Research On The Principle Of High Power And Large Bandwidth Photodetector Based On Power Synthesis Technology

Wireless communication makes the communication network more flexible and convenient.Optical fiber communication can share a huge amount of resources to anyone in the world.Radio Over Fiber(ROF)technology,which has both advantages,has developed rapidly in accordance with the current era.In ROF system,photodetectors need to work in a wide bandwidth state to meet the needs of system information capacity expansion and millimeter wave signal high frequency;and the emergence of optical fiber amplifiers requires photodetectors to withstand higher optical power.This paper starts from the study of UTC-PD,analyzes its structural characteristics and performance parameters,and finds that UTC-PD performance is superior to PIN-PD in both saturation power and working bandwidth.Therefore,the UTC-PD high-precision equivalent circuit model was established to lay the foundation for the subsequent research.Because the research on improving the performance of a single detector is quite rich,this paper proposes a bridged T power synthesis array structure based on the research of the principle of millimeter wave output combined power,combining the bandwidth advantages of traveling wave photodetector array(TWDA)and bridged T structure.This is a good solution to the problem that TWDA has improved the combined power,but the working bandwidth has not increased,and with the increase of distributed units,its performance and bandwidth have a certain degree of reduction and impact.This structure is different from TWDA's Constant-K filter structure.The coupled microstrip line replaces the series inductance and the mutual inductance between them.One microstrip line is connected in parallel with a single capacitor,and then a single photodiode is inserted.The artificial transmission line forms a single array unit,and then a single array unit is effectively cascaded to form a bridged T-type power synthesis array.The simulation results show that the bridged T detector array has a (?) times improvement over the working bandwidth of TWDA,which not only has broadband matching characteristics,but also can perform power synthesis.On this basis,a bridged T diode group power synthesis array and a bridged T linear diode cascade array are proposed.Based on the bridged T array unit,four UTC-PDs are used to form a parallel cascaded diode group and two UTC-PDs are used to replace a single UTC-PD.The results show that the structure of bridged T diode array is simpler than that of TWDA,and the bandwidth can be increased by (?) times and the response rate can be increased by 3? times,which solves the shortcomings of low response speed and insensitive response of the detector.The bridged T linear cascade array can not only accumulate synthetic output power,but also has a (?) times increase in bandwidth compared to TWDA.Compared with TWDA,the three detector arrays presented in this paper have excellent performance in bandwidth,power synthesis and overall delay.Modern communication frequency points are getting higher and higher,and the working frequency bands of communication system devices are also demanded higher and higher.For the urban areas with large population and developed commerce,or the occasions with different demands of wide working frequency band and fast response speed,suitable power synthesis arrays can be selected for application.This kind of detector array with high power and wide bandwidth has very important practical and research effects.