Glossary

The optical power loss due to microscopic bends in the fiber.

One millionth of a farad. Abbreviated ?F and, less commonly, ?fd, mf, or mfd.

Also referred to as a micron; one millionth of a meter, often abbreviated with the symbol ?.

A broadcast network configuration in which the cable is divided into two channels, each using a different range of frequencies. One channel is used to transmit signals and the other is used to receive.

Used with 100Mbps Ethernet systems to attach MAClevel hardware to a variety of physical media systems. Similar to the AUI interface used with 10Mbps Ethernet systems. The MII is a 40-pin connection to outboard transceivers or PHY devices.

A fiber-optic cable manufacturer

The loss of optical power resulting from angular misalignment, lateral displacement, or end separation.

The bandwidth-limiting characteristic of multimode fiber systems caused by the variable arrival times of various modes.

A type of dispersion or spreading that arises from differences in the amount of time that different modes take to travel through multimode fibers. Modal dispersion potentially can cause parts of a signal to arrive in a different order from the one in which they were transmitted. See also DMD.

A disturbance often measured in multimode fiber-optic transmissions that are fed by diode lasers. The higher quality the laser light feeding the fiber, the less modal noise will be measured.

A single wave traveling in an optical fiber or in a light path through a fiber. Light has modes in optical-fiber cable. A high-order mode is a path that results in numerous reflections off the core/cladding interface. A loworder mode results in fewer reflections. A zero-order mode is a path that goes through the fiber without reflecting off the interface at all. In a single-mode fiber, only one mode (the fundamental mode) can propagate through the fiber. Multimode fiber has several hundred modes that differ in field pattern and propagation velocity. The number of modes in an optical fiber is determined by the diameter of the core, the wavelength of the light passing through it, and the refractive indexes of the core and cladding. The number of modes increases as the core diameter increases, the wavelength decreases, or the difference between refractive indexes increases.

The actual diameter of the light beam traveling through the core and part of the cladding and across the endface in a single-mode fiber-optic cable. Since the mode field diameter is usually greater than the core diameter,

A device that can select, attenuate, or reject a specific mode. Mode filters are used to remove high-order modes from a fiber and thereby simulate EMD. See also mandrel wrap.

A device that removes high-order modes in a multimode fiber to give standard measurement conditions.

A device that implements modulator-demodulator functions to convert between digital data and analog signals.