Analysis of ring resonator structure with quality factor enhancement

In this work, the device is integrated with two bus waveguides and three ring waveguides. The ring and the bus waveguide is designed with a width of 250nm and a height of 400nm is considered. The mid infrared wavelength of 1550nm is considered as an input source for the coupling of light from the bus waveguide to ring waveguide. The coupling between the three ring waveguides is also observed. The multimode coupling takes place in the configuration. The guided mode resonance at 1550nm is observed. The four ports are placed at the inputs and outputs of the bus waveguide. Here the three ring structure with the bus waveguide is analyzed for spectral properties, where quality factor is of main concern. If the structure has to be implemented for a lab-on-a-chip application, sensitivity plays an important role, which in turn is related to the quality factor. Hence the enhancement of the quality factor up to 3000 with three rings is achieved. Two rings are considered as sensing ring for various parameter analyses with one of the ring as reference ring. In the designed structure, the phase shift in the transmission spectrum is observed for the bio-sensing application. The sensor in the ring resonator is based on the refractive index change. The change in the refractive index of the surrounding medium will change the effective refractive index. Hence the effective refractive index along with the group index is monitored for the bio-sensing application. A thin layer on the surface of the waveguide is highly sensitive to refractive index change in the TM mode. The configuration is simulated using Lumerical FDTD as well as Lumerical Mode solutions. The integrated optical devices has a good platform in bio-sensing application, hence the designed configuration can be further incorporated for point of care device.