Showing papers on "Supercontinuum published in 1996"

Observation of Pulse Splitting in Nonlinear Dispersive Media.

Abstract: We investigate experimentally the nonlinear dynamics of a femtosecond pulse undergoing self-focusing in a normally dispersive medium. Above a certain threshold power, we observe that the pulse splits into two pulses, and measurements of the pulse spectra provide evidence that supercontinuum generation is closely connected with the temporal splitting. We also observe that the split pulses can undergo additional splittings. Our observations are in good agreement with the predictions of the theoretical model based on the nonlinear Schr\"odinger equation describing self-focusing in dispersive media.

1 Tbit/s (100 Gbit/s × 10 channel) OTDM/WDM transmission using a single supercontinuum WDM source

Abstract: 100 Gbit/s/spl times/10 channel (1 Tbit/s) optical signals from a single supercontinuum WDM source are successfully transmitted over a 40 km dispersion-shifted fibre using a 400 GHz channel-spaced arrayed-waveguide grating WDM MUX/DEMUX as well as a 100 Gbit/s-10 Gbit/s all-optical TDM MUX/DEMUX.

Error-free 500 Gbit/s all-optical demultiplexing using low-noise, low-jitter supercontinuum short pulses

Abstract: Error-free 500 Gbit/s-to-10 Gbit/s all-optical demultiplexing based on four-wave mixing (FWM) in a 300 m polarisation-maintaining dispersion-shifted optical fibre is successfully demonstrated utilising low-noise 1 ps supercontinuum pulses with ultra-low timing jitter of <100 fs.

100 Gbit/s x 10 channel OTDM/WDM Transmission using a Single Supercontinuum WDM Source

Abstract: To construct large-capacity flexible optical networks, utilization of both optical time-division multiplexing (OTDM) [1] and wavelength-division multiplexing (WDM) technologies [2], [3] will be of vital importance, in which broadband low-noise optical sources are expected to play a major role.

Backscattered supercontinuum emission from high-intensity laser-plasma interactions.

Abstract: We performed high-intensity subpicosecond laser–plasma interaction experiments to examine nonlinear scattering mechanisms in underdense plasmas. At incident laser intensities of 2 × 1018 W/cm2 the stimulated-Raman-backscattered spectrum exhibited an extremely broad, supercontinuumlike structure (Δω/ω0 > 1) extending from ~500 to >1200 nm (limited only by detector sensitivity). Large-amplitude modulations in the spectrum of the backscattered light were measured and are attributed to an interaction of the stimulated-Raman-scattered radiation with ion plasma waves.

Stimulated Raman amplification of femtosecond pulses in hydrogen gas.

Abstract: We report efficient amplification of weak femtosecond supercontinuum pulses by a stimulated Raman scattering process in pressurized H2 gas excited with 350-fs-duration frequency-doubled pulses from a regenerative-amplified Ti:sapphire laser. An amplification factor of 109 is obtained at the wavelength of 465 nm for seed pulses produced by supercontinuum generation in glass.

Low-noise, pulsewidth tunable picosecond to femtosecond pulse generation by spectral filtering of wideband supercontinuum with variable bandwidth arrayed-waveguide grating filters

Abstract: Pulsewidth tunable short optical pulses (0.37 ps/spl sim/11.3 ps) are generated with an average time-bandwidth product of 0.46 by spectral filtering of a 100 nm-broadened supercontinuum with variable bandwidth arrayed-waveguide grating filters. The BER measurements show that the generated pulses are low-noise and promising for use in ultrafast optical signal processing.

100 Gbit/s × 4 ch, 100 km repeaterless TDM-WDM transmission using a single supercontinuum source

Abstract: 100 Gbit/s × 4 ch (400 Gbit/s) TDM-WDM optical signals generated by filtering 100 nm broadened supercontinuum are successfully transmitted within a 20 nm wavelength range over a 100 km dispersion-shifted fibre with a maximum power penalty of 2 dB.

Spectrally shaped rare-earth-doped fiber ASE sources for use in optical coherence tomography

Abstract: Summary form only given. Optical coherence tomography (OCT) has proven over the past few years to be a powerful new optical imaging modality. OCT uses interferometric detection and a short-coherence-length light source to achieve high sensitivity, high-dynamic range, and high resolution (1-10 /spl mu/m). Biomedical applications include ophthalmology, microscopy, endoscopy, laproscopy, dermatology, developmental biology, dentistry etc. One of the key components in OCT systems is the optical source. This paper presents preliminary results on the use of spectrally flattened rare-earth-doped fiber ASE source in OCT systems. Rare-earth-doped fibers are a very promising candidate for future OCT systems. The authors expect spectrally shaped rare earth-doped fiber ASE sources to play an important role in future OCT systems. In the near future, source powers in excess of 100 mW and coherence lengths under 10 cm should be available at a variety of wavelengths. The authors review some of the design details on this Nd source, quantify its optical parameters power, bandwidth, blindness, etc.), and present its application in tomographic biomedical imaging (e.g. skin and bone structure). The authors also compare its performance with other types of sources such as: semiconductor sources (light-emitting diodes, edge-emitting diodes, superluminescent diodes), model-lock lasers, and supercontinuum sources.

Full wave theory of Fermi photon acceleration

Abstract: We describe the interaction of an electromagnetic wave with an electron density perturbation oscillating with relativistic velocities inside a cavity. Using a linear mode coupling theory, we calculate analytically the full spectral content of the radiation remaining inside the cavity. Moreover, it is shown that the coupling mechanism can generate a broad supercontinuum spectrum, by energy transfer between the cavity modes via linear mode coupling.

Femtosecond Relaxation Dynamics in Thiophene Oligomers

Abstract: Using methyl substituted thiophene rings as starting monomers for controlled polymerization interesting materials are obtained whose optical properties depend on the length and the regiospecificity of substitution. The ground state conformation is determined by the opposite roles exerted by π-electron conjugation (favoring coplanar arrangements) and the side groups non bonded interactions (favoring twisted arrangements). Solubility is quite good for these systems even for fairly large conjugation (6 units). In this paper we present a complete characterization of the ultrafast optical dynamics of α-conjugated regiospecifically substituted 3, 3′, 4″, 3‴, 4⁗, 3⁗′ hexamethyl 2, 2′:5′, 2″:5″, 2‴:5‴, 2⁗:5⁗, 2⁗′ sexithiophene(HMT6)1. Femtosecond pump-probe experiments were carried out on HMT6 in chloroform solution (10-3 mol/l) in a cuvette of 1 mm thickness. The sample was excited by 390 nm femtosecond pump pulses with 10 nJ energy. The pump beam was focused at the sample to a spot of 250 μm diameter. The probe wavelength was varied in a wide spectral region ranging from 490 nm to 1500 nm. We used a Ti:Sapphire oscillator in Kerr-lens modelocking followed by chirped pulse amplification. The pump pulses were obtained by frequency doubling in a LiB3O5 crystal (1 mm length) a fraction of the fundamental beam at 780 nm. Probe tunability from 490 nm to 1000 nm was obtained by white light supercontinuum generation. Probe pulses tunable in the near infrared region up to 1500 nm were obtained by using a three-pass optical parametric generation and amplification system (OPA), which consists of two angle tuned β-BaB2O4 (BBO) crystals pumped by the laser beam at 780 nm2.