Open AccessCompact epsilon-near-zero silicon photonic phase modulators
Author(s) -
Isak C. Reines,
Michael G. Wood,
Ting S. Luk,
Darwin K. Serkland,
Salvatore Campione
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.021594
Subject(s) - materials science , phase modulation , figure of merit , miniaturization , optoelectronics , photonics , silicon , modulation (music) , fabrication , phase (matter) , silicon photonics , optical modulator , optics , nanotechnology , physics , phase noise , medicine , alternative medicine , pathology , quantum mechanics , acoustics
In this paper, we analyze a compact silicon photonic phase modulator at 1.55 μm using epsilon-near-zero transparent conducting oxide (TCO) films. The operating principle of the non-resonant phase modulator is field-effect carrier density modulation in a thin TCO film deposited on top of a passive silicon waveguide with a CMOS-compatible fabrication process. We compare phase modulator performance using both indium oxide (In 2 O 3 ) and cadmium oxide (CdO) TCO materials. Our findings show that practical phase modulation can be achieved only when using high-mobility (i.e. low-loss) epsilon-near-zero materials such as CdO. The CdO-based phase modulator has a figure of merit of 17.1°/dB in a compact 5 μm length. This figure of merit can be increased further through the proper selection of high-mobility TCOs, opening a path for device miniaturization and increased phase shifts.