To day we are witnessing a revolution in advanced communications, derived primarily from the liberalization of the sector and the growth of Internet users, data services and mobile telephony. The solutions that most telecommunication providers offer to meet this increase in trafic demand are diverse. On the one hand you can install more iber; although this is an expensive, impractical solution. In some other cases, the main problem facing service providers is related to the jump to a higher capacity. The best alternative is to have operators in DWDM (Dense Wavelength Division Multiplexing), which allow an economical way to increase the carrying capacity of existing networks. In this article, an analysis of DWDM networks is performed including their main characteristics and issues that inluence their design and implementation for optimal performance and scalable future.