Question
We operate a WLD and a WTC together from one power supply and want to build this in series and need to specify the power supply:
- What stability of the power supply is necessary, what ripple is allowed?
- Do you have any kind of overload protection?
- Would it do any harm to have a capacitor (i.e. 470 pF) in parallel to the laser diode?
Answer
- Power supply recommendations for low noise operation: < 5 mV p-p noise & ripple.
- Rev C of the WLD does not have overload protection. The WTC does not have overload protection. On the WLD, Rev D adds an internal thermostat that shuts down the output if the WLD heats over 105°C. It will slow-start the laser diode when the temperature then drops to 95°C.
- The laser diode has a capacitance that varies with operating level. This capacitance in parallel with the 470 pF can introduce instabilities.