基于EDFA的卫星相干光通信开环补偿技术研究
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摘要
零差探测是卫星相干光通信的主流探测方式,其主要采用光学锁相环来消除多普勒频移和激光线宽造成的频率偏移的影响。但即使在今天,光锁相环的实现依然有难度,而且存在捕获时间过长等现象。本文将光纤通信中基于数字信号处理的频偏、相偏开环补偿技术应用于卫星相干光通信背景中,实现星间光通信中存在500 MHz量级频偏时的信息解调。同时,结合EDFA和相干探测的特点,利用EDFA对接收光信号进行预先放大,提高了接收机的灵敏度。仿真结果表明当信噪比高于7 d B时,频率估计的标准差小于8 MHz;在添加预先放大器后,当信号光功率高于-57 d Bm时,误码率优于10~(-3)。
Homodyne detection is the main detection method in satellite coherent optical communication,and OPLL is used to eliminate the frequency shift caused by Doppler frequency shift and laser linewidth. But the realization of OPLL is still difficult,and the frequency capture time is too long. The open-loop frequency estimation and phase estimation theory based on DSP were applied to communications between satellites,and the demodulation with 500 MHz frequency offset was achieved. Also,combining the merits of EDFA and coherent detection,the received signal was preamplified by using EDFA to improve the sensitivity of the receiver. The simulation results show that the standard-deviation of estimated frequency is less than 8MHz when signal-noise-ration is higher than 7d B,and after adding EDFA,the BER is better than 10~(-3) when the power of received light is higher than-57 d Bm.
Homodyne detection is the main detection method in satellite coherent optical communication,and OPLL is used to eliminate the frequency shift caused by Doppler frequency shift and laser linewidth. But the realization of OPLL is still difficult,and the frequency capture time is too long. The open-loop frequency estimation and phase estimation theory based on DSP were applied to communications between satellites,and the demodulation with 500 MHz frequency offset was achieved. Also,combining the merits of EDFA and coherent detection,the received signal was preamplified by using EDFA to improve the sensitivity of the receiver. The simulation results show that the standard-deviation of estimated frequency is less than 8MHz when signal-noise-ration is higher than 7d B,and after adding EDFA,the BER is better than 10~(-3) when the power of received light is higher than-57 d Bm.
引文
[1]Sodnik Z,Furch B,Lutz H.Optical Intersatellite Communication[J].IEEE Journal of Selected Topics in Quantum Electronics,2010,16(5):1051-1057.
[2]Smutny B,Lange R.Homodyne BPSK-based optical inter-satellite communication links[J].Proc SPIE,2007,87:645703-645703-9.
[3]Ando T,Hirano Y.Coherent homodyne receiver with a compensator of Doppler shifts for inter orbit optical communication[C]//Society of Photo-Optical Instrumentation Engineers.Society of Photo-Optical Instrumentation Engineers(SPIE)Conference Series,2011:233-245.
[4]ZHANG Zhen,SUN Jianfeng,LU Bin,et al.Costas optical phase lock loop system design in Inter-Orbit coherent laser communication[J].Chinese Journal of Lasers,2015,42(8):169-174.张震,孙建锋,卢斌,等.星间相干激光通信中科斯塔斯锁相系统设计[J].中国激光,2015,42(8):169-174.
[5]Leven A,Kaneda N,Koc U V,et al.Frequency Estimation in Intradyne Reception[J].IEEE Photonics Technology Letters,2007,19(6):366-368.
[6]Hoffmann S,Bhandare S,Pfau T,et al.Frequency and Phase Estimation for Coherent QPSK Transmission With Unlocked DFB Lasers[J].IEEE Photonics Technology Letters,2008,20(18):1569-1571.
[7]Kazuro Kikuchi,Satoshi Tsukamoto.Evaluation of Sensitivity of the Digital Coherent Receiver[J].Journal of Lightwave Technology,2008,26(13):1817-1822.
[8]Ando T,Hirano Y.Coherent homodyne receiver with a compensator of Doppler shifts for inter orbit optical communication[C]//Society of Photo-Optical Instrumentation Engineers.Society of Photo-Optical Instrumentation Engineers(SPIE)Conference Series,2011:233-245.
[2]Smutny B,Lange R.Homodyne BPSK-based optical inter-satellite communication links[J].Proc SPIE,2007,87:645703-645703-9.
[3]Ando T,Hirano Y.Coherent homodyne receiver with a compensator of Doppler shifts for inter orbit optical communication[C]//Society of Photo-Optical Instrumentation Engineers.Society of Photo-Optical Instrumentation Engineers(SPIE)Conference Series,2011:233-245.
[4]ZHANG Zhen,SUN Jianfeng,LU Bin,et al.Costas optical phase lock loop system design in Inter-Orbit coherent laser communication[J].Chinese Journal of Lasers,2015,42(8):169-174.张震,孙建锋,卢斌,等.星间相干激光通信中科斯塔斯锁相系统设计[J].中国激光,2015,42(8):169-174.
[5]Leven A,Kaneda N,Koc U V,et al.Frequency Estimation in Intradyne Reception[J].IEEE Photonics Technology Letters,2007,19(6):366-368.
[6]Hoffmann S,Bhandare S,Pfau T,et al.Frequency and Phase Estimation for Coherent QPSK Transmission With Unlocked DFB Lasers[J].IEEE Photonics Technology Letters,2008,20(18):1569-1571.
[7]Kazuro Kikuchi,Satoshi Tsukamoto.Evaluation of Sensitivity of the Digital Coherent Receiver[J].Journal of Lightwave Technology,2008,26(13):1817-1822.
[8]Ando T,Hirano Y.Coherent homodyne receiver with a compensator of Doppler shifts for inter orbit optical communication[C]//Society of Photo-Optical Instrumentation Engineers.Society of Photo-Optical Instrumentation Engineers(SPIE)Conference Series,2011:233-245.