Low-loss silicon core fibre platform for mid-infrared nonlinear photonics

Haonan Ren; Li Shen; Antoine F J Runge; Thomas W Hawkins; John Ballato; Ursula Gibson; Anna C Peacock

doi:10.1038/s41377-019-0217-z

Low-loss silicon core fibre platform for mid-infrared nonlinear photonics

Light Sci Appl. 2019 Nov 21:8:105. doi: 10.1038/s41377-019-0217-z. eCollection 2019.

Authors

Haonan Ren¹, Li Shen^{1

2}, Antoine F J Runge^{1

3}, Thomas W Hawkins⁴, John Ballato⁴, Ursula Gibson^{5

6}, Anna C Peacock¹

Affiliations

¹ 1Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK.
² 2Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 430074 Wuhan, China.
³ 6Present Address: The Institute of Photonics and Optical Science (IPOS), School of Physics, University of Sydney, Sydney, NSW 2006 Australia.
⁴ 3Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634 USA.
⁵ 4Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
⁶ 5Department of Applied Physics, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.

Abstract

Broadband mid-infrared light sources are highly desired for wide-ranging applications that span free-space communications to spectroscopy. In recent years, silicon has attracted great interest as a platform for nonlinear optical wavelength conversion in this region, owing to its low losses (linear and nonlinear) and high stability. However, most research in this area has made use of small core waveguides fabricated from silicon-on-insulator platforms, which suffer from high absorption losses of the use of silica cladding, limiting their ability to generate light beyond 3 µm. Here, we design and demonstrate a compact silicon core, silica-clad waveguide platform that has low losses across the entire silicon transparency window. The waveguides are fabricated from a silicon core fibre that is tapered to engineer mode properties to ensure efficient nonlinear propagation in the core with minimal interaction of the mid-infrared light with the cladding. These waveguides exhibit many of the benefits of fibre platforms, such as a high coupling efficiency and power handling capability, allowing for the generation of mid-infrared supercontinuum spectra with high brightness and coherence spanning almost two octaves (1.6-5.3 µm).

Keywords: Mid-infrared photonics; Nonlinear optics; Silicon photonics.