Fiber Optic Glossary

• Packet
  A technique used to break large quantities of data into small groups, or packets, to facilitate transmission with very few...
• Packet Format
  The exact order and size of the various control and information fields of a packet, including header, address, and data...
• Packet Switch
  A switch that moves data packets from multiple transmissions and provide for efficient sharing of communication facilities.
• Packing fraction
  The fraction of the area of an optical fiber bundle surface that is actual core area.
• 
  Panda Fiber
  Panda is a common style of PM fiber, using round and symetrical stress rods on either side of the core...
• Parabolic Profile
  In an optical fiber, a power-law index profile with the profile parameter, g, equal to. Synonym: quadratic profile.
• Parabolic Pulses
  Pulses with a parabolic intensity profile.
• Parametric Amplification
  A process of optical amplification based on a parametric nonlinearity and a pump wave.
• Parametric Fluorescence
  Light emitted by a parametric amplifier without signal or input inputs.
• Parametric Nonlinearities
  Instantaneous optical nonlinearities based on the χ(2) or χ(3) nonlinear tensor of a transparent medium.
• Parasitic Lasing
  Unwanted laser operation in a laser or amplifier device.
• Paraxial Approximation
  A frequently used approximation, essentially assuming small angular deviations of the propagation directions from some beam axis.
• Paraxial Rays
  Rays which are nearly parallel with the optical axis.
• Parity Bit
  An additional bit added to a group of bits, typically to a 7-bit character. That additional parity bit means that...
• Partitioning
  Splitting up the data in some way. Ideally, the partitioning is dictated by the nature of the data and typical...
• Passband
  The region of usable frequency in electronics or wavelength in optics.
• Passive Branching Device
  A device which divides an optical input into two or more optical inputs.
• Passive Mode Locking
  A technique of mode locking based on a saturable absorber inside the laser resonator.
• Passive Optical Component
  A device that responds to incident light but does not generate light.
• Passive Star Coupler
  Couples one or more input optical signals coming from fiber optic cables to one or more output fiber optic cables...
• Patch Cord
  A patch cord is a fiber optic cable used to attach one device to another for signal routing.
• Patch Panel
  Distribution area to rearrange fiber optic cable connections and circuits. A simple patch panel is a metal frame. One side...
• Pathological Test Code
  A special test pattern used with DTV and HDTV signals to create the longest strings of zeros and ones over...
• PBX
  An abbreviation for private branch exchange.
• 
  PC Physical Contact
  PC (Physical Contact) is the point at which the surface of one glass surface meets another in order for light...
• PCM
  Pulse-Coded Modulation.
• PCS
  Plastic-Clad Silica.
• PDCR
  An abbreviation for polarization-dependent coupling ratio.
• PE
  Abbreviation used to denote polyethylene.A type of plastic material used to make cable jacketing.
• Peak Power
  Maximum optical power of a pulse.
• Peak Wavelength
  The wavelength at which the optical power of a source is at maximum.
• Periodic Poling
  A technique for achieving quasi-phase matching of nonlinear interactions in a transparent crystal material. It involves a process which generates...
• Peripheral Device
  A piece of computer hardware such as a disk drive, printer, or modem used in conjunction with a computer and...
• Phase Constant
  The imaginary part of the axial propagation constant for a particular mode, usually expressed in radians per unit length.
• Phase Matching
  A group of techniques for achieving efficient nonlinear interactions in a medium.
• Phase Matching Bandwidth
  Width of an optical frequency range in which some process can be efficient due to more or less precise phase...
• Phase Modulators
  Devices for manipulating the phase of a laser beam.
• Phase Noise
  Noise of the optical phase of a beam or of an electric signal.
• Phase Shift Method for Distance Measurements
  A technique for measuring distances that uses a laser beam with sinusoidally modulated optical power being sent to a...
• Phase Term
  In the propagation of an electromagnetic wave in a uniform waveguide, such as an optical fiber or metal waveguide, the...
• Phase Velocity
  The velocity with which phase fronts propagate in a medium.
• Phonons
  Quantized microscopic vibrations in solid media.
• Phosphorescence
  A luminescence which lasts for some time after excitation of a medium.
• Photoconductive Sampling
  A technique of optical sampling relying on photoconductive switches.
• Photoconductive Switches
  Electric switches controlled by light via photo-induced conductivity.
• Photoconductivity
  The conductivity increase exhibited by some nonmetallic materials resulting from the free carriers generated when photon energy is absorbed in...
• Photocurrent
  The current that flows through a photosensitive device as the result of exposure to radiant power.
• Photodarkening
  The phenomenon that the optical power losses in a medium can grow when the medium is irradiated with light at...
• Photodetectors
  Devices used for the detection of light.
• Photodiode
  A semiconductor that converts light to an electrical signal, used in fiber optic receivers.
• Photodiodes
  Semiconductor devices with a p-n or p–i–n structure for the detection of light.
• Photoluminescence
  Emission of light which is caused by the irradiation of a material with other light. The term embraces both fluorescence...
• Photomultipliers
  Photodetection devices based on the photoelectric effect and charge multiplication by secondary emission.
• Photon Counting
  Photodetection at low light levels where single photon absorption events are counted.
• Photonic Bandgap Fibers
  A special type of photonic crystal fibers, relying on photonic bandgaps.
• Photonic Crystal Fibers
  Optical fibers with a built-in microstructure, in most cases consisting of small air holes in glass.
• Photonic Integrated Circuits
  Integrated circuits with optical functions.
• Photonics
  The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The...
• Photons
  Quanta of light energy.
• Photovoltaic Effect
  Production of a voltage difference across a p-n junction resulting from the absorption of photon energy. The voltage difference is...
• PHY
  Physical Layer Device. The name used for a transceiver in Fast Ethernet and Gigabit Ethernet systems.
• Physical Address
  The 48-bit MAC address assigned to a station interface, identifying that station on the network.
• Physical Contact (PC)
  Connectors aligned and mated so that no air gaps exist between them. Positive contact between fibers exist. Also see Connector...
• Physical Layer
  Layer one of the OSI reference model, it encodes, modulates and transmits data across physical links on the network. It also...
• Picosecond Lasers
  Lasers emitting pulses with picosecond durations.
• Pigtail
  A short length of fiber attached to a fiber optic component such as a laser or coupler.
• PIN
  Abbreviation for positive intrinsic negative photodiode.
• Pin contact
  A “male” contact with the engagement end that enters into the socket contact.
• PIN Photodiode
  A diode with a large intrinsic region sandwiched between p-doped and n-doped semiconducting regions. Photons in this region create electron...
• Pistoning
  The movement of a fiber optic cable axially in and out of a ferrule end, often caused by changes in...
• Planar Waveguides
  Waveguide structures guiding light only in one dimension.
• Plastic Clad Silica PCS Fiber
  A fiber made with a glass core and plastic cladding.
• Plastic Fiber
  An optical fiber having a plastic core and plastic cladding.
• Plastic Jackets
  The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to glass-clad...
• Plastic Optical Fiber POF
  An optical fiber made of plastic. In large-diameter fibers, 96% of the cross section is the core that allows the...
• Plastic-Clad Silica Fiber
  An optical fiber having a glass core and plastic cladding.
• Plating
  The overlaying of a thin coating of metal on connector shells and contacts to prevent corrosion, improve conductivity or provide...
• Plenum
  Plenum is the air-handling space such as that found above drop-ceiling tiles or in raised floors. Also, plenum is a...
• Plenum Cable
  Cable approved by Underwriters Laboratories for installation in plenums without the need for conduit because the insulation and jacket compounds...
• Plesiochronous Digital Hierarchy
  The North American Digital Hierarchy of time-division multiplexing rates.
• PMD
  An abbreviation for polarization mode dispersion.
• 
  PMD Polarization Mode Dispersion
  PMD is an effect where an electric field's direction, or polarization, splits into two components that propagate at different speeds,...
• PMDC
  An abbreviation for polarization mode dispersion compensator.
• PNDC
  Pacific Northwest Defense Coalition
• Pockels Cells
  Electro-optic devices used for building modulators.
• Pockels Effect
  The phenomenon that the refractive index of a medium exhibits a modification which is proportional to the strength of an...
• POF
  An abbreviation for plastic optical fiber.
• Point to Point Transmission
  Carrying a communication signal between two locations without branching to other locations.
• Point-to-Point
  A connection established between two specific locations, as between two buildings.
• Polarization
  With respect to light radiation, the restriction of the vibrations of the magnetic or electric field vector to a single...
• Polarization Dependent Loss
  In passive optical components, loss that varies as the polarization state of the propagating wave changes. Expressed as the difference...
• Polarization Maintaining Optical Fiber
  An optical fiber in which the polarization planes of lightwaves launched into the fiber are maintained during propagation with little...
• Polarization Mode Dispersion
  Pulse spreading in a single mode fiber which happens because of the different group velocities for each of the two...
• Polarization of Laser Emission
  Direction of the electric field oscillation of a laser beam.
• Polarization Preserving Fiber PPF
  Single-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its...
• Polarization Stability
  The variation in insertion loss as the polarization state of the input light is varied.
• Polarization Waves
  Patterns of electric or magnetic polarization of a medium which are usually caused by light waves.
• Polishing
  The optical process, following grinding, that puts a highly finished, smooth and apparently amorphous surface on a lens or a...
• Polishing and Abrasive Material
  Any of the numerous powders used for grinding and polishing glass, crystal or metal, the chief material being emery and...
• Polishing Jig
  In fiber optics, a device used to polish a biconic plug to a specified length and surface finish. Also called...

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