基于光谱整形的三角波生成方法

Generation of Triangular Waveform Based on OpticalSpectrum Manipulation

受电子瓶颈限制,电子信号发生器难以合成高速波形。微波光子学具有大带宽等优点,在宽带、高速波形生成方面有独有的优势。文章提出了一种基于光谱整形的三角波生成方法,通过傅里叶域光处理器灵活的控制光学频率梳中各个光边带的幅度和相位关系,经光电探测后可以直接得到三角波波形。灵活调整光边带相位的能力使得该方案可以补偿光纤色散,这意味该系统支持三角波波形的光纤传输。实验结果表明,该方案可以生成10 GHz重复频率的高速三角波波形,并成功实现了25km光纤传输。本方案使用了无需偏压控制的相位调制器,且避免了RF电桥等带宽受限的微波器件,生成的波形的带宽仅受调制器和光电探测器的限制。

Limited by the“electronic bottlenecks”,it is difficult for electronic signal generators to synthesize waveforms with high repetition rate.Featuring large bandwidth,microwave photonic techniques have the unique advantage in broadband and high-speed signal generation.This paper proposes a triangular wave generation method based on optical spectrum manipulation.An optical frequency comb is line-by-line shaped by a Fourier-domain optical processor,where the phase and amplitude of every comb lines is fully programmed.The triangular waveform can thus be generated after photo-detection.The line-by-line shaping also provides the ability of dispersion compensation,which means that the system supports fiber transmission.Experimental results show that the scheme can generate triangular waveforms with a repetition frequency of 10 GHz,and successfully achieves 25 km fiber transmission.This scheme uses a bias-free phase modulator,and avoids additional microwave devices such as RF couplers that suffer from limited bandwidth.The bandwidth of generated waveform is only limited by the modulator and the photodetector.