Fiber Optic Glossary

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  • 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.
    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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