Fiber Optic Glossary : R


  • Rabi Oscillations
    Oscillations of level populations under the influence of an incident light field.
  • Radiant Energy
    Energy traveling as wave motion, specifically, the energy of electromagnetic waves such as light, X-rays, radio, or gamma rays.
  • Radiant Flux
    The rate of emission or transmission of radiant energy.
  • Radiant Power
    The time rate of flow of radiant energy, expressed in watts.
  • Radiation
    The emission and/or propagation of energy through space or through a medium in the form of either waves or corpuscular...
  • Radiation Angle
    In fiber optics, half the vertex angle of the cone of light emitted at the exit face of an optical...
  • Radiation Balanced Lasers
    Lasers where the heat generation in the gain medium is compensated by optical refrigeration in the same medium.
  • Radiation Hardened Fiber
    An optical fiber made with core and cladding materials that recover, within a specified period of time, a specified percentage...
  • Radiation Mode
    For an optical fiber, an unbound mode.
  • Radiation Pattern
    The variation of the field intensity of an antenna as an angular function with respect to the axis.
  • Radiative Lifetime
    Lifetime of an electronic state in the hypothetical situation where only radiative processes depopulate that level.
  • Radiometer
    An instrument, distinct from a photometer, to measure power of electromagnetic radiation.
  • Radiometry
    The science of radiation measurement.
  • Radius Ferrule
    The ferrule of the connector has a dome tip which allows the fiber face to make physical contact with the...
  • Raman Amplifiers
    Amplifiers based on Raman gain, which results from the effect of stimulated Raman scattering.
  • Raman Gain
    Optical gain arising from stimulated Raman scattering.
  • Raman Lasers
    Lasers based on Raman gain rather than on laser gain from stimulated emission.
  • Raman Scattering
    Nonlinear scattering process involving optical phonons.
  • Raman Spectroscopy
    The field of spectroscopy that uses optical frequency shifts and intensity changes in the Raman chromophore(s) in test samples produced...
  • Random Jitter
    A phenomenon due to thermal noise which may be modeled as a Gaussian process. The peak-to-peak value of random jitter...
  • Range
    Wire range – the acceptable sizes of wires accommodated by a particular contact wire barrel size. Also the acceptable diameter...
  • Rare Earth Doped Fiber
    An optical fiber in which ions of a rare-earth element, such as neodymium, erbium or holmium, have been incorporated into...
  • Rare Earth Doped Gain Media
    Laser gain media which are doped with rare-earth ions.
  • Rare Earth Type Glass
    Optical glasses containing the oxides of rare earths such as lanthanum to impart a very high refractive index combined with...
  • Rate Equation Modeling
    A method of modeling the dynamics of laser gain media.
  • Ray
    A geometric representation of a light path through an optical medium.
  • Rayleigh Length
    The distance from a beam waist where the mode radius increased by a factor square root of 2.
  • Rayleigh Scattering
    Scattering by very small particles compared to the wavelength of the radiation being considered. A feature of Rayleigh scattering is...
  • RB
    Rhodamine B dopant.
  • RBOC
    An abbreviation for regional Bell operating company.
  • Rear accessories
    Referred to as backshells, they are mechanical devices that screw onto the accessory threads on the rear of the connector....
  • Rear mounted
    Back mounted – a connector with its mounting flange mounted inside of a panel or box.
  • Rear release
    A term indicating the direction the contact removal tool must enter the connector to allow removal of the contacts. On...
  • Receive Cable
    A known good fiber optic jumper cable attached to a power meter used as a reference cable for loss testing....
  • Receiver
    An electronic package which converts optical signals to electrical signals.
  • Receiver Overload
    The maximum acceptable value of the received average power at point R for a 10-12 bit error ratio.
  • Receiver RCVR
    A detector and signal demodulator used in optical communications systems to receive a signal and often to translate it into...
  • Receiver Sensitivity
    The optical power required by a receiver for low error signal transmission. In the case of digital signal transmission, the...
  • Receptacle
    The fixed or mounted member of a mated pair of connectors designed to be mounted to a box, panel or...
  • Reciprocity Method
    A spectroscopic method which is often used for obtaining the scaling of emission spectra of laser gain media.
  • Recirculating Fiber Loops
    Fiber loops in which light can circulate many times.
  • Recoil Limit
    A lower limit for the temperature which can be reached with some laser cooling techniques.
  • Recombination
    Combination of an electron and a hole in a semiconductor that releases energy leading to light emission.
  • Rectilinear Propagation
    Straight line travel. This denotes the fact that light travels in a straight line when traveling through a medium with...
  • Red Lasers
    Lasers emitting red light.
  • Reference Cavities
    Optical cavities serving as a kind of frequency reference.
  • Reference Surface
    In optical-fiber technology, that surface of an optical fiber that is used to contact the transverse-alignment elements of a component...
  • Reflectance
    The ratio of reflected power to incident power. Note: In optics, frequently expressed as optical density or as a percent; in...
  • Reflection
    The abrupt change in direction of a light beam at an interface between two dissimilar media so that the light...
  • Reflection Loss
    At a discontinuity or impedance mismatch, e.g., in a transmission line, the ratio of the incident power to the reflected...
  • Reflectometer
    An instrument for measuring the reflectance of a surface. In telecommunication, an optical time domain reflectometer (OTDR) is an optoelectronic...
  • Refracted Ray
    A ray that undergoes a change of velocity, or in the general case, both velocity and direction, as a result...
  • Refraction
    The changing of direction of a lightwave in passing through a boundary between two dissimilar media, or in a graded-index...
  • Refractive Index
    A property of optical materials that relates to the velocity of light in the material.
  • Refractive Index Profile
    The description of the refractive index along a fiber diameter.
  • Refractometer
    An instrument used to measure the refractive index of solids and liquids. Several types exist, the most common being the...
  • Refractometry
    The method used to determine the refractive index of a given substance.
  • Regenerative Amplifiers
    Optical amplifiers with a resonator in which a light pulse can do multiple round trips before being coupled out.
  • Regenerative Repeater
    A repeater designed for digital transmission in which digital signals are amplified, reshaped, retimed, and retransmitted.
  • Regenerator
    A receiver-transmitter device that detects a weak signal, converts it to its original state, and then transmits is as a...
  • Relative Index
    The ratio of the velocities of light in two adjacent media, neither of which is air.
  • Relative Intensity Noise
    Noise of the optical intensity normalized to its average value.
  • Relative Refractive Index
    The quantity equal to the refractive index of one medium divided by that of a second medium.
  • Relaxation Oscillations
    Small mutually coupled oscillations of the laser power and laser gain around their steady-state values.
  • Remote Station
    Any piece of equipment attached to a LAN by a telephone company supplied link. Technically, that includes all devices that aren't...
  • Removal tool
    A device used to remove contacts from a connector.
  • Repeater
    A receiver-transmitter device that detects a weak signal and boosts its power for continued transmission. This device is also called...
  • Repeaters and Regenerators
    A device that receives a fiber optic signal and regenerates it for retransmission, used in very long fiber optic...
  • Repetitively Pulsed Laser
    A pulsed laser that emits a recurring pulsed output. Frequency of the pulses emitted is known as pulsed recurrence frequency...
  • Replaceable Element Attenuator
    An attenuator in which levels of attenuation are changed by exchanging elements, each of which have a fixed value of...
  • Request to Send
    In a communications network, a signal from a remote receiver to a transmitter for data to be sent to that...
  • Residual Loss
    The loss of the attenuator at the minimum setting of the attenuator.
  • Resonant Frequency Doubling
    Frequency doubling with a nonlinear crystal placed in a resonant enhancement cavity.
  • Resonator
    A volume, bounded at least in part by highly reflecting surfaces, in which light of particularly discrete frequencies can set...
  • Resonator Design
    The description of the optical components from which an optical resonator is made and their exact arrangement.
  • Resonator Modes
    Modes of an optical or microwave resonator.
  • Responsivity
    Photocurrent per unit optical power incident on a photodetector.
  • Return Path
    A communications connection that carries signals from the subscriber back to the operator. The return path allows for interactive television...
  • Return to Zero
    A digital coding scheme where signal level is low for a 0 bit and high for a 1 bit during...
  • RFI
    Radio frequency interference
  • RGB Sources
    Source of red, green and blue light which is usually provided in the form laser beams.
  • Ribbon Cable
    A cable that incorporates multiple fibers, jacketed side by side in a ribbonlike form (with parallel elements).
  • Ring Lasers
    Lasers with a ring resonator. In contrast to a standing-wave laser resonator, such a ring resonator allows for two different...
  • Ring Network
    A network topology in which terminals are connected in a point-to-point serial fashion in an unbroken circular configuration.
  • Ring Topology
    A system of local area networking in which each node or station is connected to two others, ultimately forming a...
  • Rip Cord
    Of an optical cable, a parallel cord of strong yarn that is situated under the jacket(s) of the cable for...
  • Rise Time
    The time for the leading edge of a pulse to increase from 10% to 90% of its peak value.
  • Riser
    Riser is the vertical telecommunications infrastructure in commercial buildings. Copper or fiber telecommunications cable extends vertically from the Main Distribution...
  • RJ 45
    RJ-45 is the 8-conductor version of an RJ-11. It looks like a regular modular phone connector, only it's wider. You...
  • Rod Lasers
    Solid-state lasers with a rod-shaped gain medium.
  • Router
    A device that has enough intelligence to be connect one, or many, devices to other devices. Typically used in Local...
  • Routing
    The dynamic exchange of network interconnection and topology information among the systems on interconnected networks.
  • RS 250C
    An American National Standards Institute recommended standard for video transmission used to evaluate the quality of a received picture quality....
  • Ruby Laser
    Ruby is an aluminum oxide crystal in which some of the aluminum atoms have been replaced with chromium atoms. Chromium gives ruby...

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