Many people are curious. No matter who bought the laser diode, it will burn the tube in daily use. Do you know why the laser diode is so easily damaged? How can we avoid it in the process of use? Let's take a look at it together.

Static electricity is particularly destructive to laser diodes. Many people don't pay attention to it. Just touching the pin and connecting a wire can bring hundreds of thousands of volts of static electricity. Although people don't feel it, it is enough for the laser chip to break down. Laser diode is particularly sensitive to current, and it is easy to overheat, age or even burn out as long as the current exceeds the rated value in normal operation. Especially with power supply without constant current function, such as direct DC power supply or simple current limiting resistor, the risk is higher. Heat dissipation is also on the one hand. Although the efficiency of laser diode is high, its heat output is not small at all. Many people ignore heat dissipation, thinking that it is enough to put it in a metal shell. In fact, thermal grease, heat sink and even active air cooling should be added.

Finally, optical feedback leads to damage, which is an unexpected reason for many people. If the light emitted by the laser is reflected back (for example, hitting the metal surface or mirror surface), it will enter the diode cavity again, interfere with the laser oscillation, and even directly break through the internal structure.

Therefore, in some precision applications, isolators or inclined mounting are usually added to prevent the laser from reflecting back to the chip.

Matters needing attention in the use of laser diode

Operation with anti-static measures

Wear an antistatic bracelet, ground it, or operate it on an antistatic mat.

This really can't be saved, especially when you debug or replace the module.

Using constant current drive power supply

Don't connect the power cord directly, even if it is low voltage, it may be damaged by current surge.

Constant current drive can not only stabilize the output, but also effectively prolong the service life, especially for high-power laser diodes, which is very critical.

Attach importance to heat dissipation design

Low-power diodes can conduct heat by metal shell, but those with power greater than 50mW must have good heat dissipation structure.

For example, aluminum-based cooling base, heat-conducting silicone grease, and fan if necessary. If the temperature is well controlled, it is no exaggeration to double the service life.

Avoid optical feedback and external reflection.

Try not to let the laser shine directly on the mirror or smooth metal during debugging.

In the laboratory or testing equipment, the laser module will be installed with a few degrees tilt, just to prevent the reflected light from hitting back directly.

The above article is to tell you what to pay attention to when using laser diodes and how laser diodes can be damaged. I believe you should have a clear understanding after reading it.