Experimental Research And Analogue Simulation Of The Performance Degradation Of Laser Diode Induced By Radiation

The laser diode?LD?is a core device in space optical communication.The radiation damage induced by radiation particles when the LD operates in the space radiation environment is widely concerned,especially the performance degradation of the multiple quantum LD induced by space radiation.According to the research status at home and abroad,the radiation experiments including the ⁶⁰Co-?ray radiation at different doses,the reactor neutron radiation at different fluences,and the proton radiation at different high energies were carried out.The radiation sensitive parameter degradations of the multiple quantum LDs were analyzed.The degradation mechanisms of the radiation sensitive parameters were demonstrated in detail.The simulation of the neutron radiation effects on the LDs was also carried out.Combined with the results of radiation experiments and simulation,the degradation mechanisms of the LDs induced by neutron radiation were analyzed.The main contents of the paper are as follows:?1?The experiments of the LDs radiated by ⁶⁰Co-?rays at different does were carried out.The dose rate of ⁶⁰Co-?rays is 0.1 rad?Si?/s.The photoelectric parameters of the LDs such as the P-I characteristic curves,the V-I characteristic curves and the C-V characteristic curves were tested before and after irradiation.The experimental results show that the threshold currents have no significant change,the external differential quantum efficiency decreases with increasing total ionizing doses,and the capacitances and currents in the low voltage area increase with increasing total ionizing doses.?2?The experiments of the LDs radiated by reactor neutrons at different fluences were carried out.The flux of the reactor neutron beams was about 3.72×10¹⁰ n/?cm²s?,and the samples were exposed to 1 Me V neutron equivalent fluence of 1×10¹⁴ n/cm²and 2×10¹⁴ n/cm².The degradations induced by neutron displacement damage were analyzed.The formulae of threshold current and neutron fluence were achieved.The P-I characteristics curves,V-I characteristics curves,threshold current and output power versus neutron fluence were investigated.The experimental results show that the threshold current increases with increasing neutron fluence while the output power decreases with increasing neutron fluence,which is mainly due to the minority lifetime increases after neutron radiation.The current in the low voltage region increases with increasing neutron fluence,and when the neutron fluence is higher,the current in the high voltage region decreases,which is because the carrier lifetime in space charge region decreases with increasing neutron fluence.The experiments of the LDs radiated by protons with energies of 60 Me V and 90 Me V were carried out.Though the time limit of the allowed irradiation experiment,the photoelectric parameters of the LDs show nearly no change under the experimental irradiation fluence while it indicates that the LDs exhibit a certain radiation resistance.?3?Based on the Silvaco TCAD software,the analogue simulation of the LDs irradiated by neutrons was carried out.The physical device simulation models and the neutron displacement damage models of the LDs were established.The optical properties and electrical properties of the LDs were simulated.The simulation methods of the displacement damage in the LDs were concluded.The sensitive parameter degradations induced by neutron radiation were analyzed.By combining with the results of radiation experiments and simulation,the degradation mechanisms of radiation sensitive parameters were analyzed.