On the pass‑ and stop‑band optical fltering by passive silicon photonic circuits using square‑layout MZI ring(s)
M. M. Ariannejad, Jian Ding Tan, Chia Chao Kang, M. Ghasemi, S. M. Hamidi, P. K. Choudhury
Silicon photonic square-layout ring resonator-based circuits comprising Mach–Zehnder interferometers (MZIs), grating couplers, three-port splitters and combiners were designed, modeled, and fabricated for efcient control over the stop-band and pass-band fltering of transmission spectrum. It was found that exploiting square-layout rings and assigning an MZI (called the master MZI) to the grating couplers of the used photonic circuits allow engineering the optical stop-band, creation of multi pass-band and the quality of fltering. Excluding the master MZI and using only single square-layout ring of MZIs would yield a two-lobe spectrum having a sharp narrow stop-band at 1542 nm wavelength, whereas with a two-ring confguration, its width extends up to 20 nm. Furthermore, including the master MZI within the circuit confguration eliminates lobes from the transmission spectrum and recreates a single lobe with large bandwidth and almost low ripple over the hat of the lobe. The optical response of the photonic circuit containing both the two-ring and master MZI leads to the formation of a single pass-band with an almost fat-hat lobe.