Topology reconfigurable photonic reservoir computing with multiple optical feedback loops.

Conventional photonic time-delay reservoir computing (TDRC) with a single delay is constrained by a fixed ring virtual node topology, limiting its adaptability across tasks with different dynamical requirements. Here, we propose and experimentally demonstrate a task-dependent topology tuning mechanism for photonic TDRC based on multiple optical feedback loops. The resulting time multiplexed virtual network can be reconfigured directly at the hardware level through the delay configuration, and the preferred topology is found to depend strongly on the task. For chaotic time series prediction, irregular nonresonant delays increase the effective state dimension and memory depth, thereby reducing prediction error. For spatial classification, delay values close to the input scanning period improve performance by recovering two dimensional correlations from serialized inputs. These results establish multiple optical feedback loops as a practical physical route to topology reconfiguration in photonic time-delay reservoir computing.