A novel photonic analog-to-digital conversion (ADC) scheme based on time-to-frequency mapping is proposed and experimentally demonstrated. In the approach, the amplitude of the input analog signal is firstly converted into a time-varying signal by pulse position modulation, then the time variation is mapped into the optical spectrum with the help of time-to-frequency mapping offered by the chirped optical pulse. The optical spectral information can be directly encoded by using interleaving filters and a binary receiver array, which outputs the digital records of the input analog signal. Compared with the existing photonic ADC schemes, the proposed approach greatly simplifies the system configuration and uses only one modulator with a dispersive element to achieve $2^N$ quantization levels. Meanwhile, it also avoids the limitation of optical nonlinearity and realizes the linear mapping between the analog voltage and optical spectrum. A proof-of-concept experiment of the proposed approach based on time-to-frequency mapping is successfully carried out to verify the feasibility of the scheme. In addition, we also discuss the performance limitations induced by the frequency ambiguity in chirped spectra and the timing jitter in sampling.

提出并实验证明了一种基于时间到频率映射的新型光子模数转换 (ADC) 方案。该方法首先通过脉冲位置调制将输入模拟信号的幅度转换为时变信号，然后借助啁啾光学提供的时频映射将时变信号映射到光谱中。脉冲。光谱信息可以通过使用交织滤波器和二进制接收器阵列直接编码，其输出输入模拟信号的数字记录。与现有的光子 ADC 方案相比，所提出的方法大大简化了系统配置，并且仅使用一个带有色散元件的调制器来实现$2^N$量化级别。同时，也避免了光学非线性的限制，实现了模拟电压与光谱的线性映射。对所提出的基于时频映射的方法进行了概念验证实验，以验证该方案的可行性。此外，我们还讨论了由啁啾频谱中的频率模糊和采样中的定时抖动引起的性能限制。