Wavelength-agnostic 3D-Nanoprinted coupler

TL;DR

This paper introduces a wavelength-agnostic 3D nanoprinted photonic coupler with ultra-broadband performance, combining innovative design, hybrid modeling, and additive manufacturing to achieve record bandwidth and low loss for fiber-to-chip optical interfacing.

Contribution

The work presents a novel dual-ellipsoidal geometry design, a hybrid modeling workflow, and a 3D nano-printing fabrication method, enabling ultra-broadband, low-loss, and customizable photonic couplers.

Findings

Over 800 nm bandwidth with 1.3 dB insertion loss

Record low insertion loss for broadband photonic couplers

Demonstrated thermal stability and robustness

Abstract

We present a photonic coupler that exhibits effectively wavelength-agnostic performance for ultra-broadband optical interfacing. By incorporating a dual-ellipsoidal geometry, the design facilitates quasi-free-space optical propagation. We further propose a hybrid modelling workflow employs a matrix optics-based approach as an efficient pre-design tool, capturing critical geometry-to-mode mapping characteristics, significantly narrowing the parameter space required for subsequent full-vectorial finite-difference time-domain (FDTD) simulations. Our design achieves a 1 dB bandwidth exceeding 800 nm coupling from fibre to chip, with an insertion loss as low as 1.3 dB,to the best of our knowledge, a record for any reported photonic couplers. The additive manufacturing approach via 3D nano-printing enables flexible geometry customization and sub-micron integrated alignment features, facilitating seamless integration with photonic chips and optical fibers. Experimental validation demonstrates excellent stability and thermal robustness across diverse operational conditions, highlighting the design's suitability for integration into wide range of broadband photonic systems.