Friday, February 12, 2010

What's the Difference Between Loose Tube Fiber and Tight Buffer Fiber



Tight Buffer Fiber


Tight-buffered cables often are used for intra-building, risers, general building and plenum applications. Tight buffer fiber contains a thick coating of a plastic-type material which is applied directly to the outside of each individual fiber. Loose-Tube fiber optic cables are typically used for outside-plant installation in aerial, duct and direct-buried applications. Loose-tube fiber contains multiple strands of fiber in a single jacket. Since the fibers are "loose" inside the jacket, outside forces are less likely to reach the fibers. This makes it the more durable option of the two.

Loose-Tube Cable

Loose-tube fiber generally consists of 12 strands of fiber, but can range anywhere as low as 6, all the way up to 244 strands. Loose tube cables can be either dielectric or optionally armored. The modular buffer-tube design permits easy drop-off of groups of fibers at intermediate points, without interfering with other protected buffer tubes being routed to other locations. The loose-tube design also helps in the identification and administration of fibers in the system.

In a loose-tube cable design, color-coded plastic buffer tubes house and protect optical fibers. An optional gel filling compound impedes water penetration. Excess fiber length (relative to buffer tube length) insulates fibers from stresses of installation and environmental loading. Buffer tubes are stranded around a dielectric or steel central member, which serves as an anti-buckling element.
The cable core, typically uses aramid yarn, as the primary tensile strength member. The outer polyethylene jacket is extruded over the core. If armoring is required, a corrugated steel tape is formed around a single jacketed cable with an additional jacket extruded over the armor.

Here's a video example of a loose tube fiber from our YouTube Channel 

Tight-Buffered Cable

Single-fiber tight-buffered cables are used as pigtails, patch cords and jumpers to terminate loose-tube cables directly into opto-electronic transmitters, receivers and other active and passive components.Multi-fiber tight-buffered cables also are available and are used primarily for alternative routing and handling flexibility and ease within buildings.With tight-buffered cable designs, the buffering material is in direct contact with the fiber. This design is suited for "jumper cables" which connect outside plant cables to terminal equipment, and also for linking various devices in a premises network.

The tight-buffered design provides a rugged cable structure to protect individual fibers during handling, routing and connectorization. Yarn strength members keep the tensile load away from the fiber.

As with loose-tube cables, optical specifications for tight-buffered cables also should include the maximum performance of all fibers over the operating temperature range and life of the cable. Averages should not be acceptable.

Here's an example of a tight buffered cable from our channel.

Hope we've given you some good information on what you might need. For other pointers on termination, installation, search our blog and YouTube channel or you can contact Mercy Salinas about fiber optics at 888-797-3697 extension 232. You could also comment below, thanks!

"By Mercy Salinas"