This article discusses the characteristics common to laser diodes, such as high coherence, narrow spectral width and high directivity, while also explaining and defining these terms. Laser diodes (LD) are semiconductor devices that convert electrical energy into high-power optical energy. This junction is known as a p-n junction. These semiconductors are incredibly small, made of very thin slices of semiconducting. The laser diode chip is the small black chip at the front; a photodiode at the back is used to control output power. The anode connection on the right has been accidentally broken by the case cut. This comprehensive introduction explains laser diodes — electrically pumped semiconductor lasers where optical gain is obtained in a p-n or p-i-n junction.
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