mm-C4 is a multimode fiber.

Explanation

The designation "mm" in "mm-C4" typically stands for multimode, indicating that the fiber allows multiple light modes to propagate simultaneously . Multimode fibers have a larger core diameter, usually 50µm or 62.5µm, which enables multiple light paths, making them ideal for short-distance, high-bandwidth applications such as data centers, enterprise networks, and campus environments . In contrast, single-mode fibers (SM) have a much smaller core, around 8–10µm, and support only a single light path, which is optimized for long-distance transmission .

Characteristics of Multimode Fiber

• Core Size: 50µm or 62.5µm
• Light Modes: Multiple, which can cause modal dispersion over long distances
• Typical Applications: Short-range connections, high-speed LANs, data centers
• Standards: OM1, OM2, OM3, OM4, OM5, with OM5 also called wideband multimode fiber (WBMMF) supporting higher data rates
• Wavelengths: Commonly 850nm for LED or VCSEL sources, sometimes 1300nm for legacy systems

Summary

The "mm" prefix in mm-C4 clearly identifies it as multimode fiber, suitable for short-distance, high-bandwidth networking. It is not single-mode, which would be indicated by "sm" or "single-mode" in the product name . This distinction is important for ensuring compatibility with transceivers and network equipment.