Fiber Optic cables come in many varieties and configurations and without going into too much technical detail, this guide provides a basic overview on commonly used terminology , typical configurations and best practice applications of Fiber Optic Cable Assemblies. A Fiber Optic Cable assembly consist of the fiber cable itself terminated with optical connectors on either end. An assembly terminated with merely a connector on one end is commonly referred to as a fiber optic pigtail. The increased popularity of fiber optics in general and optical fiber cables in particular, is driven by the ability to transport electro-magnetic (optical) signals over short and long distances more efficiently (at higher data rates combined with a lower loss rate, attenuation and a smaller footprint) than traditional copper (CAT5/6) cables.

Optical Fiber Cable History and Structure

As light doesn't travel around curves or corners, it is the principle of guiding light by refraction that makes modern Fiber Optic Communication and Cables possible. This “guiding of light” essentially involves confining the light signal to the optical core, which in the case of Single-Mode Fiber features a diameter smaller than a human hair! To prevent light escaping (leaking) from the optical core, a transparent cladding of lower refraction is applied around the glass (silica but sometimes plastic) fiber core so light Is reflected back into the core and leakage is kept to a minimum. The transition between the core and cladding can be sharp (step-index profile) or gradual (graded-index profile) and therefore have different dispersion characteristics and result in different effective propagation distances.

The cladding with a typical diameter of 125 micrometers (µm) is subsequently coated with a tough (modern cables feature a dual layer) resin, in order to protect the fragile core from physical damage due to micro - and macro bending, moisture and to minimize attenuation. To further safeguard the delicate fibers from unwanted damage, modern day optical cables come in a variety of sheathing, (armored) Jackets and insulation. These protective layers provide protection, strength and flexibility to the cable, yet do not compromise the optical wave guide properties.

Fiber Optic Cable Color and Mode

Fiber Optic Cable Mode Color Comparison

To browse our online catalog of Single- and Multimode fiber optic cable products: Fiber Patch Cables Specialty Fiber Cables Armored Fiber Cables

Commercially available fiber cables, assemblies and patch cords can be ordered with jackets in any customized (shade of) color but standardized colors are used to identify the (generation of) Mode of the cable.

The mode of an optical fiber refers to the manner light is being propagated inside its optical core and is directly related to the diameter of the core. Fiber optic cables can be classified as either Single- or Multimode, where the latter feature a relatively much larger core and as a result support multiple transverse modes of propagation along the fiber. For the purpose and scope of this guide it is adequate to understand that Single-mode fiber (SMF) cables are designed for long distance (> 1km) communication whereas Multimode fiber (MMF) cables are applicable for short distance (< 1km) and appropriate for Datacenter, Local area - and Storage Area Networks. Standard Optical Single-Mode generation 1 and 2 (OS1 & OS2) cables feature a core/cladding diameter of 9/125 µm and for non-military applications, the use of a yellow outer jacket for Single-mode cables is recommended by the TIA-598C standard.

Optical Multimode (OM) cables can be classified into 4 different generations (as defined by by the ISO 11801 standard) , essentially representing technological differences or advances in respect to modal bandwidth, distance and fiber optic equipment compatibility. Optical Multimode generation 1 and 2 (OM1 & OM2) cables feature core/cladding diameters of 62.5/125µm and 50/125µm respectively and come standard in an Orange outer jacket. These OM1 and OM2 cables are widely deployed in premises applications and support applications ranging from Ethernet (10 Mb/s) to gigabit Ethernet (1 Gb/s) or 4Gb Fibre Channel SANs.

Aqua is the new Orange

Because of their relatively large core , OM1 and OM2 fiber were ideal for use with LED transmitters and as mentioned before these fibers support applications up to 1-4 Gigabit Ethernet (1-4 Gb/s). But as LEDs cannot be turned on/off fast enough due to a maximum modulation rate of 622 Mbit/s, they do not provide sufficient bandwidth to support 10 Gigabit Ethernet or higher bandwidth applications. This limitation has led to the replacement of LEDs by VCSELs that are capable of modulation rates of over 10 Gb/s and a migration to high speed 40G/100G fiber optic fabrics and equipment has resulted in the deployment of more sophisticated and laser optimized Multimode fiber (LOMMF) generation 3 and 4. By the end of 2009 when the OM4 standard was finalized, OM4 cables supported 125m links at 40 and 100 Gb/s. Since then Optical fiber manufacturers have greatly refined the manufacturing process and cables nowadays can be made that support 10 and 100 GbE up to 400 meters. Laser optimized multi-mode fiber (LOMMF) is designed for use with 850 nm VCSELs.

The following table provides an overview of respective specifications of the different generations Single- and Multimode fiber.

Fiber Type OS2 OM1 OM2 OM3 OM4
Core/Cladding Diameter 9/125μm 62.5/125μm 50/125μm 50/125μm 50/125μm
Cable Jacket Color Yellow Orange Orange Aqua Aqua
Wavelength (nm) 1310 1550 850 1300 850 1300 850 1300 850 1300
Max. Attenuation (dB/km) 0.35 0.20 3.00 1.00 2.70 0.80 3.00 1.00 3.00 1.00
Min. Over Filled Launch (MHz*km) N/A N/A 200 500 500 500 1500 500 3500 500
Min. Effective Modal (MHz*km) N/A N/A 200 N/A 500 N/A 2000 N/A 4700 N/A
Ethernet Transmission
1Gbps Ethernet (meter) 5000 N/A 275 550 550 550 1000 600 1000 600
10Gbps Ethernet (meter) 10000 40000 33 200*/300** 85 220*/300** 300 N/A 550 N/A
40/100Gbps Ethernet (meter) N/A N/A N/A N/A N/A N/A 100 N/A 150 N/A
Type Abbreviation Description
Plenum OFNP The best suited for plenum areas (such as the space between walls or ceilings of buildings). These fiber assemblies product the least amount of smoke during combustion.
Riser OFNR Engineered to prevent the spread of fire within a building, these assemblies are best used in between the floor areas of buildings.
Low Smoke Zero Halogen LSZH These assemblies produce a reduced amount of smoke during combustion and zero halogen, essentially preventing toxic gas from spreading during combustion.