Fiber optic patch cords are typically made using single-mode (OS1/OS2) or multimode (OM1–OM5) fiber cables, depending on distance and application.

Single-Mode Fiber (SM)

Single-mode fiber patch cords have a small core diameter of about 9 µm and are designed for long-distance transmission with low attenuation. They are usually color-coded yellow and are suitable for high-speed data transfer over long distances, such as in telecom backbones or data center interconnects. Common standards include OS1 and OS2, with OS2 being optimized for outdoor or longer reach applications .

Multimode Fiber (MM)

Multimode fiber patch cords have larger core diameters of 50 µm or 62.5 µm, allowing multiple light modes to travel simultaneously. They are ideal for short to medium distances, such as intra-data center connections. Multimode fibers are classified as OM1, OM2, OM3, OM4, and OM5, with color-coded jackets: OM1/OM2 (orange), OM3 (aqua), OM4 (violet), and OM5 (lime green). These fibers support high bandwidth over shorter distances and are commonly used in office buildings and local networks .

Construction and Protection

Patch cords are reinforced with Kevlar (aramid yarn) for strength and durability, and the fiber is surrounded by a protective jacket. Jacket materials vary depending on installation requirements: PVC for basic indoor use, plenum (OFNP) for fire-resistant air ducts, riser (OFNR) for vertical shafts, and LSZH for low-smoke, zero-halogen environments .

Connector Types

Patch cords are terminated with connectors such as LC, SC, FC, ST, MPO, MU, MT-RJ, or E2000, with LC being the most common in modern data centers. They can be simplex (single fiber) or duplex (two fibers for bidirectional transmission), .

Summary

• Single-mode (OS1/OS2): Long-distance, low attenuation, yellow jacket, 9 µm core.
• Multimode (OM1–OM5): Short to medium distance, higher bandwidth, color-coded jackets, 50–62.5 µm core.
• Jacket and reinforcement: Kevlar for strength; PVC, plenum, riser, or LSZH depending on environment.
• Connectors: LC, SC, FC, ST, MPO, etc., with simplex or duplex configurations. Choosing the correct fiber type ensures optimal performance, minimal signal loss, and compatibility with network equipment .