Topology-enabled highly efficient beam combination

TL;DR

This paper introduces a novel topology-enabled beam combination mechanism that achieves high efficiency and broadband operation by leveraging topological edge states, overcoming phase correlation limitations in coherent beam combining.

Contribution

The work presents the first experimental demonstration of TEBC using topological photonic crystals, enabling high-efficiency, broadband, phase-insensitive beam combination with reduced device complexity.

Findings

Achieved 93% efficiency in microwave beam combination.

Demonstrated broadband and phase-insensitive operation.

Reduced device footprint compared to traditional methods.

Abstract

Beam combination with high efficiency is desirable to overcome the power limit of single electromagnetic sources, enabling long-distance optical communication and high-power laser. The efficiency of coherent beam combination is severely limited by the phase correlation between different input light beams. Here, we theoretically proposed and experimentally demonstrated a new mechanism for beam combining, the topology-enabled beam combination (TEBC), from multiple spatial channels with high efficiency based on a unidirectional topological edge state. We show that the topologically protected power orthogonal excitation arising from both the unidirectional edge states and the energy conservation ensures -0.31dB (93%) efficiency experimentally for a multi-channel combination of coherent microwaves at 9.1-9.3 GHz. Moreover, we demonstrate broadband, phase insensitive, and high-efficiency beam combination using the TEBC mechanism with one single topological photonic crystal device, which significantly reduces the device footprint and design complexity. Our scheme transcends the limits of the required phase correlations in the scenario of coherent beam combination and the number of combined channels in the scenario of incoherent beam combination.