Glossary

A transformer designed to match the impedance of one circuit to another.

A condition where the impedance of a particular cable or component is different than the impedance of the device to which it is connected.

The angle between the subject light wave and a plane perpendicular to the subject optical surface.

Light in which the electric and magnetic fields of photons are completely random in orientation. Incoherent light is typically emitted from lightbulbs and LEDs.

A clear gel or fluid used between optical fibers that are likely to have their ends separated by a small amount of air space. The gel matches the refractive index of the optical fiber, reducing light loss due to Fresnel reflection.

A material in liquid, paste, gel, or film form whose refractive index is nearly equal to the core index; it is used to reduce Fresnel reflections from a fiber end-face. Liquid forms of this are also called index matching gel.

(1) The ratio of the speed of light in a vacuum to the speed of light in a given transmission medium. This is usually abbreviated n. (2) The value given to a medium to indicate the velocity of light passing through it relative to the speed of light in a vacuum.

The curve of the refractive index over the cross section of an optical waveguide.

A standard for a switched fabric communications link primarily used in high-performance computing.

The infrared spectrum consists of wavelengths that are longer than 700nm but shorter than 1mm. Humans cannot see infrared radiation, but we feel it as heat. The commonly used wavelengths for transmission through optical fibers are in the infrared at wavelengths between 1100nm and 1600nm.

A laser that transmits infrared signals.

A transmitting and receiving device that emits and receives infrared energy.

Transmission using infrared transceivers or lasers.

A laser diode in which the lasing takes place within the actual semiconductor junction and the light is emitted from the edge of the diode.

A separate duct running within a larger duct to carry fiber-optic cables.