Types of fiber optic cables and plugs
Fiber optic technology is based on a very specific medium: light pulses, emitted by a laser, transmitted inside a thin glass fiber over great distances. Fiber optic cable has to be combined from shorter sections on its way and branched out before it reaches our home or office. We present the most important information about handling these delicate cables, how to connect them and which fiber optic plugs are most commonly used today.
How a fiber optic cable is built?
An optical fiber is a microscopically thick (e.g., 25 microns, or 0.25 mm) transparent fiber, made of glass or plastic. Glass fibers are used for the long sections, and plastic ones are used only for the last section (max. 100 m), e.g. for the connection between the operator's socket and the ONT (modem or router).
To protect such a delicate medium from damage, in the cable it is surrounded by plastic insulation, sometimes additionally reinforced with non-woven or plastic strands for stiffness.
Fiber optic cable, constituting structured cabling may contain from several to a dozen, and sometimes dozens of individual fibers, placed in a common tube and sheath, protecting against mechanical damage.
As users of home or business fiber optic lines, we are unlikely to experience structured, multi-fiber cabling, as the operator will bring a single cable to our premises, to which the appropriate fiber optic connector.
How to connect fiber optics?
While connecting electrical cables (such as the copper telephone pairs to which modems and dSL routers) is a relatively easy task, while in the case of fiber optics it poses quite a problem.
First, the individual fiber is extremely thin and delicate. Secondly, in order for the light beam to pass through the joining area without hindrance, it must be precisely worked out and welded with special tools, because if the joining surfaces are not perfectly aligned and cleaned, the air or impurities that may appear between them will significantly degrade the quality or even prevent the transmission of light pulses.
Similarly, the case is with the installation of connectors on the cable - fiber optic plugs must be precisely welded to the fiber, for which, again, specialized instruments are required. If you don't have them, it will be best to buy a ready-made, factory-made cable of the appropriate length, terminated with plugs that fit the wall socket and the modem.
In general, fiber optic installations for residential and business users now use single (simplex) plugs in SC and LC (rectangular) standards. Unfortunately, these connectors cannot be used interchangeably, as they have a different shape (the SC connector is almost twice as large as the LC).
In both cases, the plugs consist of a central ceramic ferrule with an appropriately prepared surface (e.g., ground at an 8° angle in the case of the APC connector) and a plastic housing with a mechanism that facilitates precise centering, proper pressure of the ferrule surface against the socket surface, and secure latching of the plug to prevent accidental unplugging.
In case a different ONT is required on the infrastructure side of our operator fiber optic plug to the router we can lead by using a factory-made via.
How to handle fiber optics?
As we have already mentioned, optical fiber is a cable whose essential element is an extremely thin glass fiber, which makes it very fragile and susceptible to mechanical damage. Here are some basic rules to keep in mind when handling fiber optics.
Cable bending radius
Glass is not one of the materials that are overly flexible, and the fiber made of it may crack or crumble, making it impossible to transmit light with it. In addition, since the light ray travels inside the cross-section of the fiber by reflecting off the edges of the fiber, bending the medium too sharply can cause the ray to fall on the side surface at too high an angle and be largely absorbed or even reflected back in extreme cases.
Theoretically, it is assumed that the maximum bending radius should not be less than 20 times the cable diameter. In the case of an ordinary patchcord that you connect to a modem, this means that it should not be bent any more than if you wrapped it around a tennis ball.
Protection of the working surface of the plug
Smooth, sanded ferrule contact surfaces should be clean. So do not touch them with your finger, expose them to dust, or otherwise get them dirty. Ideally, non-working plugs and sockets should remain permanently plugged at their ends with special plugs.
Slack in storage
Arranged, or coiled fiber optic cables should not be squeezed too tightly with clamps, or tied to avoid dangerous bending. Also, do not lay them on or near sharp edges (such as the edge of a table or media cabinet), as on such an edge the cable may be damaged even under its own weight. Of course, fiber optic cables must also not be subjected to impact, trampling, constant movement (such as wind movement), stretching, nor should they be exposed to too high or too low temperatures and sunlight (unless they are in special insulation).
The most common damage to fiber optic cable?
Fiber optics can be damaged quite easily by not following the rules listed above. Excessive bending and impact can cause not only a complete breakage of the fiber, but also microcracks that will impede the transmission of light signals. Similarly, the operation may be affected by contamination of contacts in connectors. Fiber optic cables that are poorly installed, stored, and not routed according to good practice can cause the cable's performance to deteriorate over time.
