A laser diode driver circuit can comprise fast loop portion and a closed-loop portion. The closed-loop driver portion can provide a part of the current for a laser diode. The closed-loop drive portion output can be independent of a photodetector. The fast-loop driver portion can provide a second part of the current for the laser diode. The fast-loop driver portion can use the output of the photodiode to determine the output of the fast-loop driver portion.