In the 1960s, glass researchers from all around the world started to take on the challenge. Finally in 1970, Drs. Robert Maurer, Donald Keck, and Peter Schultz of Corning Incorporated developed a fiber that had measured attenuation of less than 20 dB per km.
Since then, we have advanced fiber optic technology so far that we can send digitized light signals hundreds of kilometers without any amplication. Today, we're approaching the theoretical limits of the technology with achievable limits of less than 0.35 dB per km over 1310 nanometers (nm) and 0.25 dB per km over 1550 nanometers.
Optical Assembly Terminology
Optical jumpers can take many forms. The most common form is a duplex jumper, with one fiber acting as a Tx (transmit leg) and the other fiber acting as the Rx (Receive leg).
Optical jumper users must understand the relationship between the connectors, cable style and glass fiber. The term "Simplex" indicates that a single optical fiber is being used in the assembly but does not mention what type of glass is to be used (e.g. singlemode, multimode, etc...). The term "Duplex" indicates that the assembly contains two optical fibers.
"Duplex" connectors allow two fibers to be terminated while "Simplex" connectors allow just one. Some simplex connectors can be joined together to form a quasi-duplex connector.
Uses of Fiber Optic Cable
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 either transparent plastic or glass, the fibers used in long-distance telecommunications applications are always glass, because of the lower optical absorption. The light transmitted through the fiber is confined due to total internal reflection within the material. This is an important property that eliminates signal crosstalk between fibers within the cable and allows the routing of the cable with twists and turns. In telecommunications applications, the light used is typically infrared light, at wavelengths near to the minimum absorption wavelength of the fiber in use.
The U.S. Military was the first to really exploit the new technology in the 1970s. They quickly recognized fiber optic technology's potential for improving communication and tactical tactical systems. Aboard the U.S.S. Little Rock, the U.S. Navy installed a fiber optic telephone link. The Air Force followed suit and developed its Airborne Light Optical Fiber Technology (ALOFT) program in 1976. These applications were so successful that money started pouring into military Research & Development teams to develop stronger fibers, tactical cables, high-performance components, and so on.
The next year in 1977, commercial applications started to take place. AT&T and GTE installed a fiber optic telephone system that met demands for a more reliable and higher performance network. In 1990, Bell Labs was able to transmit a signal at 2.5GB/s over 7500 km without having the regenerate. In 1998, they were able to send signals out at 10GB/s for over 250 miles, which is close to the theoretical limit. Distance and capabilities will increase even more once the glass becomes more pure. |