Capella, Boston University use quantum photonics to test PMD

Capella Intelligent Subsystems Inc., a provider of wavelength selective switch (WSS) technologies, says it has successfully demonstrated how quantum photonic techniques can be used to evaluate the polarization mode dispersion (PMD) of complex optical devices.

Mar 2nd, 2012

Capella Intelligent Subsystems Inc., a provider of wavelength selective switch (WSS) technologies, says it has successfully demonstrated how quantum photonic techniques can be used to evaluate the polarization mode dispersion (PMD) of complex optical devices.

The demonstration, using quantum interferometry with broadband polarization-entangled states, is the culmination of research work completed by Boston University's Quantum Communication and Measurement Laboratory (QCML) led by Professor Alexander Sergienko and funded by Capella. This research highlights the high-resolution measurements made possible by quantum photonic techniques, and validates the benefit of collaboration between industry and university research teams, according to Capella.

The need for high-resolution dispersion measurements is increasing as networks move to higher speeds. With the increasing number of optical switches and other optical components in the transmission path, the cumulative PMD of components is becoming comparable to the PMD introduced in the fiber. While coherent receivers are more tolerant of PMD, the performance penalty of PMD can still be significant as transmission bit rates increase. The evaluation of dispersion parameters from component devices is critical for managing overall system performance.

"Our team approached Capella with this project because of their team's capability to take the research results to product deployment in field," said Roman Egorov, Ph.D. candidate at Boston University. "Developments of this type are needed in the long term to meet future technology demands for ROADM-based optical transport networks."

Capella says its CRx WSS product served as an ideal test device for measurement of PMD during the demonstration due to the product’s extremely low PMD.

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