基于锁模光学频率梳的高速数据传输

High-speed data transmission based on mode-locked optical frequency comb

大数据时代网络数据流量的爆炸式增长给通信系统的容量和数据传输速率带来极大的挑战.本文基于锁模光学频率梳的宽光谱范围和高相位相干性提出了一种高频正交幅度调制信号生成方法,通过电光调制器对光学频率梳进行幅度相位整形并下变频至射频域,生成携带编码信息的高速、高阶、低相位噪声的调制信号,再结合锁模光学频率梳窄线宽、多波长的特性,仅使用单个激光器即可实现基于波分复用技术的大规模并行高速通信.仿真验证了该方案的可行性,随后在100 m的自由空间光链路中使用光子微波信号进行16元正交幅度调制通信实验,实现了误码率低于10^(–6)的14 Gbit/s数据传输.

With the rapid development of emerging technologies such as multimedia services,live broadcasting,video conferencing,and high-definition television,traditional radio frequency communication is unable to meet people's growing demand for communication capacity and transmission rate.In recent years,optical communication has received extensive attention from the industrial and scientific communities due to its advantages of large bandwidth,high speed,low power consumption,light weight,and strong anti-interference ability.As an emerging light source,the optical frequency comb(OFC)has a wide spectral range,multi-wavelength,high stability,and good phase coherence,providing a new idea for studying microwave signals with simple system structure,strong tunability and high frequency stability.At the same time,the multi-optical mode characteristics of OFC are compatible with the current communication system based on wavelength division multiplexing technology.Hundreds of laser arrays in a traditional communication system can be replaced by only one laser,which greatly reduces the power consumption of the system.Combining the above advantages,in this paper,a large-scale parallel high-speed optical communication system based on mode-locked OFC is proposed.The linewidth of the OFC locked to the rubidium atomic clock can reach 1 Hz,which is sufficient to support the transmission of high-order modulation signals.The electro-optic modulators are used to adjust the amplitude and phase of each optical mode of the mode-locked OFC and self-coherently map to the RF domain.The high-speed high-order modulation signal with coded information is obtained by frequency screening through a narrow-band filter.The communication capability of the microwave photonic modulation signal in the 16 quadrature amplitude modulation(QAM)format is verified by simulation.The 16QAM communication with the rate of 2,6,and 14 Gbit/s is realized by using the photonic microwave signal on the 100 m space optical link,and the bit error rate(BER)is less than 10^(–6).The proposed large-scale parallel optical communication system based on mode-locked OFC can achieve high-speed information transmission with a compact system structure,which is suitable for inter-satellite communication,emergency communication,military communication and other fields.