Showing papers on "Four-wave mixing published in 2003"
TL;DR: In this article, a four-wave mixing (FWM) scheme in a five-level atomic system based on electromagnetically induced transparency (EIT) was analyzed.
Abstract: We analyze a four-wave-mixing (FWM) scheme in a five-level atomic system based on electromagnetically induced transparency (EIT). We show that EIT suppresses both two-photon and three-photon absorptions in the FWM scheme and enables the four-wave mixing to proceed through real, resonant intermediate states without absorption loss. The scheme results in a several orders of magnitude increase in the FWM efficiency in comparison with a recent scheme [Phys. Rev. Lett. 88, 143902 (2002)] and may be used for generating short-wavelength radiation at low pump intensities.
381 citations
TL;DR: In this paper, the variance due to cross-phase modulation and four-wave mixing (FWM) induced intensity distortion is derived based on the Volterra series transfer function method.
Abstract: New analytical tools to calculate the variance due to cross-phase modulation (XPM) and four-wave mixing (FWM) induced intensity distortion are derived based on the Volterra series transfer function method. The analysis for both the XPM and FWM effects is based on the same system configuration with a continuous-wave (CW) probe channel plus modulated pump channels, which makes possible a fair comparison between the two nonlinear effects. Effective ways to reduce the XPM- and FWM-induced intensity distortion are given. The new results on the variance of the nonlinearity-induced intensity fluctuation also make it possible to study both synchronous wavelength-division multiplexing (WDM) systems with fixed channel delays and asynchronous WDM systems with random channel delays. The new analytical results provide accurate and efficient ways for system parameter optimization to reduce these two nonlinear effects.
109 citations
TL;DR: Phase-matched four-wave mixing in higher-order modes of microstructure fibers allows unprecedentedly high efficiencies of anti-Stokes frequency conversion to be achieved for subnanojoule femtosecond laser pulses.
Abstract: Phase-matched four-wave mixing in higher-order modes of microstructure fibers allows unprecedentedly high efficiencies of anti-Stokes frequency conversion to be achieved for subnanojoule femtosecond laser pulses. 70-fs pulses of 790-nm radiation were used to generate an anti-Stokes component at 520–530 nm in a higher-order mode of a microstructure fiber with a 4.8 μm core. The maximum ratio of the anti-Stokes signal energy to the energy of the pump component in the output spectrum is estimated as 1.7.
93 citations
TL;DR: The efficiency achieved for this process in a 9-cm-long, 13-microm-hollow-core-diameter photonic-crystal fiber, designed to simultaneously transmit a two-color pump and the FWM signal, is shown to be approximately 800 times higher than the maximum FWM efficiency attainable with the same laser pulses in the tight-focusing regime.
Abstract: Hollow-core photonic-crystal fibers are shown to substantially enhance four-wave mixing (FWM) of laser pulses in a gas filling the fiber core. Picosecond pulses of Nd:YAG fundamental radiation and its second harmonic are used to generate a signal at the frequency of the third harmonic by the FWM process 3⍵=2⍵+2⍵-⍵ . The efficiency achieved for this process in a 9-cm-long, 13-mu;m -hollow-core-diameter photonic-crystal fiber, designed to simultaneously transmit a two-color pump and the FWM signal, is shown to be ~800 times higher than the maximum FWM efficiency attainable with the same laser pulses in the tight-focusing regime.
88 citations
TL;DR: In this article, a 1550-nm InAs-InP quantum-dash semiconductor optical amplifier with four-wave mixing (FWM) and cross-gain modulation (XGM) was used for short-pulse wavelength conversion over 10 THz and error-free data conversion of a 2.5Gb/s data sequence over 7.5 THz.
Abstract: Wavelength conversion based on four-wave mixing (FWM) and cross-gain modulation (XGM) is experimentally demonstrated for the first time in a 1550-nm InAs-InP quantum-dash semiconductor optical amplifier. Continuous-wave FWM with a symmetric conversion efficiency dependence on detuning direction and FWM mediated short-pulse wavelength conversion are demonstrated. Using XGM, we have successfully implemented short-pulse wavelength conversion over 10 THz and error-free data conversion of a 2.5-Gb/s data sequence over 7.5 THz. The pulsed XGM experiments suggest that adjacent regions within an inhomogeneously broadened gain spectrum are partially coupled which increases the operational bandwidth, but at the expense of speed.
85 citations
TL;DR: In this article, a new scheme for all-optical signal reshaping is proposed, which is based on four-wave mixing (FWM) in dispersion-shifted fiber (DSF).
Abstract: A new scheme for all-optical signal reshaping is proposed. It is shown that proper adjustment of the operating conditions of a wavelength converter based on four-wave mixing (FWM) in dispersion-shifted fiber (DSF) results in significant extinction ratio enhancement and noise suppression of the converted signal. The key issue in the proposed idea is the application of the modulation bitstream on the input pump wave. Detailed numerical simulation shows that it is possible to achieve a wavelength-converted output with extinction ratio of 20 dB when the extinction ratio of the input signal is 10.5 dB, while at the same time, the improvement in the Q-factor is almost 6 (from 6.5 at the input, it becomes more than 12 at the output). The theoretical predictions have been experimentally confirmed by measuring the transfer function of the FWM in a 17-km-long DSF under different operating conditions. The obtained results are in a very good agreement with those predicted theoretically.
71 citations
TL;DR: In this article, a combination of a passively mode-locked Nd:YVO 4 pump laser with 10 ps pump pulse duration at 1064 nm and a dispersion-adapted air-silica microstructured fiber generates supercontinuum radiation with an average power of 2.4 W in a spectral range from 700 to 1600 nm.
69 citations
TL;DR: This work presents what is to their knowledge the first complete measurement of the dependence of Raman gain on chromatic dispersion, fully revealing the influence of parametric four-wave mixing on stimulated Raman scattering.
Abstract: We present what is to our knowledge the first complete measurement of the dependence of Raman gain on chromatic dispersion, fully revealing the influence of parametric four-wave mixing on stimulated Raman scattering. In particular, a threefold increase of the Raman gain is observed under phase-matching conditions, in excellent agreement with theoretical predictions. Our experiments, which were performed in a photonic crystal fiber, demonstrate that these unique fibers can be exploited to boost the performances of fiber Raman amplifiers.
67 citations
TL;DR: The four-wave mixing theory developed here is based on the full wave equation, which allows rigorous study of the unstable bands even when the detunings are of the order of the pump frequency itself.
Abstract: Four-wave mixing instabilities are theoretically studied for continuous wave propagation in ultrasmall core photonic-crystal and tapered fibers. The waveguide, or geometrical, contribution to the overall dispersion of these structures is much stronger than in conventional fibers. This leads to the appearance of unstable frequency bands that are qualitatively and quantitatively different from those seen in conventional fibers. The four-wave mixing theory developed here is based on the full wave equation, which allows rigorous study of the unstable bands even when the detunings are of the order of the pump frequency itself. Solutions obtained using the generalized nonlinear Schrodinger equation, which is an approximate version of the full wave equation, reveal that it suffers from several deficiencies when used to describe four-wave mixing processes.
58 citations
27 Oct 2003
TL;DR: In this article, a numerical study of the mixing of two fluids (pure water and a solution of glycerol in water) in a microchannel was carried out, and the mixing behavior with changes in the difference of the properties of the two fluids(e.g., viscosity, density, diffusivity) was investigated.
Abstract: A numerical study of the mixing of two fluids(pure water and a solution of glycerol in water) in a microchannel was carried out. By varying the glycerol content of the glycerol/water solution, the variation in mixing behavior with changes in the difference of the properties of the two fluids(e.g., viscosity, density, diffusivity) was investigated. The mixing phenomena were tested for three micromixers: a square mixer, a three-dimensional serpentine mixer, and a staggered herringbone mixer. The governing equations of continuity, momentum and solute mass fraction were solved numerically. To evaluate mixing performance, a criterion index of mixing of mixing uniformity was proposed. In the systems considered, the Reynolds numbers based on averaged properties were 1 and 10. For low Reynolds number (Re = 1), the mixing performance varied inversely with mass fraction of glycerol due to the dominance of molecular diffusion. The mixing performance by diffusion deteriorated due to a significant reduction in the residence time of the fluid inside the mixers.
53 citations
TL;DR: A dual electromagnetically induced transparency (EIT) based multiwave mixing scheme that retains the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves, yet is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that limits the further growth of the four-wave mixing (FWM) field.
Abstract: We propose a dual electromagnetically induced transparency (EIT) based multiwave mixing scheme that retains the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves, yet is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that limits the further growth of the four-wave mixing (FWM) field. We show that the new scheme exhibits a wave-matching condition that is fundamentally different from the conventional FWM without EIT, and the efficient generation of the mixing wave is not critically dependent upon the FWM detuning to achieve constructive interference as required in the conventional FWM. These are significant steps forward in enabling applications of ultraslow wave nonlinear optics.
TL;DR: In this article, the photorefractive nature of the photo-induced grating is confirmed by the observation of asymmetric two-beam coupling and degenerate four-wave mixing experiments.
Abstract: CdSe/CdS core/shell, tri-n-octylphosphine oxide passivated, quantum dots are used to sensitize a photorefractive polymer composite. The composite also consists of poly(N-vinylcarbazole) as the nominally charge transporting matrix and an electro-optic chromophore. The efficacy of sensitization and consequent photorefractive performance is investigated using transmission spectroscopy and ellipsometry, two-beam coupling and degenerate four-wave mixing experiments. The photorefractive nature of the photo-induced grating is confirmed by the observation of asymmetric two-beam coupling. Four-wave mixing reveals record diffraction efficiencies for a nano-particle-sensitized photorefractive polymer at the field levels applied (1.3% at 70 V.μm−1). A recently developed analytical technique is used to extract space-charge field rise time values from degenerate four-wave mixing transients. In turn, analysis of the dependence of the rise time on applied field is used to determine the zero-field charge dissocia...
TL;DR: In this article, a detailed study on super-dense wavelength division multiplexing (WDM) transmission of spectrum-sliced incoherent light used for a wide-area access network is presented.
Abstract: This paper presents a detailed study on superdense wavelength-division multiplexing (WDM) transmission of spectrum-sliced incoherent light used for a wide-area access network. The transmission performance possible with this approach is evaluated numerically with regard to the following items: the transmission limit due to the chromatic dispersion, optimized signal-to-noise ratio design for the optical spectral width taking into account the adjacent-channel crosstalk, and the nonlinear effect generated by four-wave mixing at around the zero-dispersion wavelength. Superdense WDM transmission is also performed experimentally using 25-GHz channel-spaced, 15-GHz wide, up-to 156-Mb/s signals through up to 120 km of dispersion-shifted fiber.
TL;DR: The process of optical frequency doubling in the undepleted regime can lead to the generation of an X-wave envelope with group velocity locked to the pump beam, which constitutes a novel mechanism for spatiotemporal localization of light.
Abstract: The process of optical frequency doubling in the undepleted regime can lead to the generation of an X-wave envelope with group velocity locked to the pump beam. Its parameters and its angular spectrum are directly related to the zeroth- and first-order dispersive features of the nonlinear process. This constitutes a novel mechanism for spatiotemporal localization of light.
TL;DR: In this paper, a statistical analysis is presented that takes into account both the effect on the FWM intermodulation products due to dispersive propagation, and the statistics of such inter-modulation terms, which must be considered as random processes.
Abstract: The dense wavelength-division-multiplexed system design requires an accurate knowledge of the four-wave mixing (FWM), which gives rise to intermodulation effects, especially when using very low-dispersion fibers. In this letter, a statistical analysis is presented that takes into account both the effect on the FWM intermodulation products due to dispersive propagation, and the statistics of such intermodulation terms, which must be considered as random processes. In particular, the autocorrelation function of the FWM process is calculated for the independent wavelength-division-multiplexing optical channel.
TL;DR: In this paper, the authors investigated the nonlinear interaction between two photons in a single-input pulse at an atomic two-level nonlinearity and showed that the interaction generates spatiotemporal entanglement in the output state similar to the entanglements observed in parametric down-conversion.
Abstract: We investigate the nonlinear interaction between two photons in a single-input pulse at an atomic two-level nonlinearity. A one-dimensional model for the propagation of light to and from the atom is used to describe the precise spatiotemporal coherence of the two-photon state. It is shown that the interaction generates spatiotemporal entanglement in the output state similar to the entanglement observed in parametric down-conversion. A method of generating photon pairs from coherent pump light using this quantum-mechanical four-wave mixing process is proposed.
TL;DR: In this paper, the authors show that the choice of an input polarization tilted with respect to the fiber-birefringence axis can lead to the generation of new frequencies through a four-wave mixing process that exploits non-diagonal components of the third-order susceptibility.
TL;DR: In this article, a triply vibrationally enhanced four-wave mixing method was used to measure the frequency domain coherent two-dimensional vibrational spectrum of Ni(CO)2(PPh3)2 and Ni( CO)3PPh 3 using two excitation frequencies.
TL;DR: In this paper, a new simple technique for the simultaneous measurement of nonlinear coefficient, zero-dispersion wavelength, and chromatic dispersion in dispersion-shifted fibers based on partially degenerated four-wave mixing was proposed.
TL;DR: In this article, the authors show that although the efficiency of a multi-wave mixing process can be significantly enhanced by an ultra-slowly-propagating pump wave, a three-photon destructive interference between the generated wave and the pump wave limits the final achievable conversion efficiency.
Abstract: We show that, although the efficiency of a multiwave mixing process can be significantly enhanced by an ultra-slowly-propagating pump wave, a three-photon destructive interference between the generated wave and the pump wave limits the final achievable conversion efficiency.
TL;DR: The results obtained prove that this new nondestructive method based on using Brillouin optical time-domain analysis to probe the power distribution of the four-wave mixing generated by two continuous-wave lasers is capable of providing better performance than comparable techniques.
Abstract: A new nondestructive method for measuring the spatial distribution of chromatic dispersion along an optical fiber is presented. It is based on using Brillouin optical time-domain analysis to probe the power distribution of the four-wave mixing generated by two continuous-wave lasers. The results obtained prove that this new method is capable of providing better performance than comparable techniques. Furthermore, sensing the variations of Brillouin gain maximum produces additional information about the fiber, such as presence of strain and concentration of GeO2.
10 Nov 2003
TL;DR: The results suggest that, under certain conditions, there is no loss in basing the allocation of long routes only on the amount of FWM contamination of the new path, and not on the other active paths.
Abstract: This work presents a study on the impact of the four wave mixing in dynamic optical networks. We have proposed two algorithms for routing and wavelength assignment based on the limitations imposed by four wave mixing crosstalk. When the efficiency of the effect is not very high, the algorithms present a good performance in order to minimize the four wave mixing. The results suggest that, under certain conditions, there is no loss in basing the allocation of long routes only on the amount of FWM contamination of the new path, and not on the other active paths.
TL;DR: In this article, the authors observed experimentally four-wave mixing (FWM) between a 14-nm pump and a 15-nm signal in a forward-pumped distributed Raman amplifier (DRA) over 50 km of nonzero dispersion-shifted fiber with a zero dispersion wavelength of 1497 nm.
Abstract: We observed experimentally four-wave mixing (FWM) between a 14xx-nm pump and a 15xx-nm signal in a forward-pumped distributed Raman amplifier (DRA) over 50 km of nonzero dispersion-shifted fiber with a zero dispersion wavelength of 1497 nm. The 100-mW pump Fabry-Perot (FP) spectra centered at 1440, 1450, and 1460 nm are reproduced via FWM around the single-wavelength probe signal around 1558, 1548, and 1538 nm, respectively. The suppression of DRA gain by about 2-3 dB was experimentally observed with peak FWM at minimum phase mismatching between two 14xx-nm FP pump wavelengths and two 15xx-nm signal wavelengths. This DRA gain suppression, together with the reproduced pump FP spectrum at 15xx-nm signal band, may limit the usefulness of the forward-pumped DRA, generating spectrally nonuniform FWM-induced noise floors and crosstalk in wavelength-division-multiplexed fiber-optic transmission systems.
TL;DR: In this article, a dual-pump four-wave mixing for wavelength conversion is demonstrated using a distributedfeedback laser integrated with two electroabsorption modulators, where the device acts as both the conversion medium and the dualpump source.
Abstract: Dual-pump four-wave mixing for wavelength conversion is demonstrated using a distributed-feedback laser integrated with two electroabsorption modulators. The device acts as both the conversion medium and the dual-pump source. For a given input probe signal, output conjugate signal-to-noise ratio values of greater than 10 dB were measured over probe wavelengths ranging from 1557 to 1564 nm for a probe-conjugate detuning of 0.5 nm.
TL;DR: It is shown here that a thin film of a nonlinear conjugated polymer: poly(p-phenylenevinylene) (PPV) is capable of efficiently generating the third harmonic of femtosecond pulses of light at the near infrared wavelengths, giving coherent, low divergence beams in the visible range.
Abstract: We show here that a thin film of a nonlinear conjugated polymer: poly(p-phenylenevinylene) (PPV) is capable of efficiently generating the third harmonic of femtosecond pulses of light at the near infrared (including telecommunication bands) wavelengths, giving coherent, low divergence beams in the visible range. By using more than one fundamental beam overlapping in space and in time on the PPV film, autocorrelation signals are observed as well as higher order mixing signals due to X(5) and higherorder nonlinear susceptibilities. These signals can be used for applications such as short laser pulse diagnostics and photonic signal processing and they provide information about the nonlinear properties of the material itself.
TL;DR: In this article, a parametric four-wave mixing process for 80-fs Ti:sapphire-laser pulses was proposed to achieve pump-depleting conversion of 800-nm radiation to the spectral range around 500 nm.
Abstract: Four-wave mixing processes are shown to provide a high efficiency of non-linear optical frequency conversion and spectral transformation of ultrashort pulses in supercontinuum-generating microstructure fibers. Pump-depleting conversion of 800-nm radiation to the spectral range around 500 nm is achieved by phase-matching the parametric four-wave mixing process for 80-fs Ti:sapphire-laser pulses. The ways to use microstructure fibers for generating frequency-tunable radiation through four-wave mixing with the maximum efficiency of pump-field frequency conversion are discussed.
Patent•
13 Mar 2003
TL;DR: In this article, a distributed Raman amplifier with multiple pump sources for wide band amplification of wavelength division multiplexed (WDM) signals is described, and various approaches are described to ensure that the pump wavelengths do not interact in FWM in the transmission span.
Abstract: The specification describes a distributed Raman amplifier with multiple pump sources for wide band amplification of wavelength division multiplexed (WDM) signals. It was recognized that using multiple pump sources introduces non-linear effects, such as four wave mixing (FWM). These effects are reduced by multiplexing the pump wavelengths in the multiple pump source. It was also recognized that not all of the pump wavelengths over the wavelength spectrum of the pumps contributes to FWM. Thus fewer than all of the pump wavelengths require multiplexing to eliminate FWM in the multiple wavelength pump source. Various approaches are described to ensure that the pump wavelengths do not interact in FWM in the transmission span. The selected individual pump wavelengths may be either time division multiplexed, or frequency modulated.
TL;DR: In this article, the performance of an optical wavelength-division multi-plexed system is analyzed taking the four-wave mixing (FWM) effect into account, and various other dispersion management mechanisms are also considered in addition to different channel spacing schemes to achieve a comparative study as to which scheme gives the best solution to the FWM problem.
Abstract: The performance of an optical wavelength-division multi- plexed system is analyzed taking the four-wave mixing (FWM) effect into account. The efficiency of FWM generation is observed to greatly reduce if the spacing between channels is made unequal. However, the scheme requires an increased bandwidth, which can further be reduced by utiliz- ing another scheme called repeated unequal channel spacing. Also the FWM efficiency is found to reduce in the presence of chromatic disper- sion. Use of nonuniform chromatic dispersion along the fiber length, which reduces the FWM effect while maintaining a low value of disper- sion is investigated. Various other dispersion management mechanisms are also considered in addition to different channel spacing schemes to achieve a comparative study as to which scheme gives the best solution to the FWM problem. © 2003 Society of Photo-Optical Instrumentation Engineers.
TL;DR: In this article, the authors proposed a new Raman pump module that effectively reduces four-wave mixing (FWM) nonlinear interaction among longitudinal pump modes and wavelength-division-multiplexed (WDM) signals in co-pumped distributed Raman amplifiers based on nonzero dispersion-shifted fibers (NZ-DSFs).
Abstract: We propose a new Raman pump module that effectively reduces four-wave-mixing (FWM) nonlinear interaction among longitudinal pump modes and wavelength-division-multiplexed (WDM) signals in co-pumped distributed Raman amplifiers based on nonzero dispersion-shifted fibers (NZ-DSFs). Theory and experiments confirm that the proposed pump module structure, based on polarization- and wavelength-multiplexed Fabry-Perot lasers, allows distributed amplification with high co-propagating on-off Raman gain, providing a key technology for all-Raman-based dense-WDM ultralong-haul transmission.