从理论与实验两方面分析了光网络节点设备光信噪比(OSNR)恶化量的测量.导出了单节点设备输出、输入侧光信噪比之差的公式.理论分析表明:节点设备输出、输入侧光信噪比之差值在一般测试条件下不能反映节点设备对光信号的影响,不能作为节点设备光信噪比的恶化量来衡量设备对光信号的影响;为使测量结果能反映光节点参数对光信号的综合影响,测试系统应当满足文中给出的增益条件C=1.实验结果支持了理论分析.实验结果表明,对于C=1时光信噪比恶化量为4.5 dB的光节点设备,当C从3变化到0.16时,其输入、输出侧光信噪比之差从1.8 dB变化到11.3 dB.

The measurement of optical signal noise ratio (OSNR) degradation of optical network elements is analyzed theoretically and experimentally. The formula denoting the difference of OSNR detected at input port and output port of the element is derived. Theoretical results show that the difference can not reflect the effect of the element on signal in optical domain under general condition, and can not be taken generally as OSNR degradation for evaluation in the element until the element system meets the demands of condition C=1 given in the paper. Experimental results support the theory and show that for an optical network element with OSNR degradation of 4.5 dB at C=1, when C decreases from 3 to 0.16, the difference of OSNR detected at its input port and output port varies from 1.8 dB to 11.3 dB.