Gain-assisted hybrid silicon microring electro-absorption modulators

摘要

Energy consumption and device footprint are major limiting factors in scaling current optical interconnect architectures to reach multi-terabit per second data transmission [1]. Hybrid integration of III–V on Si using a low-temperature O2 plasma-assisted wafer bonding technique [2] is an attractive platform for integrating active elements on Si in a low optical loss and high density manner. Further scaling on individual devices could enable hybrid photonic integrated circuits with complex functionality and low power consumption. A microring resonator is widely regarded as an ideal structure for very compact passive and active devices, e.g., recently demonstrated hybrid Si microring lasers [3]. Although microring structures are wavelength sensitive, they have several advantages viz. small size, resonance-enhanced efficiency and no intrinsic reflections. We propose a novel microring modulator design by incorporating a gain and a loss section in the same microring cavity. Separately biasing the two sections best uses the properties of a microring resonator. We compare this design with two other techniques that were previously employed on III–V-based electro-absorption (EA) microring modulators [4–5]. We also show the promise of the design in achieving high efficiency modulation with respect to some state of the art Si ring modulator results.