When designing a diode laser, the 2nd things to do after selecting the laser diode is to choose a laser driver. Here are some suggestions:
1. If the laser diode requires a minimum current of > 1A, most likely, a switch mode laser driver is needed, provided that the high frequency ripple noise, at about 500KHz, is not a problem for the optical system. The main advantage of the switch mode laser driver is that it has a high efficiency, thus producing less heat. The main shortcoming of this type of laser driver is that it has a high ripple noise, about 0.1% to 1% of its output current.
2. If the laser diode current required is about 1A or even less, a linear mode laser driver can be considered using. The advantage of this type of laser driver is that it has a low noise, but the main shortcoming is: low efficiency, thus produces more heat than the switch mode laser driver. For small output current, < 500mA, the heat won't be a problem. For high current, such as 1A, heat sinking mechanisms is a must.
3. We have a full line laser drivers, below is the selection guide:

4. After selecting the laser driver, PCB layout has to be carefully done, if using the DC input type laser drivers. The guidance about laying out the PCB for the laser driver can be found in the laser drivers' datasheet. For the AC input laser drivers, there is no need to do any PCB layout.