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Fiber Optics |
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| Advantages of Fiber Optics |
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| Why are fiber-optic systems revolutionizing telecommunications? Compared to conventional metal wire (copper wire), optical fibers are: |
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- 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 fiers 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.
- Flexible - Because fiber optics are so flexible and can transmit and receive light, they are used in many flexible digital cameras for the following purposes:
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- Medical imaging - in bronchoscopes, endoscopes, laparoscopes
- Mechanical imaging - inspecting mechanical welds in pipes and engines (in airplanes, rockets, space shuttles, cars)
- Plumbing - to inspect sewer lines.
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| Applications |
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| Fiber-optic cable is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals, sometimes all on the same optical fiber. |
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| Telecommunication and networking |
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| The optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. Although fibers can be made out of transparent plastic, glass, or a combination of the two, the fibers used in long-distance telecommunications applications are always glass, because of the lower optical loss. Both multi-mode and single-mode fibers are used in communications, with multi-mode fiber used mostly for short distances (up to 500 m), and single-mode fiber used for longer distance links. Because of the tighter tolerances required to couple light into and between single-mode fibers, single-mode transmitters, receivers, amplifiers and other components are generally more expensive than multi-mode components. |
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| Fiber optic sensors |
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| Optical fibers are small are useful in areas where electrical power is not needed and hence can be used as sensors to measure strain, temperature, pressure and other parameters. |
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| Optical fibers are used for seismic applications. Hydrophone systems with more than 100 sensors per fiber cable have been developed. Hydrophone sensor systems are used by the oil industry as well as a few countries' navies. Both bottom mounted hydrophone arrays and towed streamer systems are in use. |
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| Optical fiber sensors for temperature and pressure have been developed for downhole measurement in oil wells. The fiber optic sensor is well suited for this environment as it is functioning at temperatures too high for semiconductor sensors (Distributed Temperature Sensing). |
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| Another use of the optical fiber as a sensor is the optical gyroscope. which is in use in the Boeing 767 and in some car models (for navigation purposes) and the use in Hydrogen microsensors. |
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