Among the promising advantages of photonic computing over conventional computing architectures is the potential to increase computing efficiency through massive parallelism by using the many degrees of freedom provided by photonics. Here, we numerically demonstrate the simultaneous use of time and frequency (equivalently wavelength) multiplexing to solve three independent tasks at the same time on the same photonic circuit. In particular, we consider a microring-based time-delay reservoir computing (TDRC) scheme that simultaneously solves three tasks: Time-series prediction, classification, and wireless channel equalization. The scheme relies on time-division multiplexing to avoid the necessity of multiple physical nonlinear nodes, while the tasks are parallelized using wavelength division multiplexing (WDM). The input data modulated on each optical channel is mapped to a higher dimensional space by the nonlinear dynamics of the silicon microring cavity. The carrier wavelength and input power assigned to each optical channel have a high influence on the performance of its respective task. When all tasks operate under the same wavelength/power conditions, our results show that the computing nature of each task is the deciding factor of the level of performance achievable. However, it is possible to achieve good performance for all tasks simultaneously by optimizing the parameters of each optical channel. The variety of applications covered by the tasks shows the versatility of the proposed photonic TDRC scheme. Overall, this work provides insight into the potential of WDM-based schemes for improving the computing capabilities of reservoir computing schemes.

翻译：在光子计算相较于传统计算架构的诸多优势中，通过利用光子学提供的多种自由度实现大规模并行化以提高计算效率的潜力尤为突出。本文通过数值仿真，在同一光子电路上同时利用时间复用和频率（等效波长）复用技术，并行求解三个独立任务。具体而言，我们提出了一种基于微环的时间延迟储层计算（TDRC）方案，可同时完成时间序列预测、分类和无线信道均衡三项任务。该方案采用时分复用避免使用多个物理非线性节点，同时通过波分复用（WDM）实现任务并行化。各光通道上加载的输入数据经硅微环腔的非线性动态特性映射至高维空间。每个光通道的载波波长和输入功率对其对应任务的性能具有显著影响。研究结果表明，当所有任务在相同波长/功率条件下运行时，各任务的计算特性成为决定其性能水平的关键因素。然而，通过优化各光通道的参数，可以同时实现所有任务的良好性能。这些任务覆盖的多样化应用场景充分体现了所提出的光子TDRC方案的普适性。总体而言，本研究揭示了基于WDM方案在提升储层计算性能方面的潜力。