Suppose you want to shine a flashlight beam down a long, straight hallway. Just point the beam straight down the hallway — light travels in straight lines, so it is no problem. What if the hallway has a bend in it? You could place a mirror at the bend to reflect the light beam around the corner. What if the hallway is very winding with multiple bends? You might line the walls with mirrors and angle the beam so that it bounces from side-to-side all along the hallway. This is exactly what happens in an optical fiber.

The light in a fiber-optic cable travels through the core (hallway) by constantly bouncing from the cladding (mirror-lined walls), a principle called total external inflection. Because the cladding does not absorb any light from the core, the light wave can travel great distances.

Why are fiber-optic systems revolutionizing telecommunications? Compared to conventional metal wire (copper wire), optical fibers are:

• Less expensive – Several miles of optical cable can be made cheaper than equivalent lengths of copper wire. This saves your provider (cable TV, Internet) and you money.
• Thinner – Optical fibers can be drawn to smaller diameters than copper wire.
• Higher carrying capacity – Because optical fibers are thinner than copper wires, more fibers can be bundled into a given-diameter cable than copper wires. This allows more phone lines to go over the same cable or more channels to come through the cable into your cable TV box.
• Less signal degradation – The loss of signal in optical fiber is less than in copper wire.
• Light signals – Unlike electrical signals in copper wires, light signals from one fiber do not interfere with those of other fibers in the same cable. This means clearer phone conversations or TV reception.
• Low power – Because signals in optical fibers degrade less, lower-power transmitters can be used instead of the high-voltage electrical transmitters needed for copper wires. Again, this saves your provider and you money.
• Digital signals – Optical fibers are ideally suited for carrying digital information, which is especially useful in computer networks.
• Non-flammable – Because no electricity is passed through optical fibers, there is no fire hazard.
• Lightweight – An optical cable weighs less than a comparable copper wire cable. Fiber-optic cables take up less space in the ground.

Because of these advantages, you see fiber optics in many industries, most notably telecommunications and computer networks. For example, if you telephone Europe from the United States (or vice versa) and the signal is bounced off a communications satellite, you often hear an echo on the line. But with transatlantic fiber-optic cables, you have a direct connection with no echoes.

Video cables are wires that transmit video signals. To help you understand more, here are the different types of video cables.

BNC Cables

a          BNC Cables. The BNC or Bayonet Neil-Concelman connector is a type of connector that uses radio frequencies in the multi-megahertz range. It is often used in place of a coaxial cable. There are a lot of consumer electronic devices with RCA (Radio Corporation of America) jacks that you can use with a BNC cable, but you have to use adapters to be able to do so. You will mostly find it being used for analog signals, Serial Digital Interface signals, and electronic devices used for aviation, or as antenna connectors for amateur radios. BNC cables come in both 50 and 75 ohm.

b         Component Video (RCA, RGB). The RCA connector is the most common cable used by audio/video electronic devices. It usually comes in three colors. Red for the right channel, white for the left channel, and yellow for the composite video. The RGB or red-green-blue connector is a type of connector that has pin-outs. It is commonly known as VGA cable. You will mostly find it being used with video cards, monitors, or HDTVs. It is more commonly known as a VGA connector.

RGB

c          HDMI, DVI, DisplayPort Cables. The HDMI or High-Definition Multimedia Interface connector is a cable that transmits digital data. It is the digital version of RF cables, RCA or RGB cables or S-Video cables. You will mostly find it being used on cable converter boxes, BD or Blu-ray Disc players, computers, Playstation 3s, or Xbox 360s. The DVI or Digital Visual Interface cable is a connector that transmits uncompressed digital video data. You will mostly find it being used on flat screen or LCD monitors, or digital projectors. The DisplayPort cable, developed by the Video Electronics Standards Association is HDMI’s strongest competitor. It uses more advanced technology in comparison to the other types of video cables. Companies like AMD, ATI, Genesis Microchip, Samsung, Dell and Apple commonly use DisplayPort cables for their products.

d          M1 Cables. The M1 cable is a video connector that can transmit digital, analog, or USB (Universal Serial Bus) signals. It is commonly known as EVC or P&D cable. You will mostly find it being used on new models of projectors.

e          S-Video Cables. The S-Video or Separate-Video cable is a connector that can transmit analog signals in lumen (luminance) and chroma (color). It carries videos that are normally at 488i or 576i resolution. You will mostly find it being used on televisions, DVD players, and new versions of cassette recorders, digital receivers, digital video recorders, game consoles, or video cards.

mini siamese cable

f            CCTV Cables (Siamese/Power). The Siamese cable is a connector that can transmit both power and data through a single connector. The Power cable is a connector that can only transmit power data. Siamese and Power cables are used in CCTV or closed-circuit television. You will mostly find them being used in surveillance or monitoring cameras

g          Composite Video Cables. The composite video cable is a connector that can only transmit analog signal. It has three types, NTSC, PAL, or SECAM. You will mostly find it being used on VCRs, game consoles or computers that were modeled during the 1980s.

h          HDTV Breakout Cables. The HDTV cable is a connector that is mainly to transmit signals for televisions that are using high definition broadcasting.

HDTV Cables

i            RF Cables (F-Type, Coaxial). The F-type cable is a connector that is used to transmit satellite television or data over cable modems. It is often used with a splitter for use in cable televisions. The Coaxial cable or coax is a connector that is used to transmit signal for home video devices or networking in computers. Long coaxial cables are also used for amateur radios.

Video cable is essential to all sorts of technology. It makes it possible to relive captured moments, or witness things without the need to be physically there. Technology will never cease to amaze us. As it advances, more things are made possible each day.

Recently the Indian government proposed to allocate 260 million rupees ($5.4 million) under the federal budget to set up an optic-fiber cable network exclusively for the defense forces.

 Most of the bandwidth to be vacated by the defense forces would be sold during the auction of licenses to start third-generation services, expected later this year.

Sample

The government expects to generate 350 billion rupees from the proposed auction, the budget document for the fiscal year ending March 31, 2010, showed.

The budget also proposed allocating 140.15 billion rupees for Bharat Sanchar and 17.25 billion rupees for the other state-run telecom operator, Mahanagar Telephone Nigam Ltd.

The Indian government holds a 56.25% stake in Mahanagar Telephone, which is listed on the Bombay Stock Exchange and the New York Stock Exchange.

optical fiber

But in Africa, many users still can not experience the high-speed network. “You can see, I try to click on the link but it’s not coming fast. It’s quite slow,” the Zambian national complains. “Then I have to purchase more time and it costs me another 25 meticals (about one dollar).”

Mauritius-based company SEACOM promises to revolutionise communications in Africa and lower bandwidth costs by up to 90 percent, after switching on the cable that resulted from a two-year, 600-million-dollar (427-million-euro) effort.

Countries like Kenya and Uganda can now experience broadband connections for the first time, while others like South Africa — which already has high-speed Internet — expect the new cable to lower costs by boosting competition.

But many end users will have to wait to see the benefits.

In fact, many don’t know SEACOM exists.

At the Teledata Internet cafe, employee Zacarias Tovela said SEACOM hadn’t changed web surfing there yet.

Internet Cafe

“I know there’s a new service called SEACOM, but I don’t know if we’re connected to it or not,” he said.

SEACOM spokesman Frederic Cornet said the company sells bandwidth wholesale to local service providers, who until now have relied on slower, costlier satellite connections.

The new cable will also boost telephone service in countries where international calls can be a shout in the dark.

SEACOM says land-based infrastructure is being rolled out in most countries along the coast to distribute the new network to users along the length of the continent.

Meanwhile, ordinary users hope the benefits will start arriving soon.

Orray Carlos, owner of Internet Express cafe in Maputo, laughed as he watched his connection speed bounce anaemically around one megabyte per second. SEACOM promises speeds of 1.2 terabytes per second — one million times faster.

I have heard optical fiber for the first time on my first physics class, and I have spent a lot of time on it. Now let me tell you something about optical fiber.

An optical fiber is a glass or plastic fiber that carries light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss, and they are also immune to electromagnetic interference. Fibers are also used for illumination, and are wrapped in bundles so they can be used to carry images, thus allowing viewing in tight spaces. Specially designed fibers are used for a variety of other applications, including sensors and fiber lasers

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optical fiber

Light is kept in the core of the optical fiber by total internal reflection. This causes the fiber to act as a waveguide. Fibers which support many propagation paths or transverse modes are called multi-mode fibers (MMF), while those which can only support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a larger core diameter, and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 550 metres (1,800 ft).

Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then spliced together either mechanically or by fusing them together with an electric arc. Special connectors are used to make removable connections.