| The arrival of the era of big data really makes people realize the importance and value of information.At the same time,broadband fixed network and mobile network are developing side by side.People continue to pursue faster communication and more information.Network TV,social network,cloud computing,internet of things,even the development of AI technology all need the support of optical fiber communication.The 5G standard has just landed,and the tests of all links are also in full swing.Because of the commercialization in 2020,optical fiber communication plays a crucial role in it.As an important photoelectric device at the receiving end of the system,the study of the nonlinear saturation characteristic of the optical detector become more important.The light detector diversifies numerously and has long history.And there is the InGaAs/InP material PIN photodetector with superior performance,wide application.This thesis focuses on the theoretical and experimental research on the nonlinear performance of high power excitation.The main research and achievements are listed as follow:1.The basic working principles of InGaAs/InP photodetectors are studied theoretically.The nonlinearity genesis principles of PIN photodetector under high optical power injection were studied physically and theoretically with the implementation of carrier constituity equation.2.The influence of the InGaAs/InP PIN photodetector's absorption region thickness on its DC photoresponse saturation characteristicis investigated.The photoresponse currents of the photodetector are calculated under the condition of fixed bias voltage or the condition of fixed bias electric field intensity in absorption area.And the perfornance of their 1dB compression points changing with the thickness of absorption area is obtained.With the simplified calculation of the photodector's efficiency-bandwidth product,an optimized absorption area's thickness of 300nm is obtained.3.The time domain analysis method for the photodetector's 1dB compression point of its AC photoresponse current is proposed.The photodetector's AC saturation charateristics are analyzed in time domain with device performance simulation and experiments.The consistency between the time domain analysis method(TDAM)and the frequency domain analysis method(FDAM)is verified theoretically.Comparing with the FDAM,the TDAM is more obvious in analyzing the photodetector's saturation characteristics.And the the photodetector's photoresponse current saturation characteristics under pulse excitation are analyzed.4.The photodetector's DC and AC saturation characteristics are studied and compared,there is a 1.54dB difference at 1dB compression point between the two kinds of photoresponse current with a 300nm thick absorption layer and-2V biasing voltage.At the 1dB compression point of the AC photoresponse current,the peak value of the AC input signal will always be lower than the value of the 1dB compression ponit of the DC photoresponse current.5.Time domain test system is designed and built.Photodetector's AC saturation characteristics are measured using time domain method.The photodetector's photoresponse currents are measured under different input light intensities which is modulated with different modulation frequencies at 100MHz,200MHz and 300MHz and different depth.Their photoresponse curves are drawn and the AC saturation 1dB compression points are found.6.3dB bandwidth The swept-frequency test method for determining the photodetector's 3dB bandwidth,the frequency domain small signal and large signal measurment methods for determining the 1dB compression point of the photodetector's photoresponse current are studied.The results show that the value at the ldB compression point of the photodetector's photoresponse current obtained by frequency domain small sigal measurement method is larger than that obtained by frequency domain large sigal measurement method. |
PDF Full Text Request