How can we guarantee the quality of laser diodes? Regardless of whether the manufacturer is still a user, the quality of the laser diode is expected to increase, but there are many manufacturers who have made various efforts, and there is no reason to make it have quality advantages. It is precisely because of its certain premise in production that it is not available, how can we guarantee the quality of such products?

In order for these products to have good quality, first of all, we need to have good capabilities. This is all the focus. Obviously, in the procurement process of laser diodes, users also need to have a comparative study of the manufacturer's research capabilities. In order to improve the quality of the products, manufacturers must have good experience in production. Experience and ability are the primary focus of product quality. If a manufacturer has no good experience in production, there is no better quality.

In addition to the above, in the use of such products, is there a good quality, but also need to see how reliable the manufacturers have, there are some manufacturers in the market, there is no other Reliability, precisely because it has no better enhancement in reliability, so there is no more expectation in the production, which will reduce the quality of the product.

How laser diodes work

The laser diode is a p-n junction formed of a p-type semiconductor and an n-type semiconductor, and a space charge layer is formed on both sides of the interface, and a self-built electric field is built. When there is no applied voltage, the diffusion current caused by the difference in carrier concentration on both sides of the p-n junction is equal to the drift current caused by the self-built electric field, and is in an electric equilibrium state.

When the outside is biased by the forward voltage, the mutual suppression of the external electric field and the self-built electric field causes the diffusion current of the carrier to increase to cause a forward current.

When the applied reverse voltage is high to a certain extent, the electric field strength in the space charge layer of the pn junction reaches a critical value to generate a multiplication process of carriers, generating a large number of electron hole pairs, and the laser diode generates a large value of the reverse hit. The current is called the breakdown phenomenon of the diode.

1. Forward characteristics

In the electronic circuit, the positive pole of the diode is connected to the high potential end, the negative pole is connected to the low potential end, and the laser diode is turned on. This connection method is called forward biasing. It must be stated that when the forward voltage applied across the laser diode is small, the diode is still not conducting, and the forward current flowing through the diode is very weak. Only when the forward voltage reaches a certain value (this value is called "threshold voltage", the xenon tube is about 0.2V, and the silicon tube is about 0.6V), the diode can be turned on. The voltage across the diode remains essentially constant after conduction (the transistor is approximately 0.3V and the silicon tube is approximately 0.7V) and is referred to as the "forward voltage drop" of the diode.