Fiber optic patch cords are classified by fiber type, connector type, and configuration, with the most common being single-mode or multimode, LC, SC, ST, and MPO connectors, and simplex or duplex arrangements.

Fiber Type

• Single-Mode (SM, OS1/OS2): Designed for long-distance communication with minimal signal loss, typically used in telecom, backbone, and outdoor networks. The outer sheath is usually yellow .
• Multimode (MM, OM1/OM2/OM3/OM4/OM5): Suitable for short-distance, high-speed links such as data centers and LANs. Core diameters are larger, supporting multiple light modes. OM1/OM2 are orange, OM3 is aqua, OM4 is violet, and OM5 is lime green .

Connector Type

• LC (Lucent Connector): Small form factor, high-density, commonly used in modern data centers and QSFP transceivers .
• SC (Subscriber Connector): Larger, robust, widely used in FTTH and CATV networks .
• ST (Straight Tip): Rugged, bayonet-style connector, often used in industrial or legacy systems .
• FC (Ferrule Connector): Screw-on type, used in high-vibration environments .
• MPO/MTP: Multi-fiber connectors for high-density applications, often in data center backbones .
• Other connectors: MU, MT-RJ, E2000, and hybrid combinations (e.g., LC to SC) for specialized setups .

Configuration

• Simplex: Single fiber, one-way communication, used for transmit-only or receive-only links .
• Duplex: Two fibers, supporting two-way communication (Tx/Rx), standard in Ethernet and PON networks .
• Armored: Extra protection against physical damage, suitable for harsh environments .
• Bend-Insensitive: Designed for tight spaces or high-density racks, minimizing signal loss around bends .
• Mode-Conditioning: Used to adapt multimode systems to single-mode equipment, ensuring signal integrity .

Jacket Material

• PVC: Standard indoor use.
• LSZH (Low Smoke Zero Halogen): Emits minimal smoke and toxic gases, common in Europe and high-safety areas .
• OFNR (Riser) and OFNP (Plenum): Fire-resistant for vertical shafts or air ducts .

Summary

Choosing the right fiber optic patch cord depends on distance, network speed, environment, and connector compatibility. Single-mode is preferred for long-haul links, multimode for short-distance high-speed connections. LC and SC are the most widely used connectors, while duplex configurations dominate modern networks. Specialized cords like armored, bend-insensitive, or mode-conditioning types are selected based on installation conditions and performance requirements .