Abstract: As optical transport networks migrate towards supporting optical channel (or superchannel) bitrates of 100Gbps, 400Gbps, or even 1 Tbps, it becomes more important to conduct careful analysis, precise characterization, and optimized mitigation of polarization mode dispersion (PMD) in order to deliver optimal performance in fiber-optic communication systems. Telecommunication service providers need their system vendors to match the performance of their platforms to the overall system PMD accumulation, including both fiber and component PMD. The fiber PMD is a characteristic of the optical fiber plant and is very heterogeneous in both its design and time of installation. Today all installed fiber plants require mitigation solutions for PMD-induced impairments when transporting optical channels with bitrates of 40Gbps and higher. The component PMD is due to discrete components present in the optical path of a lightwave channel, such as Wavelength Selective Switches (WSS), amplifiers, Dispersion Compensating Modules (DCM), and multiplexer/demultiplexer structures. The proliferation of components, especially WSSs, has rapidly accelerated recently with the introduction of Reconfigurable Optical Add Drop Multiplexers (ROADM). Each component contributes a relatively small value to the overall system PMD. Until recently, these components were not considered to be important contributors to the total. The significance of component PMD suddenly became very apparent because ROADM introduction into the fiber-optic network fabric increased the number of components at least ten-fold. Depending on the Link Design Value (LDV) of network fabric, the component PMD can now contribute an amount similar to or even greater than the PMD penalty incurred in the fiber. Today's state of the art tedmiques in PMD measurement focus solely on characterizing fiber PMD. In our research we have developed a new method to measure very small values of PMD (or Differential Group Delay (DOD)) in discrete components of optical fiber communication systems based on the utilization of quantum interferometry. We designed a polarization counterpart of the Hong-Ou-Mandel (HOM) interferometer with entangled photons operating in the telecommunication region of the optical spectrum. Using this setup we were able to demonstrate close to 1 fs resolution while measuring DGD values of a 1x9 port Wavelength Selective Switch (WSS), based on Micro Electro Mechanical System (MEMS). We used a specially designed source of broadband polarization entangled photon pairs generated in the process of collinear type-II Spontaneous Parametric Down Conversion (SPDC). Our result paves the way for building future test and measurement devices that will be capable of resolving even smaller PMD values in discrete components of future optical communication systems, ultimately with atto-second resolution.

This book contains a series of tutorial essays on polarization mode dispersion (PMD) by the leading experts in the field. It starts with an introductory review of the basic concepts and continues with more advanced topics, including a thorough review of PMD mitigation techniques. Topics covered include mathematical representation of PMD, how to properly model PMD in numerical simulations, how to accurately measure PMD and other related polarization effects, and how to infer fiber properties from polarization measurements. It includes discussions of other polarization effects such as polarization-dependent loss and the interaction of PMD with fiber nonlinearity. It additionally covers systems issues like the impact of PMD on wavelength division multiplexed systems. This book is intended for research scientists or engineers who wish to become familiar with PMD and its system impacts. This book covers controversial questions — like the best way to represent PMD — from the perspective of several different experts, giving both the beginner and the advanced reader a balanced view of these questions.

This book describes the experimental and theoretical bases for the development of specifically quantum-mechanical approaches to metrology, imaging, and communication. In particular, it presents novel techniques developed over the last two decades and explicates them both theoretically and by reference to experiments which demonstrate their principles in practice. The particular techniques explored include two-photon interferometry, two-photon optical aberration and dispersion cancellation, lithography, microscopy, and cryptography.

"FET is the IST Programme nursery of novel and emerging scientific ideas. Its mission is to promote research that is of a long-term nature or involves particularly high risks, compensated by the potential of a significant societal or industrial impact. " -- ISTweb, Directorate F, Future and Emerging Technologies home page.