Type 2602 SourceMeter Application Test Types (III)

TEC Testing and Control

Many laser diode modules are equipped with a semiconductor cooler (Peltier device). Generally, a TEC controller can be used to control the temperature of the entire module during the LIV test sweep. The temperature set point can also be adjusted to verify the function of the TEC and to check the resistance of the thermistor after reaching the new set temperature.

Excessive mechanical shear loading is probably the most common failure mechanism for Peltier devices. During the transport and installation of the Peltier device, mechanical shear loading can cause delamination or breakage of some or all of the device components. Simple AC or reverse DC resistance tests can determine the quality of the Peltier device before and after installation. DC resistance measurements are not accurate due to self-heating effects of the component components and the resulting thermal excursions. The Model 2510-AT TEC SourceMeter provides the necessary bipolar source current and voltage measurements to facilitate this test.

Isolation Testing

The switch matrix allows for easy isolation testing of the components of a laser diode module. For example, the electrical isolation between a thermistor and a laser diode can be tested by applying a voltage between the thermistor and the laser diode while keeping the two terminals of the thermistor and the laser diode at the same potential, which prevents current from flowing through the components themselves.