Aramid Yarn (Kevlar): Strength member used to provide longitudinal support for connector retention. Offers some cable cut-through resistance.
Armoring: Protective layer between jacketing layers which provided protection against severe mechanical and chemical environments.
Attenuation: Expressed in dB per kilometer, measures decreases in signal strength in a transmission line between two points. For optics it usually expresses the loss on an optical fiber or network comparing the ratio of light output vs light input. A lower figure in dB means a lower level of attenuation.
Band width: A measure of information-carrying capacity of a multi-mode optical fiber expressed in units of MHz-km.
Broad band: Denotes data transmission capabilities exceeding that of a standard direct modulation transmission found in high grade voice communications. Broad band allows several simultaneous channel transmissions due to the propagation of a carrier signal.
Buffering: A material extruded tightly or as a tube over a fiber to protect it from the environment. The loose tube configuration also isolates the fiber from stresses on the cable.
Bend radius (minimum): Radius to which a fiber or cable can be bent before breakage or excessive signal attenuation occurs.
Cladding: A dielectric material surrounding the case of an optical fiber which has a lower index of refraction in order to reflect light back to the core.
Coating: A material directly over the cladding which protects the fiber from the environment.
Connector coupler: A device which allows two similar connectors interfaces to be mechanically aligned and joined.
Core: The central region of an optical fiber through which light is transmitted.
Detector: Transducer device in a receiver which produces electrical output signal from a received incident optical signal.
Dispersion: Causes band width limitations and broadens the input pulse along the fiber length. Components of dispersion are : A) model dispersion in multi-mode fiber caused by varying optical path lengths. B) material dispersion caused by differential delay on various wave lengths of light signal in fiber. C) dispersion found in both single and multi-mode fiber which is caused by light entering and traveling in both core and cladding materials.
Emitter: A device in a transmitter which produces a coherent or incoherent light from an electrical input signal.
Fresnel reflection: The refraction losses of a portion of light signal due to differences in refraction index which occurs at the air/glass interfaces at the entrance and exit ends of optical fibers.
Fusion Splice: A permanent joint accomplished by melting two optical fibers together.
|
Grading-index: Fiber design which provides high band widh capabilities by having a core whose refractive index is lower toward the outside and increases toward the center of the core ths bending the rays inward which allows them to propagate faster in the lower index of the refraction region.
Laser Diode (LD): High output fiber optic light source usually used in expensive, long distance systems.
Light Emitting Diode (LED): Moderate output fiber optic light source used in inexpensive, short distance systems.
Local Area Network (LAN): A geographically limited communication network used for transportation of data voice and video.
Loose Tube: Type of fiber optic cable construction where the fiber is contained within a loose tube in the cable jacket.
Multi-mode fiber: A large cored optical wave guide in which a large number of modes may propagate. Typical core/cladding sizes are 50/125, 62.5/125 and 100/140 (measured in microns).
Modem (optical): Receive and transmitting device which converts electrical analog or digital signal into a corresponding optical signal.
Microbending: Curvature of a fiber which causes loss of light and consequently an increase in attenuation of the fiber.
Multiplexer (Mux): A device often capable of bi-directional data transmission which puts two or more signals into a single channel.
Numerical aperture: Light gathering capabilities of a fiber. Dependent on the differences in index of refraction between the core and the cladding.
Optical Waveguide: Another name for an optical fiber.
Patchcord or Cable Assembly: A short fiber optic cable with connectors on both ends.
PCS Fiber: An optical fiber with a plastic or polymer cladding instead of glass.
Pigtail: A fiber optic cable with a connector on one end and a bare fiber on the other.
Plenum: Duct work inside the building in which cables are routed.
Repeater: A fiber optic transmitter and a receiver connected back-to-back to extend the operation range of a system.
Single-mode fiber: Fiber in which the signal travels in one mode. The fiber's core/cladding size is approximately 8.7/125 (measured in microns).
Splicing: The permanent joining of fiber ends without connectors by means of fusion or mechanical splices.
Step-index fiber: Fiber having a uniform refractive index within the core and a sharp decrease in refractive index at the cladding. Typically used for single mode. |
