Fiber Optic Glossary : H


  • Half Duplex
    A communications system that can transmit in only a single direction at a time. Half duplex is abbreviated HD.
  • Half Power Point
    The value on either the leading or trailing edge of a laser pulse at which the power is one-half of...
  • Halogen
    A term used to identify any of the four elements: chlorine, fluorine, bromine and iodine, grouped together because their chemical properties...
  • Handshaking
    An exchange of predetermined signals for purposes of control when a connection is established between two data sets. A preliminary procedure,...
  • Hard Clad Silica Fiber
    A type of optical fiber in which a silica core is surrounded by a hard polymer or similar material much...
  • Hard Sheath Cable
    Cable or wire contained within a continuous inner or outer metallic sheath.
  • Harmonic Distortion
    Interference resulting from some type of harmonic signal, measured in decibels (dB).
  • Harmonic Frequency
    A frequency that appears as the result of a strong signal at a lower frequency.
  • Harmonic Mode Locking
    Pulse trains with high pulse repetition rate are sometimes obtained with harmonic mode locking, where multiple ultrashort pulses are circulating...
  • HDSL
    An abbreviation for high-bit-rate digital subscriber loop.
  • HDTV
    An abbreviation for high-definition TV.
  • Head End
    1) A central control device required within some LAN and MAN systems to provide such centralized functions as remodulation, retiming,...
  • Header
    That part of a message, at the beginning, which contains destination, address, source address, message numbering, and possible other information. It...
  • Heat Sink
    A substance or device used to dissipate or absorb unwanted heat, as from a manufacturing process (or, with lasers, from...
  • Helium Neon Laser
    The most commonly used gas laser. The HeNe laser has an emission that is determined by neon atoms by virtue...
  • Hertz HZ
    Unit of frequency in the International System of Units (SI), abbreviated Hz Cycles per second used to measure the repetition...
  • HFC Network
    A telecommunication technology in which optical fiber and coaxial cable are used in different sections of the network to carry...
  • Hierarchy
    A set of transmission speeds arranged to multiplex signals at successively higher data rates.
  • HIFPI
    High performance parallel Interface as defined by ANSIX3T9.3 document.
  • High density connector
    A connector having its pins arranged close together without compromising system performance.
  • High Harmonic Generation
    When a very intense laser pulse, usually generated with a mode-locked laser and a regenerative amplifier (typically with chirped-pulse amplification),...
  • High Loss Fiber
    Optical fiber in which the attenuation exceeds the normally acceptable level for long-haul or data communications use.
  • High Power Laser
    May be several vastly different power levels, depending upon applications. For fiber test equipment, high-power pulse lasers typically range from 60mW...
  • Higher Order Solitons
    A higher-order soliton is a soliton pulse the energy of which is higher than that of a fundamental soliton by...
  • HIPPI
    Abbreviation for high performance parallel interface as defined by the ANSI X3T9.3 document, a standard technology for physically connecting devices...
  • Hockey Puck
    A polishing fixture used to facilitate the manual finishing of the endfaces of certain types of optical fiber connectors.
  • Hologram
    An interference pattern that is recorded on a high resolution plate. The two interfering beams formed by a coherent beam from...
  • Homogeneous Broadening
    Homogeneous broadening is an increase of the linewidth of an atomic transition caused by effects which equally affect different radiating...
  • Homogeneous Cladding
    In an optical fiber, a cladding in which the nominal refractive index is constant throughout.
  • Homogeneous Saturation
    If a strong light beam is amplified in a gain medium, the gain can be saturated. This saturation is called...
  • Horizontal Cabling
    The portion of telecommunications cabling that provides connectivity between the horizontal cross-connect and the work-area telecommunications outlet. The horizontal cabling...
  • Horizontal Cross Connect
    A cross-connect of horizontal cabling to other cabling, e.g., horizontal, backbone equipment.
  • Hot Plate
    Heat source used to produce a mirror finish on the end of a plastic fiber optic cable.
  • HSPN
    High Speed Plastic Network- a program funded by the US Government to promote plastic fiber optic cabling components and applications.
  • Hub
    Hubs act as the center of a "star" topology. They have between 4 and 20+ ports. Internally, hubs are "dumb"...
  • Hybrid Cables
    A cable design to meet many requirements. Most commonly, hybrid cables will contain a mixture of twisted-pair and coaxial, or...
  • Hybrid Fiber Coax HFC
    The use of fiber to distribute cable-television signals to nodes, which in turn distribute them to homes over coaxial...
  • Hybrid Mode
    A mode consisting of components of both electrical and magnetic field vectors in the direction of propagation. Note: In fiber...
  • Hybrid Network
    A LAN with a mixture of topologies and access methods. For example, a network that includes both a token ring and...
  • Hybrid Optical Integrated Circuit
    Device in which the various circuit elements are fabricated in different substrate materials and then appropriately joined together so that...
  • Hydrogen Losses
    Increases in fiber connector attenuation that occur when hydrogen diffuses into the glass matrix and absorbs some light.
  • Hydroxyl Ion Absorption
    In optical fibers, the absorption of electromagnetic waves, including the near-infrared, due to the presence of trapped hydroxyl ions remaining...
  • Hyper Raman Scattering
    Hyper Raman scattering is a modified version of Raman scattering, where the scattered light occurs at frequencies somewhat lower than...

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