Jiang Fan, Yu Yuan, Cao Tong, Tang Haitao, Dong Jianji, Zhang Xinliang
Opt Lett. 2016 Jul 15;41(14):3301-4. doi: 10.1364/OL.41.003301.
We propose a flat-top bandpass microwave photonic filter (MPF) with flexible tunability of the bandwidth and center frequency based on optical nonlinearities in a Fabry-Pérot semiconductor optical amplifier (FP-SOA). Phase-inverted modulation induced by cross-gain modulation (XGM) and optical spectral broadening induced by self-phase modulation (SPM) are exploited to achieve flat-top and bandwidth tuning, respectively. Wideband and continuous tuning of the center frequency is achieved by altering the bias current of the FP-SOA. Experimental results demonstrate a flat-top single-passband MPF with its center frequency tunable from 6.0 to 18.3 GHz by adjusting the bias current from 54.05 to 107.85 mA. The 3-dB bandwidth of the passband when centered at 10.0 GHz is shown to be variable from 680 to 1.43 GHz, by increasing the injected optical power from -1 to +5 dBm. During the bandwidth tuning, the amplitude ripple within the passband is maintained at less than ±0.5 dB. Excellent main to secondary sidelobe ratio exceeding 45 dB is achieved when the MPF is centered at 18.3 GHz.
我们提出了一种基于法布里-珀罗半导体光放大器（FP-SOA）中的光学非线性效应的平顶带通微波光子滤波器（MPF），其带宽和中心频率具有灵活的可调性。利用交叉增益调制（XGM）引起的相位反转调制和自相位调制（SPM）引起的光谱展宽，分别实现平顶和带宽调谐。通过改变FP-SOA的偏置电流实现中心频率的宽带连续调谐。实验结果表明，通过将偏置电流从54.05 mA调整到107.85 mA，可实现中心频率在6.0至18.3 GHz范围内可调的平顶单通带MPF。当中心频率为10.0 GHz时，通过将注入光功率从-1 dBm增加到+5 dBm，通带的3 dB带宽可从680 MHz变化到1.43 GHz。在带宽调谐过程中，通带内的幅度纹波保持在±0.5 dB以内。当MPF中心频率为18.3 GHz时，实现了超过45 dB的优异主旁瓣比。
