Experimental investigation on ring resonator based filters in SiON technology

Promising candidates for filtering, packing, separating and managing large numbers of channels in a Dense Wavelength Division Multiplexing DWDM systems are the circuits based on ring resonators. Rings with Free Spectral Range FSR ranging from few GHz [1] up to some THz [2] have been demonstrated in various technologies, both passive and active. However, there are several constraints in using ring resonators: losses, tolerances sensitivity, technological issues, tunability, transfer function and so on. In this contribution we analyse the characteristics of a single ring, try to find the limits of various known ring based circuits and present the results of an experimental investigation on rings realised with SiON technology with an index contrast ∆n=6% [3, 4].