Enhanced linear absorption coefficient of in-plane monolayer graphene on a silicon microring resonator.

We demonstrate that enhanced linear absorption coefficient (LAC) of in-plane monolayer graphene is determined by the optical transmission spectra of a graphene layer coated symmetrically coupled add-drop silicon microring resonator (SC-ADSMR), of which the value is around 0.23 dB/µm. In contrast to the traditional cut-back method, the measured results aren't dependent on the coupling efficiency between the fiber tip and the waveguide. Moreover, precisely evaluation of graphene layer coated silicon microring resonator (SMR) is crucial for future optoelectronic devices with compact footprint and low power consumption.