Research On High-speed Space Laser Communication Technology In Mid-infrared Band

Compared with the traditional microwave communication,space laser communication has the advantages of high transmission rate,good security,strong anti-electromagnetic interference ability,small size,light weight,and low power consumption.It has broad application prospects in high-speed data transmission in deep space such as Moon to Earth and Mars to Earth,and near earth high-speed data transmission between satellites and ground.At present,the commonly used wavelengths for space laser communication are near infrared bands(0.8?m,1.064?m and 1.55?m).The development of space laser communication technology based on the near-infrared band is reaching maturity and is gradually moving towards aerospace,aviation,and marine engineering applications.Compared with the near-infrared band,the mid-infrared band(3?m?5?m)has the advantages of small atmospheric attenuation and strong resistance to atmospheric turbulence,which can effectively improve the availability of laser communication links such as Mars-to-ground,moon-to-ground,and satellite-to-ground,and has been widely concerned in recent years.In order to meet the demand of high-speed data transmission in space information network,the high-speed space laser communication technology in mid-infrared band is studied in this thesis.The following research work has been completed:1?Using the optical difference frequency generation effect(DFG)in the nonlinear crystal,the mid-infrared high-speed optical signal generation method based on wide-range all-optical wavelength conversion is proposed.The scheme design of the mid-infrared high-speed optical signal generation device is completed.The theoretical analysis and numerical simulation research on near-infrared high-speed laser signal and wide-range wavelength conversion from near-infrared to mid-infrared are carried out,.The research results show that the generation rate of mid-infrared high-speed optical signals based on wide-range all-optical wavelength conversion can reach the order of 10Gbps,which is an order of magnitude higher than the traditional direct modulation scheme of quantum cascade lasers.2?Theoretical studies on the influence of laser transmission characteristics in the infrared and near-infrared bands of atmospheric turbulence are carried out.Based numerical simulation methods,the influence of intensity scintillation and beam wander on the BER of satellite ground laser communication uplink and downlink is analyzed,and the field experiment of influence for laser transmission characteristics in mid-infrared band and near-infrared band are carried out.Numerical simulation and experimental results show that the wavelength is longer,the anti-turbulence ability is stronger,and the BER of system is lower.The mid-infrared band laser has obvious advantages over the near-infrared band.3?Using the optical difference frequency generation effect(DFG)in the nonlinear crystal,the mid-infrared high-speed optical signal reception method based on wide-range all-optical wavelength conversion was proposed.The scheme design of the mid-infrared high-speed optical signal reception device was completed.The theoretical analysis and numerical simulation research on mid-infrared wide-range wavelength conversion and near-infrared high-speed laser signal reception are carried out.The research results show that the reception rate of mid-infrared high-speed optical signals based on wide-range all-optical wavelength conversion can reach the order of 10Gbps,which is an order of magnitude higher than the direct detection scheme of traditional mid-infrared detectors.4?High-speed space laser communication in mid-infrared band based on wide-range all-optical wavelength conversion is studied.Firstly,the experiment of10Gbps Differential Phase Shift Keying(DPSK)mid-infrared high-speed laser communication is studied.Based on periodic lithium niobate Mg O(Mg O:PPLN),the high-speed optical signal of 1550nm near-infrared on-off keying(OOK)and DPSK high-speed optical signal and 3594nm mid-infrared high-speed optical signal are realized.The free space transmission experiment and performance test are carried out.The results show that the power loss increases by 3.5d B compared with back-to-back transmission at BER 10^-6.Then 5Gbaud(10Gbps)Quadrature Phase Shift Keying(QPSK)mid-infrared high-speed laser communication experiment was carried out.The conversion between 1550nm near-infrared QPSK high-speed optical signal and3594nm mid-infrared high-speed optical signal is realized.free space transmission experiment and performance test are carried out.The results show that the power loss is less than 2.6d B compared with back-to-back transmission at BER 10^-6.