title: Optical nonlinearity enhancement with graphene-decorated silicon waveguides.
abstract: Broadband on-chip optical frequency combs (OFCs) are important for expanding the functionality of photonic integrated circuits. Here, we demonstrate a huge local optical nonlinearity enhancement using graphene. A waveguide is decorated with graphene by precisely manipulating graphene's area and position. Our approach simultaneously achieves both an extremely efficient supercontinuum and ultra-short pulse generation. With our graphene-decorated silicon waveguide (G-SWG), we have achieved enhanced spectral broadening of femtosecond pump pulses, along with an eightfold increase in the output optical intensity at a wavelength approximately 200 nm shorter than that of the pump pulses. We also found that this huge nonlinearity works as a compressor that effectively compresses pulse width from 80 to 15.7 fs. Our results clearly show the potential for our G-SWG to greatly boost the speed and capacity of future communications with lower power consumption, and our method will further decrease the required pump laser power because it can be applied to decorate various kinds of waveguides with various two-dimensional materials.
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishizawa
authors.affiliation: NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.|NTT Device Technology Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Rai
authors.initials: R
authors.lastname: Kou
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.|Tokyo Denki University, Department of Electrical and Electronic Engineering, 5 Senjyu Asahi-cho, Adachi-ku, Tokyo, 120-8551, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Goto
authors.affiliation: NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.|NTT Device Technology Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Tai
authors.initials: T
authors.lastname: Tsuchizawa
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.|NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matsuda
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hitachi
authors.affiliation: Tokyo Denki University, Department of Electrical and Electronic Engineering, 5 Senjyu Asahi-cho, Adachi-ku, Tokyo, 120-8551, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nishikawa
authors.affiliation: NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.|NTT Device Technology Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamada
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Tetsuomi
authors.initials: T
authors.lastname: Sogawa
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-0198, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Gotoh