Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27240%2F16%3A86097270" target="_blank" >RIV/61989100:27240/16:86097270 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1364/OE.24.005026" target="_blank" >http://dx.doi.org/10.1364/OE.24.005026</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1364/OE.24.005026" target="_blank" >10.1364/OE.24.005026</a>

Result language

angličtina

Original language name

Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides

Original language description

Fiber-chip edge couplers are extensively used in integrated optics for coupling of light between planar waveguide circuits and optical fibers. In this work, we report on a new fiber-chip edge coupler concept with large mode size for silicon photonic wire waveguides. The coupler allows direct coupling with conventional cleaved optical fibers with large mode size while circumventing the need for lensed fibers. The coupler is designed for 220 nm silicon-on-insulator (SOI) platform. It exhibits an overall coupling efficiency exceeding 90%, as independently confirmed by 3D Finite-Difference Time-Domain (FDTD) and fully vectorial 3D Eigenmode Expansion (EME) calculations. We present two specific coupler designs, namely for a high numerical aperture single mode optical fiber with 6 mu m mode field diameter (MFD) and a standard SMF-28 fiber with 10.4 mu m MFD. An important advantage of our coupler concept is the ability to expand the mode at the chip edge without leading to high substrate leakage losses through buried oxide (BOX), which in our design is set to 3 mu m. This remarkable feature is achieved by implementing in the SiO2 upper cladding thin high-index Si3N4 layers. The Si3N4 layers increase the effective refractive index of the upper cladding near the facet. The index is controlled along the taper by subwavelength refractive index engineering to facilitate adiabatic mode transformation to the silicon wire waveguide while the Si-wire waveguide is inversely tapered along the coupler. The mode overlap optimization at the chip facet is carried out with a full vectorial mode solver. The mode transformation along the coupler is studied using 3D-FDTD simulations and with fully-vectorial 3D-EME calculations. The couplers are optimized for operating with transverse electric (TE) polarization and the operating wavelength is centered at 1.55 mu m.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

JA - Electronics and optoelectronics

OECD FORD branch

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Project

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Continuities

O - Projekt operacniho programu

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

OPTICS EXPRESS

ISSN

1094-4087

e-ISSN

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Volume of the periodical

24

Issue of the periodical within the volume

5

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

5026-5038

UT code for WoS article

000371435000069

EID of the result in the Scopus database

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