自由空间光通信(Free Space Optical Communication,FSOC)尤其是基于相干体制的卫星激光通信,正逐渐成为突破微波通信瓶颈、建设天地一体化网络、实现高速数据传输的重要手段。总结了欧空局、德国、日本及国内卫星相干激光通信的重要进...自由空间光通信(Free Space Optical Communication,FSOC)尤其是基于相干体制的卫星激光通信,正逐渐成为突破微波通信瓶颈、建设天地一体化网络、实现高速数据传输的重要手段。总结了欧空局、德国、日本及国内卫星相干激光通信的重要进展,给出了成功验证的相干激光通信系统的激光器、传输速率、多普勒频移补偿范围等参数,重点分析了基于Costas光锁相环(Optical Phase-Locked Loop,OPLL)技术的零差相干激光通信系统,并提炼出关键技术以及未来星间相干激光通信的发展趋势,可为卫星相干激光通信的研究提供一定的参考。展开更多
激光在大气信道中传输时易受到大气湍流等影响,导致接收机对开关键控(On-Off Keying,OOK)信号发生错误判决,进而产生误码率门限,严重恶化了自由空间光通信(Fee Space Optical Communication,FSOC)的传输性能。采用自适应阈值进行判决虽...激光在大气信道中传输时易受到大气湍流等影响,导致接收机对开关键控(On-Off Keying,OOK)信号发生错误判决,进而产生误码率门限,严重恶化了自由空间光通信(Fee Space Optical Communication,FSOC)的传输性能。采用自适应阈值进行判决虽然能抑制误码率门限,但是需已知比特级(ns级)的信道状态信息(Channel State Information,CSI),在高速激光通信中难以实现。基于大气信道的缓慢变化特征,对接收信号按照亚毫秒级时隙(0.01 ms级)进行分段检测,降低了高速信号的检测难度,并通过优化误码率求解出了最佳的分段阈值,从而抑制了误码率门限现象。与此同时,提出了正交偏振态导频光与信号光同传的系统方案,以估计大气信道模型与接收信号的分段阈值。仿真结果表明,在Log-Normal大气信道模型下,该方法虽然引入了3~6 dB的光功率损耗,但是有效抑制了误码率门限,且仅需估计毫秒级的CSI,降低了阈值判决的实现难度。展开更多
Free-space optical communication(FSOC)enables high-speed,secure,and scalable data transmission,with great potential for space–ground networks.However,existing FSOC systems predominantly employ point-to-point transmit...Free-space optical communication(FSOC)enables high-speed,secure,and scalable data transmission,with great potential for space–ground networks.However,existing FSOC systems predominantly employ point-to-point transmitters,each requiring bulky beam steering devices with complex control mechanisms,which severely limits their feasibility for multi-node micro-platform applications.Here,to address such a challenge,we propose a novel point-to-multipoint FSOC scheme based on reconfigurable SiC gratings,which are directly fabricated in stretchable PDMS films via femtosecond laser-induced carbide precipitation.The reconfigurable SiC transmission gratings are with good transparency(~91.9%at 1550 nm),dynamic beam steering capability(hundred-milliradian level),and an ultralightweight design(single grating:0.4 g).The SiC fringes are specially fabricated within the internally symmetric region of the PDMS film to mitigate the structure distortion during stress regulation,significantly enhancing the long-range transmission capability in degraded atmospheric channels.The system supports 1-to-7 and 1-to-9 dynamic optical communication for 1D and 2D configurations,respectively.In a state-of-the-art 225-meter outdoor experiment,the system achieves reliable 10 Gbps transmission for each node.This portable FSOC system overcomes the limitations of conventional systems,enabling scalable and flexible multibeam steering.This approach establishes a robust foundation for long-range,multinode,and high-capacity FSOC networks among spatial micro-platforms such as unmanned aerial vehicles and micro-satellites.展开更多
自由空间光通信(FSOC,Free Space OpticalCommunication),或称无线光通信、无纤光通信,这是以激光作为信息载体、不需要任何有线信道为传输媒介的通信方式,可用于空间及地面间通信。其传输特点是光束以直线传播。一、自由空间光通信的原...自由空间光通信(FSOC,Free Space OpticalCommunication),或称无线光通信、无纤光通信,这是以激光作为信息载体、不需要任何有线信道为传输媒介的通信方式,可用于空间及地面间通信。其传输特点是光束以直线传播。一、自由空间光通信的原理FSOC技术以小功率的红外激光束为载体,在位于楼顶或窗外的收发器间传输数据。展开更多
文摘激光在大气信道中传输时易受到大气湍流等影响,导致接收机对开关键控(On-Off Keying,OOK)信号发生错误判决,进而产生误码率门限,严重恶化了自由空间光通信(Fee Space Optical Communication,FSOC)的传输性能。采用自适应阈值进行判决虽然能抑制误码率门限,但是需已知比特级(ns级)的信道状态信息(Channel State Information,CSI),在高速激光通信中难以实现。基于大气信道的缓慢变化特征,对接收信号按照亚毫秒级时隙(0.01 ms级)进行分段检测,降低了高速信号的检测难度,并通过优化误码率求解出了最佳的分段阈值,从而抑制了误码率门限现象。与此同时,提出了正交偏振态导频光与信号光同传的系统方案,以估计大气信道模型与接收信号的分段阈值。仿真结果表明,在Log-Normal大气信道模型下,该方法虽然引入了3~6 dB的光功率损耗,但是有效抑制了误码率门限,且仅需估计毫秒级的CSI,降低了阈值判决的实现难度。
基金supported by the National Natural Science Foundation of China(U2141231,62275100,T2325014)Natural Science Foundation of Jilin Province(20240101020JJ)+1 种基金Natural Science Foundation of Chongqing Municipality(CSTB2023NSCQ-MSX0030)National Ten Thousand Talent Program for Young Top-notch Talents.
文摘Free-space optical communication(FSOC)enables high-speed,secure,and scalable data transmission,with great potential for space–ground networks.However,existing FSOC systems predominantly employ point-to-point transmitters,each requiring bulky beam steering devices with complex control mechanisms,which severely limits their feasibility for multi-node micro-platform applications.Here,to address such a challenge,we propose a novel point-to-multipoint FSOC scheme based on reconfigurable SiC gratings,which are directly fabricated in stretchable PDMS films via femtosecond laser-induced carbide precipitation.The reconfigurable SiC transmission gratings are with good transparency(~91.9%at 1550 nm),dynamic beam steering capability(hundred-milliradian level),and an ultralightweight design(single grating:0.4 g).The SiC fringes are specially fabricated within the internally symmetric region of the PDMS film to mitigate the structure distortion during stress regulation,significantly enhancing the long-range transmission capability in degraded atmospheric channels.The system supports 1-to-7 and 1-to-9 dynamic optical communication for 1D and 2D configurations,respectively.In a state-of-the-art 225-meter outdoor experiment,the system achieves reliable 10 Gbps transmission for each node.This portable FSOC system overcomes the limitations of conventional systems,enabling scalable and flexible multibeam steering.This approach establishes a robust foundation for long-range,multinode,and high-capacity FSOC networks among spatial micro-platforms such as unmanned aerial vehicles and micro-satellites.
文摘自由空间光通信(FSOC,Free Space OpticalCommunication),或称无线光通信、无纤光通信,这是以激光作为信息载体、不需要任何有线信道为传输媒介的通信方式,可用于空间及地面间通信。其传输特点是光束以直线传播。一、自由空间光通信的原理FSOC技术以小功率的红外激光束为载体,在位于楼顶或窗外的收发器间传输数据。
