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Fiber Optic Technology - Part Two - Fiber Cables & Construction

This is the second article in our series on Fiber Optics, and it focuses on the different fiber cable types; construction and specifications; and cable selection criteria.

Whether the installation is for an Inside Plant or Outside Plant, the choice of cable type is very important for the installer of fiber optic cabling systems.

Inside Plant (ISP)

Inside Plant cabling is mostly multimode in short lengths, rarely longer than a few hundred feet, with 2 to 48 fibers per cable typically and in a variety of different constructions and jacket materials. Some users install hybrid cable with both multimode and singlemode fibers. 

ISP cabling is designed to perform in applications such as connecting outside plant cables to terminal equipment; linking various devices in a premises network; intra-building; risers; general building; and plenum applications. Splicing is practically unknown in ISP applications. Most connectors are SC (Stab and Click or Subscriber Connector) with a few STs (Stab and Turn or Straight Tip). 

Indoor Distribution Fiber 
DINTEK's Light-LINKS Indoor Fiber Distribution Cable

Indoor Tight Buffer Distribution Fiber Optic Cable has individually thermoplastic color coded 900μm buffered fibers. The buffered fibers are then surrounded by all-dielectric aramid strength members for strength and minimization of stress during installation. 

The core groups are then protected with an overall jacket. Fibers are bundled in groups of 6 or 12, called subunits.

Note: No fiber cable should be installed indoors unless it is UL listed for flame retardancy.

DINTEK's Termination Kit

​Termination is by installing connectors directly on the ends of the fibers, primarily using adhesive technology. Testing is done by a source and meter, but every installer has a flashlight type tracer to check fiber continuity and connection. 

Premises installers need only a Termination Kit for attaching connectors and a simple test kit for their installations. 

Working in crowded telecom closets or communications rooms is the norm.

Outside Plant (OSP) 

Outside plant installations are all singlemode fiber and cables often have very high fiber counts, up to 288 fibers. OSP cables are designed to perform in outside applications such as ducts, aerial and direct buried applications. They are optimized for resisting moisture and rodent damage and come in a variety of fiber counts, constructions and jacket materials. 

Installation requires special pullers or plows, and even trailers to carry giant spools of cable, so therefore more investment is required in the tools and test equipment, such as pullers, splicers, OTDRs (Optical Time-Domain Reflectometer) and even splicing vans.

  • Used mainly by telephone companies, CATV and Internet ISPs.
  • Typically goes relatively long distances up to hundreds of kilometers.

  • Outside plant installations are always singlemode fiber.
  • Optimized cable designs for resisting moisture and rodent damage.

Loose Tube Cables

Loose Tube Cables are composed of several fibers together inside a small plastic tube, which are in turn wound around a central strength member and jacketed, providing a small, high fiber count cable. 

This type of cable is ideal for outside plant trunking applications, as it can be made with the loose tubes filled with gel or water absorbent powder to prevent harm to the fibers from water. It can be used in conduits, strung overhead or buried directly into the ground. Since the fibers have only a thin buffer coating, they must be carefully handled and protected to prevent damage.

Main Features 

  • All dielectric central strength member
  • Excellent attenuation performance
  • Water blocking for moisture protection
  • Polyethylene jacket for weather and UV protection

​Recommended Applications

  • Building interconnections and data trunk
  • Long haul networking
  • Ducts between buildings and aerial lashing
  • Applications requiring good ozone, moisture, weather resistance.

OSP cable design can vary in many different ways. Some typical variations are:
Central Tube
Water Blocking - Liquid / Tape / Powder / Gel
Full / Partly Flooded
Armored - Aluminium / Steel / Interlocked

High Density 

One of the significant advantages of fiber cable is the density it can achieve. This density can be accomplished via two methods:

​Ribbon fiber offers the highest packing density, since all the fibers are laid out in rows, typically of 12 fibers, and laid on top of each other. This way 144 fibers only have a cross section of about 1/4 inch or 6 mm. Some cable designs use a "slotted core" with up to 6 of these 144 fiber ribbon assemblies for 864 fibers in one cable! Since it's outside plant cable, it's gel-filled for water blocking.

​As mentioned earlier, these cables are composed of several fibers together inside a small plastic tube, which are in turn wound around a central strength member and jacketed, providing a small, high fiber count cable.

Indoor/Outdoor Fiber

DINTEK Light-Links Indoor/Outdoor Fiber Optic Cable

Indoor/Outdoor fiber cable is water-blocked, sunlight resistant, has an indoor/outdoor tight buffer and is Riser Rated, OFNR.

Indoor/Outdoor cable offers a premises fiber optic cable versatility. It can be installed in open spaces, trays, conduits, inner-ducts, trenches, steam tunnels and building riser locations. 

Dry-water blocking technology eliminates the need to clean off the traditional gel-based water-blocking compounds and the outer jacket is UL listed sunlight resistant polymer which allows exposure to long-term direct sunlight without the concern of material degradation. 

DINTEK Light-LINKSTM Indoor/Outdoor Fiber Optic Cables are ideal for applications that span indoor and outdoor environments, therefore eliminating the need for entrance facility splice points, which saves money and installation time. 

Aerial Cable 

DINTEK Armored Aerial Cable

Aerial cables are for outside installation on poles. They can be lashed to a messenger or another cable (common in CATV) or have metal or aramid strength members to make them self supporting.

DINTEK Light-LINKSTM Outdoor Armored Aerial Fiber Cables are designed to provide high fiber counts with the versatility and flexibility that is required for the most demanding of installations.

Inside the cable or inside each tube in a loose tube cable, individual fibers will be color coded for identification. Fibers follow the convention created for telephone wires except fibers are identified individually, not in pairs. For splicing, like color fibers are spliced to ensure continuity of color codes throughout a cable run.

Connector Color Codes

Since the earliest days of fiber optics, orange, black or gray was multimode and yellow was singlemode. 

However, the advent of metallic connectors like the FC and ST made color coding difficult, so colored boots were often used.

The TIA 568 color code for connector bodies and/or boots is beige for multimode fiber, blue for singlemode fiber, and green for APC (angled) connectors.

​Fiber optic "cable" refers to the complete assembly of fibers, strength members and jacket. Fiber optic cables come in lots of different types, depending on the number of fibers and how and where it will be installed. Choose cable carefully as the choice will affect how easy it is to install, splice or terminate and, most important, what it will cost!

The factors to be considered when choosing a fiber optic cable are:
  • Current and future bandwidth requirements
  • Acceptable attenuation rate
  • Length of cable
  • Cost of installation
  • Mechanical requirements (ruggedness, flexibility, flame retardance, low smoke, cut-through resistance)
  • Signal source (coupling efficiency, power output, receiver sensitivity)
  • Connectors and terminations
  • Cable dimension requirements
  • Physical environment (temperature, moisture, location)
  • Compatibility with existing systems.
What hazards will it face?

​A cable's job is to protect the fibers from the hazards encountered in an installation. Will the cables be exposed to chemicals or have to withstand a wide temperature range? What about being gnawed on by rodents or other animals? Inside buildings, cables don't have to be so strong to protect the fibers, but they have to meet all fire code provisions. Outside the building, it depends on whether the cable is buried directly, pulled in conduit, strung aerially etc.

Your best bet is to contact a few cable manufacturers (two minimum, three preferred) and give them the specifications. They will want to know where the cable is going, how many fibers you need and what kind ie singlemode or multimode or both, in what we call "hybrid" cables. You can also have a "composite" cable that includes copper conductors for signals or power. The cable companies will evaluate your requirements and make suggestions. Then you can get competitive bids.

Since the plan will call for a certain number of fibers, consider adding spare fibers to the cable - fibers are cheap! That way, you won't be in trouble if you break a fiber or two when splicing, breaking-out or terminating fibers. And request that the end user considers their future expansion needs. Most users install a lot more fiber than needed, especially adding singlemode fiber to multimode fiber cables for campus or backbone applications.

Contact your local DINTEK distributor or email our sales team on This email address is being protected from spambots. You need JavaScript enabled to view it. to discuss your cable requirements!

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