Harnessing plasma absorption in silicon MOS ring modulators

High-bandwidth, low-power and compact silicon electro-optical modulators are essential for future energy-efficient densely integrated optical data communication circuits. The all-silicon plasma-dispersion-effect ring resonator modulator is an attractive prospect. However, its performance currently limited by the trade-off between modulation depth switching speed, dictated quality factor. Here we introduce a mechanism to leap beyond this limitation harnessing plasma absorption induced in metal–oxide–semiconductor waveguide enhance extinction ratio of low-quality-factor, high-speed modulator. fabricated devices demonstrate ~27 dB bias ~3.5 V. Modulation enhancement has been observed operation frequencies ranging from kilohertz gigahertz, with up 100 Gbit s−1 on–off keying demonstrated, paving way evolution interconnects Gbaud per wavelength. effect demonstrated modulators.