Fiber Optic Glossary : A

• A B Switch
  A device that accepts inputs (optical or electrical) from a primary path and a secondary path to provide automatic or...
• abaxial spherical aberration
  A type of aberration in which a symmetrical light patch is formed at points that do not lie on the...
• Abbe condenser
  A two-lens combination designed by the physicist Ernst Abbe. It is located below the stage of a microscope and functions...
• Abbe constant
  The constant of an optical medium that describes the ratio of its refractivity to its dispersion. A high V-value indicates...
• Abbe illumination
  A form of illumination where the source is imaged directly onto the object being viewed or projected. This requires a...
• Abbe prism
  A particular form of roof prism that can be used to invert an image. Because of the perpendicular end faces,...
• Abbe refractometer
  An optical instrument used to measure the of index of refraction of an unknown sample of optical glass. Designed by...
• Abbe sine condition
  A condition, first stated by Abbe, that must be met by any spherically corrected lens if it is also to...
• Abbe-Porro prism
  A compact version of the traditional Porro image-erecting prism used in binoculars.
• ABCD Matrix
  A 2-by-2 matrix describing the effect of an optical element on a laser beam.
• Aberration
  Deviation from what is normal, correct, or natural. In optics, aberrations may be defects in a lens system that cause...
• Aberration Sensor
  An optical instrument with knife-edge scanning technology that can detect and measure abberations in an optical system.
• Ablation Threshold
  The point at which absorbed laser energy is sufficient to break the bonds between molecules of a material.
• Ablative Photodecomposition
  The phenomenon whereby pulsed ultraviolet radiation is absorbed by a material, causing excitation within and between molecules sufficient to break...
• Ablative Wall Flashlamp
  A high-brightness, short-duration source in which low-pressure gas initiates the discharge to vaporize material from the tube wall, leading to...
• Abney effect
  The hue shift that results when purity and, consequently, saturation are varied.
• Abrasion Mark
  Any scratch, dig, or mark on an optical surface caused by friction in polishing, mishandling, or environmental factors.
• Abrasive
  A material such as silicon carbide, aluminum oxide, silica, cerium oxide, emery or rouge that is used to figure, shape,...
• Abridged Spectrophotometer
  An instrument used to measure transmission or reflection as a function of wavelength, using narrow bandpass filters rather than the...
• Absolute Colorimetric
  A rendering intent that does not change colors from the source space falling within the destination gamut, but clips out-of-gamut...
• Absolute Luminance Threshold
  Lower limit of luminance necessary for vision. About 10 -2 ml at the fovea, 10 -5 ml for peripheral...
• Absolute Magnification
  The magnification equal to the distance of distinct vision (250 mm) divided by the equivalent focal length of the lens....
• Absolute Purity Threshold
  Least purity seen as different from white.
• Absolute Refractive Index
  The refractive index of a medium in relation to that of a vacuum.
• Absolute Temperature Scale
  Thermodynamic temperature scale, named for Lord Kelvin (1848), in which temperatures are given in kelvins (K). (In the SI system,...
• Absolute White
  A perfect diffuser that exists only as a concept, or a white with known spectral characteristics used as a reference...
• Absorb
  To transform radiant energy into a different form, usually with a resultant rise in temperature.
• Absorbance
  The ability of a medium to absorb radiation depending on temperature and wavelength. Expressed as the negative common logarithm of the...
• Absorbing Wedge
  A strip or annulus of glass whose transmission varies linearly with distance because of its varying absorption.
• Absorptance
  Ratio of the absorbed radiant or luminous flux to the incident flux.
• Absorption
  That portion of fiber optic attenuation resulting from the conversion of optical power to heat.
• Absorption Band
  A region of the spectrum in which the absorption coefficient reaches a maximum.
• Absorption Coefficient
  The absorption coefficient is a property of a material. It defines the extent to which a material absorbs energy, for...
• Absorption Hologram
  A hologram formed when the light of the illuminating beam is absorbed in correspondence with the recording exposure.
• Absorption Index
  The quantity of al/4pn, where a is the absorption coefficient, l is wavelength, and n is refractive index.
• Absorption Lens
  A lens designed to inhibit selected wavelengths from passing through it by the absorption of those wavelengths.
• Absorption Line
  The narrowest range of wavelengths or frequency of radiant energy that can be absorbed by a medium.
• Absorption Meter
  A measuring device that uses a light-sensitive cell or detector to determine the amount of light transmitted by a...
• Absorption Peak
  In the field of spectroscopy, the maximum wavelength of radiation that can be absorbed by a sample.
• Absorption Spectrophotometer
  An optical instrument used to detect and measure the absorption spectra of specimens.
• Absorption Spectroscopy
  A study of the energies and wavelengths of radiation absorbed by atoms and molecules of materials under various physical...
• Absorption spectrum
  Also called spectral window of absorption. The spectrum formed by radiation that has been filtered through a material medium, in...
• AC
  Abbreviation for alternating current. An electric current that reverses its direction at regularly recurring intervals.
• Accelerated Aging
  The operation of a sample population of the lasers for an extended period of time under harsher conditions then those...
• 
  Acceptance Angle
  The maximum angle within which light will be accepted by an element, such as a detector or waveguide. In the...
• 
  Acceptance Cone
  In fiber optics, the cone within which optical power may be coupled into the bound modes of an optical fiber....
• Acceptance Pattern
  A curve expressing an optical fiber's total transmitted power as a function of its launch angle at the input.
• Access Network
  Part of the telecommunication network that connects to individual and corporate users.
• Accessories
  Sometimes referred to as “Rear Accessories” or “Backshells” are mechanical devices such as strain reliefs, cable clamps, adapters, potting boots,...
• Acousto Optic Modulators
  Optical modulators based on the acousto-optic effect.
• Acousto Optic Tunable Filter
  An optical filter that can be tuned by altering the refractive index using acoustic waves in the 40- to 68-MHz...
• Acousto Optics
  The study of the interactions between sound waves and light in a solid medium. Sound waves can be made to...
• Acoustophotorefractive Effect
  A semipermanent change in the index of refraction resulting from the interaction between high-intensity, short-duration laser pulses and propagating signal...
• Acrylate
  A polymer material used in optical fibers as a buffer coating or cladding or in capillary as a coating.
• Active Area
  The area of a detector with greatest response.
• Active Branching Device
  A device which converts an optical input into two or more optical outputs with gain or generation.
• Active Device
  A device that requires a source of energy for its operation and has an output that is a function of...
• Active Medium
  A medium in which lasing will take place, rather than absorption, at a given wavelength.
• Active Mode Locking
  A technique of mode locking based on active modulation of the intracavity losses or the round trip phase change.
• Active Port Diameter
  On a light source or detector, the diameter of the area in which light can be coupled to or from...
• Active Region
  The layer of material in a laser diode from which the optical radiation is emitted.
• Active Star
  An active device that connects two or more fiber optic link segments. Optical signals received on the input fiber of any...
• Acute Bisectrix
  In biaxial crystals, the principal angle that bisects the smaller angle between the optic axes.
• AD
  Abbreviation for analog-to-digital converter. A device used to convert analog signals to digital signals.
• Adapter
  A device for coupling two connectors.
• Adapter Sleeve
  A mechanical fixture within an adapter body that aligns and holds two terminated fiber connectors. Adapter sleeve material is typically...
• Adapters
  An adapter is a mechanical device designed to align fiber-optic connectors. It contains the split sleeve, also known as the...
• ADC
• Add Drop Multiplexing
  A multiplexing function offered in connection with SONET that allows lower level signals to be added or dropped from a...
• Additive Pulse Mode Locking
  A technique for mode locking a laser using a nonlinear interaction in an external resonator.
• additive-pulse mode locking
  A technique for mode locking a laser, using a nonlinear interaction in an external resonator
• Address
  A number specifying a particular user device attachment point... The location of a terminal, a peripheral device, a node, or any...
• Adiabatic Soliton Compression
  A pulse compression technique based on the adaptation of solitons to slowly varying propagation parameters.
• Adjustable Attenuator
  An attenuator in which the level of attenuation is varied with an internal adjustment. Also known as Variable Attenuator.
• ADM
  Abbreviation for add-drop multiplexer.A device which adds or drops signals from a communications network.
• ADSL
  Asymmetric Digital Subscriber Line. Most common form of DSL where the data rate being transmitted to the subscriber is high...
• Adsorption
  In chemistry, the taking up by the surface of a solid or liquid (adsorbent) of the atoms, ions, or molecules...
• AEA
  American Electronics Association
• Aerial Plant
  Cable that is suspended in the air on telephone or electric utility poles.
• AFCEA
  An acronym for Armed Forces Communications and Electronics Association.
• AGC
  Abbreviation for automatic gain control. A process or means by which gain is automatically adjusted in a specified manner as...
• Aging
  The operation of a sample population of the lasers for an extended period of time under specified conditions.
• Algorithm
  A procedure for solving a mathematical problem, as of finding the greatest common divisor, in a finite number of steps that...
• Aligned Bundle
  An assembly of fibers in which the coordinates of each fiber are the same at the two ends of the...
• Alignment Laser
  A laser, usually employing helium-neon or other gases as the active medium, used for alignment in industrial applications.
• Alignment Sensitivity
  The sensitivity of a laser, an optical resonator or some other device with respect to misalignment.
• All Dieletric Cable
  Cable made entirely of dielectric (insulating) materials without any metal conductors, armor, or strength members.
• All Silica Fiber
  Also known as all-glass fiber. A fiber with both a silica core and a silica cladding, regardless of the presence...
• All Solid State Lasers
  Laser systems containing solid-state devices only.
• Alpha
  A positive number that indicates the core refractive index shape and ranges from one to infinity.
• Alternate Buffer
  In a data communications device, the section of memory set aside for the transmission or receipt of data after the...
• AM
  Abbreviation for amplitude modulation. A transmission technique in which the amplitude of the carrier varies in accordance with the...
• Ambient Temperature
  The average or mean temperature of the surrounding air, which comes in contact with the equipment and instruments under...
• Amp
  An abbreviation for ampere.
• Amplification
  The growth of the radiation field in the laser resonator cavity. As the light wave bounces back and forth between...
• Amplification Factor
  The factor by which the power of a signal is amplified.
• Amplified Spontaneous Emission
  A background noise mechanism common to all types of erbium-doped fiber amplifiers (EDFAs). It contributes to the noise figure of...
• Amplifier
  A device that enlarges and strengthens a signal's output without significantly distorting its original waveshape. There are amplifiers for acoustical,...
• Amplifier Chains
  Amplifiers consisting of several stages.
• Amplifier Noise
  Noise introduced to a signal in an amplifier device.

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