Broadband three-mode converter and multiplexer based on cascaded symmetric Y-junctions and subwavelength engineered MMI and phase shifters

TL;DR

This paper introduces a scalable on-chip three-mode converter and multiplexer using cascaded Y-junctions, subwavelength engineered MMI, and phase shifters, achieving broad bandwidth and low loss for mode-division multiplexing.

Contribution

It presents a novel three-mode architecture with subwavelength metamaterials, enabling scalable, broadband mode conversion on silicon photonics.

Findings

Simulated bandwidth of 161 nm

Insertion loss below 1.18 dB

Crosstalk below -20 dB

Abstract

Mode-division multiplexing has emerged as a promising route for increasing transmission capacity while maintaining the same level of on-chip integration. Despite the large number of on-chip mode converters and multiplexers reported for the silicon-on-insulator platform, scaling the number of multiplexed modes is still a critical challenge. In this paper, we present a novel three-mode architecture based on multimode interference couplers, passive phase shifters and cascaded symmetric Y-junctions. This architecture can readily operate up to the third-order mode by including a single switchable phase shifter. Moreover, we exploit subwavelength grating metamaterials to overcome bandwidth limitations of multimode interference couplers and phase shifters, resulting in a simulated bandwidth of 161 nm with insertion loss and crosstalk below 1.18 dB and -20 dB, respectively.