Three Commonly Used Light Sources in Fiber Optic Communication

Light sources are devices that generate the optical signals transmitted through fiber optic cables. In fiber communication, the most commonly used light sources are LEDs (Light Emitting Diodes) and laser diodes. LEDs are used in short-distance, low-speed systems due to their broader spectral width. Optical fiber primarily uses infrared light, not visible light, due to lower signal attenuation. Common wavelengths are 1310nm and 1550nm, where silica glass fiber has minimal loss (as low as 0. Lasers or LEDs generate the light, which carries data through total internal reflection within. Most systems use a "transceiver" which includes both transmission and receiver in a single module. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. It often uses glass or plastic cables, which address the problems of traditional copper cables' poor speed and limited distance bandwidth carrying. VCSEL (Vertical Cavity Surface Emitting Laser)- VCSELs (pronounced 'vixel') emerged in the 80's as a new kind of semi-conductor laser and were soon recognized for their potential in fiber optics. When Gigabit Ethernet products were developed LEDs could not modulate (turn on and off) at required. [PDF]