A simple and novel method to obtain an FSR free silicon ring resonator

A simple and novel method to make a silicon ring resonator without the limit of free spectral range (FSR) is presented. For many applications, a ring resonator is desired with an ultra-wide FSR, a high quality factor, a large extinction ratio and low-fabrication complexity. In this paper we propose a novel method to obtain such a ring resonator, which is a single all-silicon micro-ring with a FSR as large as 150 nm around 1550 nm. It's based on the well-known phenomenon of resonance splitting

Using backscattering and backcoupling in silicon ring resonators as a new degree of design freedom

Silicon optical ring resonators are potentially valuable for many applications. Due to the limited design freedom (coupling coefficient and roundtrip length), the functionality and performance cannot always be fully explored and optimized. In addition, high-contrast silicon ring resonators suffer from parasitic coupling between their clockwise and counterclockwise modes as well as parasitic coupling from the input to both circulating modes, which degrades or even distorts the response. Herein, an overview is given to harness these effects as additional design parameters to overcome the detrimental effects and realize novel functionalities in silicon ring resonators. Through simulations and experimental characterization, it is shown how the manipulation of backreflection and backcoupling enables various novel functions, including tunable Fano resonances with maximum slope rate over 700 dB nm(-1), tunable electromagnetically induced transparency, which slows light down over 1100 ps, a single-mode silicon ring resonator with a free spectral range over 150 nm and tuning efficiency over 11 times higher compared to that of conventional silicon ring resonators, fundamental suppression of inevitable backscattering, spectral tuning, single sideband filtering, and ultrahigh Q/large finesse resonances

Tunable electromagnetically induced transparency in integrated silicon photonics circuit

We comprehensively simulate and experimentally demonstrate a novel approach to generate tunable electromagnetically induced transparency (EIT) in a fully integrated silicon photonics circuit. It can also generate tunable fast and slow light. The circuit is a single ring resonator with two integrated tunable reflectors inside, which form an embedded Fabry-Perot (FP) cavity inside the ring cavity. The mode of the FP cavity can be controlled by tuning the reflections using integrated thermo-optic tuners. Under correct tuning conditions, the interaction of the FP mode and the ring resonance mode will generate a Fano resonance and an EIT response. The extinction ratio and bandwidth of the EIT can be tuned by controlling the reflectors. Measured group delay proves that both fast light and slow light can be generated under different tuning conditions. A maximum group delay of 1100 ps is observed because of EIT. Pulse advance around 1200 ps is also demonstrated. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen