Hugo Zbinden

Statistical prediction and experimental verification of concatenations of fiber optic components with polarization dependent loss

Due to the statistical nature of the evolution of the polarization state in optical fibers and components, it is difficult to measure the global polarization dependent loss (PDL) of a series of concatenated components, each having a different PDL value. The global PDL of concatenated components with PDL cannot be obtained by a simple addition of the single PDL values, moreover, it requires a statistical description. In the present work the statistics of the PDL resulting from the concatenation of several components with PDL, connected by standard optical fibers or by elements having some polarization mode dispersion (PMD) is discussed. Simulations and experimental results supporting the existing theory are presented.

Introduction to guided-wave quantum optics (GWQO): science, technology, and magic

In this paper we propose various applications of guided wave optics to quantum optics experiments. As quantum optics moves on to multiparticle and multiport configurations, guided wave optics, incorporating both integrated optics and fiber optics, could provide a realistic means of constructing experiments and devices.

Photon-bunching measurement after two25−km-long optical fibers

To show the feasibility of a long distance partial Bell-State measurement, a Hong-Ou-Mandel experiment with coherent photons is reported. Pairs of degenerate photons at telecom wavelength are created by parametric down conversion in a periodically poled lithium niobate waveguide. The photon pairs are separated in a beam-splitter and transmitted via two fibers of 25km. The wave-packets are relatively delayed and recombined on a second beam-splitter, forming a large Mach-Zehnder interferometer. Coincidence counts between the photons at the two output modes are registered. The main challenge consists in the trade-off between low count rates due to narrow filtering and length fluctuations of the 25km long arms during the measurement. For balanced paths a Hong-Ou-Mandel dip with a visibility of 47.3% is observed, which is close to the maximal theoretical value of 50% developed here. This proves the practicability of a long distance Bell state measurement with two independent sources, as e.g. required in an entanglement swapping configuration in the scale of tens of km.