Nouvelle méthode de mesure de la réponse impulsionnelle des fibres optiques

Abstract

A new technique for measuring the temporal transfer function of optical fibers is described. The method consists of placing the fiber under test in one arm of a Mach-Zehnder interferometer excited by a broadband source. The temporal impulse response is obtained from a holographic reconstruction. The method requires only short lengths of single-mode or multimode fibers (less than 1 m). We have measured a dispersion of 0.3 nsec/km.nm at 0.59 microm with a single-mode fiber, in good agreement with theory. The arrival times of the various modes of multimode fibers are resolved.

Ultrashort Pulse Characterization

“…Alternatively, the spectrum from both pulses can be taken from a quadratic equation involving both the DC and AC intensities. This method can be used to measure the dispersion introduced by a sample [92], or to completely characterize a weak or complex pulse by referencing against a simple strong pulse that has been fully characterized by any complete characterization device [93]. Temporal analysis by dispersing a pair of light electric fields (TADPOLE) is a technique that enables the characterization of an unknown pulse by spectral interferometry with a reference that has been characterized using a self-referencing technique.…”

Similariton-Based Spectral Interferometry for Signal Analysis on Femtosecond Time Scale

“…We applied the classic method of SI [2] to completely characterize and study the generation process and peculiarities of nonlineardispersive similariton of a passive fiber. Fig.…”

“…The known spectral phase of the similariton-reference allows to retrieve the signal spectral phase, and by measuring also the signal spectrum, to reconstruct the complex temporal amplitude of the signal through Fourier transformation. Thus, the method of similariton-based SI joins the advantages of both the classic SI [2] and spectral shearing interferometry [3][4][5], combining the simplicity of the principle and configuration with the self-referencing performance [46,47]. Experimentally examining the similariton-based SI, we carried out the comparative measurements with a prototype of the femtosecond oscilloscope (FO) based on the pulse spectrotemporal imaging in the similariton-induced temporal lens.…”

Visible–infrared two-dimensional Fourier-transform spectroscopy

“…Une alternativeà l'interférométrie temporelle pourraientêtre une détection par interférométrie spectrale dans l'infrarouge [21]. La stabilisation et le contrôle du délai τ s'est en effet avérée aussi contraignante (voir section 2.2.5) que les précautionsà prendre [24,25] pour mesurer le champ inconnu par interférométrie spectrale par transformée de Fourier [43][44][45]. Le montage d'interférométrie temporelle a pourtant deux avantages.…”

“…Ce spectromètre permet en outre de mesurer les délais τ et les phases spectrales et absorption induites par les morceaux de verre dispersif. Pour ces dernières mesures, extrêmement précises [24,25], nous avons utilisé l'interférométrie spectrale par transformée de Fourier [43][44][45] (voir aussi la détermination du déplacement réel d'un moteur par cette technique section 2.2.3, page 72).…”