CMOS-compatible ring-based active devices have attracted significant attention for their ability to confine and manipulate light on a compact SOI platform. Active modulation of a ring resonator is typically achieved by changing the intensity response. As an alternative to intensity modulation, the phase modulation of the ring resonator can be converted into intensity modulation of a Mach-Zehnder interferometer (MZI) by means of a ring-assisted Mach-Zehnder interferometer (RAMZI) structure. We theoretically demonstrate an all-optical single resonance switching using a silicon RAMZI by optically controlling the intracavity loss of the side-coupled silicon ring based on inverse Raman scattering (IRS). The RAMZI structure improves the modulation robustness against fabrication deviations by relaxing the coupling condition for the ring resonator, without compensating the modulation performance. In silicon, the IRS produces optical loss with a bandwidth of 105 GHz at the anti-Stokes wavelength, which blueshifts 15.6 THz from the control light. For our proposed RAMZI structure, the IRS induced loss is spectrally wider than the linewidth of the side-coupled ring, but narrower than the free spectral range (FSR) of the ring, guaranteeing single resonance selectivity. When the control light pulse of 200 ps switches from off (zero) to on (20pJ), the transmission of the anti-Stokes resonance transfers from 1.7% to 92.3%. The proposed structure provides the potential to multichannel all-optical routers on a CMOS compatible platform.

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Silicon Photonics VIII
Department of Electronics

Xiong, Y. (Yule), & Ye, W.N. (2013). All-optical single resonance control using a silicon-based ringassisted mach-zehnder interferometer. In Proceedings of SPIE - The International Society for Optical Engineering. doi:10.1117/12.2000995