Zhang Jiejun, Yao Jianping
Opt Lett. 2016 Jan 15;41(2):273-6. doi: 10.1364/OL.41.000273.
We propose and experimentally demonstrate a microwave photonic integrator based on a multichannel fiber Bragg grating (FBG) working in conjunction with a dispersion compensating fiber (DCF) to provide a step group delay response with no in-channel dispersion-related distortion. The multichannel FBG is designed based on the spectral Talbot effect, which provides a large group delay dispersion (GDD) within each channel. A step group delay response can then be achieved by cascading the multichannel FBG with a DCF having a GDD opposite the in-channel GDD. An optical comb, with each comb line located at the center of each channel of the FBG, is modulated by a microwave signal to be integrated. At the output of the DCF, multiple time-delayed replicas of the optical signal, with equal time delay spacing are obtained and are detected and summed at a photodetector (PD). The entire operation is equivalent to the integration of the input microwave signal. For a multichannel FBG with an in-channel GDD of 730 ps/nm and a DCF with an opposite GDD, an integrator with a bandwidth of 2.9 GHz and an integration time of 7 ns is demonstrated.
我们提出并通过实验证明了一种基于多通道光纤布拉格光栅（FBG）的微波光子积分器，该积分器与色散补偿光纤（DCF）协同工作，以提供具有无通道内色散相关失真的阶跃群延迟响应。多通道FBG基于光谱塔尔博特效应设计，该效应在每个通道内提供大的群延迟色散（GDD）。然后，通过将多通道FBG与具有与通道内GDD相反的GDD的DCF级联，可以实现阶跃群延迟响应。一个光梳，其每条梳状线位于FBG每个通道的中心，由要积分的微波信号调制。在DCF的输出端，获得具有相等时间延迟间隔的光信号的多个时间延迟副本，并在光电探测器（PD）处进行检测和求和。整个操作等效于对输入微波信号的积分。对于通道内GDD为730 ps/nm的多通道FBG和具有相反GDD的DCF，展示了一个带宽为2.9 GHz且积分时间为7 ns的积分器。
