A complete and very compact thermal control solution for DWDM (Dense Wavelength Division Multiplexing) laser modules can be made using a MAX8520/21 and a single op amp. Because DWDM uses multiple lasers on a single fiber, careful control of the laser output frequencies is required. This design can easily provide the level of performance needed for 25GHz channel spacing making it an ideal foundation for designers working on DWDM fiber optic systems. ……