Wafer-scale integrated active silicon photonics for manipulation and conversion of light

Abstract

Silicon photonics is an emerging platform that promises to revolutionize integrated optics. This is expected to happen by inheriting the cost-effective, very large scale integration capabilities from complementary metal-oxide-semiconductor (CMOS) process. The compatibility with CMOS also merges the electronics and photonics world in a single platform. While electronics are key for computations, photonics are key for communications. While the computations within a micro-processor was scaling, the communication scaling was limited by high-cost and high-power optical interconnects. The communication bottlenecks in micro-processors, data-centers, super-computers and tele-communications industry indicated a challenge for energy-efficient and low power optical interconnects for the last decade. This challenge have produced preliminary key silicon photonics components, including on-chip lasers, low-loss silicon waveguides, high-speed silicon modulators and detectors. However, the holistic approach was not used for addressing the needs for photonic components, photonics and electronics integration. Here, we demonstrate two major breakthroughs. First one is an ultralow power intrachip electronic-photonic link. This photonic link required to find efficient ways to realize active photonic filters, modulators, transmitters, detectors and receivers that operate with close to single femtojoule energy while tackling wafer-scale fabrication and thermal variations. To integrate these photonics components with electronics with little to no excess energy consumption, a seamless interface between electronics and photonics wafers was introduced, through-oxide-vias (TOVs). When the electronic-photonic integration was complete with TOVs, a communication link that operate at 5Gb/s with an energy consumption as low as 250fJ/bit, is demonstrated. Second, second-order nonlinear effects were missing in silicon due to its crystalline symmetry. The crystalline symmetry of silicon is broken with an applied DC field, generating second-order nonlinear susceptibility in CMOS compatible silicon photonics platform. The field induced second-order nonlinear effects are demonstrated in the form of DC Kerr effect and second harmonic generation in silicon.