What do OM2 and OM3 designate in fiber optics?

• A. Coaxial cable standards
• B. Multimode fiber categories
• C. Singlemode fiber grades
• D. Plastic optical fiber types

Answer: (B)

OM2 and OM3 are designations for categories within multimode fiber performance. They indicate the fiber’s modal bandwidth and how well it can carry high-speed signals over distance. Multimode fiber carries many light paths, and higher bandwidth means less modal dispersion, allowing higher data rates to travel farther. OM2 is a standard grade with moderate bandwidth, suitable for traditional Ethernet links, while OM3 is a higher-performance category optimized for longer runs and higher speeds (such as 10 Gbps) using common 850 nm light sources. They are not coaxial cable standards or plastic optical fiber types; they specifically define performance class within multimode fiber. Choosing OM3 over OM2 helps when you need greater reach or faster networks, whereas OM2 may suffice for shorter, lower-speed connections.