Advantages and Disadvantages of Optical Fibers

Optical Fibers

Optical fibers are the dielectric waveguide that dominates the communication and instrumentation systems. The optical fibers consists of a central core, cladding layer and a protective jacket.

An Optical Fiber

They operate at optical frequencies (10^{13   _} 10¹⁶ Hz). Light, when launched into the fiber gets trapped and propagates mostly in the core due to the difference in refractive index between core and cladding. This mechanism is called total internal reflection. 

In this article, the advantages and disadvantages of optical fibers are listed down.

Advantages
Enormous potential bandwidth

The optical carrier frequency is in the range 10^{13   _} 10¹⁶  Hz. This yields a greater potential transmission bandwidth than metallic cable system. The higher the carrier frequency, the more the bandwidth available and the greater the information carrying capacity.

Small size and weight

Optical fibers have very small diameter even when covered with protective coatings. They are lightweight and compact when compared to metallic cables.

Electrical isolation

Optical fibers are fabricated from glass or plastic polymer which are electrical insulators. They do not exhibit earth loop and interface problems. They do not create spark hazard or short circuits. Therefore, optical fibers can be used in electrically hazardous environment and around volatile liquids and gases.

Immune to interference and crosstalk

Optical fibers are free from electromagnetic and radio frequency interference because they are non-conductors of electric current. Optical fibers can be used in electrically noisy environment. The crosstalk is negligible in optical fibers even when many fibers are cabled together.

Signal security

Optical fibers provide a high degree of security  as the light from it does not radiate significantly. The transmitted optical signal can not be obtained from a fiber in a non-invasive manner. Also, any attempt to acquire a signal transmitted optically may be detected.

Low transmission loss

Optical fibers have considerably less signal loss than metallic cables. Fibers are fabricated with losses as low as 0.2 dB km -1 (decibel per kilometer).

Ruggedness and flexibility

The fibers can be bent to small radii or twisted without damage though it is made out of glassy substance. The cable structures are developed to be flexible, compact and extremely rugged. The optical fiber cables are superior in terms of storage, transportation, handling, installation and maintenance to copper cables.

System reliability and ease of maintenance

The low signal loss of optical fiber cables reduces the requirement for intermediate repeaters or line amplifiers to boost the signal strength. The optical fibers are tolerant to changes in environmental conditions and immune to corrosive materials. These enhance the signal reliability. The optical fiber cables last longer and maintenance cost is also cheaper.

Potential low cost

The optical fiber transmission medium is provided by glass, generally. The glass is made from sand which is an abundant resource. This pulls down the cost of optical fibers. Moreover, optical fiber cables have low Ioss, require few intermediate repeaters and associated electronics. This reduces the overall system costs. The costs related to shipping, handling, installation and maintenance are also lower.

Disadvantages
Interfering costs

Optical fiber cable systems must be connected to standard electronic facilities, which often require expensive interfaces.

Low strength

Optical fibers have significantly lower tensile strength which can be improved by coating the fiber with standard Kevlar and a protective jacket of PVC.

Remote electrical power

Occasionally, it is necessary to provide electrical power to remote interface or regenerating equipment. This can not be accomplished with the optical cable, so additional metel cables must be included in the cable assembly.

Bending losses

The bending of cables cause irregularities in the cable dimensions, resulting in a loss of signal power.

Specialized tools, equipment and training

Optical fiber car require special tools to splice and repair cables. They require special test equipment to make routine measurements. Repairing fiber cables is difficult and expensive. Technicians require special skills and training to work on optical cables. Sometimes, it is difficult to locate faults in optical cables because there is no electrical continuity.

Also Read: Comparison of Different Types of Optical Fibres