CWDM Network Elements
To understand how to implement CWDM in access networks, we must cover a certain set of technologies that enable us to describe the functionality of CWDM systems. With this in mind, this section covers certain component technologies that basically differentiate CWDM systems from their DWDM counterparts. Among these are low-cost vertical cavity surface emitting lasers (VCSELs); gain-flattened, thin film filters; and so on.
Vertical Cavity Surface Emitting Laser
A VCSEL is a semiconductor laser diode that emits light perpendicular to the p-n junction (unlike semiconductor lasers, which emit light in the plane of the p-n junction). VCSELs can be integrated as onboard components with other electronic components without prepackaging. ...