Ultra-miniaturized Bloch mode metasplitters for one-dimensional grating waveguides

TL;DR

This paper introduces ultra-miniaturized, multi-channel power splitters in one-dimensional grating waveguides that preserve Bloch mode profiles, enabling compact, efficient, and broadband photonic circuit components.

Contribution

It presents the first implementation of multi-channel power splitters in 1D grating waveguides with preserved Bloch modes and ultra-compact footprint, using a pixelated metamaterial approach and heuristic algorithms.

Findings

Achieved 3.80 dB and 5.36 dB average losses per channel for 1x2 and 1x3 splitters.

Demonstrated 15 nm 1 dB bandwidth with uniform output across channels.

Maintained crystal lattice-sensitive Bloch mode profiles without perturbation.

Abstract

We present, for the first time, power splitters with multiple channel configurations in one-dimensional grating waveguides (1DGWs) that maintain crystal lattice-sensitive Bloch mode profiles without perturbation across all output channels, all within an ultra-miniaturized footprint of just 2.1 x 2.2 {\mu}m^2. This novel capability reduces the need for transition regions, simplifies multi-channel configurations of 1DGWs, and maximizes the effective use of chip area. The pixelated metamaterial approach, integrated with a time-domain heuristic algorithm, is utilized to concurrently achieve broadband operation, optimized dispersion control, and minimal loss. We experimentally demonstrate that our 1x2 and 1x3 metasplitters achieve average minimum losses per channel of 3.80 dB and 5.36 dB, respectively, just 0.80 dB and 0.59 dB above ideal splitting. The measurements for both designs demonstrate a 1 dB bandwidth of 15 nm, with excellent uniformity across all output channels. These versatile metasplitter designs can serve as fundamental building blocks for ultrahigh-bandwidth, densely integrated photonic circuits and in scenarios where slow light is essential.