Fiber Optic Cables Are Everywhere: How Do They Work?Engineering360 News Desk | June 16, 2016
Fiber optic cables are composed of one or more transparent fibers enclosed in protective coverings and strength members. Fiber optic cables allow signals, such as light, to travel through without interference. A real fiber optic cable is made of glass which is incredibly pure to allow light to pass through over very long distances. The glass is then coated in two layers of plastic.
The plastic gives the equivalent mirror effect which creates total internal reflection. Light traveling through the fiber bounces at shallow angles and stays completely within the fiber. This happens when the light hits the interface at angle larger than the critical angle. At this angle it will not pass through to the second medium at all.
Information, such as analog voice signals, is translated into digital signals. The digital information is then sent bit-by-bit (1's and 0's) by a laser; modern lasers can send the information at rates of billions of bits per second.
Today's system uses different colored lasers to fit multiple signals into the same fiber. This information can be carried over long distances (60 miles) with equipment huts every 40 to 60 miles; these huts retransmit the signal down the next segment at full strength.
Fiber optic cables play an important role in long distance communication such as telephone and Internet lines. These cables often are significantly less expensive than copper wires.
Cable types can include:
Simplex- Simplex cables are fiber optic cables with a single optical fiber. They are used in applications that only require one-way data transfer. Simplex is available in singlemode and multimode.
Duplex- Duplex cables are fiber optic cables with two optical fibers. They are usually set up side-by-side and can be used for applications that require simultaneous, bi-directional data transfer. Duplex fiber is available in singlemode and multimode.
Multifiber- Multifiber cable is a fiber optic cable with several optical fibers.
Patch cord - Patch cords are short lengths of fiber optic cable with connectors that can be directly attached to other equipment for connecting and managing convenience.
Bare fiber - Bare fiber refers to a fiber optic core and cladding only. This fiber is primarily used for connecting equipment on one end to a light source on the other. Bare fiber can be terminated, polished, or prepared for pig-tailing.