Pulsed Fiber Laser Differential Multi-pulse Position Modulation

With the continuous exploration of human space,various detectors and massive data are sent back to the ground.Space optical communication technology is gaining more and more attention due to its advantages of large bandwidth,high speed and good secrecy.Pulse position modulation(PPM)has the advantages of high modulation efficiency,good transmission efficiency and strong anti-interference,which makes it the most widely used modulation mode in the space optical communication system.Based on the characteristics of space optical communication technology,the modulation technology of optical communication is analyzed,and the advantages and disadvantages of differential pulse position modulation(DPPM)and multi pulse position modulation(MPPM)are integrated,and a new pulse position modulation technology(DMPPM)is proposed.The principle of DMPPM modulation is analyzed,and the DMPPM mapping method and the location of spatial signals are studied.The DMPPM modulation characteristics are analyzed theoretically and simulated,and compared with the three PPM modulation methods,it is concluded that the DMPPM modulation has obvious advantages in the average time slot number,bandwidth utilization,average power and peak power.The influence of DMPPM modulation on the characteristics of fiber laser is studied.The protection period of the DMPPM information frame,the width of the laser pulse and the modulation number are analyzed.At the same time,the influence of the parameters of the laser on the transmission rate of the DMPPM is analyzed.It shows that the DMPPM can improve the repetition rate of the laser and transmit the information of high transmission rate.The DMPPM modulation system is built to produce the DMPPM modulation signal.By adjusting the pump current,the output mirror transmission rate and the numerical change of the length of the cavity,the transmission rate and bandwidth are increased with the increase of the pumping current,which decreases with the increase of the length of the cavity,and decreases with the increase of the transmission rate of the transmission mirror.The DMPPM modulated waveform is observed through an oscilloscope.Data indicate that the DMPPM mode based on fiber laser can improve the transmission rate of deep space communication system,and ensure the good reliability of communication system.