Certified Fiber Optics Practice Exam

Which types of sources are commonly used in Local Area Networks (LANs)?

1. LED sources

2. Laser sources

3. Both LED and Laser sources

4. Copper sources

The correct answer is: LED sources

In the context of Local Area Networks (LANs), the commonly used sources for fiber optic cables are LED sources. LEDs (Light Emitting Diodes) are favored in LAN applications due to their cost-effectiveness and simplicity in manufacturing. They emit light over a broader wavelength range and are typically used for multimode fiber applications, which are often utilized in LAN settings for shorter distance data transmission. LED sources are particularly effective in shorter distances because they have a lower power output, making them ideal for the limited range of a LAN where high-speed data transfer over short distances is required. The use of LEDs also aligns with the typical structure of LANs, where the cost and ease of installation are significant considerations. While laser sources are used in some fiber applications, particularly for longer distance communications due to their ability to transmit signals over greater distances with less signal loss, they are generally not as common in typical LAN configurations. Copper sources, while prevalent in networking, refer to traditional cabling infrastructures (such as Ethernet) and are not related to fiber optic networks. In summary, the focus on LED sources in LANs is due to their practical advantages for short-distance data communication, making them the most appropriate choice for this context.