共查询到18条相似文献,搜索用时 453 毫秒
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利用螺旋波导对频率调制脉冲进行压缩可大幅度提高脉冲峰值功率。利用所编Matlab程序对螺旋波导的色散特性进行了计算和分析,获得了波纹幅度和纵向周期长度等结构参数对其色散特性的影响规律;给出了脉冲功率压缩比的计算公式,对不同脉宽和频带宽度、不同频率调制形式的微波脉冲通过螺旋波导后的功率压缩比进行了计算和分析。计算表明:脉冲的频率调制形式对功率压缩比影响较大;相同频率调制形式下,脉冲长度越长,工作频带越宽,功率压缩比越高。为了获得尽可能高的功率压缩比,需对脉冲的频率变化方式进行调节,使其与螺旋波导色散特性匹配。同时还需要在高的功率压缩比和高的压缩效率之间做出权衡。计算得到,当注入脉冲的脉宽为40ns、工作频带为8.8~9.5GHz、频率调制形式与螺旋波导色散特性匹配时,功率压缩比达到了15,压缩效率约为40%。 相似文献
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根据超短光脉冲在光纤中传输的非线性薛定谔方程,模拟了不同色散参量情况下色散补偿和色散位移光纤对增益开关半导体激光器产生的光脉冲的压缩,给出了光脉冲在经过色散补偿光纤前后的啁啾曲线。结果表明,使用色散参量D分别为-150,-180和-20ps/(nm·km)的色散补偿光纤可以实现其他脉冲压缩方法的压缩效果,最大压缩因子达到6.09,但色散参量越大,所需光纤长度就越短。此外,脉冲经过色散补偿光纤后线性啁啾几乎为零。还利用色散位移光纤对脉冲进行孤子压缩,脉冲宽度由最初的45ps减小到1.23ps。指出采用这2种光纤相结合的方法可以对光脉冲实现高效压缩。 相似文献
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运用场匹配法和傅里叶级数理论,提出一种原则上可数值求解任意轴对称渐变型类周期慢波结构色散特性的方法。采用该方法编制了计算渐变型波纹波导和渐变型盘荷波导色散曲线的Matlab程序,详细分析并讨论了这两类典型渐变型类周期慢波结构的色散特性。数值计算结果与多维全电磁模拟软件模拟结果的数据吻合度较高,验证了该数值算法的可靠性。另外,该方法具有较强的普适性和扩展性,也可退化到任意轴对称周期慢波结构色散特性的求解,为慢波结构的设计提供一种简单有效的途径。 相似文献
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A method of considerably elevating (by 20–30 times) the peak power of frequency-modulated microwave pulses by passive compression
in a waveguide with a helically corrugated surface used as a dispersive medium is considered. It is shown that the use of
a sectioned compression waveguide (i.e., a waveguide consisting of several sections connected to each other with slightly
differing parameters) considerably improves precise tuning of the dispersion characteristic of the system to a desired law
of frequency modulation of an input pulse. An algorithm for selecting optimal parameters of the sections is developed, and
a high efficiency of the method is demonstrated by several examples. 相似文献
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V. L. Bratman G. G. Denisov N. G. Kolganov S. V. Mishakin S. V. Samsonov D. I. Sobolev 《Technical Physics》2011,56(2):269-273
The effect of passive compression of frequency-modulated pulses in dispersive media is used to raise the microwave radiation
peak power to a multigigawatt level. A waveguide with a helically corrugated surface is applied as a dispersive medium, and
a relativistic 3-cm backward-wave oscillator with an accelerating voltage decaying within the pulse duration serves as a source
of frequency-modulated pulses. The compression of pulses to an FWHM of 2.2 ns attended by a rise in the peak power by a factor
of 4.5 (to 3.2 GW) is demonstrated with a SINUS-6 accelerator. 相似文献
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V. L. Bratman G. G. Denisov S. V. Samsonov A. W. Cross K. Ronald A. D. R. Phelps 《Radiophysics and Quantum Electronics》2007,50(1):36-48
We show theoretically that the use of a circular oversized waveguide with a helically corrugated internal surface as a dispersive
medium ensures efficient compression of frequency-modulated microwave pulses up to peak powers of about 10 GW. According to
the calculations, a pulse with the required frequency modulation can be obtained in a relativistic backward-wave oscillator
operated in the 3-cm wavelength range and producing an output power of hundreds of megawatts. In a demonstration experiment,
a 80-ns pulse of kilowatt power with frequency modulation in a 5% band was compressed to a 1.5-ns pulse with a 25-fold power
amplification.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 1, pp. 40–53, January 2007. 相似文献
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Savilov AV 《Physical review letters》2002,88(6):064801
A spatially modulated (corrugated) electron beam provides Bragg-type scattering of two waveguide modes. This allows the use of corrugated beams as quick active elements in rf-pulse compressors. In an illustrative example shown with a peak power compression ratio of 20-40, a 10-20 ns output pulse with a peak power of tens of MW is predicted for a millimeter-wavelength compressor. 相似文献
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Samsonov SV Phelps AD Bratman VL Burt G Denisov GG Cross AW Ronald K He W Yin H 《Physical review letters》2004,92(11):118301
A new method to generate ultrahigh-power microwave pulses compatible with mildly relativistic electron sources is proposed. This method involves a novel microwave compressor in the form of a metal helically corrugated waveguide, which can enhance the power of frequency-modulated nanosecond pulses up to the multigigawatt level. The results of the proof-of-principle experiments at kilowatt power levels are in good agreement with theory. 相似文献
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Subpicosecond pulse compression in nonlinear photonic crystal waveguides based on the formation of high-order optical solitons 下载免费PDF全文
We investigate by numerical simulation the compression of subpicosecond pulses in two-dimensional nonlinear photonic crystal (PC) waveguides. The compression originates from the generation of high-order optical solitons through the interplay of the huge group-velocity dispersion and the enhanced self-phase modulation in nonlinear PC waveguides.Both the formation of Bragg grating solitons and gap solitons can lead to efficient pulse compression. The compression factors under different excitation power densities and the optimum length for subpicosecond pulse compression have been determined. As a compressor, the total length of the nonlinear PC waveguide is only ten micrometres and therefore can be easily incorporated into PC integrated circuits. 相似文献
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Yong Lee 《Optical and Quantum Electronics》2001,33(7-10):767-774
A strong polarization dependence of pulse compression was experimentally observed using an InGaAsP/InP slab-type coupled waveguide structure consisting of two dissimilar waveguides. This polarization dependence strongly demonstrated that the observed pulse compression results from dispersion compensation due to group velocity dispersion (GVD) associated with supermodes. High mode-conversion efficiency over a wide spectral band in mode converters and the possibility of continuous control of supermode GVD by current injection were demonstrated by numerical simulation. 相似文献