Which statement about multimode fiber wavelengths is true according to common practice?

Which statement about multimode fiber wavelengths is true according to common practice?

• A. The two most common wavelengths are 850 and 1300
• B. The two most common wavelengths are 1310 and 1550
• C. The two most common wavelengths are 780 and 980
• D. The two most common wavelengths are 900 and 1500

Answer: (A)

Multimode fiber systems prioritize wavelengths that align with inexpensive light sources and practical transmission windows for short to moderate distances. The most common pair is 850 nm and 1300 nm. At 850 nm, inexpensive LEDs and VCSELs are highly efficient and widely used, making short-range multimode links cost-effective. At 1300 nm, silica fiber offers low attenuation and manageable dispersion, allowing longer links than at 850 nm while still using multimode fiber. This combination has become the standard for typical multimode Ethernet and LAN applications. Other wavelengths listed tend to be associated with different roles or fiber types. For example, 780 nm and 980 nm are not the standard data-carrying wavelengths for multimode networks, and 900/1500 nm aren’t the typical pair used for multimode transmission. While 1310/1550 nm are key windows for single-mode fiber, they are not the conventional choice for multimode systems.

Multimode fiber systems prioritize wavelengths that align with inexpensive light sources and practical transmission windows for short to moderate distances. The most common pair is 850 nm and 1300 nm. At 850 nm, inexpensive LEDs and VCSELs are highly efficient and widely used, making short-range multimode links cost-effective. At 1300 nm, silica fiber offers low attenuation and manageable dispersion, allowing longer links than at 850 nm while still using multimode fiber. This combination has become the standard for typical multimode Ethernet and LAN applications.

Other wavelengths listed tend to be associated with different roles or fiber types. For example, 780 nm and 980 nm are not the standard data-carrying wavelengths for multimode networks, and 900/1500 nm aren’t the typical pair used for multimode transmission. While 1310/1550 nm are key windows for single-mode fiber, they are not the conventional choice for multimode systems.