Photonic crystal fibers for supercontinuum generation (original) (raw)
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Dispersion-Engineered Photonic Crystal Fibers for CW-Pumped Supercontinuum Sources
Journal of Lightwave Technology, 2000
We report recent advances on the spectral control of continuous-wave-pumped supercontinuum sources. We show that the generated infrared SC spectrum can be tailored by using photonic crystal fibers with two zero-dispersion wavelengths. The dynamics of the spectral broadening is studied, and we show that slightly different nonlinear mechanisms occur as the zero-dispersion wavelengths are brought closer to each other. We also report the generation of a visible continuous-wave-pumped supercontinuum by using dispersion engineered photonic crystal fibers in which the zero-dispersion wavelength slightly decreases as a function of length over 200 m. The resulting supercontinuum source spans from 650 nm to 1380 nm with an average output power of 19.5 W. The nonlinear mechanisms producing this spectacular effect are carefully investigated with support of numerical simulations. We show that the generation of visible wavelengths is due to the trapping of dispersive waves by powerful red-shifting solitons.
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.
This paper presents the design of a photonic crystal fiber, which promises to yield very large optical nonlinearity ~151 W^(-1) km^(-1) at 1.55 μm wavelength. The fiber possess two zero dispersion points whose location can be tuned by varying air hole diameter and hole pitch. The fiber dispersion is anomalous between these two zero dispersion points and its value is moderate. The fiber has been used to numerically simulate optical supercontinuum (SC) generation using low power pump pulses of 50 fs duration at 1.55 μm wavelength. At the end of 15 cm fiber SC broadening of about 1200 nm and 1700 nm can be achieved with pulses of 1 kW and 5 kW peak power respectively.
This paper presents the design of an index guided highly birefringent photonic crystal fiber which promises to yield very large birefringence ( ) at 1550 nm and ( ) at 1064 nm as well as large effective nonlinearity( ). Optical supercontinuum generation in the proposed fiber using a 1064 nm pump source with peak power of 1 kW has been also presented. Finite difference time domain method (FDTD) has been employed to examine the optical properties such as fiber birefringence, mode field, V-parameter, walk-off and optical nonlinearity, while the Split-step Fourier method is used to solve the nonlinear Schrödinger equation felicitating the study of supercontinuum generation. Simulation results indicate that horizontal input pulse yields superior continuum in comparison to that of the vertically polarized input. However, the broadening of the continuum is about 1450 nm in case of horizontally polarized input light whereas it is approximately 2350 nm for vertically polarized.
Optics Express, 2007
We theoretically study broadband supercontinuum generation in photonic crystal fibers exhibiting two zero dispersion wavelengths and under continuous-wave pumping. We show that when the pump wavelength is located in between the zero-dispersion wavelengths, a wide and uniform spectral broadening is achieved through modulation instability, generation of both blue-shifted and red-shifted dispersive waves and subsequently through soliton self-frequency shift. This supercontinuum is therefore bounded by these two dispersive waves which allow the control of its bandwidth by a suitable tuning of the fiber dispersion. As a relevant example, we predict that broadband (1050-1600 nm) continuous-wave light can be generated in short lengths of microstructured fibers pumped by use of a 10-W Ytterbium fiber laser.
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.
2007
We theoretically study broadband supercontinuum generation in photonic crystal fibers exhibiting two zero dispersion wavelengths and under continuous-wave pumping. We show that when the pump wavelength is located in between the zero-dispersion wavelengths, a wide and uniform spectral broadening is achieved through modulation instability, generation of both blue-shifted and red-shifted dispersive waves and subsequently through soliton self-frequency shift. This supercontinuum is therefore bounded by these two dispersive waves which allow the control of its bandwidth by a suitable tuning of the fiber dispersion. As a relevant example, we predict that broadband (1050-1600 nm) continuous-wave light can be generated in short lengths of microstructured fibers pumped by use of a 10-W Ytterbium fiber laser.
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...
Applied Physics Express, 2014
This paper presents the design of an index guided highly birefringent photonic crystal fiber which promises to yield very large birefringence (~3.33 × 10) at 1550nm and (~1.75 × 10) at 1064nm as well as large effective nonlinearity (~80). Optical supercontinuum generation in the proposed fiber using a 1064 nm pump source with peak power of 1kW has been also presented. Finite difference time domain method (FDTD) has been employed to examine the optical properties such as fiber birefringence, mode field, V-parameter, walk-off and optical nonlinearity, while the 2 Split-step Fourier method is used to solve the nonlinear Schrödinger equation felicitating the study of supercontinuum generation. Simulation results indicate that horizontal input pulse yields superior continuum in comparison to that of the vertically polarized input. However, the broadening of the continuum is about 1450 nm in case of horizontally polarized input light whereas it is approximately 2350 nm for vertically polarized. Recently, Rakhi et. al. [32] have reported very large birefringence (~ 5.45 × 10) in