Fiber optic cables: types and characteristics

Fiber optic cable is a fundamentally different type compared to other types of cables. Its information is transmitted by a light signal. Its main element is a transparent optical fiber, through which light travels for huge distances (up to tens of kilometers) with a slight attenuation. The structure of this fiber cable is very simple and similar to the structure of a conventional cable, only a thin (diameter of about 1-10 microns) optical fiber is used in the center, and a glass or plastic coating is applied instead of internal insulation that does not allow light to go beyond the optical fiber

Metal fiber cable coating is usually absent, since shielding from external electromagnetic interference is not required, but sometimes it is still used for mechanical protection from the environment (such a fiber optic cable is sometimes called armor, it can combine several cables under one shell). Fiber optic cable has exceptional characteristics for noise protection and secrecy of transmitted information. 

In principle, no external electromagnetic interference can distort the light signal, and this signal itself does not generate external electromagnetic radiation. It is almost impossible to connect to this type of fiber cable for unauthorized network interference since this requires breaking the integrity of the optical fiber. The cost of fiber optic cable is constantly decreasing and is now approximately equal to the cost of a thin coaxial cable. 

However, fiber cable has some disadvantages. The most important of them is the high complexity of installation (when installing connectors, micron accuracy is required, the attenuation in the connector strongly depends on the accuracy of the optical fiber chip and the degree of its polishing). Therefore, most often fiber optic cable is sold in the form of pre-cut pieces of different lengths, at both ends of which the desired type of connectors is already installed. 

Fiber cables are also sensitive to mechanical influences (shock, ultrasound) – it is the so-called microphone effect. Soft sound-absorbing shells are used to reduce it. There are two different types of fiber optic cables:

  • Multimode optical fiber cable that is considered to be cheaper but of lower quality;
  • The single-mode fiber cable is more expensive, but with better characteristics. 

The main differences between these types are related to the different modes of the passage of light rays in the fiber optic cable. In a single-mode fiber cable, almost all the laser beams travel the same path, resulting in all of them reaching the receiver at the same time, and the signal form is virtually undistorted. For a single-mode fiber cable, laser transceivers are applied that use light exclusively with the desired wavelength. 

Such transceivers are still relatively expensive and not very durable. However, in the future, the single-mode fiber optic cable should become the main one due to its excellent characteristics. In a multimode fiber cable, the paths of light beams have a noticeable spread, resulting in a distorted signal form at the receiving end of the cable. Currently, multimode optical fiber cable is the main type of cables, since it is cheaper and more affordable. 

If you would like to obtain an optical fiber product, you should choose the Optromix company. Optromix is a provider of top quality special fibers and broad spectra optical fiber solutions. The company delivers the best quality special fibers and fiber optic cables, fiber optic bundles, spectroscopy fiber optic probes, probe couplers, and accessories for process spectroscopy to clients. If you have any questions or would like to buy an optical fiber, please contact us at info@optromix.com

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