Photonic Integrated System Based InGaN Directional Coupler

With the rapid development of wireless communication technology,photonic devices have come to lie at the heart of the communication revolution,and the integration of various photonic devices used to realize optical interconnects,including light source,waveguide and photodiode is of considerable interest for compact photonic platforms.Besides,from a materials point of view,GaN and its alloys,represented by(Al,In,Ga)N,can be used simultaneously provide light emission,optical transmission and photodetection functionalities.High-quality GaN-on-silicon materials,which provide the material basis for the development of on-chip optical interconnection and optical communication,have increasingly matured by introducing suitable buffer layers to compensate the residual stress due to lattice mismatch and thermal expansion.An on-chip multicomponent system is implemented by integrating a transmitter,InGaN waveguide,InGaN directional coupler and receivers into a single chip.First,we propose and fabricate a photonic integrated system based on InGaN directional coupler.When InGaN waveguide is employed,the on-chip photonic integration can be realized without silicon removal and backside III-nitride thinning,leading to a simpler process flow for fabricating on-chip multicomponent systems.However,in order to improve the photon response speed of VLC,we innovatively increase the silicon dioxide isolation layer and reduce the effective size of active region of diode devices to reduce the junction capacitance.Then,based on beam propagation method(BPM),the transmission and coupling efficiency of InGaN directional coupling region are simulated to optimize device structure.Finally,the device is physically characterized by the test platform.The monolithic system experimentally demonstrates in-plane data transmission at 80 Mbps and spatial light communication at 100 Mbps,paving the way for diverse applications from on-chip to in-plane light communication in the visible light spectrum.