We demonstrate a tunable optical tapped delay line (OTDL) using delays based on orbital angular momentum (OAM) modes to perform data correlation and equalization for a quadrature phase-shift-keyed (QPSK) signal. The system: (i) creates N signal replicas as N taps on different OAM modes through mode multicasting, (ii) tunes the complex tap weights (i.e., amplitude and phase of the modes), (iii) applies a tunable mode-dependent delay to each replica, and (iv) coherently combines the taps in order to realize the OTDL functions of correlation and equalization. The experiment results: (i) identify the correlation occurrence of a sequence of 2 or 3 symbols in an incoming 10 or 20 Gbaud QPSK signal, and (ii) equalize the distortion caused by chromatic dispersion for a 20-Gbaud QPSK data signal and reduce error vector magnitude (EVM) from $\sim$25.4 to $\sim$12.9%.

我们展示了一种可调谐光学抽头延迟线 (OTDL)，它使用基于轨道角动量 (OAM) 模式的延迟来执行正交相移键控 (QPSK) 信号的数据相关和均衡。系统：(i) 通过模式多播在不同的 OAM 模式上创建 N 个信号副本作为 N 个抽头，(ii) 调整复杂的抽头权重（即模式的幅度和相位），(iii) 应用可调谐的模式相关延迟到每个副本，以及 (iv) 相干地组合抽头以实现相关和均衡的 OTDL 功能。实验结果：(i) 识别传入的 10 或 20 Gbaud QPSK 信号中 2 或 3 个符号序列的相关发生，以及 (ii) 均衡 20 Gbaud QPSK 数据信号的色散引起的失真并减少误差矢量幅度 (EVM) 来自$～$25.4 到 $～$12.9%。