全光时钟提取结构应对输入信号的恶化程度有一定的容忍度。在一种半导体光放大器(SOA)+啁啾光纤布拉格光栅(CFBG)+受激布里渊散射(SBS)的方式实现非归零(NRZ)码信号的全光时钟提取结构中,半导体光放大器和啁啾光纤布拉格光栅共同作用实现了非归零码信号的时钟分量增强,基于受激布里渊散射的全光时钟提取结构提取出非归零码的光时钟信号。实验通过对不同恶化程度的非归零码信号的时钟提取比较发现,恶化信号的信噪比是影响光时钟提取的关键。输入非归零码信号的信噪比越差,光时钟信号光谱的噪声水平越高,提取出的光时钟信号的幅度越低。当时钟增强非归零码信号的时钟数据抑制比低于-10 dB时,无法实现非归零码信号的时钟提取。

The all optical clock recovery scheme has certain tolerance for degraded input signal. A novel scheme including semiconductor optical amplifier (SOA), chirped fiber Bragg grating (CFBG), and stimulated Brillouin scattering (SBS) is proposed and demonstrated to recover the clock from the input degraded non-return-to-zero (NRZ) data stream. SOA and CFBG enhance the clock component, and the clock information is extracted from the clock component enhanced signal based on SBS. For different degraded signals, the signal-to-noise ratio (SNR) of the input stream is the key factor to the clock recovery. When the input SNR is worse, the noise of recovered clock spectrum is higher, and the amplitude of extracted optical clock is lower. The clock of NRZ signal could not be recovered as the clock-to-data ratio of the enhanced signal is less than -10 dB.