All-optical pulse width and wavelength conversion at 10 Gb/s usinga nonlinear optical loop mirror

An all-optical pulse width and wavelength converter is demonstrated using a nonlinear optical loop mirror. The conversion of a 10 Gb/s, 8 ps pulse width data stream at 1551 nm to a 23 ps pulse width data stream at 1543 nm is demonstrated. The control pulse energy required for switching is 10 pJ. Bit-error-rate measurements are presented     

Generation of 10 GHz similariton pulse trains from 1.2 km-long erbium-doped fibre amplifier for application to multi-wavelength pulse sources

A 10 GHz similariton pulse train is generated from a 1.2 km-long erbium-doped fibre amplifier and applied to a multi-wavelength pulse source. Slicing the spectrum of the similariton pulse train, a 10 Gbit/s transmitter was constructed, which has excellent Q-factors of over 25.3 dB in the entire bandwidth. Such uniform characteristics of the sliced pulse train originate from the high spectral flatness of the similariton.     

Propagation Characteristics of Infrared Pulse Waves through Windblown Sand and Dust Atmosphere

The physics characteristics of the windblown sand and dust atmosphere at the sand bench of Yellow River in China are discussed. The pulse distortion and time delay of infrared nanosecond pulse propagating through the atmosphere having sand and dust particles are investigated at 1.06 and 3.8 μm, respectively. It is shown that the delay of 10 ns laser pulse propagating through 5 km windblown sand and dust atmosphere are over 1 ns and 10 ns at 1.06 and 3.8 μm, respectively. The pulse spread increases slightly with wavelength increase. The pulse spread of a 10 ns laser pulse is over 40 ns at 3.8 μm. The pulse delay and spread increase rapidly with the sand particle density increasing in atmosphere. The narrower the pulse width is, the more the pulse distortion is. Hence, at infrared band, for a laser pulse propagating in sand and dust atmosphere, the pulse delay and spread are quite severe and need be taken into account for a narrower pulse laser system.     

Efficient high-power diode-end-pumped TEM00 Nd:YVO4 laser

We demonstrate a compact and efficient diode-end-pumped TEM₀₀ laser with output power of 25.2 W for 52 W of incident pump power by use of a single YVO₄ crystal with a Nd concentration of 0.3 at.%. In Q-switched operation 21-W of average power at a pulse repetition rate of 100 kHz and ~1.1-mT pulse energy at a pulse repetition rate of 10 kHz were produced. At 10 kHz, the pulse width is around 10 ns and the peak power is higher than 100 kW     

电光调Q射频激励波导CO2激光器

报道了电光调Q射频波导CO2激光器,其中波导长度400mm,在插入电光调Q晶体但不加调制电压情况下,激光器的连续输出功率为3.5W。调Q脉冲重复频率1Hz～10kHz可调,在10kHz重复频率时,获得了脉冲峰值功率为200W,脉冲宽度为400ns的输出。     

一种电磁脉冲辐射系统设计

提出一种电磁脉冲辐射系统设计方案,此系统由Marx发生器、短路-锐化组合开关型脉冲形成线和带低频补偿的高功率超宽带横向电磁波(TEM)喇叭天线组成.Marx发生器产生的单极脉冲经过短路-锐化组合开关型脉冲形成线锐化成双极脉冲,然后馈入天线进行辐射.仿真结果表明,在充电电压为10 kV时,电磁脉冲源可产生脉冲宽度1.41...     

Unipolar pulse transmission by a coaxial cable loaded with a tunnel-diode-pair unilateral regenerator

An application of a tunnel-diode-pair unilateral pulse regenerator to unipolar pulse transmission is described. An experiment performed at around 10-MHz repetition rate showed that an arbitrary unipolar pulse pattern was regenerated and transmitted unilaterally over a coaxial cable with an error rate of 10^-11per section.     

10ns～500ns宽度连续可调的快速光脉冲发生器

脉宽可调的脉冲发生器常用于精密检测。本文阐述了一种运用叠加原理设计的脉冲宽度从10ns到500ns连续可调的快速光脉冲发生器。在驱动电路中应用了脉冲叠加原理。     

Malfunctioning of Microcontroller Irradiated with Ultrashort Ultrabroadband Pulse Trains

Effect of the number of ultrashort ultrabroadband pulses with a repetition rate of 1 kHz on malfunctioning of microcontroller in radio transparent housing is studied when the device is irradiated using pulse trains at a pulse duration of about 10^–10 s and radiation frequencies ranging from 1 to 30 GHz. The radiation is received by internal conducting stripes that connect the electronic circuit and external outputs. The malfunction probability is determined by the number of pulses in the pulse train, pulse number, and electric field strength. It is shown that malfunctioning is predominantly caused by the leading pulses in the pulse train.     

脉冲数目和重复频率对纳秒激光推进的影响

以抛物形点聚焦激光推进器模型为研究对象,数值模拟了脉冲重复频率在2~50Hz范围内吸气式多脉冲纳秒激光推进的流场演变过程,分析了脉冲数目和重复频率对推进性能的影响。结果表明:随着脉冲数目的增加,喷管内气体密度减小、温度升高,导致平均冲量耦合系数下降,但纳秒脉冲激光作用获得的平均冲量耦合系数明显高于微秒脉冲激光;相同脉冲数目条件下,随着脉冲重复频率的增大,流场恢复时间缩短,使得流场状态不能及时恢复,导致平均冲量耦合系数下降,其中脉冲重复频率f10 Hz时的下降趋势明显大于f10 Hz。     

An Adjustable Constant Current Stimulator for Electrophysiologic Experiments

An adjustable constant current stimulator has been designed and built which allows automation of many electrophysiologic experiments. It provides current continuously adjustable from 0 to 50 ?A, pulse intervals from 10 ms to 10 min, and pulse duration from 40 ?s to 10 s.     

LD抽运的Nd~(3+):YAG-Cr~(4+):YAG组合单晶自调Q激光器的研究

用激光二极管 (LD)连续抽运单体复合型Cr4+∶YAG Nd3 +∶YAG单晶微棒 ,获得重复频率为 10kHz ,脉冲宽度为 10ns的调Q激光输出。输出平均功率为 18mW ,实验结果与理论计算的脉冲宽度和重复频率与抽运功率之间的关系基本相符     

High Peak Pulse Power Silicon Double-Drift IMPATT Diodes

The performance of high peak pulse power silicon double-drift IMPATT devices operated at medium pulse repetition frequency are discussed. Several devices were characterized and achieved more than 45-W peak pulse power with 10-percent duty cycle at 9.7 GHz. Conversion efficiencies in the order of 9.7-11.2 percent were observed. These results compare with previously reported 19-W peak power, 10-percent duty-cycle, and 9.5-percent efficiency.     

CdTe电光调频晶体用于电光调Q研究

本文研究了CdTe电光调Q晶体及电光调频晶体的调制特性,报道了采用 CdTe电光调频晶体进行电光调 Q的光栅选支射频激励波导 CO2激光器,调 Q激光脉冲重复频率 1Hz～10 kHz可调,在 10 kHz重复频率时,获得激光脉冲峰值功率为 300 W,脉冲宽度为 150 ns.     

Optoelectronic 10 Gbit/s code generation by a picosecond photoconductive device

A high-speed silicon-on-sapphire photoconductive switch activated by an optical picosecond pulse code is used as a 10 Gbit/s electrical pulse code generator. The optical pulse code is generated by a picosecond pulse train which passes a multiple beam path optical delay line and can be manipulated by spatial filtering.     

Distributed Waveform Generator: A New Circuit Technique for Ultra-Wideband Pulse Generation, Shaping and Modulation

A new circuit technique, the distributed waveform generator (DWG), is proposed for low-power ultra-wideband pulse generation, shaping and modulation. It time-interleaves multiple impulse generators, and uses distributed circuit techniques to combine generated wideband impulses. Built-in pulse shaping can be realized by programming the delay and amplitude of each impulse similar to an FIR filter. Pulse modulation schemes such as on-off keying (OOK) and pulse position modulation (PPM) can be easily applied in this architecture. Two DWG circuit prototypes were implemented in a standard 0.18 $muhbox{m}$ digital CMOS technology to demonstrate its advantages. A 10-tap, 10 GSample/s, single-polarity DWG prototype achieves a pulse rate of 1 GHz while consuming 50 mW, and demonstrates OOK modulation using 16 Mb/s PRBS data. A 10-tap, 10 GSample/s, dual-polarity DWG prototype was developed to generate UWB pulses compliant with the transmit power emission mask. Based on the latter DWG design, a reconfigurable impulse radio UWB (IR-UWB) transmitter prototype was implemented. The transmitter's pulse rate can be varied from 16 MHz range up to 2.5 GHz. The bandwidth of generated UWB pulses is also variable, and was measured up to 6 GHz (${- 10} {rm dB}$ bandwidth). Both OOK and PPM modulation schemes are successfully demonstrated using 32 Mb/s PRBS data. The IR-UWB transmitter achieves a measured energy efficiency of 45 pJ/pulse, independent of pulse rate.      

高重频可调小型高功率半导体激光电源研究

为了获得高功率、高重频半导体激光脉冲,设计了一种体积小、重量轻、造价低的纳米级大功率半导体激光器驱动电源。采用改进的单稳态触发器产生窄脉冲,经放大后驱动快速开关MOSFET获得大电流窄脉冲;电源脉冲电流驱动能力0A～80A,脉冲上升时间2.8ns,下降时间3.8ns,脉冲宽度5ns～500ns范围内可调,最小5.2ns,重复频率可达200kHz。用该电源实验测试了激光波长为905nm的半导体激光器,在重复频率为10kHz时,激光脉冲峰值功率达到70W以上。结果表明,采用窄脉冲驱动MOSFET可以得到高重复频率10ns以内的大电流窄脉冲,可以驱动大功率半导体激光器,若驱动100A以上的激光器需进一步研究。     

Complete dispersion compensation for 400-fs pulse transmission over10-km fiber link using dispersion compensating fiber and spectral phaseequalizer

We have demonstrated essentially complete dispersion compensation for 400-fs pulses over a 10-km fiber link using dispersion compensating fiber and a programmable femtosecond pulse shaper functioning as a spectral phase equalizer. The pulse shaper impresses adjustable quadratic and cubic phases onto the spectrum and removes all the residual dispersion and dispersion slope in the dispersion compensated fiber link. Our work shows that the pulse shaper technique provides a powerful and convenient tool for programmable fiber dispersion compensation over broad optical bandwidth. This allows distortion-free femtosecond pulse transmission over a fiber link in excess of 10 km without requiring the exact trimming of the dispersion-compensating fiber     

10J／0.4ms重复脉冲Nd：YAG激光器

报道了一种频率为１、５、１０和２０ＨＺ,单脉冲能量超过１０Ｊ,脉冲宽度小于０．４ｍｓ,能量外流地４％的重复脉冲Ｎｄ：ＹＡＧ激光器。     

一种有载频超宽带脉冲源设计

针对无载频脉冲低频分量大、辐射效率低、频带可调性差等问题,设计了一种以阶跃恢复二极管、D触发器及超宽带调制器为主的宽频带、高重复频率、低振铃水平的有载频超宽带脉冲源。该脉冲源电路由驱动电路、高速开关电路、整形电路、超宽带调制器及振荡器电路组成。实测结果表明,脉冲源输出脉冲信号重复频率可达125 MHz,脉冲宽度600 ps（底宽）,脉冲振铃水平低于10%,峰-峰值为5.4 V,-10 dB带宽可达4.2 GHz。脉冲信号中心频率与载频相同,可在6.6~8.5 GHz之间灵活设置。利用所设计的脉冲源进行时域测量,其结果与矢量网络分析仪频域测量结果相比幅频特性均方根误差小于0.21 dB。该脉冲源可应用于超宽带时域测量、短距离高速无线通信、高精度室内定位等应用。