Single-channel laser diode driver selection guide

To select a single-channel laser diode driver you need to consider:

• The maximum intended operating current for the laser diode, keeping in mind possible degradation due to aging of the laser.
• The maximum voltage drop, which is the sum of the diode operating voltage and the ohmic loss in the cables and connectors.
• Any requirements for regulating the temperature of the laser diode or other optical components (such as nonlinear crystals or laser media).

The first two items are critical since the driver needs to have the necessary capability. Precise temperature regulation, if that is a requirement, can be accomplished either with one of our integrated laser diode/TEC drivers or with our stand-alone TEC controller. Please see those pages for more information.

Our laser diode controllers are current sources. You command a specific current, and the voltage that results is a characteristic of the load (the diode plus cables and connectors) rather than the driver. The driver shuts off to protect itself when the output voltage drawn exceeds its capabilities. The limit at which this occurs is termed the compliance voltage.

Each product line is optimized for a different range of applications. Our MV product line has a high compliance voltage, suitable for driving multiple diodes in series. The LV and HCV product lines are for driving single diodes, although the HCV has a compliance voltage sufficient for two diodes in series. The HV product line is for diode stacks.

When a driver is optimized for high current it may become excessively noisy or exhibit regulation problems at low current. For this reason some of our controllers also specify a minimum current. In these cases the firmware will prevent the driver from turning on below this point. If your requirements include operation under these conditions please contact us.

On some products the firmware multiplies the current by the voltage and insures that the result does not exceed a maximum output power limit. This protects the driver while allowing performance flexibility, since the maximum current available will depend on the load characteristics.