What is a constant-current driver for laser diodes?

A constant-current driver is an electronic circuit that regulates the current flowing through a laser diode to an exact value – independent of input voltage and temperature variations. This is necessary because a laser diode's optical output depends linearly on current, not on voltage. A simple voltage supply would, with small temperature or supply fluctuations, lead to large current and therefore optical-output swings – in the worst case destroying the diode. Good drivers offer: constant-current regulation, soft-start, over-temperature protection, ESD protection and often analog/TTL modulation for pulsed operation. Matching drivers are available in our „Laser drivers“ category.