Carbon-nanotube-on-waveguide thermo-optic tuners.

Abstract

We demonstrate on-waveguide thermo-optic tuners based on solution-processed metallic carbon nanotubes (CNTs) on silicon-on-insulator (SOI) and silicon nitride (SiN) microring resonators operating around 1550nm. On SOI microring resonators using planarized wire waveguides, a thermo-optic power efficiency of 29mW/FSR and a thermal transient of 1.3μs are achieved. The heater is shown to be more power-efficient than conventional metal heaters and has lower thermal transient than both metal heaters and graphene-based heaters. On SiN microring resonators using rib waveguides, improvement in power efficiency with an increase in coverage of CNTs is demonstrated, indicating localized heating using the CNTs; this is favorable for low thermal cross-talk. An optimal power efficiency of 142mW/FSR and a thermal transient of 5.8μs are achieved.