Wavelength filter exploiting serially coupled ring resonators fabricated by a standard silicon CMOS technology

Abstract

A photonic compact eight-channel wavelength filter has been proposed and fabricated by incorporating serially connected ring resonators based on a silicon rib waveguide.Eight different rings are subsequently addressed by a common input bus and individually out-coupled by output buses. A vertical grating coupler is attached to the input and output buses for efficient light coupling. Each of the launched optical signals is routed to the drop port of the corresponding channel, whose center wavelength is dependent on the size of the ring. The device was designed by using a finite-difference time-domain method and fabricated by exploiting a standard complementary metal-oxide-semiconductor silicon-on-insulator technology. The silicon rings, serially placed with a gap of 50 μm, have radii varying from 6.0 to 6.07 μm, leading to a channel wavelength ranging from 1546.3 to 1557.6 nm. As regards, the overall performance of the fabricated device, the quality factor is ∼13,600, the channel spacing ∼1.6 nm, the propagation loss ∼3 dB, and the channel crosstalk ∼27 dB. Finally, a group of optical signals modulated by a data signal at 3.2 Gbps were appropriately routed to yield a decent eye diagram. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:933–936, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26682