Si-Photonics-Based Layer-to-Layer Coupler Toward 3D Optical Interconnection

Abstract

SUMMARY To realize three-dimensional (3D) optical interconnection on large-scale integration (LSI) circuits, layer-to-layer couplers based on Si-photonics platform were reviewed. In terms of optical cross talk, more than 1 µm layer distance is required for 3D interconnection. To meet this requirement for the layer-to-layer optical coupler, we proposed two types of couplers: a pair of grating couplers with metal mirrors for multi-layer distance coupling and taper-type directional couplers for neighboring layer distance coupling. Both structures produced a high coupling efficiency with relatively compact (∼100 µm) device sizes with a complementary metal oxide semiconductor (CMOS) compatible fabrication process.

Tailoring light on three-dimensional photonic chips: a platform for versatile OAM mode optical interconnects

“…Remarkably, most optical devices based on silicon photonics, including lasers, 14 – 16 modulators, 17 , 18 switches, 19 , 20 filters, 21 , 22 and (de)multiplexers, 23 , 24 have been widely implemented. Moreover, to further increase the density of integration, three-dimensional (3D) photonic chips have also been demonstrated with the advent of multilayer photonic structures 25 , 26 . However, these state-of-the-art integration technologies are typically implemented in a modified complementary-metal-oxide-semiconductor process, with the disadvantages of inflexibility and complex process.…”

“…Moreover, to further increase the density of integration, three-dimensional (3D) photonic chips have also been demonstrated with the advent of multilayer photonic structures. 25,26 However, these state-of-the-art integration technologies are typically implemented in a modified complementarymetal-oxide-semiconductor process, with the disadvantages of inflexibility and complex process. Thus, flexible fabrication of 3D photonic chips is still a challenge.…”

Selective Out‐of‐Plane Optical Coupling between Vertical and Planar Microrings in a 3D Configuration

“…3D photonic integrated circuits (PICs) are key to overcome intrinsic limitations in 2D PICs and push optical systems toward low-power consumption and high-density functionalities in a 3D integrated photonic chip. [1][2][3] In conventional 2D PICs, where all devices reside in the same plane, microring resonators are the main building blocks for various on-chip photonic and functionality such as opto-plasmonic coupling, [24] out-of-plane directional control of light emission, [25] microcavity-based spin-orbit coupling, [26] or even optofluidic detection in lab-ina-tube systems. [27] Intriguingly, such vertical ring resonators are compatible with on-chip monolithic integration if manufactured by rolled-up nanotechnology.…”

“…3D photonic integrated circuits (PICs) are key to overcome intrinsic limitations in 2D PICs and push optical systems toward low‐power consumption and high‐density functionalities in a 3D integrated photonic chip. [ 1–3 ] In conventional 2D PICs, where all devices reside in the same plane, microring resonators are the main building blocks for various on‐chip photonic and optoelectronic systems, [ 4 ] serving as optical filters, [ 5 ] modulators, [ 6 ] and frequency comb generators, [ 7 ] to name a few. Furthermore, micro/nanoresonator coupling in one plane has been widely investigated [ 8–13 ] for applications such as wavelength division multiplexing, [ 14 ] sensing, [ 15 ] and lasing modulation.…”