Ultra-broadband all-optical nonlinear activation function enabled by MoTe₂/optical waveguide integrated devices

Area of Science:

• Photonics and Materials Science
• Integrated Optics
• Artificial Intelligence Hardware

Background:

• All-optical nonlinear activation functions (NAFs) are essential for optical neural networks (ONNs).
• Current on-chip NAFs struggle with integration, latency, power consumption, and high activation thresholds.
• Advancements in integrated ONNs necessitate improved NAFs for efficient computation.

Purpose of the Study:

• To develop an integrated nonlinear optical activator for advanced ONNs.
• To overcome limitations of existing all-optical NAFs.
• To demonstrate the potential of 2D materials in photonic devices.

Main Methods:

• Butt-coupling integration of 2D Molybdenum Ditelluride (MoTe2) with optical waveguides (OWGs).
• Characterization of the activator's ultra-broadband response (visible to near-infrared).
• Application of the developed NAFs in simulating MNIST and CIFAR-10 image recognition.

Main Results:

• Achieved an ultra-broadband response from visible to near-infrared wavelengths.
• Demonstrated a low activation threshold (0.94 μW) and ultra-fast response rate (2.08 THz).
• Attained high accuracy in image recognition: 97.6% for MNIST and 94.6% for CIFAR-10.

Conclusions:

• The developed nonlinear optical activator shows significant potential for high-density, low-threshold, ultra-broadband 3D ONNs.
• Integration of 2D materials offers a promising route for next-generation optical computing.
• This work paves the way for practical implementation of efficient ONNs.