Modulation control and spectral shaping of optical fiber supercontinuum generation in the picosecond regime

Numerical simulations are used to study how fiber supercontinuum generation seeded by picosecond pulses can be actively controlled through the use of input pulse modulation. By carrying out multiple simulations in the presence of noise, we show how tailored supercontinuum Spectra with increased bandwidth and improved stability can be generated using an input envelope modulation of appropriate frequency and depth. The results are discussed in terms of the non-linear propagation dynamics and pump depletion.Comment: Aspects of this work were presented in Paper ThJ2 at OECC/ACOFT 2008, Sydney Australia 7-10 July (2008). Journal paper submitted for publication 30 July 200

Broadband spectrally flat and high power density light source for fiber sensing purposes

We present a new kind of broadband continuous-wave source which outperforms any other broadband superluminescent or amplified spontaneous emission source both in terms of output spectral density and bandwidth. Our source covers the wavelength band of interest for fibre applications (from 1450 to 1625 nm) and has an output power of approximately 1.3 W. The source is obtained by pumping a conventional non-zero dispersion-shifted fibre with a continuous-wave Raman fibre laser tuned to the region of small anomalous dispersion of the fibre. The laser beam undergoes an extreme spectral broadening in the fibre. Our experimental results show clearly that the modulation instability (MI)-induced soliton fission is the key element leading to this spectral broadening. Modulation instability is seeded by fast intensity instabilities present in the laser output. We show that this source features good power stability and we believe that it might have very interesting applications in fibre sensing, for instance to avoid the need of amplification in the interrogation of remote Bragg gratings or to improve the resolution and dynamic range of optical coherence tomography setups.Ministerio de Educación y CienciaComunidad de Madri

Dual-fibre stretcher and coma as tools for independent 2nd and 3rd order tunable dispersion compensation in a fibre-based 'scan-free' time domain optical coherence tomography system

International audienceDispersion compensation up to the third order is experimentally demonstrated by using a dual-fibre stretcher combined with the coma of an imaging lens, in a fibre-based scan-free time domain optical coherence tomography system, leading to an axial resolution of less than 3µm

Improving the efficiency of optical coherence tomography by using the non-ideal behaviour of a polarising beam splitter

We present a new way of improving the efficiency of optical coherence tomography by using the polarisation crosstalk of a polarising beam splitter to direct most of the available source optical power to the sample. The use of a quarter wave plate in both the reference and the sample arms allows most of the sample power to be directed to the detector while adjusting the reference arm to ensure noise optimised operation. As a result, the sensitivity of such a system can be improved by 6 dB, or alternatively the acquisition time can be improved by a factor of 4 for shot noise limited performance

Double étireurs à fibres et coma d'une lentille pour ajuster indépendamment la dispersion du 2nd et du 3e ordre dans un système fibré de tomographie par cohérence optique temporelle affranchi d'un système de balayage.

La compensation de la dispersion de vitesse de groupe jusqu'au 3e ordre est démontrée expérimentalement en utilisant un double système d'étireurs fibrés couplé à l'aberration de coma d'une lentille d'imagerie dans un système de tomographie par cohérence optique temporelle affranchi d'un système de balayage. Grâce à ce système de compensation de la dispersion, une résolution en profondeur de moins de 3 microns est possible