Weight and Size of Optical fiber cable
One of the most attractive features of optical fiber cable is its reduced weight and size compared to its ancestor, the legacy cable. Fiber optic cable is significantly smaller and lighter than copper telephone cables for the quantity of output they deliver. A single fiber cable with less than 3 millimeters diameter and less than 10 kilograms weight/kilometers is equivalent in data carrying capacity of a1000 pair jelly filled copper telephone cable that has around 50 millimeters diameter and more than 1000 kilograms weight per kilometer. Thus by using fiber optic cables the cost of laying the cable is dramatically reduced.
The data rate of installed systems in use in 1998 was generally 150 or 620 Mbps on a single (unidirectional) fiber. Current optical network systems offers high bit rates such as 2.4 Gbps, 10 Gbps, 40 Gbps and even 100Gbps. Researches have been progressing to implement 400 Gbps and 800 Gbps systems practically. This is very high in digital transmission terms. In telephone transmission terms the very best coaxial cable systems give about 2,000 analog voice circuits. A 150 Mbps fibre connection gives just over 2,000 digital telephone (64 Kbps) connections.
Fiber cable costs significantly less than copper cable for the same transmission capacity. This is obvious from the above description and comparison of weight and size of both types of cables. Cable material cost is less that will directly benefit to the reduction of cable cost to the advantage of customers. Installation material cost is also less that will finally contribute to the cost saving for network builders.
Immunity to Electromagnetic Interference
As optical fibers are dielectric in nature and do not conduct electricity, they do not pick up or create electrical interference, which is the major source of noise. This contributes to less number of errors. There are very few sources of things that can distort or interfere with optical signal. Optical fiber cables can be placed almost any place where electrical cables would have problems.
Distances between Regenerators
As optical signal travels along a communication line it loses strength and picks up noise. The traditional way to regenerate the signal, restoring its power and removing the noise, is to use a either a repeater or an amplifier. In long-haul optical transmission cables, the repeater spacing is typically more than 80 kilometers. This is more than 6 times longer distance compared with the 12 km for the coaxial cable electrical technology. The number of required repeaters and their spacing is a major factor in system cost. Recent installation practices along with availability of ultra low levels of attenuation in fibers, repeater distances can be further increased.
The maximum theoretical capacity of installed fiber is almost infinite. This means that additional capacity can be had on existing fibers as new technology becomes available. All that must be done is change the equipment at either end and change or upgrade the regenerators. Optical networks once installed can accommodate with any data carrying capacity.
It is possible to tap fiber optical cable. But it is very difficult to do and the additional loss caused by the tap is relatively easy to detect. There is an interruption to service while the tap is inserted and this can alert operational staff to the situation. In addition, there are fewer access points where an intruder can gain the kind of access to a fibre cable necessary to insert a tap. Insertion of active taps where the intruder actually inserts a signal is even more difficult. However, there are some limitations: Remember Edward Snowden and his revealing?