Design and modeling of double Panda-microring resonator as multi-band optical filter

Abstract

In this paper, the behavior of light within a double stage developed add-drop ring resonator called a double Vernier Panda-ring resonator (DVPR) is investigated using the signal flow graph technique in the Z-domain and Mason’s gain rule. The system included a double stage of add-drop ring resonators that each add-drop ring is attached to two small lateral resonators. The light transmission through the DVPR system is studied and the system responses analyzed in terms of the fundamental physical properties such as the free spectral range (FSR), structural dispersion, group delay, finesse, Q-factor and resonant bandwidth. Based on the coupling strength between the add-drop rings and the small lateral resonators (indirect couplers), different values of extended FSR from 64 nm to 90 nm were realized in the wavelength region of 1.4–1.7μm. Results analyzed for four values of indirect coupling strengths and the optimum layout was determined, which led to realize of a FWHM as narrow as 0.47 nm, the extended FSR of 81 nm for the center wavelength of 1535 nm, the structural dispersion of 6.0 fs/pm and a group delay of 3.9 ps. The superiority of DVPR design rather than the conventional Vernier ring-based filter is in achieving several values for extended FSRs, which provides different optical communication channels. These characteristics of our proposed structure ensure the tuning of optical communication channels by means of an optical device, which is desirable in the optical communication networks