Open AccessIntegration of low loss vertical slot waveguides on SOI photonic platforms for high efficiency carrier accumulation modulators
Author(s) -
Weiwei Zhang,
Martin Ebert,
Bigeng Chen,
Jamie D. Reynolds,
Xingzhao Yan,
Han Du,
Mehdi Banakar,
D. T. Tran,
Kapil Debnath,
Callum Littlejohns,
Shinichi Saito,
David J. Thomson
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.397044
Subject(s) - materials science , waveguide , silicon on insulator , optics , optoelectronics , silicon photonics , slotted waveguide , dielectric , photonic integrated circuit , silicon , photonics , electrical engineering , slot antenna , physics , directional antenna , antenna (radio) , engineering
Silicon accumulation type modulators offer prospects of high power efficiency, large bandwidth and high voltage phase linearity making them promising candidates for a number of advanced electro-optic applications. A significant challenge in the realisation of such a modulator is the fabrication of the passive waveguide structure which requires a thin dielectric layer to be positioned within the waveguide, i.e. slotted waveguides. Simultaneously, the fabricated slotted waveguide should be integrated with conventional rib waveguides with negligible optical transition losses. Here, successful integration of polysilicon and silicon slot waveguides enabling a low propagation loss 0.4-1.2 dB/mm together with an ultra-small optical mode conversion loss 0.04 dB between rib and slot waveguides is demonstrated. These fabricated slot waveguide with dielectric thermal SiO 2 layer thicknesses around 6 nm, 8 nm and 10 nm have been characterized under transmission electron microscopy allowing for strong carrier accumulation effects for MOS-capacitor electro-optic modulators.