Light History and Theory
Believe it or not, fiber optic technology has been around for some time now, with research into the matter spanning as far back as the 1840's and practical modern applications beginning in the 1970's. The progress in fiber optics we have seen in the past four decades places this technology as a preeminent factor of modern data transmission. Fiber Optic Transmission offers us bandwidths previously only imagined and looks to be the dominant form of connectivity in our conceivable future, and so considering the new capabilities fiber extends to us, we must also ask ourselves, "where and how do I jump in?"
Firstly, we must differentiate between internal and external fiber systems. Internal fiber transmission systems describe all-fiber routed, contained networks, such as the LAN of a college or business campus; these interconnect several servers in one community. Regardless of what sort of service connection these systems use externally, all users in the system are connected to one another via fiber, so all user-to-user transmissions enjoy the high-bandwidths of fiber. Internal fiber systems are becoming more and more prevalent as the technological needs of businesses, schools, and laboratories evolve and require higher in-system bandwidths to function.
External fiber systems describe a fiber connection routed to one location, tapped from a much larger fiber transmission line, owned (typically) by a telecommunications corporation. External fiber optic connection is only an option to those who live in areas with large scale fiber transmission lines already installed- this means a service provider has run massive aquatic lines, ground lines, and aerial lines of fiber to offer service to anyone interested in these areas. Customers pay to tap into these larger transmission lines to connect fiber optically.
Optical fiber offers unbeatable bandwidths in any scenario, however internal and external systems utilize fiber in very different ways; external systems offer high bandwidth connectivity to individual locations while internal systems connect many users to one another at high bandwidths.
Optical Fiber Transmission System: How does Optical Fiber Work?
So, how does a fiber optic system work once you are connected? I am glad you asked. A fiber optic transmission system works by first translating electronic/binary information into optical information; this is done in the transmitter - any form of data that can be modulated can be converted into optical data. Once this translation is complete the newly optical signal is transmitted along light sensitive fiber lines until it reaches a receiver. The receiver then converts the optical information back to its original electronic/binary form, at which point it is readable by your computing systems. Many fiber optic systems utilize transceivers, which acts as a receiver and transmitter in one unit.
Naturally, the cores of fiber optic cables must be light conductive and so are constructed of glass (and sometimes plastic); this medium is dielectric and therefore immune to electromagnetic interference (EMI) and radio frequency interference (RFI), allow very low loss of signal, are capable of high bandwidths, are small, lightweight, and can operate in a wide range of temperatures effectively. At Cables For Less, we offer only high quality silica based glass fiber cables, ensuring clear and dependable transmissions. The light signals themselves are emitted via lasers, LEDs, or the more recently created VCSEL light sources. This light exists on the infrared frequency of energy and is thus invisible to the human eye, but rest assured, though your data is invisible to us; it is being transmitted at a higher bandwidth than ever before!
What makes a fiber cable a fiber cable? The Body of a Fiber Optic Cable (There are three C's in every fiber optic cable: core, cladding, and coating)
The core is constructed of specially treated glass or plastic and runs along the center of the fiber cable. Usually core diameters measure 9, 50, or 62.5 microns and because they serve as the medium for the majority of light propagation, cores must be as pure as possible, free of any imperfections lest they disrupt transmissions.
The cladding then, wraps the core and is comprised of many layers of the same material as the core. The cladding ensures total internal reflection, in other words it keeps photons (the electromagnetic energy that is light) from escaping the fiber by bouncing them back into the cable over and over as the light travels- cladding achieves this because it is constructed specifically to have a lower index of refraction than that of the core, so instead of light refracting through the cladding, the cladding reflects the light back into the core continually. Cladding is typically 125 microns thick.
Finally we have the coating, which as you may have guessed, wraps the core and cladding and serves to provide protection against abrasions and add overall strength to the cable. The initial layer of coating is between 240-250 microns thick and may be supplemented with a secondary layer, boosting its thickness to 900 microns.
To put these measurements in perspective, a common human hair is between 50-120 microns thick.
Beyond the three C's great variation exists among fiber optic cables depending on their purpose and installation, but these three always exist in some form.
Erbium and Specially Treated Fiber Glass
Glass is a medium through which light can travel in and of itself, but to increase its usefulness in fiber systems, glass cores are mixed together with a small amount of the rare-earth element erbium. This process is called doping. Erbium atoms promote certain energy levels or frequencies, so that if light emitted from a laser passes through the erbium-doped silica, the erbium acts to stabilize and amplify the photonic (or light) energy at these frequencies. All of this means that, through erbium-doped silica, our signals are stabilized and strengthened, allowing them retain integrity while traversing longer distances.
The Useable Wavelengths of Fiber Technology
As fiber technology was explored, it was discovered that certain wavelengths of light were highly functional in fiber transmissions while others simply were not. In glass fiber, attenuation (light loss) is mainly attributable to scattering and absorption of light- scattering occurs when light bounces off of atoms or molecules in the fiber while absorption occurs when minute amounts of water in the fiber absorb light. Both of these dilemma were discovered to be avoidable by using particular wavelengths of 850nm, 1300/1310nm, and 1550nm. Plastic optical fibers have lower absorption at shorter wavelengths and so operate at 650nm and 850nm wavelengths. So it goes that transmitters (LEDs and lasers) emit light on these frequencies, receivers (photodetectors) are calibrated to be receptive at these frequencies, and our fibers themselves are constructed to operate at these frequencies. You'll notice that some single-mode fibers are calibrated to operate at 1310nm, a nominal difference, established early on by AT&T when they dictated most optical jargon.
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Plastic Optical Fiber (POF) |
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650nm |
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850nm |
850nm |
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1300nm |
1310nm |
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1490-1625nm |
Fiber Optic Jacket Color Code
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Fiber Type |
Cable Jacket Color |
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Multimode (50/125) (OM2) |
Orange |
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Multimode (50/125) (850nm Laser-optimized) (OM3, OM4) |
Aqua |
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Multimode (62.5/125) (OM1) |
Orange |
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Single-mode (OS1, OS2) |
Yellow |
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At Cables For Less we offer a variety of high quality Fiber Optic solutions at great prices!
Visit our Fiber Optics section and shop from our ever-growing selection of patch cables such as 62.5/125 or 50/125 Multimode, Singlemode with any combination of LC, SC, ST, FC, MPO and MTRJ connectors. Of course we also carry a complete line of OM1, OM2 as well as 10GB OM3 and OM4 up to 100 Meters Don’t see the fiber cable you need pre-made? Not a problem with our custom calculator, which allows you to build your fiber to exact specification! See our assortment of pre-made and customizable patch panels, collection of fiber couplers and termination boxes. Don’t forget our networking converters and MPO trunks, cassettes, and fan-out kits we even carry fiber optic cleaning supplies!