UNIT 4. Assignment 1. Copper vs Fiber
As the name suggests, fibre optic technology uses pulses of light to carry data along strands of glass or plastic. It's the technology of choice for the government's National Broadband Network (NBN), which promises to deliver speeds of at least 100Mbps. When we're talking about 'speed' were actually talking about throughput (or capacity) — the amount of data you can transfer per unit time. And fiber optics can definitely transfer more data at higher throughput over longer distances than copper wire. For example, a local area network using modern copper lines can carry 3000 telephone calls all at once, while a similar system using fiber optics can carry over 31,000.
So what gives it the technical edge over copper wires?
Traditional copper wires transmit electrical currents, while fiber optic technology sends pulses of light generated by a light emitting diode or laser along optical fibers. In both cases you're detecting changes in energy, and that's how you encode data. With copper wires you're looking at changes in the electromagnetic field, the intensity of that field and perhaps the phase of the wave being sent down a wire. With fiber optics, a transmitter converts electronic information into pulses of light — a pulse equates to a one, while no pulse is zero. When the signal reaches the other end, an optical receiver converts the light signal back into electronic information, the throughput of the data is determined by the frequency range that a cable will carry — the higher the frequency range, the greater the bandwidth and the more data that can be put through per unit time.
And this is the key difference — fiber optic cables have much higher bandwidths than copper cables. Optical fiber can carry much higher frequency ranges — note that light is a very high frequency signal — while copper wire attenuates or loses signal strength at higher frequencies. Also, fiber optic technology is far less susceptible to noise and electromagnetic interference than electricity along a copper wire. You can send the signal for over 200 kilometers without any real loss of quality while a copper cable signal suffers a lot of degradation over that distance.
Where to next?
Just as copper wire technology has improved from the telegraph line to co-axial cables and today's ADSL-2 internet connections, fiber optics will also improve in the future.