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Topic: Polarization mode dispersion

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	IEC: On-Line Education: WPF: Polarization Mode Dispersion
		Polarization mode dispersion (PMD) occurs when different planes of light inside a fiber travel at slightly different speeds, making it impossible to transmit data reliably at high speeds.
		PMD is the single biggest challenge facing system vendors and carriers as they attempt to deploy 40 Gbps optical networks.
		However, PMD is not just a problem at 40 Gbps; it is also evident in 10 Gbps optical networks as well.
	www.iec.org /online/tutorials/polar_mode (260 words)

	Polarization Mode Dispersion (PMD) (Site not responding. Last check: 2007-10-15)
		Polarization is a property of light that causes it to be broken down into two waves that are 90° out of phase with each other.
		Polarized sunglasses are designed such that they only pass the polarization not associated with reflections, thus most reflected light almost disappears.
		PMD was one of the biggest risk elements associated with the introduction of 10 Gb/s transport speeds and stands as one of the key barriers to the leap to 40 Gb/s.
	www.mrfiber.com /PMD.htm (308 words)

	Polarization mode dispersion - Wikipedia, the free encyclopedia
		Polarization mode dispersion (PMD) is a form of modal dispersion where two different polarizations of light in a waveguide, which normally travel at the same speed, travel at different speeds due to random imperfections and asymmetries, causing random spreading of optical pulses.
		is the PMD parameter of the fiber, typically measured in ps/√km, a measure of the strength and frequency of the imperfections.
		A PMD compensation system is a device which uses a polarization controller to compensate for PMD in fibers.
	en.wikipedia.org /wiki/Polarization_mode_dispersion (671 words)

	Dispersion (optics) - Wikipedia, the free encyclopedia
		The transverse modes for waves confined laterally within a finite waveguide generally have different speeds (and field patterns) depending upon the frequency (that is, on the relative size of the wave, the wavelength, compared the size of the waveguide).
		The overall dispersion of the optical resonator is a major factor in determining the duration of the pulses emitted by the laser.
		In the technical terminology of gemology, dispersion is the difference in the refractive index of a material at the B and G Fraunhofer wavelengths of 686.7 nm and 430.8 nm and is meant to express the degree to which a prism cut from the gemstone shows "fire", or color.
	en.wikipedia.org /wiki/Dispersion_(optics) (1378 words)

	Dispersion- Developer Zone - National Instruments
		Dispersion shifting is done by designing fibers to have large negative waveguide dispersion, which offsets positive material dispersion at wavelengths longer than 1.28 Âµm, shifting the region of low chromatic dispersion near the erbium-fiber amplifier band.
		Thus the characteristic material dispersion is proportional to the second derivative (or, equivalently, to the slope of the slope) of the plot of refractive index versus wavelength, not directly to the slope of the refractive index curve itself.
		Dispersion compensation modules can be added to existing fiber systems to upgrade them for higher-speed transmission or operation in the 1550-nm band, or fiber with different dispersion can be integrated into the transmission paths of new systems to "tailor" overall dispersion properties.
	zone.ni.com /devzone/cda/ph/p/id/64 (4222 words)

	The Effects of Dispersion on High-speed Fiber Optic Data Transmission: Fiber Bandwidth isn't Infinite
		Multimode graded-index fiber improved the situation a bit, but it was single-mode fiber that eliminated severe multimode fiber related dispersion and left only chromatic dispersion and polarization mode dispersion to be dealt with by engineers.
		The expected power penalty due to dispersion is given by a parabolic function of the ratio of symbol rate to dispersion limited bandwidth times a coefficient, “c,” which relates to the roll-off of a raised cosine receiver response.
		For multilongitudinal mode (MLM) laser, usually Fabry-Perot (FP) type, the spectral width is the root-mean-square spectral width, and for single-longitudinal mode (SLM) lasers, usually distributed feedback (DFB) lasers, the spectral width is the width at the 20 dB down points divided by 6.07.
	www.fiber-optics.info /articles/dispersion.htm (2355 words)

	Measurement of polarization-mode dispersion - includes related articles on Jones calculus, the Poincare Sphere, and the ...
		Historically, polarization-mode dispersion, or PMD is the third of a series of dispersive effects in optical fiber.
		Polarization-mode dispersion is a fundamental property of single-mode optical fiber and components in which signal energy at a given wavelength is resolved into two orthogonal polarization modes of slightly different propagation velocity.
		For fibers that exhibit a large degree of coupling of energy between polarization modes, PMD scales with the square root of fiber length and is often specified in picoseconds per root kilometer.
	www.findarticles.com /p/articles/mi_m0HPJ/is_n1_v46/ai_16645505 (879 words)

	Polarization mode dispersion compensation - Patent 6559991
		This comprises a polarisation independent circulator 100 having ports `a`, `b` and `c`, a polarisation beam splitter 101, a pair of optical fibres 102a and 102b provided with chirped Bragg reflection gratings 103a and 103b, and controllable extension means 104 for differentially axially straining the optical fibres 102.
		Another alternative is to substitute a length of polarisation maintaining fibre with a single chirped Bragg reflection grating for the polarisation beam splitter 101 and pair of fibres 102 with their gratings 103, and to bend the polarisation maintaining fibre so as to induce changes in its birefringence beat length.
		The mating faces of the anvils have mating transverse corrugations whose periodicity is matched with the polarisation mode beat length of the fibre 110.
	www.freepatentsonline.com /6559991.html (5599 words)

	Dispersion Compensation (Site not responding. Last check: 2007-10-15)
		Dispersion is a phenomenon that occurs in all types of optical fiber.
		Chromatic dispersion is due to an inherent property of silica fiber.
		Dispersion management refers to the process of designing the fiber and compensating elements in the transmission path to keep the total dispersion to a small number.
	www.mrfiber.com /Dispersion_Compensation.htm (850 words)

	3.2.8 Measurements of Polarization Mode Dispersion in Optical Fibers
		Polarization dispersion arises in single-mode fibers when there is imperfect circular symmetry in the fiber core.
		Among the methods of PMD measurement, the fixed analyzer technique is perhaps the simplest to use.
		A new value for the polarization mode coupling factor of 0.805 (a 2% discrepancy with the old value of 0.824) was found.
	www.itl.nist.gov /div898/pubs/ar/ar1998/node19.html (412 words)

	GAP-Optique Université de Genève
		Reproducibility of the results is given for high and low polarization mode coupling fibers, and the influence of several effects on beatlength measurement precision, such as spatial reflectometer resolution, fiber twist, and the presence of circular birefringence, is discussed.
		This method uses a polarisation optical time-domain reflectometer(P-OTDR), and is based on a measurement of the degree of polarisation of the backscattered light as a function of distance in the fiber.
		Polarisation mode coupling length is obtained from local birefringence and polarisation mode dispersion measurements.
	www.gap-optique.unige.ch /Publications/LookUp.asp?Group=1 (4220 words)

	CD and PMD in Optical Fiber
		This program calculates the effects of chromatic dispersion (CD) and polarization mode dispersion (PMD) on a "10010110" NRZ optical signal through a single mode optical fiber.
		Launching the optical signal into a fiber with some arbitrary initial polarization could result in some of the optical energy propagating along the fast axis and some propagating along the slow axis.
		The polarization properties of an optical fiber are determined by a number of effects, among which are, the shape of the index profile along the fiber, the mechanical stress put on the fiber, and temperature changes along the fiber.
	www.mathcad.com /library/LibraryContent/MathML/fiberdispersion.htm (638 words)

	Polarization Mode Dispersion Application > CMA 5000 Polarization Mode Dispersion Application
		At each measurement, the PMD coefficient and the second order PMD values are automatically computed in order to fully characterize each fiber for maximum data rate operation.
		In addition, with the CMA 5000 PMD application, there is no communication needed between the source and the receiver, thus it is an excellent tool for measuring polarization mode dispersion on installed cables.
		The CMA 5000 PMD application utilizes an easy-to-use touch screen interface, that simplifies utilization and minimizes setup in several ways (for example not requiring input of source data such as the coherence length), thus reducing the cost of training while increasing productivity.
	www.nettest.com /Products/Products/CMA,_,5000,_,Polarization,_,Mode,_,Dispersion,_,Application/Overview.aspx (372 words)

	Polarization Mode Dispersion
		To enable high speed transmission in PMD impaired systems, mitigation measures have to be taken and due to the statistical nature of the fiber’s PMD characteristics adaptive compensation is required.
		An optical PMD compensator consists of a PMD equalizer, a polarization controller and a feedback loop, using a suitable monitor signal.
		The PMD equalizer is a birefringent element of either fixed or variable DGD, while the polarization controller is used to match the axes of the equalizer with the principal axes of the fiber.
	www.om.tu-harburg.de /Forschung/Pmd (437 words)

	Cabling Installation & Maintenance - Polarization Mode Dispersion
		While research on polarization mode dispersion goes on for the next generation networks [2, 3], it is essential to know how PMD influences today's network performance.
		Understanding the causes of PMD, and the advantages and disadvantages of the different measurement methods that are available for field-testing, are key for building reliable and profitable high capacity networks.
		Along with chromatic dispersion (CD), polarization dependent loss (PDL) and loss [4] polarization mode dispersion is an important piece of the puzzle for today's fiber certification.
	cim.pennnet.com /whitepapers/wp.cfm?id=641 (168 words)

	Journal Papers
		Eyal, Y. Li, W.K. Marshall, M. Tur and A. Yariv, Statistical Determination of the length dependence of high-order polarization mode dispersion, Opt.
		Eyal, M. Tur, “A modified Poincare sphere technique for the determination of polarization mode dispersion in the presence of differential loss/gain”.
		Eyal, M. Ben-Artzi, O. Shapiro and M. Tur, "Description of polarization dispersion effects in embedded fiber optic sensors using the principal states of polarization".
	www.eng.tau.ac.il /~avishay/list_of_publications.htm (633 words)

	40 Gb/s Systems and Polarization Mode Dispersion: Technology and Marketing Issues:
		In 2006, we saw some movement in the market, and major conventions in Europe and the U.S. demonstrated a presence of new and established players.
		This report analyzes technological and marketing aspects of 40 Gb/s transmission and associated with such transmission Polarization Mode Dispersion harmful effect.
		The report deals with a number of 40 Gb/s transmission issues, with the major emphasis on Polarization Mode Dispersion problems.
	www.mindbranch.com /products/R606-43.html (241 words)

	Appliance for measuring polarization mode dispersion and corresponding measuring process (US5712704)
		representative of the polarization mode dispersion of the waveguide (2).
		The measuring appliance comprises at least one birefringent element (17) positioned on the interferometer (5), capable of producing an algebraic difference of relative phase shifts in each of the two interference light beams (23, 24) equal to π.
		Appliance for measuring the polarization mode dispersion (PMD) of a waveguide (2) comprising:
	www.delphion.com /details?pn10=US05712704 (340 words)

	e-Prints Soton - Polarization mode dispersion reduction in spun silica holey fibres (Site not responding. Last check: 2007-10-15)
		Polarization mode dispersion reduction in spun silica holey fibres
		Fuochi, M., Hayes, J.R., Petrovich, M.N., Baggett, J.C., Monro, T.M. and Richardson, D.J. Polarization mode dispersion reduction in spun silica holey fibres.
		Measurements of differential group delay (DGD) confirm that significant reductions in polarization mode dispersion (PMD) can be readily achieved using this approach.
	eprints.soton.ac.uk /41708 (342 words)

	Japanese Patent 3664305 B2 - polarization mode dispersion snubber (Site not responding. Last check: 2007-10-15)
		With the polarization mode dispersion compensation instrument which outputs light signal which polarization mode dispersion was controlled at doing compensation as the difference in transmission delay of TE polarization component of this light signal if light signal which has done optical fiber propagation was inputed and TM polarization component became minimum
		With above-mentioned 1 input polarization splitter which parts light signal which was done splitting at optical coupler of 2 outputs to TE polarization component and TM polarization component
		Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g.
	cxp.paterra.com /jppatent3664305.html (358 words)

	Encyclopedia of Laser Physics and Technology - polarization mode dispersion, PMD
		In optical fibers, there is usually some slight difference in the propagation characteristics of light waves with different polarizations – even for fibers which according to the design should have a perfect rotational symmetry and thus no birefringence.
		This effect, resulting from random imperfections or bending of the fibers, can have adverse effects on optical data transmission over long distances at very high data rates, because portions of the transmitted signals in different polarization modes will arrive at slightly different times and thus deteriorate the received signal.
		For achieving the highest possible bit rates, one may have to employ a scheme to implement the compensation of polarization mode dispersion.
	www.rp-photonics.com /polarization_mode_dispersion.html (242 words)

	General Photonics Corporation - Polarization Mode Dispersion Development Platform
		General Photonics Corporation - Polarization Mode Dispersion Development Platform
		The PMD-601 is an integrated, flexible platform for developing PMD related techniques, especially PMD emulation and compensation.
		Up to six individual modules with different functions for PMD effects, including programmable or fixed DGDs, dynamic polarization controllers and a high-speed in-line polarimeter (providing instantaneous DOP information for PMD monitoring), can be configured according to various requirements or applications.
	www.generalphotonics.com /PMD601.htm (135 words)

	Nonlinear propagation in fiber optic systems including Polarization Mode Dispersion (Site not responding. Last check: 2007-10-15)
		Polarization mode dispersion: Combination of distributed birefringence and mode coupling
		The group carries out research in a wide range of basic and applied topics in nonlinear optics.
		The research, which is carried out within the competence centre CHACH at Chalmers and in collaboration with Ericsson Telecom, is intended to lead to a better understanding of the physical processes behind the signal impairment and hopefully to suggestions for how these effects can be suppressed.
	www.gridcore.se /presentations/optoel03/text15.html (168 words)

	Photonetics 3633 - For Sale at Used-Line
		Photonetics 3633 WIN-PMD & Fiberwhite 3627 (Polarization Mode Dispersion Analyzer/Superluminescent Erbium Doped Fiber Source) w/ opt.AN-11
		Please send me a quote for the following item: ------------------ Photonetics 3633 WIN-PMD + Fiberwhite PMD Polarization Mode Dispersion Analyzer Photonetics 3633 WIN-PMD & Fiberwhite 3627 (Polarization Mode Dispersion Analyzer/Superluminescent Erbium Doped Fiber So ------------------ Your prompt reply is appreciated.
		Photonetics 3633 WIN-PMD + Fiberwhite PMD Polarization Mode
	www.used-line.com /c4478727s31-aaa.htm (162 words)

	Polarization-Mode Dispersion Publications
		PMD Measurement Techniques and How to Avoid the Pitfalls
		440 KB Recent Progress in Polarization Mode Dispersion Measurement
		P.A. Williams, Venice Summer School on Polarization Mode Dispersion, Jun 24-26, 2002, Venice, Italy (2002)
	www.boulder.nist.gov /div815/81503_pubs/pmd.htm (413 words)

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