Dual Micro-Ring Resonators with Angular GST Modulation: Enabling Ultra-Fast Nonlinear Activation for Neuromorphic Photonics

TL;DR

This paper introduces a dual micro-ring resonator system with angular GST modulation for ultra-fast, energy-efficient nonlinear activation in neuromorphic photonics, achieving high contrast, narrowband transmission, and multi-level optical processing.

Contribution

The work presents a novel dual ring architecture with angular GST placement, enabling precise nonlinear activation functions and improved spectral control over traditional single ring designs.

Findings

Achieves ultra narrowband transmission with 0.47 nm FWHM.

Provides high contrast transmission from 0 to 0.85 over 4 nm spectral window.

Operates effectively at reduced temperatures (100°C).

Abstract

Photonic technologies are emerging as powerful enablers for neuromorphic computing by delivering ultrafast and energy efficient neural functionalities. In this work, we propose and demonstrate a novel all-optical dual micro ring resonator architecture incorporating the phase change material Ge2Sb2Te5 (GST) to implement highly precise nonlinear activation functions (NLAFs). Our approach introduces angular positioning of GST segments within the rings, enabling fine-grained control over optical transmission dynamics. Through a systematic evaluation of sixteen distinct phase configurations, we identify an optimal GST placement 180 deg in the first ring and 90 deg in the second that achieves ultra narrowband transmission with a full width at half maximum (FWHM) of just 0.47 nm. This dual ring configuration provides two distinct resonant wavelengths, facilitating enhanced nonlinear modulation and multi level optical signal processing that closely mimics biological neuron behavior. Notably, the device achieves high contrast transmission, 0 to 0.85, across a 4 nm spectral window while operating at significantly reduced temperatures (100 deg C), outperforming traditional GST based designs. Furthermore, the dual-ring architecture enables independent optimization of spectral selectivity and switching contrast capabilities previously unattainable with single ring structures. These results establish a promising pathway toward scalable, high speed neuromorphic photonic systems, offering both the precision and switching speed required for practical on chip neural processing.