Technology Overview
Fiber-optic communication has long been the backbone of the Internet, as it provides far more bandwidth, reliability, and security than other technologies. Still, for all the advantages of fiber optics, 100% fiber optic communication networks, including the last mile to the customer premises, are not ubiquitous even today. The upfront cost to lay new fiber is very high so investments in new fiber networks are often influenced by market forces.
Optical fibers transmit optical signals in the form of pulses of light from a laser source to a photodetector. These pulses of light represent the bits of digital data that become our voice call or our multimedia content. Optical fibers have relatively low attenuation and interference characteristics, and high bandwidth potential, which provide a very significant advantage over copper wire communications in long-distance and/or high-demand applications.
Low Attenuation – an optical signal can be transmitted much farther through the fiber than an electrical signal in a copper wire before that signal needs to be amplified. Furthermore, since optical communications are digital, amplification (or regeneration) of the optical signals does not also amplify the signal noise in the same way an electronic amplifier might, thus allowing clear voice and low error data communication over very long ranges.
Low Interference – an optical signal propagating through a fiber is not readily affected by its external environment, while electromagnetic interference is very much a concern in copper wire. There is little cross-talk concern between neighboring fibers, and as such it is possible to bundle many of these very thin fibers (over 100) into a single transmission line.
High Bandwidth – using dense wavelength division multiplexing (DWDM), a single fiber can carry many different channels of data, each channel using light of slightly different wavelength. In a DWDM system, very narrow spectral width pulses of light of slight differing wavelengths are combined using an optical multiplexer (MUX) and the mixed optical signal is transmitted though the optical fiber. An optical demultiplexer (DEMUX) is used on the other side to separate the signals.
DWDM – in combination with optical transmission lines containing dozens of optical fibers, allows vast amounts of data to be moved through an optical network. As consumer data requirements continue to grow, for example more and more people streaming increasing amounts of content in HD and now 4K, the speeds and bandwidth that optical communications can provide will be more and more critical.