High Efficient Ge Surface Absorption Through Hybridized Cavity and Horizontal Surface Plasmon Modes

Author

Yi-ting Liao ; Lee, Ming-Chang M.

Author_Institution

Inst. Photonics Technol., Nat. Tsing Hua Univ., Hsinchu, Taiwan

Volume

33

Issue

13

fYear

2015

fDate

July1, 1 2015

Firstpage

2765

Lastpage

2769

Abstract

A new Au-SiO₂-Si stack grating structure to efficiently couple normally incident light to Au-Ge surface plasmon modes for enhancing Ge surface absorption is presented. Through an optimized design on the grating dimension, the surface plasmon modes are hybridized with a cavity mode for both suppressing light reflection and transmission to the Ge substrate. About 70% Ge absorption occurs in a 0.15-μm shallow layer near the Ge surface at the wavelength of 1.38 μm. Such a short absorption length is desirable for implementing a low-noised Ge avalanche photodiode.

Keywords

avalanche photodiodes; diffraction gratings; germanium; gold; light absorption; light reflection; light transmission; micro-optics; optical couplers; optical design techniques; silicon; silicon compounds; surface plasmons; Au-Ge; Au-SiO₂-Si; gold-germanium surface plasmon modes; gold-silica-silicon stack grating structure; high efficient germanium surface absorption; horizontal surface plasmon modes; hybridized cavity mode; light reflection suppression; light transmission suppression; low-noised germanium avalanche photodiode; optical coupling; size 0.15 mum; wavelength 1.38 mum; Absorption; Gold; Gratings; Optical surface waves; Reflection; Substrates; Surface waves; Ge avalanche photodiodes; grating high index waveguide structure; high index waveguide structure; localization of light; plasmon modes; surface plasmon modes;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2015.2412372

Filename

7058392