The DLD-127A is a 400 watt laser diode driver/current source designed to drive laser diodes and other lowimpedance loads at up to 10 volts and 40 amps. It is optimized for diode pumping of solid state lasers, illumination, and other high power applications. The DLD-127A can be operated continuously (CW), pulsed (Quasi-CW) or can be analog modulated by an external analog modulation input. It can generate output pulse widths of 50s to DC at up to 10KHz, with an analog modulation bandwidth of 10KHz. The DLD-127A can be operated in either laser current (constant current) or optical power (constant power) control modes. The control mode is user-selectable, and signals to monitor the output current are available through the user interface connector. In constant power control mode, a user-supplied photodiode may be connected to the DLD-127A to provide optical feedback to control the current source through the on-board photodiode amplifier. In constant current control mode, the laser current is monitored, and controls the driver output. The output