Quadruple optical ring resonator based filter on silicon-on-insulator

Free spectral range (FSR) expansion upto 705.39 THz has been achieved using quadruple optical ring resonator (QORR) made of high index contrast Silicon on insulator (SOI) waveguides. SOI waveguide not only takes care of bending loss, microrings made of SOI waveguides provide higher integration density because of its size. Group delay and resulting dispersion and finesse have been studied. Delay line signal processing technique coupled with Mason's rule has been used to analyze the QORR performance. Vernier principle has been used to enhance the FSR. FSR obtained in this work is the maximum to the best of the author's knowledge for similar class of optical passive devices. Further adequate suppression of the spurious interstitial mode is in the level of approximately −35 dB with almost zero resonance loss. Further the performance of such device has been compared with QORR with similar architecture but made of with conventional glass silica waveguides.