ha l - 00 11 52 83 , v er si on 1 - 2 1 N ov 2 00 6 Optical Coherence Spectro - Tomography by all - Optical Depth - Wavelength analysis

2 1 N ov 2 00 6 Optical Coherence Spectro - Tomography by all - Optical Depth - Wavelength analysis

Current spectroscopic optical coherence tomography (OCT) methods rely on a posteriori numerical calculation. We present an alternative for accessing optically the spectroscopic information in OCT, i.e. without any post-processing, by using a grating based correlation and a wavelength demultiplexing system. Conventional A-scan and spectrally resolved A-scan are directly recorded on the image sen...

ha l - 00 11 54 20 , v er si on 1 - 2 1 N ov 2 00 6 Learning and discrimination through STDP in a top - down modulated associative memory ∗

This article underlines the learning and discrimination capabilities of a model of associative memory based on artificial networks of spiking neurons. Inspired from neuropsychology and neurobiology, the model implements top-down modulations, as in neocortical layer V pyramidal neurons, with a learning rule based on synaptic plasticity (STDP), for performing a multimodal association learning tas...

ar X iv : a st ro - p h / 01 11 13 6 v 1 7 N ov 2 00 1 1 Active Optics in Modern , Large Optical Telescopes

High-resolution microwave frequency dissemination on an 86- km urban optical link

we report the first demonstration of a long-distance ultra stable frequency dissemination in the microwave range. A 9.15 GHz signal is transferred through a 86-km urban optical link with a fractional frequency instability of 1.3×10 at 1 s integration time and below 10 at one day. The optical link phase noise compensation is performed with a round-trip method. To achieve such a result we impleme...

Luminescent Ions in Silica-Based Optical Fibers

We present some of our research activities dedicated to doped silica-based optical fibers, aiming at understanding the spectral properties of luminescent ions, such as rare-earth and transition metal elements. The influence of the local environment on dopants is extensively studied: energy transfer mechanisms between rare-earth ions, control of the valence state of Chromium ions, effect of the ...