Fibre Optics: What Influences Your Cables Life-Span?

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Cable Performance in Fibre Optics

In the Fibre Optics Industry, each cable is made up of thin strands of glass. It is typically used to transmit light.  The speed of light in a vacuum is 299,792,458 meters per second. Very minute optic light is absorbed by the glass. Light getting in at one end endures frequent total internal reflection inside the fibre before the light travels out the other end. How it travels inside the fibre depends on the type of fiber being used.

 

 

 

Fibre optic cable carries information, such as computer data, telephone calls and video signals.  Signals can be converted into either visible light signals or infrared pulses. These signals can be transmitted over very long distances when using single mode fibers.

Fiber cables using a light beam are much cheaper than copper cables needed to carry electrical signals over a copper wire. Computer networking companies use it as it provides a faster and more reliable system solution.

 

Typical Cable Life Span in Fibre Optics

Having a long life span is an important requirement for any fibre optic cables used. Investment in different optical technologies has heightened the importance of quality and the life expectancy of fiber cables.  However, one question that is still often asked before deploying a fibre optic network is ‘how long will it last?’ and ‘is there any way to improve its longevity?’

 

Factors That Influence How Long Your Fibre Optic Cables Will Last

There are many factors that affect the life and performance of optical fiber. Understanding these factors will not just help enhance its life, but also ensure better performance and endurance.

 

Fibre Optics Surface flaws

Most optical engineers would know that ‘pristine silica glass fiber is a material that is free of defects. It is immensely resistant to degradation as well. Most fibre optic cables will have some surface flaws. This can result in reducing the material’s longevity under certain conditions.

 

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One of the factors to consider here is the stress intensity factor “K”. Referring to the stress applied to the Fibre optics. Fibre optic manufacturers carry out “proof testing” for this very reason. The test consists of stretching the fibre to a pre-set level for a specified duration of time to check its durability.

 

Fibre Optics Installation strains

Whether it is optic fibre or normal copper cables, stress is the major enemy of the longevity of cables. So, it is very important that the installation process is done carefully by the operative. The installer will ensure that the use of suitable strength elements limits the stress applied to the cable. This should be no more than 1 percent proof test level. It is pertinent to mention that the deployment process should not overstrain the cable.

 

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Fibre Optics Environmental factors

The consistency of optical fibres not only relies on the initial fibre strength but is also influenced by time, temperature, applied stress, and environmental corrosion.

– Under permanent or temporary stress over a period of time micro-cracks can grow.

– Extremely High Temperatures may also result in cracks on the cable.

– However water is the most common concern.

(This can be either in a liquid state or atmospheric moisture such as humidity.) 

It is suggested to check the tendency of fibre to suffer stress corrosion. This can be done by reviewing its “stress corrosion susceptibility parameter”, which is commonly referred to as “N”. The higher value of ‘N’ it has the more durable and longer life it will have. This information can be found in the technical specifications of the datasheet.

 

Technical

 

Numerous defects are already contained within the fiber optic cable; categorised as either intrinsic or extrinsic absorption.

Intrinsic Absorption is very low compared to other forms of loss. The main cause of Intrinsic Absorption in the Infrared region is the characteristic vibration frequency of atomic bonds.

Extrinsic Absorption is much more significant than Intrinsic Absorption. It is caused by impurities introduced into the glass during the manufacturing process like Iron, Nickel, and Chromium.

Our video #5 what is Attenuation Part 1 goes into more detail. Please follow the link below for further information.

 

Fibre Optics Maintenance

Just like anything else, fibre optic installations require maintenance work. In the events of debris build-up, the connectivity and longevity of optic cables may be affected significantly. This can lead to slower download speeds and more interruptions. A fiberscope and routine inspections of the cables will resolve any issues. Professional support may be a great help for this task as it requires specific tools and expertise.

 

 

Conclusion

As we can see the performance and lifespan of fibre optic cables can be altered by natural or human influences, as well as by the fused silica itself. Fibre optic cables are designed to last for years, if not decades if proper installation and maintenance is upheld. The life expectancy can be improved to a great extent if suitable care is applied during installation and post-installation.