Common fiber optics cheat sheet

Only the most common types will be included. No old or special stuff like FDDI, angled connectors, MTRJ…

Multimode fiber

Multimode has a bigger core compared to single-mode fiber (see table below). This means that multiple rays of light are sent through the core. This creates a limitation compared to single-mode: each beam of light has an individual path and can reach the end of the fiber at a different time (= modal dispersion) which creates a limit on data and distance.

Multimode uses LED (850nm) as light source, which is cheaper. VCSEL operates at 1300nm.

Type Core Optics Distance 1G Distance 10G Distance 40G Distance 100G
OM1 62,5 μm SX, LX*, LRM* 300m / 984ft 30m / 98ft Not supported Not supported
OM2 50 μm SX, LX*, LRM* 600m / 1968ft 150m / 492ft Not supported Not supported
OM3 50 μm SX, SR, LX4, LRM 1000m / 3280ft 300m / 984ft 100m / 328ft 100m / 328ft
OM4 50 μm SX, SR, LX4, LRM 1100m / 3608ft 550m / 1804ft 150m / 492ft 150m

* = requires mode-conditioning patch cord

Single-mode fiber

Single-mode has a smaller core (9 micrometer), which allows only one ray of light. This allows larger distance. Single-mode used laser as light source, which is more expensive. Single-mode operates at 1310 or 1550nm wavelength.

Type Core Optics Distance 1G Distance 10G Distance 40G Distance 100G
OS1/OS2 9 μm LX, LH, ZX 100km 40km 40km 40km


Type Name Image
LC Little Connector, Lucent Connector
SC Square Connector, Subscriber Connector,…
ST Straight Tip, Stab-Twist


I won’t discuss GBICs, XFP’s, MT-RJ…

  • SFP: 100Mbps or 1Gbps (small form-factor pluggable)
    • available in fiber (LC connector) or copper (RJ45)
  • SFP+: same size as SFP, 10Gpbs
    • SFP’s should work fine in SFP+ ports
    • available in fiber (LC connector) or copper (RJ45 connector)
  • SFP28: enhanced SFP+, same zize, 25Gbps
    • LC connector
  • QSFP+: 4 channels of each 10Gbps = 40Gbps
    • larger than SFP(+)
    • LC connector
  • QSFP28: (quad small form-facotr pluggable 28); 4 channels of 25gbps = 100Gbps
    • same size as QSFP+
    • LC connector
Copper SFP
Copper SFP

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