Grating couplers integrated on Mach-Zehnder interferometric biosensors operating in the visible range
D. Duval, J. Osmond, S. Dante, C. Domínguez, and L. M. Lechuga
IEEE Photonics Journal, 5 Nº2, 2013, 3700108/1-8 - DOI: 10.1109/JPHOT.2013.2251873
Abstract: We present the design, fabrication and characterization of sub-micronic grating couplers integrated on Si3N4 rib waveguide Mach-Zehnder Interferometers (MZI) for biosensing applications working in the visible spectral range for both TE and TM polarizations. Depending on the waveguide structure, a maximum of 11.5% of coupling efficiency has been experimentally obtained at 658 nm, while a limit of detection of 1.6×10-7 in refractive index unit is achieved for the biosensor. These results represent an important milestone towards the achievement of a truly portable and multiplexed point-of-care platform using the integrated MZI sensor.