Control of near-infrared supercontinuum bandwidth by adjusting pump pulse duration (original) (raw)
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Pulse breaking and supercontinuum generation with 200-fs pump pulses in photonic crystal fibers
Journal of The Optical Society of America B-optical Physics, 2002
We have carried out a detailed experimental study of the behavior of 200-fs pulses in highly nonlinear photonic crystal fiber to elucidate the mechanisms for supercontinuum generation. To avoid unwanted polarization effects, our experiments were performed using polarization-maintaining fiber. The experimental evidence shows that, as in conventional fibers, Raman scattering leads to the breakup of higher-order solitons, which is accompanied by the generation of radiation at shorter wavelengths than the pump, leading eventually to an ultrabroad supercontinuum.
JOSA B, 2002
Supercontinuum generation is investigated experimentally and numerically in a highly nonlinear indexguiding photonic crystal optical fiber in a regime in which self-phase modulation of the pump wave makes a negligible contribution to spectral broadening. An ultrabroadband octave-spanning white-light continuum is generated with 60-ps pump pulses of subkilowatt peak power. The primary mechanism of spectral broadening is identified as the combined action of stimulated Raman scattering and parametric four-wave mixing. The observation of a strong anti-Stokes Raman component reveals the importance of the coupling between stimulated Raman scattering and parametric four-wave mixing in highly nonlinear photonic crystal fibers and also indicates that non-phase-matched processes contribute to the continuum. Additionally, the pump input polarization affects the generated continuum through the influence of polarization modulational instability. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate the importance of index-guiding photonic crystal fibers for the design of picosecond and nanosecond supercontinuum light sources.
White-light supercontinuum generation with 60-ps pump pulses in a photonic crystal fiber
Optics Letters, 2001
The generation of a spatially single-mode white-light supercontinuum has been observed in a photonic crystal fiber pumped with 60-ps pulses of subkilowatt peak power. The spectral broadening is identified as being due to the combined action of stimulated Raman scattering and parametric four-wave-mixing generation, with a negligible contribution from the self-phase modulation of the pump pulses. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate that ultrafast femtosecond pulses are not needed for efficient supercontinuum generation in photonic crystal fibers.
Optics Communications, 2011
We study experimentally the spectral evolution of supercontinua in two different microstructured fibers that are pumped with nanosecond pulses from dual-wavelength sources of either 1064/532 nm or 946/473 nm output. The experimental findings are compared with simulations based on numerically solving the nonlinear Schrödinger equation. The role of cascaded cross-phase modulation processes and the group-delay properties of the fiber are emphasized and demonstrated to determine the extent of the broadening of the continua to the visible wavelengths.
Visible supercontinuum generation in photonic crystal fibers with a 400W continuous wave fiber laser
Optics Express, 2008
We demonstrate continuous wave supercontinuum generation extending to the visible spectral region by pumping photonic crystal fibers at 1.07 μm with a 400 W single mode, continuous wave, ytterbium fiber laser. The continuum spans over 1300 nm with average powers up to 50 W and spectral power densities over 50 mW/nm. Numerical modelling and understanding of the physical mechanisms has led us to identify the dominant contribution to the short wavelength extension to be trapping and scattering of dispersive waves by high energy solitons.
Supercontinuum generation at 800 nm in all-normal dispersion photonic crystal fiber
Optics express, 2014
We have numerically investigated the supercontinuum generation and pulse compression in a specially designed all-normal dispersion photonic crystal fiber with a flat-top dispersion curve, pumped by typical pulses from state of the art Ti:Sapphire lasers at 800 nm. The optimal combination of pump pulse parameters for a given fiber was found, which provides a wide octave-spanning spectrum with superb spectral flatness (a drop in spectral intensity of ~1.7 dB). With regard to the pulse compression for these spectra, multiple-cycle pulses (~8 fs) can be obtained with the use of a simple quadratic compressor and nearly single-cycle pulses (3.3 fs) can be obtained with the application of full phase compensation. The impact of pump pulse wavelength-shifting relative to the top of the dispersion curve on the generated SC and pulse compression was also investigated. The optimal pump pulse wavelength range was found to be 750 nm <λ<sub>p</sub><850 nm, where the distortions o...
Supercontinuum generation by higher-order mode excitation in a photonic crystal fiber
Optics Express, 2008
We describe an experiment in which a train of femtosecond pulses is coupled into a photonic crystal fiber (PCF) by means of an offset pumping technique that can selectively excite either the mode LP 01 or LP 11 or LP 21 . The PCF presents a wide range of wavelengths in which the fundamental mode experiences normal dispersion, whereas LP 11 and LP 21 propagate in the anomalous dispersion regime, generating a supercontinuum based on the soliton fission mechanism. We find that the existence of a cutoff wavelength for the higher-order modes makes the spectral broadening asymmetrical. This latter effect is particularly dramatic in the case of the LP 21 mode, in which, by using a pump wavelength slightly below cut-off, the spectral broadening occurs only on the blue side of the pump wavelength. Our experimental results are successfully compared to numerical solutions of the nonlinear Schrödinger equation. and four-wave mixing with Q-switched pulses in endlessly single-mode photonic crystal fibers," Opt. Express 12, 299-309 (2004), http://www.opticsinfobase.org/abstract.cfm?URI=oe-12-2-299 . 8. P. A. Champert, V. Couderc, P. Leproux, S. Février, V. Tombelaine, L. Labonté, P.Roy, P. Nérin, and C. Froehly, "White-light supercontinuum generation in normally dispersive optical fiber using original multiwavelength pumping system," Opt. Express 12, 4366-4371 (2004), http://www.opticsinfobase.org/abstract.cfm?URI=oe-12-19-4366 . 9. I. Cristiani, R. Tediosi, L. Tartara, and V. Degiorgio, "Dispersive wave generation by solitons in microstructured optical fibers,'' Opt. Express 12, 124-135 (2004), http://www.opticsinfobase.org/abstract.cfm?URI=oe-12-1-124\. 10. G. Genty, M. Lehtonen, H. Ludvigsen, and M. Kaivola, "Enhanced bandwidth of supercontinuum generated in microstructured fibers," Opt. Express 12, 3471-3480 (2004), http://www.opticsinfobase.org/abstract.cfm?URI=oe-12-15-3471\. 11. A. V. Gorbach, D. V. Skryabin, J. M. Stone, and J. C. Knight, "Four-wave mixing of solitons with radiation and quasi-nondispersive wave packets at the short-wavelength edge of a supercontinuum," Opt. Express 14, 9854-9863 (2006), http://www.opticsinfobase.org/abstract.cfm?URI=oe-14-21-9854.
Supercontinuum generation in photonic crystal fiber
Reviews of modern physics, 2006
A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.
Infrared supercontinuum generation in soft-glass photonic crystal fibers pumped at 1560 nm
Nonlinear Optics, 2013
In this work we present results on supercontinuum (SC) generation in a photonic crystal fiber (PCF) fabricated from lead-bismuthgallium-oxide glass (PBG-08). Due to high refractive index, high nonlinearity and high transmittance, the PBG-08 glass-based fibers seem to be excellent media for broad supercontinuum generation in the infrared spectral region. In our experiment, a short-length piece of PCF (5-6 cm) is pumped by a femtosecond chirped pulse amplification (CPA) setup, which may be seeded by two different fiber-based oscillators. This compact and cost-effective system allows to generate SC spanning from 900 to 2400 nm. The paper describes in detail the fabrication process of the fiber, as well as the SC generation results.
Photonic crystal fibers for supercontinuum generation
Frontiers of Optoelectronics in China, 2011
Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations of the laser can be exploited to enhance the broadening process. The physics behind the supercontinuum generation is investigated by sweeping the fiber length, the zero dispersion wavelength, and the fiber nonlinearity. We show that by applying gain-switching a high average output power of up to 30 W can be maintained and the spectral width can be improved by 90%. The zero dispersion wavelength should be close to but below the pump wavelength to achieve the most visible light. By increasing the nonlinearity the fiber length can be reduced from 100 m to 25 m and the efficiency of visible light generation is improved by more than 200%.