单项选择题
A. the signal to noise of the current optical amplifier
B. the signal to noise of the previous amplifier or source
C. the signal to noise introduced by the optical multiplexer
D. the accumulated noise to signal ratio of the optical channel
单项选择题 The dispersion of a non-zero dispersion shifted fiber is 6 ps/nm*km at 1550 nm and 10 ps/nm*km at 1610 nm. What is the minimum dispersion compensation required if an L-Band DWDM signal travels through 200 km of fiber and has a dispersion tolerance of 1800 ps/nm？（）
单项选择题 Forlaserswithtightlycontrolledwavelengths，approximatelyhowfarapartarethecentersofadjacentwavelengthswhen100GHzspacingisusedinaDWDMsystem？（）
多项选择题 Click the Exhibit button. Within an ONS 15454， you are provisioning a circuit on an unprotected SNCP ring. In the exhibit， which two must you configure？（）