Metasurface‐Based Fiber‐to‐Chip Multiplexing Coupler

Abstract

Here, a metasurface‐based fiber‐to‐chip multiplexing coupler is presented that can realize flexible mode conversion and multiplexing coupling between few‐mode fibers and on‐chip single‐mode waveguides. The proposed approach makes use of the symmetrical characteristics of fiber eigenmodes and high freedom of light phase manipulation to obtain the functional phase distribution of metasurfaces. The use of cylindrical nanopillar as metasurface nanostructures ensures its polarization independent optical response. Several fiber‐to‐chip multiplexing couplers are demonstrated by using the angular spectrum methods and the finite‐difference time‐domain (FDTD) simulations. It is found that the two or three modes can be flexibly demultiplexed and then be coupled into the corresponding on‐chip waveguides with low crosstalk. Further, two possible fabrication schemes for multiplexing couplers are proposed and then the related fabrication tolerances and misalignment effects are evaluated and discussed. Compared with traditional on‐chip couplers, metasurface‐based couplers have advantages of ultracompact footprint and low crosstalk. Such study explores the application of metasurfaces in multiplexing coupling between few‐mode fiber and on‐chip single‐mode waveguides, which is expected to break through the bottleneck of current mode‐division multiplexing technologies in optical interconnection and meet the ever‐increasing demand for large data throughput of the photonic integrated chips.

From Volumetric to Planar Multiplexing: Phase‐Coded Metasurfaces without the Bragg Effect

“…[17][18][19][20][21] Numerous metasurfacebased multiplexing technologies have been explored for the design of metasurfaces to squeeze more functionality into a given area. [22][23][24][25] As these independent DoFs can be synergistic for the multiplexing, it is conceivable that the orthogonal phaseencoding strategy would complement a new physical dimension over conventional ways and motivate the development of multitasked planar devices. Here, we propose and implement a mul-tiplexing method for metasurfaces where the output is optically selected by one of the orthogonal codes carried by an incident plane wave in its transverse phase distribution.…”

Efficient Fiber‐to‐Chip Interface via an Intermediated CdS Nanowire

“…So far, a variety of effective coupling approaches have been demonstrated, [5] including end-fire coupling, [6][7][8][9][10][11] grating coupling, [12][13][14][15][16][17][18] and fiber-taper-assisted adiabatic coupling. [19][20][21][22][23][24] While they have been successfully applied with high efficiency and broad bandwidth, [8,24] high flexibility and large alignment tolerance remain challenging.…”