Compact titanium dioxide waveguides with high nonlinearity at telecommunication wavelengths

• Published in: Optics express Vol. 26; no. 2; pp. 1055 - 1063
• Main Authors: Guan, Xiaowei, Hu, Hao, Oxenløwe, Leif K, Frandsen, Lars H
• Format: Journal Article
• Language: English
• Published: United States 22.01.2018
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.26.001055

Dense integration of photonic integrated circuits demands waveguides simultaneously fulfilling requirements on compactness, low loss, high nonlinearity, and capabilities for mass production. In this work, titanium dioxide waveguides with a thick core of 380 nm exhibiting a compact mode size (0.43 μm ) and a low loss (5.4 ± 1 dB/cm) at telecommunication wavelengths around 1550 nm have been fabricated and measured. A microring resonator having a 50 μm radius has been measured to have a loaded quality factor of 53500. Four-wave mixing experiments reveal a nonlinear parameter for the waveguides of 21-34 W m corresponding to a nonlinear index around 2.3-3.6 x 10 m /W, which results in a wavelength conversion efficiency of -36.2 dB. These performances, together with the potentially simple dispersion engineering to the fabricated waveguides by the post processes, yield a strong promise for the titanium dioxide waveguides applied in photonic integrated circuits, especially for nonlinear implementations.