Multiple Layers of Silicon-Silica (Si-SiO2) Pair onto Silicon Substrate towards Highly Efficient, Wideband Silicon Photonic Grating Coupler

A single mode waveguide grating coupler based on multiple Si-SiO2 pairs onto Si substrate has been designed. Numerical analysis has been carried out to calculate optimum thickness of the layers of Si-SiO2 that ensures the constructive interference between reflected waves and actual guided wave for high coupling efficiency. Based on the results, an optimal design is developed and modeled by using a 2-D finite difference time domain (2-D FDTD) simulator that dictates a coupling efficiency of as much as 78% (-1.07 dB) at the wavelength of 1550 nm, and a 1-dB bandwidth of 77 nm. The numerical method will be useful to calculate the optimum thicknesses of the layers for any reflector based grating coupler of different materials.

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Novel Low-Loss Fiber-Chip Edge Coupler for Coupling Standard Single Mode Fibers to Silicon Photonic Wire Waveguides

Photonics ◽

10.3390/photonics8030079 ◽

2021 ◽

Vol 8 (3) ◽

pp. 79

Author(s):

Siwei Sun ◽

Ying Chen ◽

Yu Sun ◽

Fengman Liu ◽

Liqiang Cao

Keyword(s):

Optical Fibers ◽

Silicon Photonics ◽

Coupling Efficiency ◽

Single Mode ◽

Spot Size ◽

Silicon On Insulator ◽

Multiple Structure ◽

Silicon Photonic ◽

Mode Size ◽

Photonic Wire

Fiber-to-chip optical interconnects is a big challenge in silicon photonics application scenarios such as data centers and optical transmission systems. An edge coupler, compared to optical grating, is appealing to in the application of silicon photonics due to the high coupling efficiency between standard optical fibers (SMF-28) and the sub-micron silicon wire waveguides. In this work, we proposed a novel fiber–chip edge coupler approach with a large mode size for silicon photonic wire waveguides. The edge coupler consists of a multiple structure which was fulfilled by multiple silicon nitride layers embedded in SiO2 upper cladding, curved waveguides and two adiabatic spot size converter (SSC) sections. The multiple structure can allow light directly coupling from large mode size fiber-to-chip coupler, and then the curved waveguides and SSCs transmit the evanescent field to a 220 nm-thick silicon wire waveguide based on the silicon-on-insulator (SOI) platform. The edge coupler, designed for a standard SMF-28 fiber with 8.2 μm mode field diameter (MFD) at a wavelength of 1550 nm, exhibits a mode overlap efficiency exceeding 95% at the chip facet and the overall coupling exceeding 90%. The proposed edge coupler is fully compatible with standard microfabrication processes.

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Vertical Injection and Wideband Grating Coupler Based on Asymmetric Grating Trenches

10.21203/rs.3.rs-1018030/v1 ◽

2021 ◽

Author(s):

Md Asaduzzaman ◽

Robert J. Chapman ◽

Brett C. Johnson ◽

Alberto Peruzzo

Keyword(s):

Fdtd Method ◽

Coupling Efficiency ◽

Silicon On Insulator ◽

Subwavelength Structures ◽

Grating Coupler ◽

Subwavelength Gratings ◽

Vertical Injection ◽

Index Variation ◽

2D Fdtd ◽

Difference Time

Abstract A Silicon-on-insulator (SOI) perfectly vertical fibre-to-chip grating coupler is proposed and designed based on engineered subwavelength structures. The high directionality of the coupler is achieved by implementing step gratings to realize asymmetric diffraction and by applying effective index variation with auxiliary ultra-subwavelength gratings. The proposed structure is numerically analysed by using two-dimensional Finite Difference Time Domain (2D FDTD) method and achieves 76% (-1.19 dB) coupling efficiency and 39 nm 1-dB bandwidth.

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A high efficiency silicon nitride waveguide grating coupler with a multilayer bottom reflector

Scientific Reports ◽

10.1038/s41598-019-49324-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Jianxun Hong ◽

Andrew M. Spring ◽

Feng Qiu ◽

Shiyoshi Yokoyama

Keyword(s):

Silicon Nitride ◽

Integrated Circuits ◽

High Efficiency ◽

Photonic Integrated Circuits ◽

Coupling Efficiency ◽

Optical Characterization ◽

Grating Coupler ◽

Waveguide Grating ◽

Quarter Wave

Abstract We propose a high efficiency apodized grating coupler with a bottom reflector for silicon nitride photonic integrated circuits. The reflector consists of a stack of alternate silicon nitride and silicon dioxide quarter-wave films. The design, fabrication and optical characterization of the couplers has been presented. The measured fiber to detector insertion loss was −3.5 dB which corresponds to a peak coupling efficiency of −1.75 dB. A 3 dB wavelength bandwidth of 76.34 nm was demonstrated for the grating coupler with a 20-layer reflector. The fabrication process is CMOS-compatible and requires only a single etching step.

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Large-Area Binary Blazed Grating Coupler between Nanophotonic Waveguide and LED

The Scientific World JOURNAL ◽

10.1155/2014/586517 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

Hongqiang Li ◽

Wenqian Zhou ◽

Meiling Zhang ◽

Yu Liu ◽

Cheng Zhang ◽

...

Keyword(s):

Incident Angle ◽

Coupling Efficiency ◽

Silicon On Insulator ◽

Grating Coupler ◽

Large Area ◽

Blazed Grating ◽

Light Emitting ◽

Arrayed Waveguide ◽

First Time ◽

Difference Time

A large-area binary blazed grating coupler for the arrayed waveguide grating (AWG) demodulation integrated microsystem on silicon-on-insulator (SOI) was designed for the first time. Through the coupler, light can be coupled into the SOI waveguide from the InP-based C-band LED for the AWG demodulation integrated microsystem to function. Both the length and width of the grating coupler are 360 μm, as large as the InP-based C-band LED light emitting area in the system. The coupler was designed and optimized based on the finite difference time domain method. When the incident angle of the light source is0°, the coupling efficiency of the binary blazed grating is 40.92%, and the 3 dB bandwidth is 72 nm at a wavelength of 1550 nm.

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