Integration of high transmittance photonic crystal H2 nanocavity and broadband W1 waveguide for biosensing applications based on Silicon-on-Insulator substrate

• Published in: Optics communications Vol. 330; pp. 175 - 183
• Main Authors: Zhou, Jian, Tian, Huiping, Yang, Daquan, Liu, Qi, Ji, Yuefeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2014
• Subjects: Biosensor; Nanocavity; Photonic crystal; SOI; Waveguide; Nanocavity; SOI; Photonic crystal; Waveguide; Biosensor
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2014.04.075

In this paper, we exhibit an integration of simultaneously high transmittance and high extinction ratio H2-type photonic crystal (PhC) nanocavitiy and broadband W1 waveguide above Silicon-on-Insulator (SOI) substrate. The integrated structure can be used as an opto-fluidic architecture for label-free biochemical detection with high resolution and large sensing range. With the plane-wave expansion (PWE) method, the results show a single resonant mode operation at normalized frequency between 0.2213 (2πc/a) and 0.2917 (2πc/a), which correspond to wide resonant wavelength ranges from 1440 to 1898nm. By applying three-dimensional finite-difference time-domain (3D-FDTD) technique, we simulate the change of optical properties caused by the H2 structural variation. Through modifying the number and sizes of the air-holes near to the defect cavity, over 95% transmission efficiency is achieved, accompanied with an improved extinction ratio of 25dB. Combined broadband W1 waveguide with high transmittance H2 nanocavity well meets the demand of extensive biosensing. In addition, a high resolution that we show to be Ο(10−6) refractive index units (RIU) under optimal conditions.