Energy-Efficient All-Optical Control of Silicon Microring Resonators via the Optical Gradient Force

All-optical control of silicon photonic devices plays a key role in on-chip all-optical computing, switching and signal processing. However, due to the weak intrinsic nonlinear effects of silicon, current integrated devices are limited by high power consumptions. Here, an all-optical controllable optomechanical microring resonator (OMMR) is proposed and fabricated on the silicon platform. Due to the mechanical Kerr effect induced by the optical gradient force (OGF), we realize seamless wavelength tuning over a range of 2.56 nm which is 61% of the free-spectral range, with a high tuning efficiency of 80 GHz/mW. By controlling the pump power, the OMMR indicates three working regions, which are the cutoff region, amplified region and saturate region. Accordingly, this function is similar to a transistor. Furthermore, the dynamic properties of the OMMR are investigated. By analyzing the dynamic responses, we demonstrate that the OMMR is driven by the OGF, rather than other nonlinear effects. The method simplifies the experimental setup, compared with measuring the intrinsic mechanical frequency of the OMMR. This all-silicon device is energy-efficient and compatible with complementary metal-oxide semiconductor (CMOS) processing. We believe that this work is important for on-chip all-optial signal processing and beneficial to futher studies on integrated optomechanics.