离散色散光域傅里叶变换的延时和带宽扩展研究

光域傅里叶变换为射频频谱分析提供了一种新的解决方案。光域傅里叶变换主要受限于大的二阶色散的获得，而离散傅里叶变换只需要控制离散点的相位，理论上可以解决大色散的获得问题。文章利用光纤环作为离散色散器件，用线性调频信号作为待测信号，进行了光域离散傅里叶变换的研究。该系统是一个快速傅里叶变换系统，每次变换用时约2.07 ns。用示波器观测线性调频信号变换前与变换后的波形延迟，可以测出该系统的变换延时，约为100 ns,其延时大小主要取决于系统中的光纤长度。该系统可以实现对信号的不间断处理。为了扩展系统的瞬时带宽，对片上集成光微环组方案的可实现性进行了分析。

Delay and Bandwidth Expansion of Discrete Dispersive Fourier Transform in the Optical Domain

Objective The optical-domain Fourier transform provides a new solution for radio-frequency spectrum analysis. While this transform is limited by the acquisition of a large second-order dispersion, the discrete Fourier transform needs to control only the phase of discrete points, which can theoretically solve the problem of obtaining a large dispersion. Methods This study used a fiber optic ring as a discrete dispersion device and a linear frequency modulation signal as the test signal to study the optical-domain discrete Fourier transform. Each transformation in this fast Fourier transform system takes approximately 2.07ns. By observing the waveform delay of the linear frequency modulation signal before and after transformation using an oscilloscope, the transformation delay of the system (~100ns) can be measured. The feasibility of the on-chip integrated optical microring group scheme was examined to expand the instantaneous bandwidth of the system.