S. Pitois

20-GHz-to-1-THz Repetition Rate Pulse Sources Based on Multiple Four-Wave Mixing in Optical Fibers

In this paper, we theoretically and experimentally study the generation of very high-repetition-rate pulse sources based on multiple four-wave mixing in optical fibers. More precisely, we described the generation of nearly transform-limited pulses at repetition rates of 20, 40, 80, 160, 320, 640 GHz, and 1 THz with a wavelength tunability close to 20 nm around 1555nm. In particular, frequency resolved optical gating analyses show that 170-fs transform-limited pulses have been generated at 1 THz

Frequency-agile dual-comb spectroscopy

Scientists propose and experimentally demonstrate a new architecture for dual-comb spectroscopy based on all-fibre tunable frequency comb sources using standard telecommunication fibre optics components, opening the way for practical dual-comb spectroscopy.

Polarization attraction using counter-propagating waves in optical fiber at telecommunication wavelengths.

In this work, we report the experimental observation of a polarization attraction process which can occur in optical fibers at telecommunication wavelengths. More precisely, we have numerically and experimentally shown that a polarization attractor, based on the injection of two counter-propagating waves around 1.55microm into a 2-m long high nonlinear fiber, can transform any input polarization state into a unique well-defined output polarization state.

Generation of a 160-GHz transform-limited pedestal-free pulse train through multiwave mixing compression of a dual-frequency beat signal

We report the experimental generation of a 160-GHz picosecond pulse train at 1550 nm, using multiple four-wave mixing temporal compression of an initial dual-frequency beat signal in the anomalous-dispersion regime of a nonzero dispersion-shifted fiber. Complete intensity and phase characterizations of the pulse train were carried out by means of a frequency-resolved optical gating technique, showing that 1.27-ps transform-limited pedestal-free Gaussian pulses were generated.

Observation of light-by-light polarization control and stabilization in optical fibre for telecommunication applications

In many photonics applications, especially in optical fibre based systems, the state of polarization of light remains so far an elusive uncontrolled variable, which can dramatically affect the performances of that systems and which one would like to control as finely as possible. Here, we experimentally demonstrate light-by-light polarization control via a nonlinear effect occurring in single mode optical fibre. We observe a polarization attraction and stabilization of a 10 Gbit/s optical telecommunication signal around 1550 nm. We also validate the potentiality of the device to annihilate very fast nanosecond polarization bursts. This result confirms yet another fascinating possibility to all-optical control the light properties in optical fibre.

Linear and Nonlinear Characterizations of Chalcogenide Photonic Crystal Fibers

In this paper, we investigate the linear and nonlinear properties of GeSbS and AsSe chalcogenide photonic crystal fibers. Through several experimental setups, we have measured the second- and third-order chromatic dispersion, the effective area, losses, birefringence, the nonlinear Kerr coefficient as well as Brillouin and Raman scattering properties.

Regenerative 40 Gbit/s wavelength converter based on similariton generation

We present an all-optical regeneration technique based on spectral filtering of self-similar parabolic pulses (similaritons). In particular, we demonstrate numerically and experimentally that ghost pulses, which occur in the zero bit slots of telecommunication pulse trains, can be effectively suppressed. These results are obtained with a 40 Gbit/s pulse train.

A universal optical all-fiber omnipolarizer

Wherever the polarization properties of a light beam are of concern, polarizers and polarizing beamsplitters (PBS) are indispensable devices in linear-, nonlinear- and quantum-optical schemes. By the very nature of their operation principle, transformation of incoming unpolarized or partially polarized beams through these devices introduces large intensity variations in the fully polarized outcoming beam(s). Such intensity fluctuations are often detrimental, particularly when light is post-processed by nonlinear crystals or other polarization-sensitive optic elements. Here we demonstrate the unexpected capability of light to self-organize its own state-of-polarization, upon propagation in optical fibers, into universal and environmentally robust states, namely right and left circular polarizations. We experimentally validate a novel polarizing device - the Omnipolarizer, which is understood as a nonlinear dual-mode polarizing optical element capable of operating in two modes - as a digital PBS and as an ideal polarizer. Switching between the two modes of operation requires changing beams intensity.

All-optical nonlinear processing of both polarization state and intensity profile for 40 Gbit/s regeneration applications

In this paper, we report all-optical regeneration of the state of polarization of a 40-Gbit/s return-to-zero telecommunication signal as well as its temporal intensity profile and average power thanks to an easy-to-implement, all-fibered device. In particular, we experimentally demonstrate that it is possible to obtain simultaneously polarization stabilization and intensity profile regeneration of a degraded light beam thanks to the combined effects of counterpropagating four-wave mixing, self-phase modulation and normal chromatic dispersion taking place in a single segment of optical fiber. All-optical regeneration is confirmed by means of polarization and bit-error-rate measurements as well as real-time observation of the 40 Gbit/s telecommunication signal.

Incoherent modulation instability in instantaneous nonlinear Kerr media

We demonstrate theoretically and experimentally in an optical fiber system that partially temporally incoherent light exhibits modulational instability during its propagation in an instantaneous response nonlinear medium. We show that the modulation frequency and gain are substantially increased with respect to the corresponding values of coherent modulational instability.