Mid-Infrared Grating Couplers for Silicon-on-Sapphire Waveguides

Author

Cheng, Zhenzhou ; Chen, Xia ; Wong, C.Y. ; Xu, Ke ; Fung, Christy K Y ; Chen, Y.M. ; Tsang, Hon Ki

Author_Institution

Dept. of Electron. Eng., Chinese Univ. of Hong Kong, Hong Kong, China

Volume

4

Issue

1

fYear

2012

Firstpage

104

Lastpage

113

Abstract

Theoretical and experimental results of mid-infrared (mid-IR) gratings for coupling between transverse-electric (TE)/transverse-magnetic (TM) mode silicon-on-sapphire (SOS) waveguides and zirconium, barium, lanthanum, aluminum, and sodium fluoride (ZBLAN) fibers are presented. The shallow-etched uniform grating, full-etched subwavelength grating, and apodized grating are analyzed theoretically. TE mode shallow-etched apodized gratings with coupling efficiency of 80.6% and TM mode full-etched apodized subwavelength gratings with coupling efficiency of 39.6% are predicted at the wavelength of 2.75 by finite-difference time-domain (FDTD) simulation. An co-doped ZBLAN fiber laser is set up to be used as a mid-IR light source at 2.75 . Coupling efficiencies of 32.6% and 11.6% to TE mode and TM mode SOS waveguides, respectively, were obtained experimentally with uniform grating couplers. The dependence of coupling efficiency on etch depth, grating period, fill factor, and incident angle are also studied.

Keywords

aluminium compounds; barium compounds; diffraction gratings; fibre lasers; finite difference time-domain analysis; integrated optics; lanthanum compounds; optical couplers; optical waveguides; silicon-on-insulator; sodium compounds; zirconium compounds; TE mode shallow-etched apodized gratings; ZBLAN fiber laser; ZrF₄BaF₂LaF₃AlF₃NaF; coupling efficiency; fill factor; finite-difference time-domain simulation; full-etched subwavelength grating; incident angle; mid-infrared grating couplers; shallow-etched uniform grating; silicon-on-sapphire waveguides; Couplers; Couplings; Fiber gratings; Gratings; Optical fiber couplers; Silicon; Mid-infrared (mid-IR); gratings; integrated optics; silicon-on-sapphire (SOS); subwavelength structures;

fLanguage

English

Journal_Title

Photonics Journal, IEEE

Publisher

ieee

ISSN

1943-0655

Type

jour

DOI

10.1109/JPHOT.2011.2179921

Filename

6105500