Multimode systems are less expensive than singlemode systems, not because the fiber is cheaper (it isn't) nor because cable is cheaper (the same), but because the large core of multimode fiber allows the use of cheaper LED or VCSEL sources in transmitters, making the electronics. Multimode systems are less expensive than singlemode systems, not because the fiber is cheaper (it isn't) nor because cable is cheaper (the same), but because the large core of multimode fiber allows the use of cheaper LED or VCSEL sources in transmitters, making the electronics. Choosing between single-mode (SMF/OS2) and multimode (MMF/OM3–OM5) fiber is more than a cabling preference, it determines your reachable distance, optics cost, upgrade path, and even day-to-day operability (polarity, cleaning, testing). The differences are well known in theory, but real-world. This guide compares multimode cable prices across OM1–OM5 and explains what really moves the number: fiber grade, fiber count, jacket rating, and whether assemblies are factory-terminated. Single-mode fiber (SMF) is the preferred choice for longer distances, inter-building campus links, and future high-speed upgrades. And lots of data centers and providers will only do single-mode cabling for new installs.