How Optical Fiber Cable is being laid

 Optical Fiber Cable (OFC) through which mobile communication, internet all are possible is being laid by machine called HDD machine. 

Underground cable is placed into ducts which are being built below the ground surface. In urban areas where space for telecommunications cable is limited, it needs to be used more efficiently.

In underground installation, the PLB pipe provides protection from both physical and environmental abuse. The PLB pipe protects cable from shifting rocks, aggressive rodents, and/ or damage from hand shovels. Underground cable that is in PLB pipe (duct) is easy to replace or upgrade. The old cable can be pulled out of the PLB pipe and the new pulled in without extensive and expensive digging. Underground cable and ducts are part of the underground cable laying system.

Telecommunication PLB pipe are made from various materials and buried directly into the soil or encased in concrete. Fiber optic cables have provided a more optimal use of available underground PLB pipe space because of its small cable diameter and the much higher communications traffic capacity of each cable.

The process through which Telecom operator lay OFC under the ground can be understood by following steps.

Trial pit

They dig two trial pits called entry and exit pits of depth 1.65meter or more. Distance between two pits is generally between 150 meter to 250 meter. This distance can be varied due to HDD machine strength.

PLB pipe 

Duct (pipe) or PLB of same length as distance between two trial pits will be required.

Start HDD machine

Now first rod of HDD machine will be inserted in entry trial pit.1 rod is generally of 3 meter. After that rod another rod will be fit to last rod end and will be inserted under ground and so on.

Back pulling PLB pipe

Once first rod (pilot) reached to exit pit, the duct will be tightened to to pilot and machine will pull the duct through those rods.

Other shots

Once full duct is pulled, all duct will be pulled through out whole distance to which we want to lay OFC.

Coupling two PLB pipes

Now Optical Fiber Cable will be pulled in ducts. Two ducts will be coupled through coupler and that point is known as coupling pointor main hole.

Inserting OFC

Optical Fiber Cable will be of length 2 km after that it will be joint to other piece of Optical Fiber Cable of length 2km.

Joining two Optical Fiber Cables

Jointing two fibers results more losses but still Telecom operators use optimum length of OFC of approx 2km. So they need to join two fibers through a machine called splicing machine.

Lets understand through an example. Suppose we need to lay cable of 40km length. Once pipes (duct) are layed through whole distance of 40km in peices of 200m approx and joint of two pipes called coupling point then Optical Fiber Cable of length 2 km will be pulled through those pipes from coupling points. You may have a doubt that if joint of fibers results in more loss then why not to use big length of cable and the answer is to get help and ensure proper maintenance, future cable fault can be restored that's why optimum length is used.

First we remove the plastic jacket of Cable through cable cutter. Then inside jacket buffer will be removed through buffer cutter then all fibers having different colour coating will be stripped through stripper so that fibers will be exposed and can be spliced both end fibers through splicing machine.