We demonstrate a simple method to extend the measurable fiber length with a fiber-optic low-coherence technique. This method is based on a cascaded structure of multistage fiber delay line laid in one arm of the low-coherence technique. By choosing different individual stages in the cascaded fiber delay line, the length of the fiber under test can be continuously measured with a different measu...

The first interferometric measurements of temporalcoherence length variation with numerical aperture (NA) are described for 650 nm, resonant-cavity light-emitting diodes (LEDs) agreeing with spectrally derived results. The interferometrically measured coherence length (22 m to 32 m) reduced by 37% for a 0.42 increase in NA. For a larger range of NA (0–1), this would give coherence lengths (10 m...

We study the maximal achievable rate R∗(n, ) for a given block-length n and block error probability over Rayleigh block-fading channels in the noncoherent setting and in the finite block-length regime. Our results show that for a given blocklength and error probability, R∗(n, ) is not monotonic in the channel’s coherence time, but there exists a rate maximizing coherence time that optimally tra...

We have experimentally investigated quantum interference corrections to the conductivity of graphene nanoribbons at temperatures down to 20 mK studying both weak localization (WL) and universal conductance fluctuations (UCFs). Since in individual nanoribbons at milli-Kelvin temperatures the UCFs strongly mask the weak localization feature we employ both gate averaging and ensemble averaging to ...

One of the main drawbacks of the swept source optical coherence tomography (SS-OCT) is its limited axial range. A novel interferometer configuration is proposed, equipped in each arm with an adjustable path length ring. By compensating the losses in the rings using semiconductor optical amplifiers, multiple paths A-scans can be obtained which when combined axially, can lead to an extremely long...

The atomic-scale structure of three nanocrystalline ZrO2 samples obtained by different techniques and possessing a different length of structural coherence has been studied using high-energy X-ray diffraction and the atomic pair distribution function technique. The studies reveal that all samples show a monoclinic-like local atomic ordering. Only when the length of structural coherence exceeds ...

The dynamics of quantum phase transitions pose one of the most challenging problems in modern many-body physics. Here, we study a prototypical example in a clean and well-controlled ultracold atom setup by observing the emergence of coherence when crossing the Mott insulator to superfluid quantum phase transition. In the 1D Bose-Hubbard model, we find perfect agreement between experimental obse...

Polarization sensitive optical low-coherence reflectometry (OLCR) is used for measuring the complex fiber Bragg gratings (FBG) reflection coefficient. We determine the beat length directly from oscillations in the OLCR amplitude with a resolution of 10(-6) and a spatial resolution only limited by the minimum beat length or the coherence length of the light source. Using the OLCR amplitude and p...

We evidence experimentally the statistical properties of frequency shifted feedback (FSF) lasers through measurements of the homodyne beat signal and interferometric autocorrelation of a dye FSF laser at the output of a Michelson interferometer. The FSF laser is found to show thermal fluctuations and photon bunching. Moreover whereas the degree of first-order coherence vanishes beyond the coher...