问题：

[多选] What two descriptions best define DWDM？ （）

A .  a WDM system that is compatible with EDFA technology
B .  an optical technology for transmitting up to 16 channels over multiple fiber strands
C .  an optical technology for transmitting up to 32 channels over multiple fiber strands
D .  a technology for transmitting multiple optical signals using less sophisticated transceiver designthen CWDM
E .  a technology for transmitting more closely packed optical signals using more sophisticatedtransceiver designs than CWDM