Abstract

On-chip formation and manipulation of ultrashort pulses would be of great interest to ultrafast optics and integrated photonics communities. One of key issues is dispersion-assisted nonlinear interactions of broadband frequency components. In this article, we show for the first time that a bilayer waveguide for quasi-TE mode without using a slot produces a quite flat and saddle-shaped dispersion profile. Different from previously reported TE-mode waveguides with flattened dispersion, the proposed waveguide exhibits a greatly simplified structure with no need for a high-aspect-ratio slot and has quite small group delay difference in a wide spectral range with four zero-dispersion wavelengths (ZDWs). We study supercontinuum generation in hybrid dispersion regime for the first time, in which the broadened spectrum covers a bandwidth with all ZDWs. It is found that one can obtain greatly improved spectral flatness in supercontinuum generation, with a power variation as small as 3 dB over a bandwidth of >500 nm. Moreover, the proposed waveguides are particularly suitable for low-distortion pulse propagation over a long distance, which is important for on-chip ultrashort pulse delivery.

Bilayer dispersion-flattened waveguides with four zero-dispersion wavelengths

Yuhao Guo, Zeinab Jafari, Anu M. Agarwal, Lionel C. Kimerling, Guifang Li, Jurgen Michel, and Lin Zhang
Opt. Lett. 41(21) 4939-4942 (2016)

Silicon waveguide with four zero-dispersion wavelengths and its application in on-chip octave-spanning supercontinuum generation

Lin Zhang, Qiang Lin, Yang Yue, Yan Yan, Raymond G. Beausoleil, and Alan E. Willner
Opt. Express 20(2) 1685-1690 (2012)

Flattened dispersion in silicon slot waveguides

Lin Zhang, Yang Yue, Raymond G. Beausoleil, and Alan E. Willner
Opt. Express 18(19) 20529-20534 (2010)

Ultra-flat dispersion in an integrated waveguide with five and six zero-dispersion wavelengths for mid-infrared photonics

Yuhao Guo, Zeinab Jafari, Lijuan Xu, Changjing Bao, Peicheng Liao, Guifang Li, Anuradha M. Agarwal, Lionel C. Kimerling, Jurgen Michel, Alan E. Willner, and Lin Zhang
Photon. Res. 7(11) 1279-1286 (2019)

Increased bandwidth with flattened and low dispersion in a horizontal double-slot silicon waveguide

Changjing Bao, Yan Yan, Lin Zhang, Yang Yue, Nisar Ahmed, Anuradha M. Agarwal, Lionel C. Kimerling, Jurgen Michel, and Alan E. Willner
J. Opt. Soc. Am. B 32(1) 26-30 (2015)