单项选择题
If the dispersion of a given fiber is 17ps/nm*km at 1550 nm and zero at 1310 nm， then what is the accumulated dispersion of an ITU wavelength after it travels 200 km？ （）
A. 0 ps/nm B. 340 ps/nm C. 200 ps/nm D. 3400 ps/nm E. More information is needed.
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 （）.
单项选择题 In the OSNR model for EDFA amplifiers， SNR OUT = 1/（1/SNR IN + FhvB/P IN ）， what does SNR IN represent？（）
