Efficient transmission control based on carrier accumulation in silicon slot photonic-crystal waveguide as an embedded layer for board level optical interconnects

We experimentally demonstrate an all-silicon optical transmission controller based on a semiconductor-oxide-semiconductor capacitor embedded in a slot photonic-crystal waveguide. We incorporate a multimode interference-based structure to reduce the coupling loss induced by the waveguide mode mismatch. We perform a detailed DC characterization of the electro-optic device including the DC modulation test and the evaluation of the resistance-capacitance constant. The measured modulation curve is in good agreement with our theoretical analysis. Calculation of the effective index change indicates as much as 30 times efficiency enhancement compared with the slotted silicon rib waveguide. Such a waveguide layer can serve as the active layer for fully embedded optical interconnect architecture with minimum power consumption.