Microwave Modeling And Parameter Extraction For High Speed PIN Photodiodes

In recent years,Optical fiber communication systems have experienced a tremendous growth in transmission capacity and speed due to its low cost,high bandwidth,little interference and reliability.The integration of an optical device with an electronic circuit can improve the performance of fiber-optic communications systems especially at high frequencies due to the reduction of parasitics,which are inevitable in a hybrid integration.Therefore,an Optoelectronic integrated circuit(OEIC)becomes indispensable in a system.In order to accurately simulate the performance of OEIC,it is indispensable to establish the equivalent circuit model of discrete optoelectronic devices.Photodetector is the main components of OEIC,it is necessary to study the high-speed,high sensitivity,high reliability of photodetector.However,the general simulation software does not contain photodetector model and it is difficult to analysis its performance;the simulation software of optoelectronic devices such as TCAD focused on the process and structure of the device,it is difficult to compatible with the circuit design software.The equivalent circuit model and parameter extraction method of high speed PIN photodetector are researched in this thesis,the main contents include:1)the theory and frequently-used performance parameters of PIN photodetector,introduce the basic process of PIN photodetector modeling;2)present an improved parameter extraction method,which is a combination of optimization and direct extraction method,the values of part parameters can be determined through the direct extraction method,the rest values of parameters can be determined through the optimization.3)give the analytical expressions for the parameter extraction,an excellent fit between measured and simulated S-parameters in the frequency range of 1 GHz?40 GHz shows the accuracy of this approach;4)analyze the nonlinearity of PIN photodetector,establish the capacitance model and dc model,and extract the parameters of the equivalent circuit model;5)improve the equivalent circuit model of heterojunction PIN photodetector considering the physical structure of the device and the convenience of parameter extraction,and extract the parameters using proposed method.The validity of the model is proven by comparison with measured and modeled S parameters in the frequency range of 1 GHz-40 GHz,and the error of the equivalent circuit model is also given.