Design Of Grating Coupled Silicon Based Photodetector And Amplifier Circuit For Optical Communication

With the continuous development in the information society,the demand for the bandwidth of short distance communication is getting higher day by day.The electric interconnection has become pivotal in restricting the overall performance of the communication system.The optical interconnection can effectively improve the transmission through bandwidth,but is constrained by its high cost and its application in short distance communication has been limited.Optical receiver is one of the core devices of optical interconnection,but the current optical receiver is mostly hybridintegrated,not only high in cost but performance and bit error rate is also affected.In contrast,monolithic integrated optical receiver can not only improve the performance but also reduce the chip area and costs.However,currently monolithically integrated optical receiver can not simultaneously achieve high speed and high sensitivity,as it is difficult to design high-performance detector based on silicon-based technology.Therefore,the study of high performance photodetector compatibled with silicon-based technology is the key to achieve monolithic integrated optical receiver.For the silicon-based photodetectors and amplifiers that can be used for monolithic integration,the following research works ate carried out in this study:1.For the 615 nm wavelength of visible light communication,a metal-semiconductors-metal photodetector compatibled with silicon technology was designed.The structural parameters of the metal grating is analyzed and optimizated by Finite Difference Time Domain method.The research indicates that when the grating period T=580nm,the grating height h=91nm and the slit width w=360nm,the absorption factor of the detector is 32% higher than that of the device without grating.Based on the simulation results,the effects of grating height,grating period and slit width on the absorptive performance of the photodetector were analyzed in detail.The simulation results indicate that the absorption enhancement was improved by the Fabry-Perot resonance and the surface plasmon polariton.2.For 850 nm optical fiber communication system,metal grating is introduced on the basis of inter digital double photodetector compatible with silicon-based technology.On the basis of UMC0.18?m process,the grating width of 0.24?m and0.4?m is chosen as the optimal structural parameter when the grating period is0.76?m and the grating height is 0.48?m.The layout and test program of the photodetector is done.Right now the research team is waiting for the film and test for further analysis.3.For the long wavelength optical communication of 1550 nm,a grating silicon-based germanium MSM photo detector is designed.When the grating period,height and width are 875 nm,335nm and 375 nm respectively,the normalized absorption of germanium layer reaches the maximum value,and the absorption coefficient increased by 5.4 times compared with the structure without grating.4.In order to realize the function of the optical receiver,the optical receiver front-end circuit was designed and simulated.The circuit achive 81.8dB gain,26.7GHz bandwidth,and 18.2pA equivalent input noise current.