Four-wave mixing parametric oscillation and frequency comb generation at visible wavelengths in a silica microbubble resonator

• DOI: 10.1364/ol.41.005266
• Publication Date: 2016-11-07T21:33:24Z
• Authors: Yong Yang; Xuefeng Jiang; Sho Kasumie; Guangming Zhao; Linhua Xu; Jonathan M. Ward; Lan Yang; Síle Nic Chormaic
• Keywords: 0103 physical sciences; FOS: Physical sciences; 01 natural sciences; Physics - Optics; Optics (physics.optics)

Frequency comb generation in microresonators at visible wavelengths has found applications in a variety of areas such as metrology, sensing, and imaging. To achieve Kerr combs based on four-wave mixing in a microresonator, dispersion must be in the anomalous regime. In this work, we demonstrate dispersion engineering in a microbubble resonator (MBR) fabricated by a two-CO$_2$ laser beam technique. By decreasing the wall thickness of the MBR down to 1.4 $��$m, the zero dispersion wavelength shifts to values shorter than 764 nm, making phase matching possible around 765 nm. With the optical \textit{Q}-factor of the MBR modes being greater than $10^7$, four-wave mixing is observed at 765 nm for a pump power of 3 mW. By increasing the pump power, parametric oscillation is achieved, and a frequency comb with 14 comb lines is generated at visible wavelengths.