Near ultraviolet light modulator based on InGaN/AlGaN MQW diode

Abstract

Compared with the direct modulation technology used in traditional visible light communication, the indirect modulation method can share a single light source in multiple channels, which features reduced system size and power consumption. In this paper, a near ultraviolet light modulator with InGaN/AlGaN multiple quantum well (MQW) structure is proposed based on GaN-on-silicon light-emitting diode (LED) wafer. Because the MQW diode structure is consistent with the light source and the photodetector (PD), the modulator can be monolithically integrated with the light source, PD, waveguide and other devices through compatible manufacturing processes. The MQW of the wafer is sandwiched by the waveguide layers and the light emitted by the light source is confined in the waveguide for transmission. The extinction ratio can be adjusted by changing the modulation voltage and the incident signal is loaded onto the optical carrier through the modulator. The optical signal is received by the MQW PD near the end of the waveguide and converted into electrical signal. The results show that the modulator has a significant modulation effect with the extinction ratio greater than 24.4 % and has important application prospects in light processing and transmission.