A fiber-optic technique is similar to the copper wire technique that fiber-optics is replacing. The difference is that fiber-optics use light pulses to transmit information down fiber lines in lieu of using electronic pulses to transmit information down copper lines. Taking a look at the parts in a fiber-optic chain will give a better understanding of how the technique works together with wire based systems. Where copper cabling makes use of electricity to transmit signals from finish to another, fiber optics use light pulses to accomplish the same purpose. The fiber cable is made of a transparent glass core surrounded by a mirror like covering called cladding. Light passes through the cable, bouncing off the cladding until it reaches the other finish of the fiber channel - this is called total internal reflection.In recent years it's become apparent that fiber-optics are steadily replacing copper wire as an appropriate means of communication signal transmission. They span the long distances between local phone systems as well as providing the backbone for lots of network systems. Other technique users include cable tv services, university campuses, office buildings, industrial plants, and electric utility companies. Optical fiber connectors are used in phone company central offices, at installations on customer premises, and in outside plant applications. Their makes use of include: - Making the connection between equipment and the phone plant in the central office - Connecting fibers to remote and outside plant electronics such as Optical Network Units (ONUs) and Digital Loop Carrier (DLC) systems - Optical cross connects in the central office - Patching panels in the outside plant to provide architectural flexibility and to interconnect fibers belonging to different service providers - Connecting couplers, splitters, and Wavelength Division Multiplexers (WDMs) to optical fibers - Connecting optical check equipment to fibers for testing and maintenance. In fiber-optic communication, a single-mode optical fiber (SMF) (monomode optical fiber, single-mode optical waveguide, or unimode fiber) is an optical fiber designed to over only a single ray of light (mode). Modes are the feasible solutions of Helmholtz equation for waves, which is obtained by combining Maxwell's equations and the boundary conditions. These modes define the way the wave travels through space, i.e how the wave is distributed in space. Waves can have the same mode but have different frequencies. This is the case in single-mode fibers, where they can have waves with different frequencies, but of the same mode, which means that they are distributed in space in the same way, and that gives us a single ray of light. Although the ray travels parallel to the length of the fiber, it is often called transverse mode since its electromagnetic vibrations occur perpendicular (transverse) to the length of the fiber. The 2009 Nobel Prize in Physics was awarded to Charles K. Kao for his theoretical work on the single-mode optical fiber At finish of the technique is a transmitter. This is the place of origin for information coming on to fiber-optic lines. The transmitter accepts coded electronic pulse information coming from copper wire. It then processes and translates that information in to equivalently coded light pulses. A light-emitting diode (LED) or an injection-laser diode (ILD) can be used for generating the light pulses. Using a lens, the light pulses are funneled in to the fiber-optic medium where they travel down the cable. The light (near infrared) is most often 850nm for shorter distances and one,300nm for longer distances on Multi-mode fiber and 1300nm for single-mode fiber and one,500nm is used for for longer distances. Think of a fiber cable in terms of long cardboard roll (from the inside roll of paper towel) that is coated with a mirror on the inside.In the event you shine a flashlight in finish you can see light come out at the far finish - even if it is been twisted around a corner. There's types of fiber optic cable often used: single mode, multimode and plastic optical fiber (POF). Light pulses move basically down the fiber-optic line because of a principle known as total internal reflection. "This principle of total internal reflection states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; in lieu, the light bounces back in. When this principle is applied to the construction of the fiber-optic strand, it is feasible to transmit information down fiber lines in the kind of light pulses. The core must a clear and pure material for the light or in most cases near infrared light (850nm, 1300nm and 1500nm). The core can be Plastic (used for short distances) but most are made from glass. Glass optical fibers are  always made from pure silica, but some other materials, such as fluorozirconate, fluoroaluminate, and chalcogenide glasses, are used for longer-wavelength infrared applications. Transparent glass or plastic fibers which permit light to be guided from finish to the other with minimal loss. Fiber optic cable functions as a "light guide," guiding the light introduced at finish of the cable through to the other finish. The light source can either be a light-emitting diode (LED)) or a laser. Even laser light shining through a fiber optic cable is subject to loss of strength, primarily through dispersion and scattering of the light, within the cable itself. The faster the laser fluctuates, the greater the risk of dispersion. Light strengtheners, called repeaters, may be necessary to refresh the signal in definite applications. The light source is pulsed on and off, and a light-sensitive receiver on the other finish of the cable converts the pulses back in to the digital ones and zeros of the original signal. Single Mode cable is a single stand (most applications use four fibers) of glass fiber with a diameter of 8.3 to ten microns that has mode of transmission. Single Mode Fiber with a comparatively narrow diameter, through which mode will propagate usually 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber. While fiber optic cable itself has become cheaper over time - a equivalent length of copper cable cost less per foot but not in capacity. Fiber optic cable connectors and the equipment needed to put in them are still more expensive than their copper counterparts. Single Modem fiber is used in lots of applications where information is sent at multi-frequency (WDM Wave-Division-Multiplexing) so cable is necessary - (single-mode on single fiber) Single-mode fiber gives you a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. Single-mode fiber has a much smaller core than multimode. The tiny core and single light-wave virtually eliminate any distortion that could result from overlapping light pulses, providing the least signal attenuation and the highest transmission speeds of any fiber cable type. Single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest usually 1300 to 1320nm.