Very Short Distance Wireless Optical Communication Based On Penetrating Silicon Wafers

Wireless optical communication has attracted much attention due to its advantages of high security,transparent protocol,small device size,large information capacity,and resistance to electromagnetic interference.One application of wireless optical communication is to transmit between devices through optical interconnection.As a way to replace electrical interconnection,optical interconnection has been widely developed.This paper Innovatively proposed a inter-board optical interconnection method,which is to apply wireless optical communication to high-speed transmission penetrating silicon wafers in a very short distance.This method is of great practical significance in some specific situations,such as optical interconnection through the silicon wafer in some complex stacking conditions and topological architectures.Aiming at the communication objectives of the application system,this thesis analyzes the beam characteristics of DFB laser,as well the beam characteristics and light intensity distribution changes of the laser after passing through different media.Due to the parallel plate interference,transmittance of the obtained laser passing through silicon wafer varies with both the incident angle and the thickness of the wafer,which induces extreme instability of the optical signal power after passing through the silicon wafer,degrading the communication performance of the system.It is inferred that reducing the surface reflectance is a powerful strategy to mitigate the impact of interference effects.This thesis employs vector diffraction theory to design a single-step cube grating structure on the double surface of a silicon wafer.Simulations show that the grating structure can transmit 100% of the 1550 nm laser and is insensitive to the incident angle and the thickness of the silicon wafer,ensuring the lossless and stable transmission through the silicon wafer and the communication performance.Furthermore,the structure can achieve nearly 100%transmittance for the light in a certain wavelength range,providing the possibility of wavelength division multiplexing.Finally,this thesis optimizes the optical design to collimate the light beam,and experimentally demonstrates the feasibility of the point-to-point communication with the obtained parameters.Considering the certain application scenarios,this thesis improves the optical path part and regulates the light field distribution on the receiving surface to change the light field on the receiving surface from Gaussian to uniform,achieving 4×32 MIMO broadcast communication from point-to-point communication.This method indicates 128 G broadcast communication bandwidth for single-channel 1G communication,and the feasibility of the program is proved theoretically.