论述了1550 nm 射频电视(CATV)通道与1490 nm 数据通道的相互干扰问题。针对1490 nm光波通过光纤中受激拉曼效应对1550 nm光波的非线性串扰和1550 nm光波通过粗波分复用(CWDM)分波器对1490 nm光波的线性串扰提出了理论计算公式,进行了定量分析和计算。结果表明,数据非线性串扰可使射频电视系统低频端的载噪比下跌9 dB;而在常规融锥型粗波分复用分波器情况下,射频电视线性串扰可使数据光接收机的光功率代价达到2.5 dB。最后指出了克服串扰的方法,如以太空闲字符扰码和高隔离度粗波分复用等。

RF-TV overlay EPON technique is investaged. First, the interference problems between 1550 nm CATV path and 1490 nm data path are described and then the theoretic formula of the nonlinear crosstalk from 1490 nm to 1550 nm lightwave via stimulated Raman scattering effect in the optical fiber and the linear crosstalk from 1550 nm to 1490 nm lightwave caused by in-sufficient wavelength isolation of the CWDM coupler are presented, based on which the quantitative analyses and computation examples are given. The results show 9 dB carrier-noise-ratio degradation at the low end of CATV band due to the nonlinear crosstalk from data and 2.5 dB optical power penalty for data receiver due to the linear crosstalk from CATV in the case of conventional taper-fused CWDM. At last proposals to solve the crosstalk problems are offered including Ethernet idle scrambling, high isolation CWDM etc..