Combined spatially and temporally multiplexed photonic reservoir computer with a diffractively coupled VCSEL-array

TL;DR

This paper presents a hybrid photonic reservoir computer using a VCSEL array with spatial and temporal multiplexing, achieving high classification accuracy and scalability.

Contribution

It introduces a novel hybrid spatio-temporal photonic reservoir with diffractive coupling, enhancing performance and scalability over previous designs.

Findings

Reduced test error to 0.026 in classification tasks.

Expanded network from 12 to 968 nodes while maintaining high speed.

Demonstrated improved performance with spatial and virtual node optimization.

Abstract

We report and analyse the classification performance of an experimental hybrid spatio-temporal photonic reservoir computer based upon a free-space VCSEL array. We demonstrate experimentally the enhancement of spatial-only reservoir operation, featuring the diffractive coupling of lasers in an external cavity, by exploiting up to 88 virtual nodes with time multiplexing. We analyse the dependance of performance on the spatial and virtual node number, and achieve an improvement for both spatial- and temporal-only reservoirs with a reduced test error of 0.026 in a classification task. Further, given the high bandwidth of the non-linear laser transformation, we demonstrate the expansion of a 12 spatial node network to a 968 node network, operating at an input time of 17.6ns, maintaining high processing speed and improving network scalability and performance.