Copper vs Fiber optic | Difference between copper and fiber

This page compares copper vs fiber optic cable and mentions difference between copper and fiber optic in data communication. The advantages and disadvantages of copper wire and fiber optic cable are also described.

Introduction:
Data transmission system consists of source (i.e. transmitter), destination (i.e. receiver) and transmission medium between them. The medium can be classified as guided or unguided. The communication is established using EM (Electro-Magnetic) waves.

In guided medium, waves are guided using solid physical medium such as copper wires or fiber optic cables. Copper wires can be twisted pair or coaxial cable. Unguided medium refers to transmission of EM waves through atmosphere and outer space. The transmission through guided medium is known as wired communication where as transmission through unguided medium is known as wireless communication.

Copper wire

Copper has electrical conductivity of 5.88 x 10⁷ Ohm-meter and thermal conductivity of 39.5 KW/m²K^o. Hence copper wires offer high current capacity for power packages and thinner wire for fine pitch packages. Moreover it offers improved heat transfer efficiency.

Copper has numerous mechanical properties such as higher tensile strength, increased ductility, Stiffness, reduced molding sway etc. Moreover it offers high mechanical stability, long term reliability and so on.

In data communication, copper as a medium offers low delay, medium bandwidth and varying path loss. Copper wire categories such as twisted pair and coaxial cable are used for data communication. In twisted pair, copper wires can be twisted into spiral shape in order to reduce noise and crosstalk. Coaxial cable is improved version of twisted pair which is consists of conductors insulated from each other and enclosed in a polyethylene jacket.

There are two types of twisted pair viz. UTP (Unshielded Twisted Pair) and STP (Shielded Twisted Pair). The UTP categories include cat-1 to cat-8.2 based on their construction, bandwidth and applications.

The common applications of copper wires are telephone cables, electric wires, ethernet cables etc. Following are the advantages and disadvantages of Twisted pair cable and coaxial cable.

Advantages of Twisted pair cable are as follows.
➨Inexpensive
➨Often available in existing phone system.
➨Well tested and easy to get.

Disadvantages of Twisted pair cable are as follows.
➨Susceptible to RFI and EMI.
➨Not as durable as coaxial cable.
➨Does not support higher speed like other media.

Advantages of Coaxial cable are as follows.
➨Fairly resistant to RFI and EMI.
➨It supports faster data rates than twisted pair.
➨It is more durable than twisted pair cable.

Disadvantages of Coaxial cable are as follows.
➨It can be affected by strong interference.
➨It is more costlier than twisted pair.
➨It is bulkier and more rigid than twisted pair.

Fiber Optic System

The demand to transmit more information, more quickly and over longer distances have pioneered the development of fiber optic cables from century old copper wires.

The fiber optic cable transmits modulated light which is immune to interference caused by electrical devices. It is the best choice if a secured network is desired.

The fiber optic cables are used to transmit television, voice and digital data signals by light waves over flexible hair like threads of glass and plastic.

Construction: Fiber optic cable consists of thousands of clear glass fiber strands with thickness of a human hair. As shown it consists of following parts.
Core : Thin glass center where light travels.
Cladding : Outer material surrounding core which reflects light back into core.
Coating : Plastic coating which protects fiber from damage and moisture.
Strength member: It is used to protect core against damage during installation or from being crushed.
Outer Jacket : It is the outermost layer of fiber cable used to protect outer coating of the cable.

The fiber optic cables are classified in two ways. The first way is by indication of how index of refraction varies across the cross section of fiber cable viz. step index and graded index. The second way is by their mode (i.e. Various paths that light rays take to pass through the fiber) viz. single mode and multimode. Refer single mode step index vs multimode graded index fiber and single mode vs multimode fiber for more information.

Advantages of Fiber optic system are as follows.
➨It is highly secure.
➨It is not affected by RFI and EMI.
➨It offers highest bandwidth available.
➨It is very durable.

Disadvantages of Fiber optic system are as follows.
➨It is extremely costly in product and service.
➨It requires sophisticated tools and methods for installation.
➨It is complex to layout and design.

Difference between copper and fiber in data communication

Following table mentions the difference between copper and fiber with respect to various parameters which help us to compare copper vs fiber in data communication domain.

Specifications	Copper Wire	Fiber optic
Transmission signal	It uses electrical signal for transmission.	It uses optical form of signal for transmission.
Distance	100 meters @1000 Mbps	> 40 Km @10,000 Mbps
Capacity or bandwidth	Moderately high, 10 Gbps	Very high, > 10 Gbps and goes up to 69 Tbps i.e. Unlimited
Repeater spacing	1 to 10 Km	10 to 100 Km
Attenuation or path loss	Low	Very Low
Life cycle	5 years	30 to 50 years
Energy consumed	>10 Watts per user	2 Watts per user
Weight	Heavier	Lighter
Handling	Heavy and thick in diameter, Strict pulling specifications	Light and thin in diameter, strong pulling strength
Noise immunity	Susceptible to EMI/RFI interference, crosstalk and voltage surges	Immune to EMI interference
Security	It emits electro-magnetic (EM) waves which interfere with other systems connected nearby. Moreover it is easy to tap the signal being transported through copper wire. As a result copper wires offer less security.	It is hard to tap the signal being transported. As a result, fiber cables offer high security.
Cost	Lower	Higher
Spark Hazard	Hazardous	No spark hazard
Durability	Lower, it can be improved with light jacketing	High
Types	STP (Shielded Twisted Pair), UTP (Unshielded Twisted Pair), Coaxial cable	Single mode fiber and Multi-mode fiber
Voice channels	24	32,000 +

Conclusion: From the above comparison between copper vs fiber optic on various parameters, we can conclude that both copper and fiber optic technologies exist together based on the requirements in terms of data rate, distance coverage and other parameters. Copper wire is used for shorter distances at moderate data rate. At the same time, fiber optic is used for longer distances at very high data rates.

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