In Cwdm equipment, we can use lasers in unregulated temperature, lower cost and which emit at wavelengths spaced 20 nm in the transmission window 1270-1610 nm. CWDM is the subject of the ITU-T recommendation G.695, which provides for flexible and scalable solutions, including the solution of 8 to 16 channels with two optical fibers (one for each direction of transmision), offering data rates of