Sub-100-nanosecond thermal reconfiguration of silicon photonic devices.

One of the limitations of thermal reconfiguration in silicon photonics is its slow response time. At the same time, there is a tradeoff between the reconfiguration speed and power consumption in conventional reconfiguration schemes that poses a challenge in improving the performance of microheaters. In this work, we theoretically and experimentally demonstrate that the high thermal conductivity of silicon can be exploited to tackle this tradeoff through direct pulsed excitation of the device silicon layer. We demonstrate 85 ns reconfiguration of 4 µm diameter microdisks, which is one order of magnitude improvement over the conventional microheaters. At the same time, 2.06 nm/mW resonance wavelength shift is achieved in these devices, which is in a par with the best microheater architectures optimized for low-power operation. We also present a system-level model that precisely describes the response of the demonstrated microheaters. A differentially addressed optical switch is also demonstrated that shows the possibility of switching in opposite directions (i.e., OFF-to-ON and ON-to-OFF) using the proposed reconfiguration scheme.