Sensitivity enhancement of 1-D photonic crystal by waveguide width variation for biosensing application

The technique to enhance and control the sensitivity of a one dimensional photonic crystal biosensor has been investigated by using 3D FDTD and Eigen mode solver in Lumerical software. Our results show that by reducing the waveguide width, sensitivity of the ID-PhC biosensor device will increase. This can be explained by observing the evanescent field strength shown by the mode profile which differs at particular width. By using this technique, the sensitivity can be enhanced and control geometrically. The highest sensitivity obtained is 307 nm/RIU. However by shifting the light energy from inside to outside of the waveguide, light confinement is sacrificed and may result in lower quality factor device.