Experimental quantum key distribution over highly noisy channels

Error filtration is a method for encoding the quantum state of a single particle into a higher dimensional Hilbert space in such a way that it becomes less sensitive to phase noise. We experimentally demonstrate this method by distributing a secret key over an optical fiber whose noise level otherwise precludes secure quantum key distribution. By filtering out the phase noise, a bit error rate of 15.3% +/- 0.1%, which is beyond the security limit, can be reduced to 10.6% +/- 0.1%, thereby guaranteeing the cryptographic security.Comment: 4 pages, 2 figure

Frequency Bin Entangled Photons

A monochromatic laser pumping a parametric down conversion crystal generates frequency entangled photon pairs. We study this experimentally by addressing such frequency entangled photons at telecommunication wavelengths (around 1550 nm) with fiber optics components such as electro-optic phase modulators and narrow band frequency filters. The theory underlying our approach is developed by introducing the notion of frequency bin entanglement. Our results show that the phase modulators address coherently up to eleven frequency bins, leading to an interference pattern which can violate a Bell inequality adapted to our setup by more than five standard deviations.Comment: 10 pages, 4 figures (extended version

Identification of gap soliton through phase measurement

Paper TuC4info:eu-repo/semantics/publishe

Measuring the nonlinear refractive index of graphene using the optical Kerr effect method

© 2016 Optical Society of America.By means of the ultrafast optical Kerr effect method coupled to optical heterodyne detection (OHD-OKE), we characterize the third-order nonlinear response of graphene and compare it to experimental values obtained by the Z-scan method on the same samples. From these measurements, we estimate a negative nonlinear refractive index for monolayer graphene, n2 = -1.1 × 10-13 m2/W. This is in contradiction to previously reported values, which leads us to compare our experimental measurements obtained by the OHD-OKE and the Z-scan method with theoretical and experimental values found in the literature and to discuss the discrepancies, taking into account parameters such as doping

Supercontinuum generation in hydrogenated amorphous silicon waveguides at telecommunication wavelengths

We report supercontinuum (SC) generation centered on the telecommunication C-band (1550 nm) in CMOS compatible hydrogenated amorphous silicon waveguides. A broadening of more than 550 nm is obtained in 1cm long waveguides of different widths using as pump picosecond pulses with on chip peak power as low as 4 W. © 2014 Optical Society of America.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Observation of the formation of an optical intensity shock and wave breaking in the nonlinear propagation of pulses in optical fibers

We have observed the formation of an optical intensity shock and the subsequent wave breaking in the nonlinear propagation of 1-psec pulses in an optical fiber. The wave breaking manifests itself as the appearance of oscillations trailing the shock, which are due to the beating of widely separated frequency components which bridge the shock. The experimental results are in good agreement with numerical solutions of the nonlinear Schrodinger equation.Peer reviewedElectrical and Computer Engineerin