General Cable Fiber Optics Catalog
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Technical Information Fiber Optic Glossary Dispersion: Spread of the signal delay in an optical waveguide. It consists of various components: modal dispersion, material dispersion and waveguide dispersion. As a result of the dispersion, an optical waveguide acts as a low-pass filter for the transmitted signals. Frequency: Number of cycles per unit of time, measured in Hertz (Hz). Duplex: Referring to a type of data transmission, either half or full. Half duplex permits only one-way communication. Full duplex allows simultaneous two-way transmission. Gigabit: One billion bits of information. Electromagnetic Interference (EMI): Flowing currents generate magnetic fields. Depending on the strength and proximity, these magnetic fields can induce unwanted current in nearby conductive media, negatively affecting signal transfer. End Finish: Quality of the surface at an optical fiber's end, commonly described as mirror, mist, hackle, chipped, cracked or specified by final grit size used in polishing. ETL: Abbreviation for Edison Testing Laboratory, which is a division of Intertek Group plc. ETL specializes in electrical product testing, EMC testing and benchmark performance testing. FDDI (Fiber Distributed Data Interface): A standard for a 100 Mbs fiber optic area network. Fiber: Any filament or fiber made of dielectric materials that guides light. Fiber Channel: A high speed point-topoint, ANSI Optical Communications Standard that supports data transfer rates up to 1,062.5 Mbs (1 Gps). Fiber Cleaving: Controlled fracture of an optical fiber along a crystalline plane which results in a smooth surface. Fiber Optics: Branch of optical technology dealing with the transmission of radiant power through fibers made of transparent materials such as glass, fused silica or plastic. FOTP: Abbreviation for fiber optic test procedures, which are defined in TIA/EIA Publication Series 455. 52 Fusion Splice: Splice accomplished by the application of localized heat sufficient to fuse or melt the ends of two lengths of optical fiber, forming a continuous single fiber. Gigahertz (GHz): One billion Hertz. Graded-Index Fiber: An optical fiber core that has a nonuniform index of refraction. The core is composed of concentric rings of glass, which have refractive indices that decrease from the center axis. The refractive index is changed in a systematic way from the center to the edges in order to decrease modal dispersion. Hertz: Measurement unit of frequency. Hybrid Cable: A fiber optic cable containing two or more different types of fiber (e.g., multimode and singlemode). Index of Refraction: The ratio of light velocity in a vacuum to its velocity in a given transmission medium. Infrared (IR): The range of electromagnetic wavelengths between the visible part of the spectrum (750nm) and microwaves (30µm). Insertion Loss: The attenuation caused by insertion of an optical component such as a connector, splice or coupler. Intensity: Irradiance. Interbuilding: Between buildings. Intrabuilding: Within a building. Jumper: Fiber optic cable that has connectors terminated on both ends. KPSI: Abbreviation used to denote a measurement unit of thousands of pounds per square inch. Commonly used in the fiber proof test tensile strength measurement. Kevlar: DuPont trade name for aramid material (see Aramid Yarn). Kilometer: Unit of measure for length equal to 1000 meters and about 3,281 feet. Laser: A device which produces a narrow band of light and is used as a transmitting device for light signals traveling along optical fibers. Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Launch Angle: Angle between the propagation direction of the incident light and the optical axis of an optical waveguide. LED: Acronym for Light Emitting Diode. It is a semiconductor device that emits incoherent light from a p-n junction (when biased with an electrical current). Light: In the laser and optical communications fields, the portion of the electromagnetic spectrum that can be handled by the basic optical techniques used for the visible spectrum extending from the near ultraviolet region of approximately 0.3 micron, through the visible region and into the mid-infrared region of about 30 microns. Light Diffusion: Scattering of light by reflection or transmission. Diffuse reflection results when light strikes an irregular surface such as a frosted window or coated light bulb. Light Emitting Diode: See LED. Lightwaves: Electromagnetic waves in the region of optical frequencies. The term "light" was originally restricted to radiation visible to the human eye, with wavelengths between 400 and 700nm. However, it has become customary to refer to radiation in the speed regions adjacent to visible light as "light" to emphasize the physical and technical characteristics they have in common with visible light. Loose Tube: Type of cable design in which coated fibers are encased in buffer tubes offering excellent fiber protection and segregation. Mainly used in outdoor cable types. MDPE: Acronym for Medium Density Polyethylene. MDPE is a form of polyethylene commonly used as a jacketing material for outdoor fiber optic cables (see PE).