A new spectrum shaping method, based on electro-optic modulation, to alleviate gain narrowing in chirped pulse amplification (CPA) system, is described and numerically simulated. Near-Fourier transform-limited seed laser pulse is chirped linearly through optical stretcher. Then the chirped laser pulse is coupled into integrated waveguide electro-optic modulator driven by an aperture-coupled-stripline (ACSL) electrical-waveform generator, and the pulse shape and amplitude are shaped in time domain. Because of the direct relationship between frequency interval and time interval of the linearly chirped pulse, the laser pulse spectrum is shaped correspondingly. Spectrum-shaping examples are modeled numerically to determine the spectral resolution of this technique. The phase error introduced in this method is also discussed.

A new spectrum shaping method, based on electro-optic modulation, to alleviate gain narrowing in chirped pulse amplification (CPA) system, is described and numerically simulated. Near-Fourier transform-limited seed laser pulse is chirped linearly through optical stretcher. Then the chirped laser pulse is coupled into integrated waveguide electro-optic modulator driven by an aperture-coupled-stripline (ACSL) electrical-waveform generator, and the pulse shape and amplitude are shaped in time domain. Because of the direct relationship between frequency interval and time interval of the linearly chirped pulse, the laser pulse spectrum is shaped correspondingly. Spectrum-shaping examples are modeled numerically to determine the spectral resolution of this technique. The phase error introduced in this method is also discussed.

Due to the demand of complicated-time-shape seed laser pulse for inertial confine fusion (ICF) research, by using the pulse-shaping system based on aperture-coupled striplines, we design the front-end laser pulse temporal waveform, which totally meets the requirement of physical experiments. Besides, we precisely calculate the numerical relationship between the voltage coupling coefficient of the aperture-coupling striplines and its aperture width with a new method. In order to meet the demand of high-contrast laser pulse waveform, we put forward a new scheme based on double-electrode integrated wave-guide modulator. The system is capable of providing 1～3 ns pulse envelope, high contrast (>100∶1) and slippery waveform, meeting the “ShenGuang Ⅱ” eight lines and the ninth facility demand of the front-end temporal shaping laser pulse.

针对激光惯性约束聚变实验研究对高功率激光驱动器前端系统复杂时间形状种子激光脉冲的需求, 应用孔径耦合带状线集成波导整形系统设计了满足需要的前端整形激光脉冲。用一种新方法精确计算了孔径耦合带状线电脉冲整形器的耦合系数和孔径宽度的数值关系, 并针对高衬比度整形激光脉冲的需求, 提出了高衬比度双极型集成波导整形系统方案。由该系统可以得到100 ps脉冲前沿、1～3 ns脉冲宽度可调、高衬比度(大于100∶1)、光滑无纹波调制、可精确满足神光II八路及第九路装置需求的前端整形激光脉冲。

A new laser pulse-shaping system using an electro-optic modulator driven by an aperture-coupled-striplines (ACSL) electrical-waveform generator has been discussed in this paper. The ACSL electrical-waveform generator consists of two striplines coupled through an aperture in their common ground plane. Replacing the aperture layer, the electrical-waveform can produce arbitrary electrical pulse with 150 ps structure. Giving the arbitrary electrical pulse to the electro-optic modulator, arbitrary optic pulse can be gotten. By the new technique, the laser pulse-shaping system is capable of producing arbitrarily shaped laser pulses with about 150 ps structure, 1～3 ns pulse envelope, high contrast waveform and slippery transition waveform.

实现了一种新型的激光脉冲整形系统,该系统使用了一个由孔径耦合带状线(ACSL)电脉冲整形器驱动的电光调制器。一个电脉冲整形器由两条通过其公共接地板上的耦合孔径发生耦合作用的带状传输线所组成的四端口装置。更换具有不同耦合孔径的公共接地板,该电脉冲整形发生器可以具有150 ps时间结构的任意整形电脉冲。将任意整形的电脉冲输入到电光调制器上,就可以得到任意整形的激光脉冲。利用该系统,激光脉冲整形系统能够产生具有150 ps前后沿,1～3 ns脉冲宽度可调、高对比度、光滑过渡以及任意整形的激光脉冲。