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Topic: Equilibrium mode distribution


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In the News (Thu 8 Jan 09)

  
  Definition: equilibrium mode distribution   (Site not responding. Last check: 2007-10-08)
Note 2: After the equilibrium length has been traversed, the numerical aperture of the fiber's output is independent of the numerical aperture of the optical source, i.e., beam, that drives the fiber.
This is because of mode coupling and stripping, primarily by small perturbations in the fiber's geometry which result from the manufacturing and cabling processes.
Note 3: In the ray-optics analogy, the equilibrium mode distribution may be loosely thought of as a condition in which the "outermost rays" in the fiber core are stripped off by such phenomena as microbends, and only the "innermost rays" continue to propagate.
www.its.bldrdoc.gov /fs-1037/dir-014/_2052.htm   (271 words)

  
 Optical mode mixer using fiber optic bundle - Patent 5754716   (Site not responding. Last check: 2007-10-08)
For example, modal equilibrium may be achieved using an optical source with a output modal distribution corresponding to the steady state mode distribution of the fiber of interest.
Thus, by giving the input light beam an angular width equal to the equilibrium distribution numerical aperture of the fiber and adjusting the source spot size on the fiber input face to match the optical power distribution in a cross section of the fiber equilibrium mode equilibrium may be achieved.
Mode mixers based upon non-symmetric fiber cross sections are physically compact yet suffer losses incurred in the conversion of the mode field distributions from circularly symmetric to non-symmetric distributions.
www.freepatentsonline.com /5754716.html   (5720 words)

  
 Equilibrium length - Wikipedia, the free encyclopedia
Equilibrium length For a specific excitation condition, the length of multimode optical fiber necessary to attain equilibrium mode distribution.
Equilibrium length is sometimes used to refer to the longest such length, as would result from a worst-case, but undefined, excitation.
Synonyms equilibrium coupling length, equilibrium mode distribution length.
en.wikipedia.org /wiki/Equilibrium_length   (82 words)

  
 [No title]
B.3.2.3 Cladding mode stripper A suitable cladding mode stripper shall be used to remove the optical power propagating in the cladding, and to ensure that all the leaky modes are stripped away from the fibre.
B.2.1.2.1 Cladding mode stripper A cladding mode stripper encourages the conversion of cladding modes to radiation modes; as a result, cladding modes are stripped from the fibre.
B.2.1.2.2 Mode filter The mode filter is a device used to select, reject or attenu- ate a certain number of modes, and should assure the establishment of a mode distribution close to the EMD.
www.nmedia.net /ccitt/1988/3_3/3_3_02.txt   (7318 words)

  
 Glossary of Terms: Fiber Optic Interconnection Solutions: Tyco Electronics   (Site not responding. Last check: 2007-10-08)
Cladding mode A mode confined to the cladding; a light ray that propagates in the cladding.
Equilibrium mode distribution The steady modal state of a multimode fiber in which the relative power distribution among modes is independent of fiber length.
Mode In guided-wave propagation, such as through a waveguide or optical fiber, a distribution of electromagnetic energy that satisfies Maxwell's equations and boundary conditions.
www.tycoelectronics.com /fiberoptics/glossary.stm   (2631 words)

  
 Joseph Story: Distribution of Powers
As it is tacitly assumed, as a fundamental basis in the constitution of the United States, in the distribution of its powers, it may be worth inquiry, what is the true nature, object, and extent of the maxim, and of the reasoning, by which it is supported.
The latter, by the mode of their appointment, as well as by the nature and permanency of it, are too far removed from the people to share much in their professions.
It was said, that the several departments of power were distributed, and blended in such a manner, as at once to destroy all symmetry and beauty of form; and to expose some of the essential parts of the edifice to the danger of being crushed by the disproportionate weight of the other parts.
www.lonang.com /exlibris/story/sto-307.htm   (5764 words)

  
 Connector Loss Tests
The standard recommended core mode filter for smaller fibers is 12.5-mm diameter mandrel around which the fiber is wrapped five times under zero tensions.
It is necessary to use to remove these modes, a cladding mode stripper, which incorporates a fiber, stripped of its cladding buffer, and covered in Corona Dope (available from TV repair suppliers) or some other liquid with a refractive index higher than the cladding.
Long-launch or receive conditions mean that equilibrium mode distribution (EMD), illustrated in Figure 11, exists in the fiber.
www.fiber-optics.info /articles/connectorloss.htm   (1685 words)

  
 [No title]
A mode confined to the cladding; a light ray that propagates in the cladding.
Three major types are: (a) mode dispersion caused by differential optical path lengths in a multimode fiber; (b) material dispersion caused by a differential delay of various wavelengths of light in a waveguide material; and (c) waveguide dispersion caused by light traveling in both the core and cladding materials in single­mode fibers.
Due to this mode mixing, the bandwidth of long multimode fibers is greater than the value obtained by linear extrapolation from measurements on shod fibers.
www.com.itd.umich.edu /cabling/fib-glos.html   (4287 words)

  
 Antiquity of Man Mode 3 technologies
The key to the technological mode classification is that it is normative and progressive; nominative in the sense that it describes the predominant method of stone tool productiqn and, in particular, of core reduction.
Mode 4 technologies expanded along the southern Siberian corridor, and reached, in a diffuse form (as was the case with Mode 2) northern China, Korea and Japan, where they met with Mode 1-2 towards the end of the Pleistocene.
The Mode 3 hypothesis accounts for the extended temporal spread of the events associated with the evolution of modern humans, and provides a framework for interpreting these within their specific regional contexts rather than as lagged indications of universal human characteristics.
www.antiquityofman.com /mode3technologies.html   (17847 words)

  
 Fiber Optic Glossary: M
In a fiber, mode coupling occurs until equilibrium mode distribution (EMD) is reached.
Mode Evolution: The dynamic process a multilongitudinal mode laser undergoes whereby the changing distribution of power among the modes creates a continuously changing envelope of the laser's spectrum.
Mode Field Diameter (MFD): A measure of distribution of optical power intensity across the end face of a single-mode fiber.
www.fiber-optics.info /glossary-m.htm   (1150 words)

  
 The Factor Distribution of Income   (Site not responding. Last check: 2007-10-08)
The mode of analysis is essentially derived from a Hobbesian framework; a framework of amoral individual calculating rationality.
If rents have indeed been skewing the distribution of income in favour of elite private interests, whereas contributions to growth have been coming from increasingly disadvantaged labour and public domain interests, then it is likely that the under-rewarded factors will be unable to maintain the growth of their contributions.
One of the main weaknesses of this mode of analysis is the idea that additions to rents, profits or wages would be spent in a way determined by their source.
keithrankin.co.nz /krnkn96_Auck_pap.html   (7740 words)

  
 Kingfisher Application Note: Modal Distribution & Noise in Multimode Fiber
The paths (or modes) nearest to the axis of the core are called low order modes, and the paths with the most deviation are called high order modes.
It is the high order modes that get attenuated (lost), and as they do so, light gradually transfers from the lower to the higher order modes.
This condition is called an equilibrium mode distribution, and is the condition traditionally used to measure individual multimode components.
www.kingfisher.com.au /appnotes/A04.htm   (1122 words)

  
 Punctuated Equilibria
This pattern includes the characteristically abrupt appearance of new species, the relative stability of morphology in widespread species, the distribution of transitional fossils when those are found, the apparent differences in morphology between ancestral and daughter species, and the pattern of extinction of species.
Paleospecies, then, have to be recognized as species from morphology alone, where the available morphological characters are drawn from a skewed distribution, the pattern of fossilization is skewed, and the geographic correlates of fossilization are limited in extent.
Second, the mode of speciation most often seen is also identified from modern populations.
www.talkorigins.org /faqs/punc-eq.html   (3019 words)

  
 Fiber Optic Glossary: E   (Site not responding. Last check: 2007-10-08)
Light is not distributed in the fiber core uniformly.
Rather, it follows a distribution that typically peaks in the center of the core and then tails off near the core-cladding interface.
in which the relative power distribution among modes is independent of fiber length.
www.mrfiber.com /glossary-e.htm   (465 words)

  
 Mandrel wrapping
Mandrel wrapping: In multimode fiber optics, a technique used to modify the modal distribution[?] of a propagating optical signal.
It has application in optical transmission performance tests, to simulate, i.e., establish, equilibrium mode distribution[?] in a launch fiber (a fiber used to inject a test signal in another fiber that is under test).
If the launch fiber is fully filled ahead of the mandrel wrap, the higher-order modes will be stripped off, leaving only lower-order modes.
www.ebroadcast.com.au /lookup/encyclopedia/ma/Mandrel_wrapping.html   (158 words)

  
 Fiber optic mode conditioner - Patent 4998792
A method of conditioning the mode distribution of light in a fiber optic conductor comprising the steps of directing said light through a low-pass mode filter to eliminate the higher-order modes from said light and directing said mode-filtered light through a mode scrambler to redistribute the remaining modes of said mode-filtered light.
Apparatus for conditioning the mode distribution of light in a fiber optic conductor comprising a low-pass mode filter for eliminating the higher-order modes from said light, a mode scrambler for redistributing the lower-order modes of said light into higher-order modes, and means for successively directing said light through said mode filter and said mode scrambler.
The spatial and angular light energy distribution of a multimode fiber varies considerably depending on fiber core diameter, numerical aperture (NA), the length of the fiber and the source launch conditions.
www.freepatentsonline.com /4998792.html   (2308 words)

  
 Bandwidth Market, Ltd   (Site not responding. Last check: 2007-10-08)
mode [identification friend or foe]:  The number or letter referring to the specific pulse spacing of the signals transmitted by an interrogator.
mode partition noise:  In an optical communications link, phase jitter of the signal caused by the combined effects of mode hopping in the optical source and intramodal distortion in the fiber.
mode volume:  The number of bound modes that an optical fiber is capable of supporting.
www.telequipment.com /resources/glossary/M4.html   (2334 words)

  
 Vinam Canada Inc | Fiber Optic Accessories | Patch Cords | Connectors | Enclosures
Equilibrium length — Applies to multimode fiber: the length required to produce equilibrium mode distribution.
Leaky Modes — In the boundary region between the guided modes of an optical waveguide and the light waves, which are not capable of propagation, there are so-called leaky modes which are not guided but are capable of limited propagation with increased attenuation.
Mode Field Diameter — The diameter of the one mode of light propagating in a single-mode fiber.
www.vinam.com /glossary.php   (7193 words)

  
 OPTEK Technologies - Fiber Optic Glossary
Attenuation caused by high-order modes radiating from the outside of a fiber optic waveguide which occur when the fiber is bent around a small radius.
Communications system that distributes broadcast and non-broadcast signals as well as a multiplicity of satellite signals, original programming and other signals by means of a coaxial cable and/or optical fiber.
A mode confirmed to the cladding; a light ray that propagates in the cladding.
www.optekinc.com /products/fiber_glossary.asp   (7172 words)

  
 Lognormal Distribution
Lognormal distributions (with two parameters) have a central role in human and ecological risk assessment for at least three reasons.
The lognormal distribution is used to model continuous random quantities when the distribution is believed to be skewed, such as certain income and lifetime variables.
The median is exp(μ) and the mode is exp(μ – σ
www.mlahanas.de /Math/Lognormal.htm   (1439 words)

  
 Water mass distribution and spreading
In the following we present the large-scale distribution of the AAIW in the South Atlantic and discuss its sources and its circulation pattern.
The resulting distribution of potential vorticity of the AAIW layer is shown in Fig.
The rather homogeneous potential vorticity distribution in the gyre indicates that the recirculation dominates the spreading of the AAIW, whereas the influence of the water inputs from the Pacific and Indian Oceans is relatively small.
www.aoml.noaa.gov /phod/docs/schmidjpo2000/node3.html   (1838 words)

  
 Atmospheric effects   (Site not responding. Last check: 2007-10-08)
Note: In multimode fibres, the term equilibrium numerical aperture is sometimes used.
ray emerging from a fibre in which equilibrium mode distribution has been established.
Colloquially, the sine of the radiation or acceptance angle of an optical fibre, multiplied by the refractive index of the material in contact with the exit or entrance face.
www.physics.mq.edu.au /~qap/PHYS278/PHYS278AA_LEC6_files/slide0022.htm   (171 words)

  
 Glossary
The diameter of a single mode fiber core is generally less than 10 microns; multimode fiber core is typically 50, 62.5, or 100 microns.
Three types are: a) mode (modal) dispersion caused by differential optical path lengths in a multimode fiber; b) material dispersion caused by a differential delay of various wavelengths of light in a fiber; and c) waveguide dispersion caused by light traveling in both the core and cladding materials in single mode fibers.
Because the mode field diameter is greater than the core diameter, MFD replaces core diameter as a practical parameter.
www.exsellsales.com /html/fiberfacts2.html   (4636 words)

  
 Normal Mode Approach   (Site not responding. Last check: 2007-10-08)
The justification for linearising is the observation that the bulk plasma remains essentially static whilst experiencing only small magnitude perturbations when examined over timescales that are long compared with those associated with the small scale dynamics.
One approach in studying linear stability and waves is to reformulate equation (2.3) as a normal mode problem.
The addition of a fast particle distribution upon a steady-state background plasma may perturb the stable eigenvalues of the system so that weakly growing or decaying oscillatory waves are obtained as illustrated in Fig.
www.ipp.mpg.de /~Simon.Pinches/thesis/node12.html   (348 words)

  
 Bandwidth Market, Ltd   (Site not responding. Last check: 2007-10-08)
  Note 2: After the equilibrium length has been traversed, the numerical aperture of the fiber’s output is independent of the numerical aperture of the optical source, i.e., beam, that drives the fiber.
  This is because of mode coupling and stripping, primarily by small perturbations in the fiber’s geometry which result from the manufacturing and cabling processes.
  Note 3: In the ray-optics analogy, the equilibrium mode distribution may be loosely thought of as a condition in which the “outermost rays” in the fiber core are stripped off by such phenomena as microbends, and only the “innermost rays” continue to propagate.
www.telequipment.com /resources/glossary/E5.html   (1705 words)

  
 E&CE 477 Lab #1 - ATTENUATION MEASUREMENT
The number of modes propagating in the fiber is significantly smaller than the number of modes generated by the source at the launching end of the fiber, therefore, only a portion of light can be coupled into the fiber.
It is important to have equilibrium mode distribution, EMD, in the fiber before measuring the fiber loss.
The source is always positioned some distance from the fiber end such that for any specific (theta), the edges of the light cone coincide with the fiber edges as shown in the figure.
ece.uwaterloo.ca /~ece477/Labs/Lab1.html   (1863 words)

  
 * Equilibrium - (Telecom): Definition
equilibrium length: For a specific excitation condition, the length of necessary to attain.
() Note: Equilibrium length is sometimes used to refer to the longest such length,...
This phone is really great since it stands to an equilibrium with its price, and can be the best affordable gadget for a college student because of its recording function...
en.mimi.hu /telecom/equilibrium.html   (66 words)

  
 All You Need to Know about Punctuated Equilibrium (almost)
Darwinian "gradualness" has little to do with the rate or tempo of evolution; it is a mode of change that is dependent on population phenomena.
Eldredge and Gould thought of PE as being adequately explained by, and being a direct consequence of, allopatric speciation theory, which in their eyes was the dominant mainstream theory of speciation in current evolutionary biology.
Punctuated equilibrium is a valid scientific hypothesis, and when geological strata are complete with good temporal resolution and the fossil record is well-represented, the hypothesis is testable.
ucsu.colorado.edu /~theobal/PE.html   (3214 words)

  
 Yenra Glossary E
equilibrium length - For a specific excitation condition, the length of multimode optical fiber necessary to attain equilibrium mode distribution.
equilibrium mode distribution - That condition in a multimode fiber wherein after propagation has taken place for a certain distance, called the Aequilibrium length,@ the relative power distribution among modes becomes statistically constant and remains so for the course of further propagation down the fiber.
equilibrium mode simulator - For an optical fiber, a device or optical system used to create an approximation of the equilibrium mode distribution.
www.yenra.com /glossary/e.html   (7917 words)

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