3$\times$3 Slot waveguide crossing based on Maxwell's fisheye lens

TL;DR

This paper introduces a novel 3x3 silicon slot waveguide crossing using Maxwell's fisheye lens, achieving low loss, minimal crosstalk, and ultra-wide bandwidth in a compact footprint for optical communication circuits.

Contribution

It presents the first design of a Maxwell's fisheye lens-based 3x3 slot waveguide crossing with superior performance and minimal size, scalable for more waveguides.

Findings

Average insertion loss of 1.2 dB

Crosstalk lower than -15.1 dB

Operates over 415 nm bandwidth

Abstract

Intersection of two or more silicon slot waveguides is inevitable in modern optical integrated circuits based on silicon on insulator (SOI) platform. In this article, we design a Maxwell's fisheye lens as the crossing medium for three Si slot waveguides and numerically investigate its characteristics such as insertion loss, crosstalk and bandwidth. For the 3$\times$3 slot waveguide crossing, the average insertion loss of 1.2 dB and crosstalk levels lower than -15.1 dB are achieved in an ultra-wideband wavelength range of 415 nm covering the entire O, E, S, C, L, and U bands of optical communications. The footprint of the 3$\times$3 silicon slot waveguide crossing presented in this article is merely 2$\times$2 $\mu m^2$ which is considerably smaller compared to the previously designed Si slot waveguide crossings even with fewer number of ports. The proposed design can be expanded to support the intersection of more slot waveguides.