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.

Time-Domain Least Square Channel Estimation for Polarization-Division-Multiplexed CO-OFDM/OQAM Systems

Abstract: Suppressing the intrinsic imaginary interference (IMI) effect induced by the multiple-path fading channel is the key technology for maintaining the good performance of the orthogonal frequency-division multiplexing offset-quadrature amplitude modulation (OFDM/OQAM) systems. Recently, the first theoretical discussion on the IMI effect and the corresponding frequency-domain channel estimation method for polarization-division-multiplexed (PDM) coherent optical OFDM/OQAM (CO-OFDM/OQAM) system has been studied. The full-loaded and the half-loaded channel estimation methods have been proposed to mitigate the IMI effect. However, for these frequency-domain methods, the condition that the symbol interval is much longer than the maximum channel delay spread has to be satisfied. When the transmission distance is long, the frequency-domain residual errors induced by the chromatic dispersion (CD) and polarization mode dispersion (PMD) reduce the channel estimation accuracy evidently. In this paper, we systematically discuss the time-domain channel transmission model for PDM CO-OFDM/OQAM systems. With the analysis of the distribution of the received additive noise, we propose the time-domain least square (TDLS) channel estimation method for PDM CO-OFDM/OQAM systems. Compared with the frequency-domain methods, the TDLS method promotes the system robustness against both the IMI effect and the additive noise significantly. The computational complexities and the transmission performance have been compared for both the TDLS and the frequency-domain full-loaded methods. The theoretical analysis is validated by numerical Monte Carlo simulations of the PDM CO-OFDM/OQAM system.

Polarisation mode dispersion measurements in long single mode fibres

Abstract: A new method to measure polarisation mode dispersion is described, in which the accuracy is more than 0.1 ps. 0.17 ps polarisation mode dispersion was obtained for about 1 km length of fibre. The result is compared with the retardation obtained for a short length of the fibre.

Appliance for measuring polarization mode dispersion and corresponding measuring process

Abstract: An appliance for measuring polarization mode dispersion (PMD) of a waveguide (2) comprises a source (1, 6) of wide-band polarized light, an interferometer (5) capable of receiving a light beam (21) sent by the source (1, 6), a detector (3) capable of detecting the light beam (25) from the interferometer (5), and an electronic processing unit (4) connected to the detector (3), capable of extracting a value τ representative of the polarization mode dispersion of the waveguide (2). The interferometer (5) divides a measuring light beam (22) sent by the source (1) into two interference light beams (23, 24). 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.

Time evolution of polarization mode dispersion in optical fibers

Abstract: The fluctuation of polarization mode dispersion (PMD) due to environmental change is an important issue for fiber-optic communication systems. We measure the time evolution of PMD for installed aerial and buried cables and for a spooled fiber in a temperature controlled chamber. The results show that PMD fluctuates much more rapidly for aerial cables than for buried cables. The magnitude of PMD is different for the three fibers and our results also show that the magnitude of PMD fluctuation depends on the magnitude of the PMD.

Polarization-mode dispersion detecting method, and a dispersion compensation controlling apparatus and a dispersion compensation controlling method

Abstract: A dispersion compensation controlling apparatus used in a very high-speed optical communication system adopting optical time division multiplexing system comprises a first specific frequency component detecting unit (2 a) detecting a first specific frequency-component in a baseband spectrum in a transmission optical signal inputted to a receiving side over a transmission fiber as a transmission line (6 a), a first intensity detecting unit (3 a) detecting information on an intensity of the first specific frequency component detected by the first specific frequency component detecting unit (2 a and a polarization-mode dispersion controlling unit (220 a) con trolling a polarization-mode dispersion quantity of the transmission line (6 a) such that the intensity of the first specific frequency component detected by the first intensity detecting unit. (3 a) becomes the maximum, thereby easily detecting and compensating polarization-mode dispersion generated in a high-speed optical signal.