We report the design and the fabrication of an integrated optofluidic ring resonator based on liquid core antiresonant reflecting optical waveguide (ARROW) operating around λ=635nm with a water filled core (nc=1.33). This waveguide permits a strong coupling between light and analyte as the same microchannel can be used for delivering sample and for confining light. A rectangular-shaped ring resonator has been realized by using four 90-bent waveguides and an multimode interference coupler is used for coupling light from the input bus waveguide to the resonator. The resulting device is very compact, with a total length of 2.5 mm and a required liquid volume of about 0.11nl. The device has been simulated with a two dimensional finite-difference time-domain method for different refractive index core n_c=1.32 (methanol) and n_c=1.43 (dimethylformamide). Moreover, we carried out optical measurements by measuring the transmitted spectrum from the output bus waveguide in both cases. The experimental results confirm that ring with a good quality factor (Q~800) can be achieved in good agreement with the numerical results.

Date Published: 17 January 2011
PDF: 7 pages
Proc. SPIE 7943, Silicon Photonics VI, 794309 (17 January 2011); doi: 10.1117/12.874806

Published in SPIE Proceedings Vol. 7943:
Silicon Photonics VI
Joel A. Kubby; Graham T. Reed, Editor(s)