DocumentCode :
844111
Title :
Single-mode and polarization-independent silicon-on-insulator waveguides with small cross section
Author :
Chan, Seong Phun ; Png, Ching Eng ; Lim, Soon Thor ; Reed, Graham T. ; Passaro, Vittorio M N
Author_Institution :
Sch. of Electron. & Phys. Sci., Univ. of Surrey, Guildford, UK
Volume :
23
Issue :
6
fYear :
2005
fDate :
6/1/2005 12:00:00 AM
Firstpage :
2103
Lastpage :
2111
Abstract :
The fabrication restrictions that must be imposed on the geometry of optical waveguides to make them behave as single-mode devices are well known for relatively large waveguides, with shallow etch depth. However, the restrictions for small waveguides (∼1 μm or less in cross section) are not well understood. Furthermore, it is usually a requirement that these waveguides are polarization independent, which further complicates the issues. This paper reports on the simulations of the conditions for both single-mode behavior and polarization independence, for small and deeply etched silicon-on-insulator (SOI) waveguides. The aim is to satisfy both conditions simultaneously. The results show that at larger waveguide widths, waveguide etch depth has little effect on the mode birefringence because the transverse-electric (TE) mode (horizontal-polarized mode) is well confined under the rib region. However, at smaller rib widths, the etch depth has a large influence on birefringence. An approximate equation relating the rib-waveguide width and etch depth to obtain polarization-independent operation is derived. It is possible to achieve single-mode operation at both polarizations while maintaining polarization independence for each of the waveguide heights used in this paper but may be difficult for other dimensions. For example, a 1-μm SOI rib waveguide with an etch depth of 0.64 μm and rib width of 0.52 μm is predicted to exhibit such characteristics.
Keywords :
birefringence; etching; light polarisation; optical design techniques; optical fabrication; optical waveguide theory; rib waveguides; silicon-on-insulator; 0.52 mum; 0.64 mum; 1 mum; SOI rib-waveguide; Si; etch depth; fabrication restrictions; horizontal-polarized mode; mode birefringence; polarization-independent silicon-on-insulator waveguides; single-mode silicon-on-insulator waveguides; small cross section waveguide fabrication; transverse-electric mode; Birefringence; Equations; Etching; Geometrical optics; Optical device fabrication; Optical devices; Optical polarization; Optical waveguides; Silicon on insulator technology; Tellurium; Polarization independence; rib waveguides; silicon-on-insulator (SOI); single-mode condition (SMC);
fLanguage :
English
Journal_Title :
Lightwave Technology, Journal of
Publisher :
ieee
ISSN :
0733-8724
Type :
jour
DOI :
10.1109/JLT.2005.849883
Filename :
1440518
Link To Document :
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