Experimental demonstration of the Vernier effect using series-coupled racetrack resonators

Abstract

We demonstrate the design and performance of series-coupled racetrack resonators in silicon-on-insulator. The device was modeled and optimized by tuning various parameters such as power coupling factors and resonator dimensions. The Vernier effect is experimentally verified with an extended free spectral range of 36.2 nm and an interstitial resonance suppression of more than 11 dB. To the best of our knowledge, we have shown the closest match between experimental and theoretical results for the Vernier effect. Devices exhibiting similar performance to the one reported on here should be useful in applications such as wavelength division multiplexers and optical sensors.