The fiber optic technology is claimed to be reliable, future-proof, super fast, and provide unlimited bandwidth – yet at unsurpassed price/performance ratio. Even if this may sound too good to be true, there is a reason for this, and it all comes down to physics.
Telecommunications, computers, and entertainment are converging on the information superhighway of broadband – bringing people, cities and regions closer together.
Being always on and always connected with high bandwidth offers low-cost access to a wide range of applications, from business, entertainment to transactions and real-time services such as online medical consultations, education and training, community information, etc. The most powerful and future-proof solution to address all these tasks is fiber optic technology.
Optical fiber is made from optically pure glass as thin as a human hair and the only broadband technology that offers virtually unlimited bandwidth potential. One single fiber has the capacity to simultaneously carry millions of telephone conversations or ten thousand 4K digital TV channels. The digital information is sent in the form of laser-generated light, which enables transfer speeds of several Terabit/s (theoretically unlimited) – more than enough for tomorrow's demanding applications.
Sound, text, or pictures are first converted to digital electric pulses, which are then converted to light pulses by a laser diode. These pulses are fed into and guided through the fiber to a receiving diode at the other end, where they are converted back to sound, text, or pictures. The purity of the fiber enables light to be guided through hundreds of kilometers without amplification. Moreover, since glass is an organically adapted material, optical fiber does not contribute to waste or emissions. Other advantages of optical fiber technology are:
Still you may have heard about other broadband technologies based on copper cables, CATV networks and wireless solution. Technologies involving advanced coding to get existing infrastructure up to speed. DOCSIS 3.1, G.Fast, 5G etc. are typical abbreviations used in the industry, some claiming to challenge fiber optic technology. But let us look at the facts – Every time a new technology has or will challenge fiber optics, it has or will fail.
So how can we know this for sure? Well, the basic physics behind Communications and Information Theory was defined well before anyone even could imagine the potential of fiber optic technology. In the 1940's, the Nobel prize winner in Physics, Claude Shannon (shown in the image), derived the following simple yet effective formula:
Maximum Data Rate = B log2(1 + S/N) bits per second
Where B is the bandwidth of the channel, and the quantity S/N is the signal-to-noise ratio. Without getting too involved in theory, we can see that the noise level, N, is the most critical factor that limits the maximum data rate. This formula is valid for all kinds of transmission systems, copper based, fiber or wireless. In a copper wire such as a DSL line or CATV network, the noise increases over distance in such a way that the data rate will be severely limited when the distance increases. On the other hand, an optical fiber is almost immune to noise and the signal can be transported hundreds of kilometers without degradation. This is illustrated in the graph below. G. Fast, a modern DSL technology offers enough data link speeds for short distances but drops rapidly over distance. The fiber optic transmission link is almost unaffected by the distance and offers full speed over the whole range.
We now understand why fiber optic technology is the obvious choice if maximum performance is required. But what about cost? Installing new fiber cables should be more expensive than using existing copper cables?
The answer is – No, not necessarily. To gain gigabit speeds on copper wires or coax networks, advanced encoding and decoding equipment is needed. This equipment is not for free. Considering that even with the smartest algorithms, the S/N will limit the maximum distance, it is easy to understand that there is a need for active transcoders close to end users. Shorter distances mean more sites with active equipment which increases the cost of the network. In addition, the number of sites increases the maintenance cost exponentially.
So, back to the question in the headline – Fiber optic technology has unquestionably the highest capacity, today and in the future. In most situations, it will also offer the lowest total cost. Is this true always, everywhere and forever? Of course not. There is a need for mobility, so 5G and other wireless techniques are required, however, it is arguably time to question all types of fixed connections to fiber optics!
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This article was originally published in December 2020 and has been updated with minor edits.