Metamaterial-enabled arbitrary on-chip spatial mode manipulation

Abstract

On-chip spatial mode operation, represented as mode-division multiplexing (MDM), can support high-capacity data communications and promise superior performance in various systems and numerous applications from optical sensing to nonlinear and quantum optics. However, the scalability of state-of-the-art mode manipulation techniques is significantly hindered not only by the particular mode-order-oriented design strategy but also by the inherent limitations of possibly achievable mode orders. Recently, metamaterials capable of providing subwavelength-scale control of optical wavefronts have emerged as an attractive alternative to manipulate guided modes with compact footprints and broadband functionalities. Herein, we propose a universal yet efficient design framework based on the topological metamaterial building block (BB), enabling the excitation of arbitrary high-order spatial modes in silicon waveguides. By simply programming the layout of multiple fully etched dielectric metamaterial perturbations with predefined mathematical formulas, arbitrary high-order mode conversion and mode exchange can be simultaneously realized with uniform and competitive performance. The extraordinary scalability of the metamaterial BB frame is experimentally benchmarked by a record high-order mode operator up to the twentieth. As a proof of conceptual application, an 8-mode MDM data transmission of 28-GBaud 16-QAM optical signals is also verified with an aggregate data rate of 813 Gb/s (7% FEC). This user-friendly metamaterial BB concept marks a quintessential breakthrough for comprehensive manipulation of spatial light on-chip by breaking the long-standing shackles on the scalability, which may open up fascinating opportunities for complex photonic functionalities previously inaccessible.

Photonic multiplexing architectures for optical neuromorphic computation

“…In addition to the approaches to ONNs introduced above, polarization-and mode-division multiplexing can also be employed to enhance the transmission capacity of optical communications [134][135][136] and computing parallelism of ONNs. We note that MDM and PDM are generally compatible with other multiplexing techniques, and thus can potentially lead to dramatic increases in the ONNs' computing power.…”

Photonic Multiplexing Techniques for Optical Neuromorphic Computing

“…In addition to the approaches to ONNs introduced above, polarization-and modedivision multiplexing can also be employed to enhance the transmission capacity of optical communications [134][135][136] and computing parallelism of ONNs. We note that MDM and PDM are generally compatible with other multiplexing techniques, and thus can potentially lead to dramatic increases in the ONNs' computing power.…”

Scalability of Large-Scale Photonic Integrated Circuits

“…Compared with copper lines, the capacity and the bandwidth density of the optical interconnect can be scaled by adopting high-level modulation formats, or by multiplexing signals into all the available physical dimensions, such as wavelength, − mode, − and polarization. , Currently, the state-of-the-art capacity of an optical multiplexing chip is on the order of 10 Tb/s . However, looking into the next 10 years and beyond, the current technologies are far from enough to enable Pb/s capacity on a chip.…”