UV Photonic Integrated Chip Based on Epitaxial III-N on Si for Short-Range On-Chip Data Transmission

Integrating multiple optical devices on a single chip to create the so-called photonic integrated circuit (PIC) provides the advantages of compact size and low cost, with broad application prospects in fields, such as information processing, sensing, photoelectricity coupling, optical communication, and interconnection. However, compatibilities of material and fabrication are the main impediments to realize the PIC. Herein, we propose a PIC solution based on the epitaxial III-V on Si, with all active devices (a light source, an electroabsorption modulator, and two photodiodes) adopting the same InGaN/AlGaN multiple quantum wells (MQW) diode structure to solve the abovementioned compatibility problems. The light-emitting peak wavelength of the integrated near ultraviolet (UV) light source is 385 nm. Because the MQW layer is sandwiched into the waveguide (WG), all the signal conversion and transmission are limited in the WG with relatively high coupling efficiency. ON-chip data transmission can be realized using direct modulation via the light-emitting diode or the indirect modulation via the electroabsorption modulator at a single light path. The extinction ratio of the InGaN/AlGaN MQW modulator under a reverse bias voltage of 8 V is approximately 8.4% and can be further increased by enlarging the bias. The proposed UV PIC solution features simple structure and fabrication, with potential value in UV microscopy, biosensing, and ON-chip data communication.