The last page on there has a bit of information.
Test/Dummy loads for setting the current on a laser driver.
Measuring current without a dummy load/test load is done by placing a multi-meter’s probes between the + and – sides of the load between the current source and the load in mA or Amps. This setup works but when adjusting a trim potentiometer on the laser driver it risks damage to the laser diode if too much current is accidentally applied.
Using a dummy load or test load allows the setup of a laser driver’s current, in mA or Amps. The basic dummy load is made up of a 1-Ohm resistor and silicon diodes; each silicon diode creates a 0.7V drop in the voltage thus creating a load. This load simulates the voltage drop that an actual laser diode would create, and allows a laser driver’s maximum current to be measured with a multi-meter. The setup of a dummy varies between different laser diodes according to the voltage needed. In the case of an IR diode needed 2.2v three INF4001 silicon diodes would create a 2.1v load on the driver. A red laser diode typically running at 3.0v four silicon diodes would be used creating a load of 2.8v. Blu-ray diodes would use six INF4001 or equivalent silicon diodes to create a load of 4.2v load. These are basic setups, check the specification sheet if available and adjust the test load to your needs, (<voltage needed>/0.7 = number of diodes) needed to simulate your load. As you can see it doesn’t always add up to the exact voltage so err on the side of caution.