Polarization mode dispersion

About: Polarization mode dispersion is a research topic. Over the lifetime, 5147 publications have been published within this topic receiving 80055 citations. The topic is also known as: PMD.

Method and apparatus for measuring polarization mode dispersion of optical devices

Abstract: Apparatus for measuring very low levels of polarization mode dispersion of optical devices, that is inexpensive, robust and portable, comprises a broadband source and a polarizer for directing substantially completely polarized broadband light into the device under test with the polarization in a plane substantially perpendicular to the propagation direction of the light. Light leaving the device is analyzed spectrally to produce a spectrum of intensity in dependence upon wavelength or frequency of such light for each of at least two mutually orthogonal polarization axes in a plane perpendicular to the propagation axis of the light leaving the device. The spectra are used to compute Stokes parameters s1, s2 and |s3| for each of a plurality of wavelengths within the bandwidth of the broadband light. The polarization mode dispersion of the device is characterized in dependence upon the Stokes parameters using one of several techniques including standard Fixed Analyzer techniques and polarimetric techniques, especially the Poincare sphere technique. The apparatus is particularly suitable for measuring PMD of components of optical telecommunications systems, including optical fibers, optical isolators, couplers, light amplifiers, and dispersion compensators.

Experimental demonstrations of dual polarization CO-OFDM using mid-span spectral inversion for nonlinearity compensation.

Abstract: We experimentally demonstrate fiber nonlinearity compensation in dual polarization coherent optical OFDM (DP CO-OFDM) systems using mid-span spectral inversion (MSSI). We use third-order nonlinearity between a pump and the signal in a highly nonlinear fiber (HNLF) for MSSI. Maximum launch powers at FEC threshold for two 10 × 80-km 16-QAM OFDM systems were increased by 6.4 dB at a 121-Gb/s data rate and 2.8 dB at 1.2 Tb/s. The experimental results are the first demonstration of using MSSI for nonlinearity compensation in any dual polarization coherent system. Simulations show that these increases could support a 22% increase in total transmission distance at 1.2-Tb/s system without increasing the number of inline amplifiers, by extending the fiber spans from 90 to 110 km. When spans of 80 km are used, simulations reveal that MSSI system performance shows less degradation with increasing transmission distance, and an overall transmission distance increase of more than 70% is expected using MSSI.

Fixed and Tunable Management of Fiber Chromatic Dispersion

Abstract: Publisher Summary It is noted that the essence of chromatic dispersion lies in the fact that in any medium other than a vacuum and in any waveguide structure, different electromagnetic frequencies propagate at different speeds. Chromatic dispersion in optical fibers is therefore, because of the frequency–dependent nature of the propagation characteristics, for both the material and the waveguide structure. Chromatic dispersion, essentially, is a linear effect that can be compensated by adding the complementary dispersion before any significant nonlinearities intervene. It is noted that nonlinearities do intervene in many of the systems and the periodic dispersion mapping is required for managing them. The issues surrounding the compensation of chromatic dispersion in high-performance optical systems have been addressed in the chapter. The chapter also describes the effects of dispersion, the various fixed compensation techniques, the need for tunable compensation and its potential solutions, and also the techniques for monitoring accumulated dispersion. Chromatic dispersion phenomenon exhibits profound implications for opticalfiber communications systems.

Experimental demonstration of the system performance degradation due to the combined effect of polarization-dependent loss with polarization-mode dispersion

Abstract: The combined effect of polarization-mode dispersion (PMD) and polarization-dependent loss (PDL) is investigated experimentally using a recirculating fiber-loop testbed for 10-Gb/s nonreturn-to-zero transmissions over an 800-km fiber link. We find that the PDL of inline components combined with the link PMD will increase the penalty distribution. As the average link PDL varies from 1.0 to 2.1 dB with an average PMD of 18 ps, the system penalty distribution tail at 2% probability increases from 2.5 to 4.3 dB.

Polarization mode dispersion characterization apparatus and method

Abstract: The invention relates to an entangled-photon apparatus capable of measuring particular characteristics of an optical element, device or channel. Specifically, the apparatus and a method of using said apparatus to measure polarization mode dispersion in an optical communications fiber is disclosed. The apparatus includes a source of entangled photons, which are injected into the device under test, and a quantum interference device for determining the state of entanglement of said photons after they pass through the device. The quantum interference device includes a variable, polarization-specific delay element that is incremented to null out polarization mode dispersion in the device under test, and a wavelength demultiplexer/array detector that permits simultaneous measurements across a wide wavelength band. A second preferred embodiment of the invention and method is suitable for characterizing PMD in-situ that is, PMD measurements can be made while an optical fiber is in use for optical communications.