Optical fiber refers to the technology associated with data transmission using light pulses travelling along with a long fiber, usually made of plastic or glass. Transmission using fiber optic communication is preferred to use metal wires as signals are able to travel with less losses. Optical fibers are also unaffected by electromagnetic interference. The fiber optic cable uses the application of Total Internal Reflection of light.

The fibers are designed such that they facilitate the propagation of light along the optical fiber depending on the requirement of power and distance of transmission. A single mode fiber is used for long distance transmission while a multimode fiber is used for shorter distances. The outer cladding of optical fibers need better protection than metal wires.

Laying

• Survey of cable routes: Minimum possible route length vis -a- vis route having maximum number of towns with potential telecom growth. Linking of small exchanges off main road by leading in O.F.C. vis -a- vis routing the main cable itself via such exchanges .
• Testing of OFC in drums before laying: Drum should never be given any shock by dropping Drum should not be rotated on flanges Cable should not be bent while uncoiling The radius of curvature should not be less than 60CM Cable should not be twisted Use cable grip along with anti-twist device while pulling the cable
• On the basis of surveys, general permission from road and rail authorities for laying the Optical Fiber Cable along the decided routes and permission for rail / road crossings will have to be obtained .
• Soil Categorization: F or purpose of deciding the depth at which the cable is to be laid ( A) Rocky : Cable trench, where it is not possible to be dug without blasting and/or chiseling. ( B) Non Rocky : Other than above, soil mixed with stone and soft rock. T he depth is considered acceptable if it is not less by more than 8 cm from the specified depth of 1.5 m in non-rocky soil and 0.9 m in case of rocky soil
• Types of pipe to be used for Optical Fiber Cable: Optical Fiber Cables should be pulled or blown through 50mm/40 mm/32 mm (outer dia) PLB HDPE pipes having strength of 10 kg/cm2. Advantage for using pipes :1.It gives mechanical protection 2.Pipes can be laid in advance so that the cable laying is faste

2. Trenching

The traditional method of laying optical fibers still used in most developing countries is Ducting and Trenching. This involves creating a trench through manual or mechanized soil excavation. This approach is preferred in countries where manual labor is cheap.

Trench specifications are normally defined by local authorities and could be specified for each operator in countries with multiple operators.

The trenching process needs careful control to make sure the trench floor does not have any kinks and is uniform, and trenches do not have major bends.

Ducts are placed in the trenches and fiber is then blown through the ducts with specialized fiber blowers, using water or air. In Air Assisted Fiber Blowing, the blowers use compressed air to push fiber through ducts.

Mini Trenching

Mechanized equipment is used to create mini trenches in many different surfaces. This technique can be used on routes that contain asphalt surfaces such as sidewalks and roads. The technique is however not suitable for soil with cobbles or gravel, or sandy soil. This technique has an advantage over conventional cable laying methods in that it is much faster to execute. The cross-section and depth of the trench will depend on the number of ducts to be laid. While the cross-section varies between 7 and 15 cm, the depth is typically between 30 and 40 cm.

Three methods of mini trenching commonly used are:

• Standard.
• Semi Automated.
• Fully Automated.

Trenching, ducting, backfill operations and cleaning are all performed simultaneously when the fully automated method is used. When the standard and semi-automated methods are however employed, the operations are not done at the same time.

Micro Trenching

Micro trenching does not create a deep trench in asphalt as does conventional trenching, but creates a shallow trench, typically 2 cm wide and 30 cm deep. Special micro tubes are then placed in the grooves and it is filled, typically with a cold asphalt. The fibers are then blown into the tubes.

3. Blowing

When using fiber blowers, you’re combining a pulling force of compressed air and a pushing force hydraulically driven tracks during the installation. During the process, the blower operator has the control and ability to monitor the forces exerted on the cable. Because every application is different and presents its own challenges. Using blowers rather than fiber pullers is the preferred installation method for several reasons. During a pulling operation, the cable travels in a straight line until a bend or curve. Ultimately, the cable rubs at any bend or sweep and can touch the duct hundreds of times if there are undulations, typically caused by plowed or trenched duct. Friction is created each time there is contact with the duct.

• Friction is the enemy in any fiber blowing application.
• Because the blowing operation floats the cable on a cushion of air, it minimizes the contact points with the duct-reducing the friction that would be created by pulling the fiber through the duct with a fiber optic cable puller. A high-quality, silicone-based lubricant is also used to further minimize the friction, especially when navigating the bends.
• Compared to a pulling application, blowing cable is faster and puts the cable under less stress. Through cable blowing, contractors are able to install more cable per day with less manpower.
• Outside plant personnel are very familiar with the pulling method of installing cable. Thread a line through the duct, attach the line to the cable, and pull or tug the cable through the duct. The force needed to pull the cable usually comes from a capstan or hand-over-hand pulling of the rope. This force is needed to overcome the cable�s frictional resistance to movement. Length of installation is limited by the maximum force allowed on the cable.
• Air-assisted installation must overcome the same frictional force to move cable, but it does this in a very different way. The force in air blowing first comes from a mechanical device which pushes the cable; and second, from the force of moving air on the cable jacket, or alternatively, the force of air on a piston, missile, or carrier at the front end of the cable.

4. Splicing

Rather than using optical fiber connectors, it is possible to splice two optical fibers together. An fiber optic splice is defined by the fact that it gives a permanent or relatively permanent connection between two fiber optic cables.

• Mechanical splices.
• Fusion splices.
• The mechanical splices are normally used when splices need to be made quickly and easily. To under taken a mechanical fiber optic splice it is necessary to strip back the outer protective layer on the fiber optic cable, clean it and then perform a precision cleave or cut. When cleaving (cutting) the fiber optic cable it is necessary to obtain a very clean cut, and one in which the cut on the fiber is exactly at right angles to the axis of the fiber..
• Once cut the ends of the fibers to be spliced are placed into a precision made sleeve. They are accurately aligned to maximize the level of light transmission and then they are clamped in place. A clear, index matching gel may sometimes be used to enhance the light transmission across the joint.
• Mechanical fiber optic splices can take as little as five minutes to make, although the level of light loss is around ten percent. However this level of better than that which can be obtained using a connector.
• Fusion splices form the other type of fiber optic splice that can be made. This type of connection is made by fusing or melting the two ends together. This type of splice uses an electric arc to weld two fiber optic cables together and it requires specialized equipment to perform the splice. The protective coating from the fibers to be spliced is removed from the ends of the fibers. The ends of the fiber optic cable are then cut, or to give the correct term they are cleaved with a precision cleaver to ensure that the cuts are exactly perpendicular. The next stage involves placing the two optical fibers into a holder in the fiber optic splicer. First the ends if the cable are inspected using a magnifying viewer. Then the ends of the fiber are automatically aligned within the fiber optic splicer. Then the area to be spliced is cleaned of any dust often by a process using small electrical sparks. Once complete the fiber optic splicer then uses a much larger spark to enable the temperature of the glass in the optical fiber to be raised above its melting point and thereby allowing the two ends to fuse together. The location spark and the energy it contains are very closely controlled so that the molten core
• Once the fiber optic splice has been made, an estimate of the loss is made by the fiber optic splicer. This is achieved by directing light through the cladding on one side and measuring the light leaking from the cladding on the other side of the splice.

5. Testing

Testing is used to evaluate the performance of fiber optic components, cable plants and systems. As the components like fiber, connectors, splices, LED or laser sources, detectors and receivers are being developed, testing confirms their performance specifications and helps understand how they will work together. Designers of fiber optic cable plants and networks depend on these specifications to determine if networks will work for the planned applications.

• After fiber optic cables are installed, spliced and terminated, they must be tested. For every fiber optic cable plant, you need to test for continuity and polarity, end-to-end insertion loss and then troubleshoot any problems. If it’s a long outside plant cable with intermediate splices, you will probably want to verify the individual splices with an OTDR test also, since that’s the only way to make sure that each splice is good. If you are the network user, you may also be interested in testing transmitter and receiver power, as power is the measurement that tells you whether the system is operating properly.
• Fiber optics cabling is the core of today’s datacom networks. Optical fiber is the predominant media type for mission-critical datacenter links, backbone within buildings, and longer distances for campus networks. As network speeds and bandwidth demands increase, distance and loss limitations have decreased, making fiber optic cabling certification more important than ever.

6. FTH

We design and implement high speed FTTH Network which can support greater bandwidth requirement with lower break down index.Which can handle audio,video and data.

It supports

• Telephone Network
• High Speed Internet
• IPTV
• For IOT implmentation