The longitudinal offset technique for apodization of coupled resonator optical waveguide devices: concept and fabrication tolerance analysis.
In this paper, a novel technique to set the coupling constant between cells of a coupled resonator optical waveguide (CROW) device, in order to tailor the filter response, is presented. The technique is demonstrated by simulation assuming a racetrack ring resonator geometry. It consists on changing the effective length of the coupling section by applying a longitudinal offset between the resonators. On the contrary, the conventional techniques are based in the transversal change of the distance between the ring resonators, in steps that are commonly below the current fabrication resolution step (nm scale), leading to strong restrictions in the designs. The proposed longitudinal offset technique allows a more precise control of the coupling and presents an increased robustness against the fabrication limitations, since the needed resolution step is two orders of magnitude higher. Both techniques are compared in terms of the transmission esponse of CROW devices, under finite fabrication resolution steps.
Doménech
José David
JD
Optical and Quantum Communications Group, iTEAM-Universidad Politécnica de Valencia, Valencia 46470, Spain. jodogo@iteam.upv.es
Muñoz
Pascual
P
Capmany
José
J
D000465:Algorithms; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D055096:Optical Devices; D055095:Optics and Photonics; D012815:Signal Processing, Computer-Assisted