What type of light is typically used in multi-mode fiber optics?

Multi-mode fiber optics typically use LED (Light Emitting Diode) light sources. The primary reason for this is that multi-mode fibers are designed to transmit light over relatively short distances, where the wider core diameter allows multiple modes or paths of light to propagate. LED light sources emit broad-spectrum light that effectively fills the larger core of multi-mode fibers, enhancing light coupling and thereby improving the efficiency of the transmission.

LEDs are more cost-effective and simpler than laser sources and are perfectly adequate for applications such as local area networks (LANs) and short-distance communication, where high bandwidth is not as critical.

In contrast, while laser light can also be used in certain configurations, it is more commonly associated with single-mode fiber optics which require highly coherent light for longer distance transmission. Infrared and ultraviolet lights are not typically used in standard multi-mode applications for fiber optics due to their specific transmission properties and potential for attenuation over typical fiber materials.