多项选择题
A. fiber dispersion
B. signal attenuation
C. transmitter power
D. amplifier bandwidth
E. receiver dispersion tolerance
单项选择题 Ifthedispersionofagivenfiberis17ps/nm*kmat1550nmandzeroat1310nm，thenwhatistheaccumulateddispersionofanITUwavelengthafterittravels200km？（）
单项选择题 HowisaThinFilmfilterfabricated？（）
多项选择题 Click the Exhibit button. When designing a DWDM system with multiple amplified spans， a pre-amp is needed at Site B to （）.