What is the Dense Wavelength Division Multiplexing(DWDM) technology? Could any one of u tell me its use?

Answer 1

It's a techniques used in fiber optics where the effective bandwidth is increased by sending more than one light beam through the fiber. Each beam is a different wavelength (e.i. "color") so they can be separated and each can carry its own info.

Try here:

http://www.webopedia.com/TERM/D/DWDM.html