I'm making a laser diode module using a LD, a PD, and a LD driver board. With the components I would be able to monitor the optical output from the LD and then adjust current to keep the output constant. However, I wonder if I also need a TEC. The ambient temperature of my device would change fast (1℃/1min). Wouldn't it be enough to adjust the power using the PD and a LD driver IC? The temperature would not exceed the operating temperature range.