FIBER OPTIC (OPTICAL FILAMENTS)
Optical fibers (optical filaments), the thickness of human hair, in an insulated enclosure, containing glass fiber strands is a network cable. These cables, modulated light waves, environmental conditions where there is heavy is designed to move long distances. (moisture, humidity, electric field noise)
Fiber cable is composed of three parts;
Cable is the center of the light is transmitted. By cable 8 to 100 microns. Core made up pure glass, and has flexibility feature. (in constant tolerances)
Outer optical material which has %1 lower index, surrounding the core that reflects the light back into the core. Works alike mirror around core. It is 125 micron.
3. Buffer Cover
No optical property, polymer produced and plastic coating that protects the fiber from damage and moisture. Cover can be one or more layer.
Optical fibers come in two types:
• Single-mode fibers
• Multi-mode fibers
Single-mode optical fiber has a smaller core (9 microns diameter). Transmit infrared laser light wavelength of 1300 and 1550 nanometers.
Multi-mode optical fiber has a larger core diameter (50-62,5 microns diameter). Transmit infrared laser light wavelength of 850 and 1300 nanometers.
Fiber Optic Cables
- It provides wide frequency band. That means much more data transferring.
- Influence by parasites lower than metal cables.
- They are thinner and lighter than metal cables.
- Data transferring is more appropriate to long distance. Also without any loss.
- The biggest disadvantage is expensive setting up. (But, as fiber optics compared with metal cables, its long lifed duration will become more profitable.)
- More fragile filaments
- Splicing operation is done by Fusion Splice method. Therefore, required experienced person.
Let’s see how Fiber Optic works
In order to simply represent; suppose that long and straight corridor enlightened with flashlight. Light beam is going to observed along corridor. But when the corner is approaching, light won’t reach next corridor. A mirror on the corner, might be solution. Consider, mirrors located in every corner of this corridor. Whole corridor enlightened now. This is how fiber optics works.
Cladding layer of fiber optic cable, will reflect lights back into core. Just like our corridor example. Also owing to its %1 lower index, layer wont absorb any. By that way, light wave might reach long distances.
It’s rarely observed that light can be ruined into core due to dirtiness in glass. In spite of true conditions, purity of glasses and wave length might cause some data loss.
Fiber optic systems include 4 main section. Respectively;
- Produces and encodes the light signals
- Conducts the light signals over a distance
- May be necessary to boost the light signal (for long distances)
- Receives and decodes the light signals
Fiber optic is not only used on communication, data transferring and voice and image transmitting, but also takes part in health sector, inspecting mechanical welds in pipes and engines (in airplanes, rockets, space shuttles, cars).
OPGW (Optical Ground Wire)
OPGW is cable of withstanding the mechanical stresses applied to overhead cables by environmental factors such as wind and ice.
OPGW cable contains a tubular structure with one or more optical fibers in it, surrounded by layers of steel and aluminum wire.
Typically OPGW cables contain single-mode optical fibers with low transmission loss, allowing long distance transmission at high speeds. The outer appearance of OPGW is similar to ACSR cable usually used for shield wires.
OPGW as a communication medium has some advantages over buried optical fiber cable. Installation cost per kilometer is lower than a buried cable. The optical circuits are protected from accidental contact by the being beneath high voltage cables. Embedded fiber optic cables, all kinds of excavation work, cross the road, drainage systems and damage rate is high in renovation. Power transmission lines for the expropriation permits to be taken, time and cost burden is low.
OPGW used with this following two purpose;
- Grounding statics which caused by lightning strikes, phase noise to safe energy transmission lines.
- Telecommunication, (data, voice, image) sending and receiving.
Here is some reason to why communication need in high voltage transmission lane;
-To safeguard electrical transmission line
-Controlling transmission lines
-For the utility's own voice and data communication,
-May be leased or sold to third parties
Three kind of OPGW available to use today; and whole OPGWs works effective between -40 and 85.
- AlumaCore Optical Ground Wire (OPGW)
Central aluminum tube fiber is protected in the long term reliability. Ýt provides up to 144 core. Color-coded fiber optic buffer tubes which simplify the splicing process while providing
- CentraCore Optical Ground Wire (OPGW)
12 mm in diameter, is lightweight center tube. Ýt provides up to 72 core. Today's energy transmission lines due to the diameter and weight is the type usually used.
- HexaCore Optical Ground Wire (OPGW)
According to environmental and geographical conditions, in order to protect stainless steel tube, aluminum-clad steel wire or aluminum alloy wire is made with multi-layered. Might use 432 or further more cores. By our references page, “Teiaþ Ermenek ÖzelBölge” OPGW operation is very suitable example for this cable.