Nonlinear pulse compression of picosecond parabolic-like pulses synthesized with a long period fiber grating filter
TL;DR: It is found that the pulse shape launched into the HNLF is critically important for suppressing the undesired wave breaking in the nonlinear spectral broadening process.
Abstract: We demonstrate high quality pulse compression at high repetition rates by use of spectral broadening of short parabolic-like pulses in a normally-dispersive highly nonlinear fiber (HNLF) followed by linear dispersion compensation with a conventional SMF-28 fiber. The key contribution of this work is on the use of a simple and efficient long-period fiber grating (LPFG) filter for synthesizing the desired parabolic-like pulses from sech2-like input optical pulses; this all-fiber low-loss filter enables reducing significantly the required input pulse power as compared with the use of previous all-fiber pulse re-shaping solutions (e.g. fiber Bragg gratings). A detailed numerical analysis has been performed in order to optimize the system’s performance, including investigation of the optimal initial pulse shape to be launched into the HNLF fiber. We found that the pulse shape launched into the HNLF is critically important for suppressing the undesired wave breaking in the nonlinear spectral broadening process. The optimal shape is found to be independent on the parameters of normally dispersive HNLFs. In our experiments, 1.5-ps pulses emitted by a 10-GHz mode-locked laser are first reshaped into 3.2-ps parabolic-like pulses using our LPFG-based pulse reshaper. Flat spectrum broadening of the amplified initial parabolic-like pulses has been generated using propagation through a commercially-available HNLF. Pulses of 260 fs duration with satellite peak and pedestal suppression greater than 17 dB have been obtained after the linear dispersion compensation fiber. The generated pulses exhibit a 20-nm wide supercontinuum energy spectrum that has almost a square-like spectral profile with >85% of the pulse energy contained in its FWHM spectral bandwidth.
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TL;DR: The physics underlying the generation ofabolic pulses in optical fibers as well as the results obtained in a wide range of experimental configurations are reviewed.
Abstract: Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such pulses as well as the results obtained in a wide range of experimental configurations.
92 citations
Cites background from "Nonlinear pulse compression of pico..."
...of a parabolic pulse in a highly nonlinear fiber [64], [69]....
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TL;DR: In this article, a reconfigurable optical pulse generator based on the creation of a high-quality flat continuum that covers the C-band, followed by the tailoring of the spectral amplitude and phase of the continuum using a commercially available programmable optical processor, provides an arbitrary picosecond pulse shape or width.
Abstract: This paper demonstrates a reconfigurable optical pulse generator based on the creation of a high-quality flat continuum that covers the C-band, followed by the tailoring of the spectral amplitude and phase of the continuum using a commercially available reconfigurable programmable optical processor in order to provide an arbitrary picosecond pulse shape or width. The highly efficient continuum is achieved by seeding a highly nonlinear fiber with transform-limited 4 ps parabolic-shaped pulses. A 20 nm 3 dB continuum at the very high repetition rate of 40 GHz is generated. Fourier-domain pulse shaping techniques are then applied to this continuum via the programmable optical processor to generate any arbitrary pulse shape. We present two specific pulse shaping examples suitable for a variety of high-bit-rate applications. The first example shows the improvement in pulse quality using tailored compression techniques over conventional methods and the second example presents multiwavelength pulse generation, which demonstrates the flexibility and range of pulse shapes that can be achieved using this system. Experimental findings are supported with theoretical results.
48 citations
Cites result from "Nonlinear pulse compression of pico..."
...and exact pulse shaping (amplitude and phase) can be obtained in contrast to the other all-fiber examples [4], [12], [13]....
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...The pedestals in this example are higher than those obtained in other published works [4], [5], as a result of the chirp introduced by the high-power EDFA....
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...Parabolic pulse shaping has been demonstrated by linear filtering in a superstructured fiber Bragg grating (FBG) [5], longperiod gratings [4], [12], and by nonlinear filtering, employing...
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TL;DR: In this paper, the authors review recent progress on the use of fiber nonlinearities for the generation and shaping of optical pulses and on the applications of advanced pulse shapes in all-optical signal processing.
Abstract: The development of new all-optical technologies for data processing and signal manipulation is a field of growing importance with a strong potential for numerous applications in diverse areas of modern science. Nonlinear phenomena occurring in optical fibres have many attractive features and great, but not yet fully explored, potential in signal processing. Here, we review recent progress on the use of fibre nonlinearities for the generation and shaping of optical pulses and on the applications of advanced pulse shapes in all-optical signal processing. Amongst other topics, we will discuss ultrahigh repetition rate pulse sources, the generation of parabolic shaped pulses in active and passive fibres, the generation of pulses with triangular temporal profiles, and coherent supercontinuum sources. The signal processing applications will span optical regeneration, linear distortion compensation, optical decision at the receiver in optical communication systems, spectral and temporal signal doubling, and frequency conversion.
43 citations
Cites background or methods from "Nonlinear pulse compression of pico..."
...Continuum with lowspectral ripple and high-energy density in the central part is indeed achievable through parabolic pulse propagation in ND-HNL fibre [79], and low-noise multiwavelength picosecond sources covering the whole C-band of optical telecommunications have been demonstrated based on this technique [12, 16, 79] (Figure 4(b))....
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...In order to fulfill telecommunication requirements, more compact techniques for pulse shaping have been developed, which include the use of super-structured fibre Bragg gratings [15], long-period fibre grating filters [16], and arrayed waveguide gratings that are well suited for line by line processing of high-repetition periodic pulse shapes [17, 18]....
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TL;DR: Recommendation for shortest parabolic pulse formation is made based on the analysis presented, which found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femTosecond lasers for pumping.
Abstract: Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initial pulse duration, chirp and energy. Applicability of different fibers for femtosecond pulse shaping is analyzed. Recommendation for shortest parabolic pulse formation is made based on the analysis presented.
34 citations
TL;DR: This work derives the complete family of different pump signals that allow implementing a desired spectral self-imaging process and investigates the detrimental influence of group-delay walk-off and deviations in the nominal temporal shape or power of the pump pulses on the generated output frequency combs.
Abstract: Integer and fractional spectral self-imaging effects are induced on infinite-duration periodic frequency combs (probe signal) using cross-phase modulation (XPM) with a parabolic pulse train as pump signal. Free-spectral-range tuning (fractional effects) or wavelength-shifting (integer effects) of the frequency comb can be achieved by changing the parabolic pulse peak power or/and repetition rate without affecting the spectral envelope shape and bandwidth of the original comb. For design purposes, we derive the complete family of different pump signals that allow implementing a desired spectral self-imaging process. Numerical simulation results validate our theoretical analysis. We also investigate the detrimental influence of group-delay walk-off and deviations in the nominal temporal shape or power of the pump pulses on the generated output frequency combs.
16 citations
References
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TL;DR: Ultrahigh-resolution optical coherence tomography (OCT) using continuum generation in an air-silica microstructure fiber as a low-coherence light source and imaging in biological tissue in vivo was demonstrated.
Abstract: We demonstrate ultrahigh-resolution optical coherence tomography (OCT) using continuum generation in an air–silica microstructure fiber as a low-coherence light source. A broadband OCT system was developed and imaging was performed with a bandwidth of 370 nm at a 1.3‐μm center wavelength. Longitudinal resolutions of 2.5 μm in air and ∼2 μm in tissue were achieved. Ultrahigh-resolution imaging in biological tissuein vivo was demonstrated.
956 citations
TL;DR: In this paper, the authors derived a single-wave equation which describes transient stimulated Raman scattering in optical fibers and derived a formula for the small-signal gain spectrum which includes the effects of Raman scatter, four-wave mixing, and modulational instabilities.
Abstract: The authors derive a single-wave equation which describes transient stimulated Raman scattering in optical fibers. The equation is valid for forward traveling waves whose bandwidths are less than approximately=1/3 the carrier frequency. It correctly conserves a classical photon number and not the total optical energy as is appropriate for Raman scattering problems. From this equation, the authors derive a formula for the small-signal gain spectrum which includes the effects of Raman scattering, four-wave mixing, and modulational instabilities. Examples of numerical integrations are given which show the generation of short soliton pulses from the nonlinear evolution of a noise band around a continuous wave pump. >
679 citations
TL;DR: The narrowing of pulses to widths as small as 0.26 psec by various lengths, short relative to the soliton period, of single-mode, low-loss optical fiber is reported to be in at least semiquantitative agreement with prediction based on the nonlinear Schrödinger equation.
Abstract: We report the narrowing of pulses, initially 7 psec FWHM, to widths as small as 0.26 psec by various lengths, short relative to the soliton period, of single-mode, low-loss optical fiber. Since the ~1.5-μm wavelength lies in the region of negative group-velocity dispersion (∂νg/∂λ 10) soliton number. We show these results to be in at least semiquantitative agreement with prediction based on the nonlinear Schrodinger equation.
382 citations
TL;DR: This work reports programmable shaping of femtosecond optical pulses by use of a multielement liquid-crystal modulator to manipulate the phases of spatially dispersed optical frequency components.
Abstract: We report programmable shaping of femtosecond optical pulses by use of a multielement liquid-crystal modulator to manipulate the phases of spatially dispersed optical frequency components. Our approach provides for continuously variable control of the optical phase and permits the pulse shape to be reconfigured on a millisecond time scale. We use the apparatus to demonstrate femtosecond pulse-position modulation as well as programmable compression of chirped femtosecond pulses.
378 citations
TL;DR: In this article, the conditions for avoiding wave breaking during pulse propagation in optical fibers were investigated, and it was shown that pulses having a parabolic intensity variation are approximate wave-breaking-free solutions of the nonlinear Schrodinger equation in the high-intensity limit.
Abstract: A qualitative as well as quantitative investigation is made of the conditions for avoiding wave breaking during pulse propagation in optical fibers. In particular, it is shown that pulses having a parabolic intensity variation are approximate wave-breaking-free solutions of the nonlinear Schrodinger equation in the high-intensity limit. A simple expression for the compression factor of a fiber-grating compressor based on parabolic pulses is also derived.
335 citations