State-of-the-Art and Perspectives on Silicon Waveguide Crossings: A Review

Abstract

In the past few decades, silicon photonics has witnessed a ramp-up of investment in both research and industry. As a basic building block, silicon waveguide crossing is inevitable for dense silicon photonic integrated circuits and efficient crossing designs will greatly improve the performance of photonic devices with multiple crossings. In this paper, we focus on the state-of-the-art and perspectives on silicon waveguide crossings. It reviews several classical structures in silicon waveguide crossing design, such as shaped taper, multimode interference, subwavelength grating, holey subwavelength grating and vertical directional coupler by forward or inverse design method. In addition, we introduce some emerging research directions in crossing design including polarization-division-multiplexing and mode-division-multiplexing technologies.

A Review of Devices for Integrated Silicon Photonic Switches

“…Straight waveguide crossing incur a larger optical loss. Other notable crossings are reported in [58]. Silicon and silicon nitride trilayer waveguide crossings are reported in [59].…”

Asymptotically Fault-Tolerant Programmable Photonics

“…7(c) by an additional angle γ 1, and the forbidden region is still far from s = 0. In-plane crossings in silicon can achieve sub-40 dB crosstalk suppression (γ < 0.01) with insertion losses well below 0.1 dB [36][37][38][39][40]. Unlike directional couplers, crossings are inherently broadband; the insertion loss and crosstalk depend only very weakly on λ, so any crossing imperfections can be treated as (correctable) wavelengthindependent errors that do not affect the bandwidth enhancements of the MZI+Crossing scheme.…”

Optical Vortices Sharp Focusing by Silicon Ring Gratings Using High-Performance Computer Systems

“…The silicon photonics has attracted more attention from researchers in the past few decades [1][2][3][4][5]. This is due to a number of reasons, including the cheaper implementation of optical devices using standard semiconductor manufacturing technologies [2] and miniaturization of solutions for light transmission through optical fibers [3]. It is also possible to obtain a high integration density due to the large refractive index of silicon [1].…”

“…A number of classical structures in the construction of crossing silicon waveguides are well known, such as subwavelength grating, shaped taper, holey subwavelength grating [3]. In particular, the methodology for designing silicon based waveguide Bragg gratings (WBGs) in detail discusses the paper [8].…”