Photonic Generation of Chirped Microwave Pulses Using Superimposed Chirped Fiber Bragg Gratings
Photonic Generation of Chirped Microwave Pulses Using Superimposed Chirped Fiber Bragg Gratings
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DOI：
10.1109/lpt.2008.922333
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发表时间：
2008-06
影响因子：
2.6
通讯作者：
Chao Wang;J. Yao
中科院分区：
文献类型：
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作者：
Chao Wang;J. Yao
提出了一种基于频谱整形和线性频率-时间映射的光域线性啁啾微波脉冲产生方法，并进行了实验验证。在该系统中，锁模光纤激光器产生的飞秒脉冲的光谱由两个不同啁啾速率的叠加啁啾光纤布拉格光栅（SI-CFBGs）组成的光滤波器组成。SI-CFBGs形成一个腔长与共振波长线性相关的法布里-珀罗腔，从而产生自由光谱范围增加或减少的光谱响应。利用色散器件中的频率-时间映射，在高速光电探测器的输出端获得了脉冲形状与形谱相同的啁啾微波脉冲。实验验证了该技术的有效性，实验产生了中心频率为15 GHz、啁啾速率为0.0217 GHz/ps的线性啁啾微波脉冲。
A novel approach to generating linearly chirped microwave pulses in the optical domain based on spectral shaping and linear frequency-to-time mapping is proposed and experimentally demonstrated. In the proposed system, the spectrum of a femtosecond pulse generated by a mode-locked fiber laser is spectrum-shaped by an optical filter that consists of two superimposed chirped fiber Bragg gratings (SI-CFBGs) with different chirp rates. The SI-CFBGs form a Fabry-Perot cavity with a cavity length linearly dependent on the resonance wavelength, thus a spectral response with an increased or decreased free spectral range is generated. A chirped microwave pulse with the pulse shape identical to the shaped spectrum is obtained at the output of a high-speed photodetector thanks to the frequency-to-time mapping in a dispersive device. The proposed technique is experimentally demonstrated, a linearly chirped microwave pulse with a central frequency of 15 GHz and a chirp rate of 0.0217 GHz/ps is experimentally generated.