Understanding the Coming Breakthrough in Communications.

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Last week I met with the Senior Special Assistant (SSA) to the governor on due process – Elder Ufot Ebong.  The meeting was aimed at putting straight the records that ICT Entrepreneurs need a financial boost from the AKEES program.  The interaction went on well and I saw some reasons why I should do the next article as a reminder on “the need to get that important empowerment.”

But then something happened.  Along the line of discussion, the SSA quickly started searching for his phone. I was sure he had remembered something very important and the search was frantic. Looking into his bag, he retrieved the phone and opened a picture of a machine intended to be used for the installation of optic fiber cables across the entire state. “Nsekpong! Look at it, and the machine just arrived” he bellowed while presenting the said machine to me on his phone.

The project is going to be handled by Akwa Ibom State government in partnership with the ministry of Niger Delta. When this project is completed I guarantee that your era of poor network coverage will be over. I know you struggle on your GSM to make video calls but I guarantee you that if and when the project is properly executed you will be chatting with friends and family as if you are in the same room on live video calls.

But before I blow your mind with anticipation of a completely new world of communication let’s understand what the Optic Fiber Technology is all about.  I bet you, at the end of this article you will understand that if Communication is the backbone of development then this project will bring another breakthrough in our economy.

What is fiber optics?

Optic Fiber trenching machine.

Fiber Optic Cabling

We’re used to the idea of information traveling in different ways. When we speak into a landline telephone, a wire cable carries the sounds from our voice into a socket in the wall, where another cable takes it to the local telephone exchange. Cellphones (the ones we’re using now) work a different way: they send and receive information using invisible radio waves—a technology called wireless because it uses no cables. Fiber optics works a third way. It sends information coded in a beam of light down a glass or plastic pipe. It was originally developed for endoscopes in the 1950s to help doctors see inside the human body without having to cut it open first. In the 1960s, engineers found a way of using the same technology to transmit telephone calls at the speed of light (normally that’s 186,000 miles or 300,000 km per second in a vacuum, but slows to about two thirds this speed in a fiber-optic cable).

Optical technology

A fiber-optic cable is made up of incredibly thin strands of glass or plastic known as optical fibers; one cable can have as few as two strands or as many as several hundred. Each strand is less than a tenth as thick as a human hair and can carry something like 25,000 telephone calls, so an entire fiber-optic cable can easily carry several million calls.

Fiber-optic cables carry information between two places using entirely optical (light-based) technology. Suppose you wanted to send information from your computer to a friend’s house down the street using fiber optics. You could hook your computer up to a laser, which would convert electrical information from the computer into a series of light pulses. Then you’d fire the laser down the fiber-optic cable. After traveling down the cable, the light beams would emerge at the other end. Your friend would need a photoelectric cell (light-detecting component) to turn the pulses of light back into electrical information his or her computer could understand. So the whole apparatus would be like a really neat, hi-tech version of the kind of telephone you can make out of two baked-bean cans and a length of string!

 

Optical Transmitter

The Optical Transmitter can be broken down into several parts.  These consist of:

  • Modulator
  • Carrier Source
  • Channel Coupler (Input)

Firstly it must be noted that the input must be put into electrical form before the transition for either electronic or optic communications.

Modulator
The Modulator has two main functions.  First it converts the electrical message into the proper format.  Secondly it impresses this signal onto the wave generated by the carrier source.  Two distinct categories of modulation format exist: analogue and digital.  An analogue signal is continuous and reproduces the form of the original message quite faithfully.  Digital modulation involves transmitting information in discrete form, where the signal is either on (1) or off (0).  These states are the binary digits of the digital system.  The data rate is the number of bits per second (bps) transmitted.  This sequence of on or off pulses may be a coded version of an analogue message.

Carrier Source
The Carrier Source generates the wave on which the information is transmitted.  This wave is called the carrier.  For fibre optic systems a laser diode (LD) or light-emitting diode (LED) is used.  Ideally these light sources provide stable, single frequency waves with sufficient power for long distance propagation.  Actual LD’s and LED’s differ somewhat from this ideal, as they emit a range of frequencies and radiate only a few milliwatts of average power.  This power is sufficient in many cases, because receivers are so sensitive.  because a laser diode (LD) does not turn on (that is, it does not radiate) until some threshold current is applied, the modulation current may include a dc offset equal to this threshold value.  The presence of a binary 1 drives the current beyond threshold and makes the diode emit light.  A binary 0 leaves the current at threshold, where no radiation occurs.  An LED does not have a threshold and turns on whenever positive current flows through it.

Channel Coupler (Input)
The coupler feeds power into the communication channel.  In a fibre system, the coupler must efficiently transfer the modulated light beam from the source to the optic fibre.  Unfortunately, it is not easy to accomplish this transfer without relatively large reductions in power.  This large loss basically occurs because the light sources emit over a large angular extent, while fibres can only capture light within more limited angles.  Cone shapes are used to solve this problem of data loss.

Optical Receiver

The Optical Receiver can be broken down into several parts.  These consist of:

  • Channel Coupler (Output)
  • Detector
  • Signal Processor

Channel Coupler (Output)

In a fibre system, the output coupler merely directs the light emerging from the fibre onto the light detector.  This light is radiated in a pattern identical to the fibre’s acceptance cone.

Detector

The information being transmitted must now be taken off the carrier wave.  In the fibre system, the optic wave is converted into an electric current by a photodetector.

Signal Processor

For analogue transmission, the signal processor includes amplification and filtering of the signal.  In addition to filtering of the constant bias, any other undesired frequencies should be blocked from further travel.  An ideal filter passes all frequencies contained in the transmission information and rejects all the others.  This improves the clarity of the intended transmission.  Proper filtering maximises the signal power to unwanted power, reducing random fluctuations in the signal referred to as noise.
Advantages

Bandwidth – Fibre optic cables have a much greater bandwidth than metal cables. The amount of information that can be transmitted per unit time of fibre over other transmission media is its most significant advantage.  With the high performance single mode cable used by telephone industries for long distance telecommunication, the bandwidth surpasses the needs of today’s applications and gives room for growth tomorrow.

 Low Power Loss – An optical fibre offers low power loss.  This allows for longer transmission distances.  In comparison to copper; in a network, the longest recommended copper distance is 100m while with fibre, it is 2000m.

Interference – Fibre optic cables are immune to electromagnetic interference.  It can also be run in electrically noisy environments without concern as electrical noise will not affect fibre.

 Size – In comparison to copper, a fibre optic cable has nearly 4.5 times as much capacity as the wire cable has and a cross sectional area that is 30 times less.

Weight – Fibre optic cables are much thinner and lighter than metal wires.  They also occupy less space with cables of the same information capacity.  Lighter weight makes fibre easier to install.

 Safety – Since the fibre is a dielectric, it does not present a spark hazard.

 Security – Optical fibres are difficult to tap.  As they do not radiate electromagnetic energy, emissions cannot be intercepted.  As physically tapping the fibre takes great skill to do undetected, fibre is the most secure medium available for carrying sensitive data.

 Flexibility – An optical fibre has greater tensile strength than copper or steel fibres of the same diameter.  It is flexible, bends easily and resists most corrosive elements that attack copper cable.

Cost – The raw materials for glass are plentiful, unlike copper.  This means glass can be made more cheaply than copper.

So what next? We anticipate the commencement of this project which will bring great communication efficiency to our system.

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