提出并研究了一种应用于光纤载太赫兹波通信系统(ToF)中双级级联单边带(DSSB)调制的新方案。首先抑制载波双边带(DSB)调制产生太赫兹波;然后选择载波抑制DSB中的一个边带进行一级单边带(SSB)数据调制,在数据调制过程中再次采用基带SSB调制技术,由此产生DSSB调制。分析结果显示,对0.1 THz中频载波,数据速率为5 Gb/s的光载太赫兹信号进行100 km光纤传输,无色散补偿的误码率仅为1×10-11数量级,接收机灵敏度为-26.6 dBm。给出了单、双边带调制信号频率选择性衰落对比曲线图,有效地证明了DSB信号传输中色散衰落现象的存在以及SSB调制对于这种衰落现象的有效抑制,这些结论均证明新方案明显优于传统方案。
A dual-stage optical single side band(DSSB) modulation scheme to combat chromatic dispersion for the terahertz over fiber(ToF) systems application is proposed.In the scheme,terahertz wave is obtained via carrier-suppression double sideband(DSB) modulation,one sideband of terahertz wave then undergo the fisrt single sideband(SSB) modulation and the second baseband SSB modulation in the process of data modulation,which achieves cascade SSB modulation.As can ben seen from the sumulation result,for mid-frequency carrier of 0.1 THz,the bit error rate(BER) performance without dispersion compensation achives 1×10-11 and the sensitivity of the receiver is-26.6 dBm with a data rate of 5 Gb/s after 100 km transmission.Through comparing the power penalty of DSB and DSSB,we demonstrated the optical SSB modulation has better dispersion tolerance.This paper also shows the contrastive curves of frequency selective fading for the SSB and DSB modulated signals,which definitely demonstrates the existence of dispersion fading during the DSB transmission as well as the effective suppression of the fading implemented by the SSB modulation.The novel scheme′s preferences is excelled than the conventional scheme′s,which is demonstrated by these theory and simulation.