A laser diode is a semiconductor device that converts electrical current directly into coherent light. Unlike LEDs, an LD uses an optical cavity (mirrors) and stimulated emission to deliver:

Narrow spectrum (<1 nm)

High efficiency (40–60 % WPE)

Milli- to multi-watt output

Modulation up to 100 GHz

How to Choose in 30 Seconds

1. Wavelength → decided by your target (absorption line, eye-safety, fiber window).

2. Structure → need single-mode long haul? Pick DFB. Need cheap short link? FP or VCSEL.

3. Package → space-constrained consumer → TO-56; telecom outdoor → Butterfly; 3D sensing array → VCSEL COB.

Specification：

Dimensions：

Applications & Areas Used

1. Optical communications: DFB/QW 1310 nm/1550 nm (backbone), VCSEL 850 nm (data-center), 980 nm pump LDs (EDFA)

2. Industrial processing: high-power 808/915/980 nm bars—metal cutting, welding, cladding; 405-532nm short-pulse—PCB micro-via drilling, wafer dicing

3. Medical: 405 nm acne therapy, 520-532 nm vascular lesions, 650 nm low-level therapy, 808/980nm surgery/dentistry, 1064 nm lithotripsy/tumor ablation 

4. Consumer electronics: 650/780nm DVD, 405nm Blu-ray, VCSEL 850nm phone 3D face/gesture, RGB laser diodes  for laser TV/projectors

5. Sensing & metrology: 520 nm green laser level, 905 nm IR LiDAR, DFB 1650 nm gas-absorption detection