50-µm fibre optic cable.
Fibre optic cable.
Thus, there is a renewed interest in 50-micron fibre optic cable.
First used in 1976, 50-micron cable has not experienced the widespread use that 62.5-micron cable has.
To support campus backbones and horizontal runs over 10-Mbps Ethernet, 62.5-micron fibre, introduced in 1986, was and still is the predominant fibre optic cable because it offers high bandwidth and long distance.
One reason 50-micron cable did not gain widespread use was because of the light source. Both 62.5- and 50-micron fibre cable can use either LED or laser light sources. But in the 1980s and 1990s, LED light sources were common. Because 50-micron cable has a smaller aperture, the lower power of the LED light source caused a reduction in the power budget compared to 62.5-micron cable—thus, the migration to 62.5-micron cable. At that time, laser light sources were not highly developed and were rarely used with 50-micron cable—and, when they were, it was mostly in research and technological applications.
As with 62.5-micron cable, you can use 50-micron fibre in all types of applications: Ethernet, FDDI, 155-Mbps ATM, Token Ring, Fast Ethernet, and Gigabit Ethernet. It is recommended for all premise applications: backbone, horizontal, and intrabuilding connections. And it should be considered especially for any new construction and installations. IT managers looking at the possibility of 10-Gigabit Ethernet and future scalability will get what they need with 50-micron cable.
As we move toward Gigabit Ethernet, the 850-nm wavelength is gaining importance along with the development of improved laser technology. Today, a lower-cost 850-nm laser, the Vertical-Cavity Surface-Emitting Laser (VCSEL), is becoming more available for networking. This is particularly important because Gigabit Ethernet specifies a laser light source.
Other differences between the two types of cable include distance and speed. The bandwidth an application needs depends on the data transmission rate. Usually, data rates are inversely proportional to distance. As the data rate (MHz) goes up, the distance that rate can be sustained goes down. So a higher fibre bandwidth enables you to transmit at a faster rate or for longer distances. In short, 50-micron cable provides longer link lengths and/or higher speeds in the 850-nm wavelength. For example, the proposed link length for 50-micron cable is 500 meters in contrast with 220 meters for 62.5-micron cable.
Although 50-µm and 62.5-µm fibre both feature a 125-µm cladding, the core sizes differ. The smaller, 50-µm core provides a higher 850-nm bandwidth, making it ideal for inter/intrabuilding connections.