Novel Stepped-Width Design Concept for Compact Multimode-Interference Couplers With Low Cross-Coupling Ratio

Author

Feng, David J Y ; Chang, Pai-Ying ; Lay, T.S. ; Chang, T.Y.

Author_Institution

Inst. of Electro-Opt. Eng., Nat. Sun Yat-Sen Univ., Kaohsiung

Volume

19

Issue

4

fYear

2007

Firstpage

224

Lastpage

226

Abstract

We show through detailed simulations that the length of conventionally designed multimode-interference couplers for low (<50%) cross-coupling ratios can be shortened significantly by replacing a segment that is 3/2-times the coupling length by a minimum-width design. For the 15% cross-coupling device, this stepped-width design results in 32% length reduction. With additional incorporation of adiabatic tapering, the length reduction can increase to over 44%. Shortening of the device makes it possible to fabricate ring resonators with larger free spectral range, significantly increases the 1-dB bandwidth for the total transmittance, and also helps to reduce the radiative loss

Keywords

integrated optics; light interference; optical couplers; optical design techniques; adiabatic tapering; coupling length; cross-coupling ratio; multimode-interference couplers; radiative loss; ring resonators; transmittance; Bandwidth; Couplers; Optical interferometry; Optical planar waveguides; Optical ring resonators; Optical waveguide components; Optical waveguides; Planar waveguides; Propagation losses; Slabs; Multimode-interference (MMI) coupler; optical waveguide components; photonic integrated circuit; planar waveguide;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2006.890762

Filename

4077076