computer modeling program, conducted to explain the general operations of the discharge pumped He-N2system, are presented. The results of this program indicate upper laser level electron quenching and lower level pumping may be seriously limiting the achievable laser efficiency of this system. During the course of this study, it was found necessary to measure the pressure broadening coefficient of the N+2(B) rightarrowN+2(X) emission" by He. The value of this coefficient was found to be 3.5 MHz/torr ± 0.7 MHz.     

Raman Scattering and Nd3+ Laser Operation in NaLa(WO 4)2

The continuous-wave laser operation of Nd-doped tetragonal NaLa(WO ₄)₂ crystal is studied at room temperature by optical pumping in the spectral region overlapping AlGaAs diode laser emission. This crystal has inhomogeneously broadened optical bands. From the room-temperature spectroscopic parameters determined it is found that the optimum Nd concentration for the ⁴F_3/2rarr⁴I_J laser channels must be in the 3-5 at.% range. For J=11/2 and 13/2 channels (lambdaap1.06 and 1.3 mum) the most favourable polarization configuration is parallel to the crystallographic c axis, while for J=9/2 little polarization dependence of the laser efficiency is predicted. Laser operation was achieved with a 3.35 at.% Nd-doped sample grown by the Czochralski method. The laser operation was tested in an hemispherical optical cavity pumped by a Ti:sapphire laser. Stimulated emission at lambda=1056 nm was achieved for a wide spectral pumping range, lambda=790-820 nm. Stimulated Raman scattering was achieved in the picosecond regime with an efficiency similar to that of monoclinic KY(WO₄)₂ reference compound     

Er3+:YAlO3 upconversion laser

Upconversion lasing in Er:YAlO₃ is reported. Laser emission was produced using both sequential two-step pumping and cross-relaxation energy transfer. In addition, photon avalanche upconversion pumping was demonstrated. Selection among these pumping mechanisms is determined by the pump wavelength, and laser operation was obtained with excitation between 785 nm and 840 nm. The highest laser output power was achieved at 34°K, where 918 mW of pump power at 807 nm produced 121 mW of TEM₀₀ emission. The optical conversion efficiency was 13%. Repetitively Q-switched operation is reported, and the temporal- and temperature-dependence of the laser output is discussed     

An In0.52Al0.48As/n+-In0.53Ga0.47As MISFET with a heavily doped channel

An In0.52Al0.48As/n⁺-In0.53Ga0.47As MIS-type field-effect transistor (FET) with a channel doped at a 7 × 10¹⁷cm^-3level has been fabricated on an InP substrate. A device with a 2-µm channel length has yielded a maximum transconductance of 152 mS/mm,f_{T} = 12.4GHz, andf_{max} = 50GHz. At 10 GHz, the maximum available gain is 17.4 dB. The performance of this device shows that heavily doped channel FET's are very promising for high-frequency operation.     

Analytical models for n+-p+ double-gate SOIMOSFET's

Previously, we proposed n⁺-p⁺ double-gate SOI MOSFET's, which have n⁺ polysilicon for the back gate and p⁺ polysilicon for the front gate to enable adjustment of the threshold voltage, and demonstrated high speed operation. In this paper, we establish analytical models for this device, This transistor has two threshold voltages related to n⁺ and p⁺ polysilicon gates: V_th1 and V_th2, respectively. V _th1 is a function of the gate oxide thickness t_Ox and SOI thickness t_Si and is about 0.25 V when t_Ox/t_Si=5, while V_th2 is insensitive to t_Ox and t_Si and is about 1 V. We also derive models for conduction charge and drain current and verified their validity by numerical analysis. Furthermore, we establish a scaling theory unique to the device, and show how to design the device parameters with decreasing gate length. We show numerically that we can design sub 0.1 μm gate length devices with an an appropriate threshold voltage and an ideal subthreshold swing