Authored by jameswilliams

The different types of cables

Optical fibers carry light signals down in what are called modes. It sounds technical, but it just means that there are different ways of making light travel. A mode is simply the path that a beam of light follows through the fiber.

One mode goes down the fiber. Another mode is to bounce the fiber at a low angle. Other modes involve bouncing light into the fiber at other, more or less steep, angles.

Accordingly, the simplest type of mode is called singlemode. It has a very thin core about 5-10 microns (millionths of a meter) in diameter. In a single-mode fiber, all signals travel down, in the middle, without bouncing off the edges. Cable TV, internet, and telephone signals are usually carried over single-mode fibers, carried together in a huge cable.

Another type of fiber optic cable is called multi-mode. Each multi-mode optical fiber is approximately 10 times larger than that of a single-mode cable. This means that the light beams can travel through the nucleus following a variety of different paths.

In other words, in several different modes. Multi-mode cables can send information only over relatively short distances and are used (among other things) to tie computer networks together.

External network installations Telephone networks are primarily outdoor systems connecting buildings over distances as short as a few hundred meters to hundreds or thousands of kilometers. Data rates for telecommunications are typically 2.5 to 10 gigabits per second using very high power lasers that operate exclusively on single mode fibers. FTTH (Fiber To The Home) access can offer speeds of up to 100 Mbps; for example.

The current trend is to pull the fiber directly to a commercial building or a home; since the signals are now too fast for traditional twisted copper pairs. Data transmission is also increasingly heavy.

Besides for telecommunications, these fibers have many other applications. Smart highways are dotted with security cameras and fiber-connected panels. The same goes for security at airports, government and commercial buildings, etc.

Metropolitan networks owned and operated by cities can carry a wide variety of traffic; including that of surveillance cameras, emergency services, telephone, etc. In most cases, single mode is the fiber chosen.

Design of a fiber optic network: local networks Local networks generally operate over multimode fiber. Multimode systems are cheaper than single-mode systems, not because fiber is cheaper (it isn't), nor because cable is cheaper, but because the large multimode fiber core allows for the use of cheaper LED or VCSEL sources in transmitters.

Local networks will include an entrance facility where communication systems meet outside networks. This installation should not only include wiring connections but also compatible communications. As we are inside, there are issues relating to building and electrical codes to consider.

For more information about: optical network design

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