Analysis of bulk material sensing using a periodically segmented waveguide Mach-Zehnder interferometer for biosensing

Analysis of a periodically segmented Mach-Zehnder interferometer (MZI), intended for use as a biosensor, was performed using a "modular block" algorithm. The theoretical sensitivity limit increases with the number of cycles but is limited by cumulative attenuation. The periodically segmented MZI was found to exhibit better sensitivity than alternative methods under the same working conditions. However, devices with a high number of cycles (>350) were found to be impractical due to high attenuation losses. A 48-cycle periodically segmented waveguide MZI, with a predicted sensitivity limit of /spl delta/n/sub min//spl sim/3.96*10/sup -5/, requires a shorter sensing length (0.24 mm) than that of alternative devices with similar sensitivity.