Efficient and high-speed coupling modulation of silicon racetrack ring resonators at 2 µm waveband.

Significantly increased interests have been witnessed for the 2 µm waveband which is considered to be a promising alternative window for fiber and free-space optical communications. However, the less mature device technology at this wavelength range is one of the primary obstacles toward practical applications. In this work, we demonstrate an efficient and high-speed silicon modulator based on carrier depletion in a coupling tunable resonator. A benchmark high modulation efficiency of 0.75 V·cm is achieved. The 3-dB electro-optic bandwidth is measured to be 26 GHz allowing for up to 34 Gbit/s on-off keying modulation with a low energy consumption of ∼0.24 pJ/bit. It provides a solution for the silicon modulator with high-speed and low power consumption in the 2-µm waveband.