Showing papers on "Four-wave mixing published in 2005"
TL;DR: The observation of four-wave mixing phenomenon in a simple silicon wire waveguide at the optical powers normally employed in communications systems and the wavelength conversion for data rate of 10-Gbps using a 5.8-cm-long silicon wire is reported.
Abstract: We report the observation of four-wave mixing phenomenon in a simple silicon wire waveguide at the optical powers normally employed in communications systems. The maximum conversion efficiency is about -35 dB in the case of a 1.58-cm-long silicon wire waveguide. The nonlinear refractive index coefficient is found to be 9×10-18 m2/W. This value is not negligible for dense wavelength division multiplexing components, because it predicts the possibility of large crosstalk. On the other hand, with longer waveguide lengths with smaller propagation loss, it would be possible to utilize just a simple silicon wire for practical wavelength conversion. We demonstrate the wavelength conversion for data rate of 10-Gbps using a 5.8-cm-long silicon wire. These characteristics are attributed to the extremely small core of silicon wire waveguides.
415 citations
TL;DR: The characteristics of quantum-correlated photon pair generation in a DSF cooled by liquid nitrogen is described and the number of noise photons was sufficiently suppressed and the ratio of true coincidence to accidental coincidence was increased to ~30.
Abstract: Spontaneous four-wave mixing in a dispersion-shifted fiber (DSF) is a promising approach for generating quantum-correlated photon pairs in the 1.5 μm band. However, it has been reported that noise photons generated by the spontaneous Raman scattering process degrade the quantum correlation of the generated photons. This paper describes the characteristics of quantum-correlated photon pair generation in a DSF cooled by liquid nitrogen. With this technique, the number of noise photons was sufficiently suppressed and the ratio of true coincidence to accidental coincidence was increased to ~30.
202 citations
TL;DR: Optical frequency conversion by four-wave mixing (Bragg scattering) in a fiber is considered and it is found that the frequencies and polarizations of the waves are chosen judiciously enable the translation of individual and entangled states.
Abstract: Optical frequency conversion by four-wave mixing (Bragg scattering) in a fiber is considered. If the frequencies and polarizations of the waves are chosen judiciously, Bragg scattering enables the translation of individual and entangled states, without the noise pollution associated with parametric amplification (modulation instability or phase conjugation), and with reduced noise pollution associated with stimulated Raman scattering.
165 citations
TL;DR: By combining multiple photonic crystal fibers with sequentially decreasing zero-dispersion wavelengths, a 1.2 W average-power white-light continuum is produced, covering the visible-near-infrared spectrum from 0.44 to 1.89 microm, with an all-fiber picosecond ytterbium pump laser.
Abstract: By combining multiple photonic crystal fibers with sequentially decreasing zero-dispersion wavelengths we have produced a 1.2?W average-power white-light continuum, covering the visible–near-infrared spectrum from 0.44to1.89??m (10?dB width), with an all-fiber picosecond ytterbium pump laser. Wavelengths as short as the ultraviolet (0.35??m), and spectral power densities of more than 2?mW?nm in the blue spectral region, have been generated. The process is understood in terms of optimizing four-wave mixing phase matching to enhance short-wavelength generation.
143 citations
TL;DR: Optical two-dimensional Fourier transform spectroscopy is implemented near 800 nm with active stabilization and shows light-hole and heavy-hole exciton transitions as the diagonal peaks and coupling between these two resonances as off-diagonal peaks.
Abstract: Optical two-dimensional Fourier transform spectroscopy is implemented near 800 nm with active stabilization. Excitation pulse delay is stabilized during data acquisition and stepped with interferometric accuracy. The reference used for heterodyne detecting the complete transient four-wave mixing signal is also phase-stabilized. The phase evolution of the four-wave mixing signal during the initial evolution period and the final detection period is then measured and correlated. Two-dimensional spectra with absorption and emission frequency axes are obtained by Fourier transforms with respect to the corresponding time variables. Measurement performed on a GaAs multiple quantum well sample shows light-hole and heavy-hole exciton transitions as the diagonal peaks and coupling between these two resonances as off-diagonal peaks.
134 citations
TL;DR: In this article, the achievable information rates for high-speed optical transmission (40 Gb/s and above) are calculated using the finite-state-machine approach, where the combined effect of ASE noise, Kerr nonlinearity [self-phase modulation (SPM), intrachannel four-wave mixing (IFWM), intra-channel cross-phase modulation (IXPM)], stimulated Raman scattering (SRS), chromatic dispersion, and (optical/electrical) filtering is taken into account.
Abstract: There have been numerous attempts to determine the channel capacity of a nonlinear fiber-optic communication channel. The main approach was to consider amplified spontaneous emission (ASE) noise as a predominant effect and to observe the fiber nonlinearities as the perturbation of a linear case or as the multiplicative noise. In this paper, the achievable information rates for high-speed optical transmission (40 Gb/s and above) are calculated using the finite-state-machine approach. In calculations, the combined effect of ASE noise, Kerr nonlinearity [self-phase modulation (SPM), intrachannel four-wave mixing (IFWM), intrachannel cross-phase modulation (IXPM)], stimulated Raman scattering (SRS), chromatic dispersion, and (optical/electrical) filtering is taken into account.
120 citations
TL;DR: In this article, a spontaneous four-wave mixing process was employed in a dispersion shifted fiber, with which correlated photon pairs with very narrow bandwidths were generated efficiently and obtained coincidence fringes with 99% visibilities after subtracting accidental coincidences.
Abstract: This paper reports $1.5\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$ band time-bin entanglement generation. We employed a spontaneous four-wave mixing process in a dispersion shifted fiber, with which correlated photon pairs with very narrow bandwidths were generated efficiently. To observe two-photon interference, we used planar lightwave circuit based interferometers that were operated stably without feedback control. As a result, we obtained coincidence fringes with 99% visibilities after subtracting accidental coincidences, and successfully distributed entangled photons over 20-km standard single-mode fiber without any deterioration in the quantum correlation.
112 citations
TL;DR: In this paper, a 3-dB conversion range over 40 nm (1535-1575 nm) was obtained with a flat conversion efficiency of -16 dB and a polarization sensitivity of less than 0.3 dB using four-wave mixing in a 64-m-long dispersion-flattened nonlinear photonic crystal fiber.
Abstract: Polarization-insensitive widely tunable wavelength conversion has been demonstrated using four-wave mixing in a 64-m-long dispersion-flattened nonlinear photonic crystal fiber. A 3-dB conversion range over 40 nm (1535-1575 nm) is obtained with a flat conversion efficiency of -16 dB and a polarization sensitivity of less than 0.3 dB. The measured power penalty is less than 1 dB for a 10-Gb/s converted nonreturn-to-zero signal at 10/sup -9/ bit-error rate.
109 citations
TL;DR: In this article, the self-stabilizing effect of four-wave mixing (FWM) is analyzed and proven by using the undepleted approximation and the perturbation method.
Abstract: Self-stabilizing effect of four-wave mixing (FWM) is analyzed and proven in this letter by using the undepleted approximation and the perturbation method. Multiwavelength erbium-doped fiber lasers with excellent stability and uniformity are demonstrated experimentally at room temperature. The novel fiber lasers are stabilized and equalized as a result of the balance between the self-stabilizing function of FWM and the mode competition effect of erbium-doped fiber.
99 citations
TL;DR: A 10 Gbit/s nonreturn-to-zero wavelength converter based on four-wave mixing in a 20 m highly nonlinear photonic crystal fiber is demonstrated and the linewidth of the converted wavelength remained very narrow.
Abstract: We demonstrate a 10?Gbit?s nonreturn-to-zero wavelength converter based on four-wave mixing in a 20?m highly nonlinear photonic crystal fiber. The tunable wavelength conversion bandwidth (3?dB) is about 100?nm. The conversion efficiency is ?16?dB when the pump power is 22.5?dBm. Phase modulation was not used to suppress the stimulated Brillouin scattering; thus the linewidth of the converted wavelength remained very narrow. The eye diagrams show that there is no additional noise during wavelength conversion. The measured power penalty at a 10?9? bit-error-rate level is about 0.7?dB.
89 citations
TL;DR: An efficient method has been developed for the calculation of third-order time- and frequency-resolved optical signals that allows for any pulse durations and automatically accounts for pulse-overlap effects.
Abstract: An efficient method has been developed for the calculation of third-order time- and frequency-resolved optical signals. To obtain the general four-wave mixing signal, seven auxiliary density matrices have to be propagated in time. For the special cases of two-pulse photon-echo and transient-grating signals, two or three density matrices, respectively, are required. The method is limited to weak laser fields (it is thus valid within the third-order perturbation theory) but allows for any pulse durations and automatically accounts for pulse-overlap effects. To illustrate the method, we present the explicit derivation of the three-pulse photon-echo signal. Any other third-order optical signal can be calculated in the same manner. As an example, two- and three-pulse photon-echo and transient-grating signals for a weakly damped displaced harmonic oscillator have been calculated.
TL;DR: Stability enhancement on the basis of four-wave mixing (FWM) is proposed and proved for the first time to the authors' knowledge and significant uniformity and stability of the novel fiber lasers are demonstrated experimentally.
Abstract: Stability enhancement on the basis of four-wave mixing (FWM) is proposed and proved for the first time to our knowledge. This technique is applied to dual-wavelength erbium-doped fiber lasers. Significant uniformity and stability of the novel fiber lasers are demonstrated experimentally.
TL;DR: In this paper, a 40-Gb/s return-to-zero differential phase-shift keying signal is demonstrated in highly nonlinear photonic crystal fiber (HNL-PCF) for the first time.
Abstract: Wavelength conversion of a 40-Gb/s return-to-zero differential phase-shift keying signal is demonstrated in a highly nonlinear photonic crystal fiber (HNL-PCF) for the first time. A conversion efficiency of -20 dB for a pump power of 23 dBm and a conversion bandwidth of 31 nm, essentially limited by the gain bandwidth of erbium-doped fiber amplifiers, are obtained in only 50-m dispersion-flattened HNL-PCF with nonlinear coefficient equal to 11 W/sup -1//spl middot/km/sup -1/. This experiment demonstrates the potential of four-wave mixing in HNL-PCF as a modulation format and bit rate transparent wavelength conversion mechanism in future high-speed systems.
TL;DR: In this paper, the four-wave mixing in a double-V scheme via robust electron spin coherence in semiconductor quantum wells was analyzed, and the results demonstrated that the electromagnetically induced gain loss, the electromagnetic induced absorption and superluminal propagation phenomena may be realized in quantum quantum wells at room temperatures.
TL;DR: In this article, the authors proposed a novel tunable all-optical wavelength-conversion and wavelength-multicasting schemes by using orthogonally polarized nondegenerate four-wave mixing (FWM) in highly nonlinear fiber.
Abstract: All-optical wavelength conversion and multicasting with input and output wavelength tunability is a desired component for reconfigurable wavelength-division-multiplexed (WDM) networks for improving the efficiency and performance. In this paper, we propose a novel tunable all-optical wavelength-conversion-and-wavelength-multicasting schemes by using orthogonally polarized nondegenerate four-wave mixing (FWM) in highly nonlinear fiber. The input signal is amplified and serves as one of the two pumps. Wide tunability is obtained by placing a dummy pump and dummy signals at appropriate wavelengths with respect to the input wavelength and desired output wavelengths. For a 10-Gb/s NRZ system, 1:3 multicasting is demonstrated with a less than 0.6-dB power penalty, over a 25-nm tuning range for both input and output signals.
TL;DR: In this paper, a quantum theory of two-photon state generation via four-wave mixing in optical fibers is studied, with emphasis on the case where the pump is a classical, narrow (picosecond-duration) pulse.
Abstract: A quantum theory of two-photon-state generation via four-wave mixing in optical fibers is studied, with emphasis on the case where the pump is a classical, narrow (picosecond-duration) pulse. One of the experiments performed in our lab is discussed and analyzed. Numerical predictions from the theory are shown to be in good agreement with the experimental results.
Journal Article•
TL;DR: In this paper, the self-stability of multiple four-wave mixing (FWM) processes in the optical fibers is studied both theoretically and experimentally, and coupled-mode equations for the complex amplitudes of four waves are derived.
Abstract: The self-stability of multiple four-wave mixing (FWM) processes in the optical fibers is studied both theoretically and experimentally. The coupled-mode equations for the complex amplitudes of four waves are derived. The nonlinear interaction between four optical fields involves a single nondegenerate and two degenerate FWM processes in the third-order nonlinear mixings. The proposed models are compared to the conventional coupled-mode theory of FWM processes and are proven by the experiments. The energy conservation of four waves is achieved, and the power flow relationship between two pump waves and two created waves is obtained. The analytic solutions reveal the self-stability mechanism of multiple FWM processes. The self-stability prediction is experimentally testified by using a kind of photonic-crystal fiber, and such excellence can be applied to achieve dual-wavelength erbium-doped fiber lasers with the excellent uniformity and stability.
TL;DR: In this article, the self-stability of multiple four-wave mixing (FWM) processes in the optical fibers is studied both theoretically and experimentally, and coupled-mode equations for the complex amplitudes of four waves are derived.
Abstract: The self-stability of multiple four-wave mixing (FWM) processes in the optical fibers is studied both theoretically and experimentally. The coupled-mode equations for the complex amplitudes of four waves are derived. The nonlinear interaction between four optical fields involves a single nondegenerate and two degenerate FWM processes in the third-order nonlinear mixings. The proposed models are compared to the conventional coupled-mode theory of FWM processes and are proven by the experiments. The energy conservation of four waves is achieved, and the power flow relationship between two pump waves and two created waves is obtained. The analytic solutions reveal the self-stability mechanism of multiple FWM processes. The self-stability prediction is experimentally testified by using a kind of photonic-crystal fiber, and such excellence can be applied to achieve dual-wavelength erbium-doped fiber lasers with the excellent uniformity and stability.
Journal Article•
TL;DR: In this paper, a five-level tripod scheme is proposed for obtaining a high efficiency four-wave mixing process, where double-dark resonances lead to a strong modification of the absorption and dispersion properties against a pump wave at two transparency windows.
Abstract: A five-level tripod scheme is proposed for obtaining a high efficiency four-wave-mixing (FWM) process. The existence of double-dark resonances leads to a strong modification of the absorption and dispersion properties against a pump wave at two transparency windows. We show that both of them can be used to open the four-wave mixing channel and produce efficient mixing waves. In particular, higher FWM efficiency is always produced at the transparent window corresponding to the relatively weak-coupling field. By manipulating the intensity of the two coupling fields, the conversion efficiency of FWM can be controlled.
TL;DR: A depolarization technique to achieve polarization-insensitive wavelength conversion using four-wave mixing in an optical fiber and the relation between the conversion efficiency and the degree of polarization of the pump was formulated.
Abstract: We have developed a depolarization technique to achieve polarization-insensitive wavelength conversion using four-wave mixing in an optical fiber. A maximum conversion efficiency of -11.79 dB was achieved over a 3 dB bandwidth of 26 nm in a 100-m-long dispersion-flattened photonic crystal fiber. The polarization-dependent conversion efficiency was less than 0.38 dB and the measured power penalty for a 10 Gbit/s NRZ signal was 1.9 dB. The relation between the conversion efficiency and the degree of polarization of the pump was also formulated.
TL;DR: In this article, a parametric amplifier configuration that enables real-time monitoring of the net dispersion experienced by a pulse train is presented, which can be used in a feedback loop with a tunable dispersion compensator.
Abstract: This paper presents a parametric amplifier configuration that enables real-time monitoring of the net dispersion experienced by a pulse train. Fast detection or fast electronic signal processing is not required. The device exploits cascaded four-wave mixing (FWM) in an optical fiber and exhibits parametric gain and frequency conversion efficiency of more than 18 dB. Dispersion monitoring with 11-ps pulses that have experienced a net dispersion of /spl plusmn/180ps/nm are demonstrated. These pulses are similar to those to be used in high-bandwidth (/spl sim/40Gb/s) communication systems. The device is compatible with 160-Gb/s systems. Parametric amplification within the device enables simultaneous dispersion monitoring, wavelength conversion, and amplification. The monitor can be used in a feedback loop with a tunable dispersion compensator, allowing dispersion to be managed. Equations governing the FWM process are presented; there is good agreement between the simulated and measured results. The equations are further used to understand which of the several FWM processes within the device dominate.
TL;DR: In this paper, two new techniques, the hybrid amplitude/frequency shift keying (ASK/FSK) modulation and the use of prechirped pulses, are investigated.
Abstract: The performance of a wavelength-division multiplexing (WDM) optical network can be severely degraded due to fiber nonlinear effects. In the case where nonzero dispersion (NZD) fibers are employed, the four-wave mixing (FWM) effect sets an upper limit on the input power, especially in the case of narrow channel spacing. In order to reduce FWM-induced distortion two new techniques, the hybrid amplitude-/frequency-shift keying (ASK/FSK) modulation and the use of prechirped pulses are investigated. It is shown that both techniques can greatly improve the Q-factor in a 10 Gb/s WDM system. This happens even for very high input powers (/spl sim/10 dBm), where the degradation of the conventional WDM system is prohibitively high. The proposed methods are also applied and tested in higher bit rates (40 Gb/s). It is deduced that although the hybrid ASK/FSK modulation technique marginally improves the system performance, the optical prechirp technique can still be used to greatly increase the maximum allowable input power of the system.
TL;DR: In this paper, the authors proposed a scheme via four-wave mixing in a double-Λ system to generate a maximally entangled state of two light beams (the probe laser beam and the four-waving mixing beam), which propagates with ultralow group velocity.
Abstract: We propose a scheme via four-wave mixing in a double-Λ system to generate a maximally entangled state of two light beams (the probe laser beam and the four-waving mixing beam), which propagates with ultraslow group velocity. It appears to be the first scheme to achieve an ultra-slowly propagating maximally entangled state of lights.
TL;DR: In this paper, an all-optical AND logic gate based on the four-wave mixing (FWM) effect in an InGaAsP-InP microring resonator side-coupled to a bus waveguide, is proposed and simulated.
Abstract: An all-optical AND logic gate based on the four-wave mixing (FWM) effect in an InGaAsP-InP microring resonator side-coupled to a bus waveguide, is proposed and simulated. Using an ultrafast nonlinear process such as FWM, operation at a bit rate up to 160 Gb/s is demonstrated for the return-to-zero modulation format.
TL;DR: In this paper, the effect of optical limiters on phase shift-keying (DPSK) transmission in a quasi-linear highly dispersed-pulse system with and without limiters is investigated.
Abstract: Improvement of transmission performance of phase-shift-keying signals by the use of ultrafast optical limiters (amplitude regenerators) based on four-wave mixing (FWM) in fibers is theoretically and numerically studied. Theoretical analysis focuses on the nonlinear phase noise (the Gordon-Mollenauer effect) and its reduction by the limiters. It is shown that the cubic growth of the phase variance as the distance extends can be suppressed by the limiters that are periodically inserted in the system, although some additional phase noise is introduced by them. Numerical simulation is performed for nonreturn-to-zero (NRZ) differential phase-shift-keying (DPSK) transmission in a quasi-linear highly dispersed-pulse system with and without limiters. The results show that the maximum transmission distance is extended by the limiters. A clear indication of nonlinear phase-noise reduction at the high-signal-power regime, however, is not seen. This is attributed to the existence of intrachannel-FWM-induced phase fluctuation, which cannot be effectively suppressed by the amplitude limiter.
TL;DR: It is shown that the angle-wavelength spectra of light filaments excited by ultrashort pulses experience a transition from X- to O-like structures when their carrier wavelengths are switched from normal to anomalous dispersion.
Abstract: We show that the angle–wavelength spectra of light filaments excited by ultrashort pulses experience a transition from X- to O-like structures when their carrier wavelengths are switched from normal to anomalous dispersion. Calculations confirm that the O-shaped conical emission follows the elliptic geometry of the nonlinear Schrodinger equation with anomalous dispersion.
TL;DR: In this article, a quantitative treatment of the 3D susceptibility that arises from excitation with noncollinear pulses and selective interference detection of signal in one phase matched direction is developed.
Abstract: Maxwell's equations for the apparently complicated generation and propagation of femtosecond four-wave-mixing signals in optically thick samples can be solved by triple Fourier transformation into the three-dimensional (3D) frequency domain. Given the linear absorption and refractive-index spectra, the propagation problem can be solved in three dimensions under the assumption that nonlinear distortions of the excitation pulses can be neglected. A propagation function exactly incorporates the linear evolution of the excitation pulses, the nonlinear generation of the signal, and the linear propagation of the signal. A quantitative treatment of the directional filtering of the 3D susceptibility that arises from excitation with noncollinear pulses and selective interference detection of signal in one phase-matched direction is developed. This 3D treatment is used to examine the influence of phase-matching bandwidth, directional filtering, and sample absorption on femtosecond four-wave-mixing signals in the rectangular and square boxcars phase-matching geometries.
TL;DR: In this paper, local field factors of about 5 are demonstrated for the crossed Kerr effect and a narrow resonance peak observed for the conjugate reflectivity for the four-wave mixing process with increasing pump intensities.
Abstract: Kerr and four-wave mixing spectroscopy is shown to be a powerful technique to quantify the strong enhancement of the third-order optical nonlinear susceptibilities at the band edge of photonic crystals. Local field factors of about 5 are demonstrated for crossed Kerr effect and a narrow resonance peak observed for the conjugate reflectivity. Moreover, a reduction of the effective nonlinear susceptibility of the four-wave mixing process with increasing pump intensities is measured, which is due to different Kerr-induced blueshifts of the band edge for forward and backward pump beams and signal and conjugate beams. This observation definitely demonstrates the need for considering all the nonlinear processes for the optimization of nonlinear photonic crystals for a given application in optical signal processing.
TL;DR: In this article, a 40 cm-long Bi-NLF was used as a nonlinear optical medium for wavelength conversion of a 40-Gb/s nonreturn-to-zero (NRZ) signal with no additional stimulated Brillouin scattering suppression scheme.
Abstract: We experimentally demonstrate a compact and tunable four-wave-mixing-based wavelength converter using a Bi/sub 2/O/sub 3/-based nonlinear fiber (Bi-NLF). An only 40-cm-long Bi-NLF is used as a nonlinear optical medium for wavelength conversion of a 40-Gb/s nonreturn-to-zero (NRZ) signal with no additional stimulated Brillouin scattering (SBS) suppression scheme. The Bi-NLF used in this experiment has an extremely high SBS threshold owing to both its short length and relatively low Brillouin gain. The 40-cm Bi-NLF is fusion-spliced to standard single-mode fibers and its nonlinearity is measured to be /spl sim/1100 W/sup -1//spl middot/km/sup -1/. Error-free wavelength conversion over a 10-nm bandwidth at a 40-Gb/s NRZ data rate is readily achieved with a pure continuous-wave pump.