Showing papers on "Four-wave mixing published in 2013"
TL;DR: A structure supporting the coherent oscillation of two distinct Fano resonances within an individual plasmonic nanocluster is reported, showing how this coherence enhances the optical four-wave mixing process in comparison with other double-resonant plAsmonic clusters that lack this property.
Abstract: Plasmonic nanoclusters, an ordered assembly of coupled metallic nanoparticles, support unique spectral features known as Fano resonances due to the coupling between their subradiant and superradiant plasmon modes. Within the Fano resonance, absorption is significantly enhanced, giving rise to highly localized, intense near fields with the potential to enhance nonlinear optical processes. Here, we report a structure supporting the coherent oscillation of two distinct Fano resonances within an individual plasmonic nanocluster. We show how this coherence enhances the optical four-wave mixing process in comparison with other double-resonant plasmonic clusters that lack this property. A model that explains the observed four-wave mixing features is proposed, which is generally applicable to any third-order process in plasmonic nanostructures. With a larger effective susceptibility χ(3) relative to existing nonlinear optical materials, this coherent double-resonant nanocluster offers a strategy for designing high-performance third-order nonlinear optical media.
211 citations
TL;DR: In this article, nondegenerate four-wave mixing (FWM) between waves belonging to different spatial modes of a 5 km-long few-mode fiber (FMF) has been experimentally demonstrated.
Abstract: We experimentally demonstrate nondegenerate four-wave mixing (FWM) between waves belonging to different spatial modes of a 5-km-long few-mode fiber (FMF). Of the three inter-modal FWM (IM-FWM) processes possible, two have been experimentally observed. These IM-FWM processes are found to be phase-matched over very large frequency separations of several Terahertz between the waves. In contrast to FWM in single-mode fibers that require operating near the zero-dispersion wavelength to achieve phase matching, IM-FWM in a FMF can be fully phase matched in the presence of large chromatic dispersion in each spatial mode.
161 citations
TL;DR: Narrow band pairs of time-correlated photons from nondegenerate four-wave mixing in a laser-cooled atomic ensemble of ^{87}Rb using a cascade decay scheme are observed, indicating a transform-limited spectrum of the photon pairs.
Abstract: We observe narrow band pairs of time-correlated photons of wavelengths 776 and 795 nm from nondegenerate four-wave mixing in a laser-cooled atomic ensemble of ^{87}Rb using a cascade decay scheme. Coupling the photon pairs into single mode fibers, we observe an instantaneous rate of 7700 pairs per second with silicon avalanche photodetectors, and an optical bandwidth below 30 MHz. Detection events exhibit a strong correlation in time [g((2))(τ = 0) ≈ 5800] and a high coupling efficiency indicated by a pair-to-single ratio of 23%. The violation of the Cauchy-Schwarz inequality by a factor of 8.4 × 10(6) indicates a strong nonclassical correlation between the generated fields, while a Hanbury Brown-Twiss experiment in the individual photons reveals their thermal nature. The comparison between the measured frequency bandwidth and 1/e decay time of g((2)) indicates a transform-limited spectrum of the photon pairs. The narrow bandwidth and brightness of our source makes it ideal for interacting with atomic ensembles in quantum communication protocols.
136 citations
TL;DR: This work demonstrates a promising solution: generation of heralded single photons in a silica photonic chip by spontaneous four-wave mixing, and calculates that similar high-heralded-purity output can be obtained from visible to telecom spectral regions using this approach.
Abstract: A key obstacle to the experimental realization of many photonic quantum-enhanced technologies is the lack of low-loss sources of single photons in pure quantum states. We demonstrate a promising solution: generation of heralded single photons in a silica photonic chip by spontaneous four-wave mixing. A heralding efficiency of 40%, corresponding to a preparation efficiency of 80% accounting for detector performance, is achieved due to efficient coupling of the low-loss source to optical fibers. A single photon purity of 0.86 is measured from the source number statistics without narrow spectral filtering, and confirmed by direct measurement of the joint spectral intensity. We calculate that similar high-heralded-purity output can be obtained from visible to telecom spectral regions using this approach. On-chip silica sources can have immediate application in a wide range of single-photon quantum optics applications which employ silica photonics.
134 citations
TL;DR: In this paper, it was shown that four wave mixing, combined with short gain recovery time, causes QCL to operate in the self-frequency-modulated regime characterized by a constant power in time domain and stable coherent comb in the frequency domain.
Abstract: One salient characteristic of Quantum Cascade Laser (QCL) is its very shor gain recovery time that so far thwarted the attempts to achieve self-mode locking of the device into a train of single pulses. We show theoretically that four wave mixing, combined with the short gain recovery time causes QCL to operate in the self-frequency-modulated regime characterized by a constant power in time domain and stable coherent comb in the frequency domain.Coherent frequency comb may enable many potential applications of QCL in sensing and measurement.
102 citations
TL;DR: In this article, an imprinting-exfoliation-wiping method is demonstrated to reduce the number of layers of graphite nano-particles and create a femtosecond passively mode-locked erbium doped fiber laser (EDFL).
Abstract: An imprinting–exfoliation–wiping method is demonstrated to reduce the number of layers of graphite nano-particles and create a femtosecond passively mode-locked erbium doped fiber laser (EDFL). As the number of exfoliations increases from 1 to 7, the linear transmittance of the graphite nano-particle increases from 0.44 to 0.9, and the modulation depth increases from 22% to 57%. Moreover, the 2D band of the graphite nano-particles in the Raman spectrum becomes intense and symmetric, which indicates the structural properties of the graphite nano-particles approach those of few-layer graphene. The passively mode-locked EDFL pulsewidth reduces from 755 to 375 fs as the number of exfoliations increases from 1 to 7, while the spectral linewidth broadens from 3.55 to 6.85 nm. The first-order Kelly sideband on the optical spectrum is observed with a frequency spacing Dυ decreasing from ±1.45 to ±1.35 THz. The frequency spacing of the second-order Kelly sideband decreases slightly from ±2.04 to ±2.01 THz on increasing from six to seven applications of the imprinting–exfoliation–wiping process. Apart from the Kelly sidebands, two spectral peaks arise on the soliton spectrum with the six-times exfoliated graphite nano-particles due to the nonlinear four-wave-mixing (FWM) effect of Kelly sidebands during propagation in the EDFL cavity.
90 citations
TL;DR: In this article, the authors report on four-wave mixing in coupled photonic crystal nano-cavities on a silicon-on-insulator platform, where three photonic wire cavities are side-coupled to obtain three modes equally separated in energy.
Abstract: We report on four-wave mixing in coupled photonic crystal nano-cavities on a silicon-on-insulator platform. Three photonic wire cavities are side-coupled to obtain three modes equally separated in energy. The structure is designed to be self-filtering, and we show that the pump is rejected by almost two orders of magnitude. We study both the stimulated and the spontaneous four-wave mixing processes: owing to the small modal volume, we find that signal and idler photons are generated with a hundred-fold increase in efficiency as compared to silicon micro-ring resonators.
79 citations
TL;DR: In this paper, the authors present the direct observation of four-wave mixing over a detuning range of more than 3 THz in an InGaAs/AlInAs strain-compensated quantum cascade laser (QCL) amplifier emitting at 4.3μm by simultaneous injection of a single mode QCL and a broadly tunable source.
Abstract: We present the direct observation of four-wave mixing over a detuning range of more than 3 THz in an InGaAs/AlInAs strain-compensated quantum cascade laser (QCL) amplifier emitting at 4.3 μm by simultaneous injection of a single mode QCL and a broadly tunable source. From its intensity, we determine a χ(3) of 0.9 × 10−15 m2 V−2, in good agreement with transport model simulations based on the density matrix approach. This four-wave-mixing mechanism is an important driving factor in mode proliferation occurring in connection with the recent demonstration of comb generation in broadband QCLs.
75 citations
TL;DR: The use of two pumps is advantageous over single-pump SFWM approaches towards tailoring the spectral correlations within the generated photon pairs, demonstrating the ability to produce factorable photon-pair states, and hence heralded single photons in a pure wave-packet.
Abstract: We study theoretically the joint spectral properties of photon-pairs produced through spontaneous four-wave mixing (SFWM) with two spectrally distinct pump pulses in optical fibers. We show that, due to the group velocity difference between the pulses, the signature of the interaction can be significantly different from spontaneous parametric down-conversion or SFWM with a single pump pulse. Specifically, we study the case where temporal walk-off between the pumps enables a gradual turn-on and turn-off of the interaction. By utilizing this property, we develop a new approach towards tailoring the spectral correlations within the generated photon pairs, demonstrating the ability to produce factorable photon-pair states, and hence heralded single photons in a pure wave-packet. We show that the use of two pumps is advantageous over single-pump SFWM approaches towards this goal: the usage of the dual-pump configuration enables, in principle, the creation of completely factorable states without any spectral filtering, even in media for which single-pump SFWM tailoring techniques are unsatisfactory, such as standard polarization-maintaining fiber.
73 citations
TL;DR: In this article, the role of the phase-matching condition in the trade-off that occurs between the efficiency of the nonlinear process and the absorption of the twin beams was investigated.
Abstract: Nondegenerate forward four-wave mixing in hot atomic vapors has been shown to produce strong quantum correlations between twin beams of light [McCormick et al., Opt. Lett. 32, 178 (2007)], in a configuration which minimizes losses by absorption. In this paper, we look at the role of the phase-matching condition in the trade-off that occurs between the efficiency of the nonlinear process and the absorption of the twin beams. To this effect, we develop a semiclassical model by deriving the atomic susceptibilities in the relevant double-$\ensuremath{\Lambda}$ configuration and by solving the classical propagation of the twin-beam fields for parameters close to those found in typical experiments. These theoretical results are confirmed by a simple experimental study of the nonlinear gain experienced by the twin beams as a function of the phase mismatch. The model shows that the amount of phase mismatch is key to the realization of the physical conditions in which the absorption of the twin beams is minimized while the cross coupling between the twin beams is maintained at the level required for the generation of strong quantum correlations. The optimum is reached when the four-wave mixing process is not phase matched for fully resonant four-wave mixing.
72 citations
TL;DR: The experimental results do not support the speculation that such excellent coherent emissions could originate from nonlinear optical processes such as four-wave mixing or stimulated Raman scattering, leaving stimulated amplification of harmonic seed due to the population inversion generated in molecular nitrogen ions the most likely mechanism.
Abstract: Recently, amplification of harmonic-seeded radiation generated through femtosecond laser filamentation in air has been observed, giving rise to coherent emissions at wavelengths corresponding to transitions between different vibrational levels of the electronic B2Σu+ and X2Σg+ states of molecular nitrogen ions [Phys. Rev. A. 84, 051802(R) (2011)]. Here, we carry out systematic investigations on its physical mechanism. Our experimental results do not support the speculation that such excellent coherent emissions could originate from nonlinear optical processes such as four-wave mixing or stimulated Raman scattering, leaving stimulated amplification of harmonic seed due to the population inversion generated in molecular nitrogen ions the most likely mechanism.
TL;DR: Using a compact optically pumped silicon nanophotonic chip consisting of coupled silicon microrings, photon pairs in multiple pairs of wavelengths around 1.55 μm are generated, demonstrating the capability to generate wavelength division multiplexed photon pairs at freely chosen telecommunications-band wavelengths.
Abstract: Using a compact optically pumped silicon nanophotonic chip consisting of coupled silicon microrings, we generate photon pairs in multiple pairs of wavelengths around 1.55 μm. The wavelengths are tunable over several nanometers, demonstrating the capability to generate wavelength division multiplexed photon pairs at freely chosen telecommunications-band wavelengths.
TL;DR: In this paper, the authors investigated the two-dimensional condensate (optical dropletlike) soliton formation and dynamics of the generated signal and probe beams in four-wave mixing (FWM) process with atomic coherence, under competition between the third and fifth-order nonlinear susceptibilities.
Abstract: We experimentally investigate the two-dimensional condensate (optical dropletlike) soliton formation and dynamics of the generated signal and probe beams in four-wave mixing (FWM) process with atomic coherence, under competition between the third- and fifth-order nonlinear susceptibilities. With such competing nonlinearities, mutual transformations among dropletlike fundamental, dipole, and azimuthally modulated vortex FWM solitons are observed. The influence of nonlinear competition on the photonic band gap is also investigated. All the results are obtained under low powers.
TL;DR: H heralded single-photon generation in a III-V semiconductor photonic crystal platform through spontaneous four-wave mixing is demonstrated proving nonclassical operation in the single photon regime.
Abstract: In this Letter we demonstrate heralded single-photon generation in a III–V semiconductor photonic crystal platform through spontaneous four-wave mixing. We achieve a high brightness of 3.4×107 pairs·s−1 nm−1 W−1 facilitated through dispersion engineering and the suppression of two-photon absorption in the gallium indium phosphide material. Photon pairs are generated with a coincidence-to-accidental ratio over 60 and a low g(2)(0) of 0.06 proving nonclassical operation in the single photon regime.
TL;DR: The factors that limit the span in frequency combs derived from the crystalline whispering gallery mode resonators are experimentally studied and cavity dispersion is the key property that governs the parameters of the combs resulting from cascaded four wave mixing process.
Abstract: We experimentally study the factors that limit the span in frequency combs derived from the crystalline whispering gallery mode resonators. We observe that cavity dispersion is the key property that governs the parameters of the combs resulting from cascaded four wave mixing process. Two different regimes of comb generation are observed depending on the precise cavity dispersion behavior at the pump wavelength. In addition, the comb generation efficiency is found to be affected by the crossing of modes of different families. The influence of Raman lasing and its dependence on temperature is discussed.
TL;DR: Four-wave mixing can be used to generate coherent output beams, with frequencies difficult to acquire in commercial lasers, in terms of the intensity and frequency of the incoming beam as well as the atomic density of the sample.
Abstract: Four-wave mixing can be used to generate coherent output beams, with frequencies difficult to acquire in commercial lasers. Here, a single narrow external cavity diode laser locked to the two photon 5s-5d transition in rubidium is combined with a tapered amplifier system to produce a high power cw beam at 778 nm and used to generate coherent light at 420 nm through parametric four-wave mixing. This process is analyzed in terms of the intensity and frequency of the incoming beam as well as the atomic density of the sample. The efficiency of the process is currently limited when on resonance due to the absorption of the 420 nm beam, and modifications should allow a significant increase in output power.
TL;DR: In this paper, an asymmetric double quantum well (QW) structure with resonant tunneling is proposed to achieve highly efficient four-wave mixing (FWM) in a semiconductor structure with a low-light pump wave.
Abstract: An asymmetric double quantum well (QW) structure with resonant tunneling is suggested to achieve highly efficient four-wave mixing (FWM). We analytically demonstrate that resonant tunneling can induce a highly efficient mixing wave in such a semiconductor structure with a low-light pump wave. In particular, the FWM conversion efficiency can be enhanced dramatically in the vicinity of the center frequency with small propagation distance. This interesting scheme may be used to generate coherent long-wavelength radiation in solid-state systems.
TL;DR: In this article, the authors demonstrate the feasibility of VUV/soft x-ray FWM at Fermi@Elettra and discuss its applicability to probe ultrafast intramolecular dynamics, charge injection processes involving metal oxides and electron correlation and magnetism in solid materials.
Abstract: Multi-dimensional spectroscopies with vacuum ultraviolet (VUV)/x-ray free-electron laser (FEL) sources would open up unique capabilities for dynamic studies of matter at the femtosecond?nanometer time?length scales. Using sequences of ultrafast VUV/x-ray pulses tuned to electron transitions enables element-specific studies of charge and energy flow between constituent atoms, which embody the very essence of chemistry and condensed matter physics. A remarkable step forward towards this goal would be achieved by extending the four wave mixing (FWM) approach at VUV/soft x-ray wavelengths, thanks to the use of fully coherent sources, such as seeded FELs. Here, we demonstrate the feasibility of VUV/soft x-ray FWM at Fermi@Elettra and we discuss its applicability to probe ultrafast intramolecular dynamics, charge injection processes involving metal oxides and electron correlation and magnetism in solid materials. The main advantage in using VUV/soft x-ray wavelengths is in adding element-sensitivity to FWM methods by exploiting the core resonances of selected atoms in the sample.
TL;DR: A phase-sensitive four-wave mixing (FWM) scheme enabling the simultaneous conversion of the two orthogonal quadratures of an optical signal to different wavelengths is demonstrated for the first time under dynamic operation using a highly nonlinear optical fiber (HNLF) as the nonlinear medium.
Abstract: A phase-sensitive four-wave mixing (FWM) scheme enabling the simultaneous conversion of the two orthogonal quadratures of an optical signal to different wavelengths is demonstrated for the first time under dynamic operation using a highly nonlinear optical fiber (HNLF) as the nonlinear medium. The scheme is first optimized with respect to the power levels and phases of the four phase-coherent pumps. The successful modulation and wavelength conversion of the two complex quadratures of a quadrature phase-shift keying (QPSK) signal to two binary phase-shift keying (BPSK) signals is then demonstrated experimentally with no power penalty at a bit-error-ratio (BER) of 10(-9) compared to direct interferometric demodulation of the QPSK signal.
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TL;DR: In this article, a parametric wave mixing process is used to generate near-IR light at 1367 and 5230 nm generated in the co-propagating direction only is presented.
Abstract: Directional infrared emission at 1367 and 5230 nm is generated in Rb vapours that are step-wise excited by low-power resonant light. The mid-infrared radiation originating from amplified spontaneous emission on the 5D-6P transition consists of forward- and backward-directed components with distinctive spectral and spatial properties. Diffraction limited near-infrared light at 1367 nm generated in the co-propagating direction only is a product of parametric wave mixing around the 5P-5D-6P-6S-5P transition loop. This highly non-degenerate mixing process involves one externally applied and two internally generated optical fields. Similarities between wave mixing generated blue and near-IR light are demonstrated.
TL;DR: By creating lattice states with two-dimensional spatial periodic atomic coherence, this article showed that surface solitons can be well controlled by different experimental parameters, such as probe frequency, pump power, and beam incident angles, and can be affected by coherent induced defect states.
Abstract: By creating lattice states with two-dimensional spatial periodic atomic coherence, we report an experimental demonstration of generating two-dimensional surface solitons of a four-wave mixing signal in an electromagnetically induced lattice composed of two electromagnetically induced gratings with different orientations in an atomic medium, each of which can support a one-dimensional surface soliton. The surface solitons can be well controlled by different experimental parameters, such as probe frequency, pump power, and beam incident angles, and can be affected by coherent induced defect states.
TL;DR: This new light source is applied to time-resolved photoelectron imaging of carbon disulfide (CS₂) and the cross-correlation between 198 and 159 nm pulses of 18 fs is achieved without dispersion compensation.
Abstract: Sub-20 fs pulses of the third, fourth, and fifth harmonics of a Ti:sapphire laser are simultaneously generated using cascaded four-wave mixing in filamentation propagation of the fundamental frequency and the second harmonic pulses in Ne gas. Reflective optics under vacuum are employed after the four-wave mixing to minimize material dispersion of the optical pulses. The cross-correlation between 198 and 159 nm pulses of 18 fs is achieved without dispersion compensation. This new light source is applied to time-resolved photoelectron imaging of carbon disulfide (CS2).
TL;DR: In this article, the storage of an input probe field and an idler field generated through an off-axis four-wave mixing (FWM) process via a double-\ensuremath{\Lambda} configuration in a cold atomic ensemble was studied.
Abstract: We performed an experiment to observe the storage of an input probe field and an idler field generated through an off-axis four-wave mixing (FWM) process via a double-\ensuremath{\Lambda} configuration in a cold atomic ensemble. We analyzed the underlying physics in detail and found that the retrieved idler field came from two parts if there was no single-photon detuning for the pump pulse: Part 1 was from the collective atomic spin (the input probe field, the coupling field, and the pump field combined to generate the idler field through FWM; then the idler was stored through electromagnetically induced transparency). Part 2 was from the generated new FWM process during the retrieval process (the retrieved probe field, the coupling field, and the pump field combined to generate a new FWM signal). If there was single-photon detuning for the pump pulse, then the retrieved idler was mainly from part 2. The retrieved two fields exhibited damped oscillations with the same oscillatory period when a homogeneous external magnetic field was applied, which was caused by the Larmor spin precession. We also experimentally realized the storage and retrieval of an image of light using FWM, in which an image was added into the input signal. After the storage, the retrieved idler beams and input signal carried the same image. This image storage technique holds promise for applications in image processing, remote sensing, and quantum communication.
TL;DR: It is revealed that the growth of higher-order sidebands is strongly influenced by the competition with cascade FWM between the pump and the first-order quasi-phase matched sidebands.
Abstract: We experimentally study the dynamics of the generation of multiple sidebands by means of a quasi-phase-matched four-wave mixing (FWM) process occurring in a dispersion-oscillating, highly nonlinear optical fiber. The fiber under test is pumped by a ns microchip laser operating in the normal average group-velocity dispersion regime and in the telecom C band. We reveal that the growth of higher-order sidebands is strongly influenced by the competition with cascade FWM between the pump and the first-order quasi-phase matched sidebands. The properties of these competing FWM processes are substantially affected when a partially coherent pump source is used, leading to a drastic reduction of the average power needed for sideband generation.
TL;DR: A general theory of autoresonant three-wave mixing in a nonuniform media is derived analytically and demonstrated numerically and it is shown that due to the medium non uniformity, a stable phase-locked evolution is automatically established.
Abstract: Resonant three-wave interactions appear in many fields of physics e.g. nonlinear optics, plasma physics, acoustics and hydrodynamics. A general theory of autoresonant three-wave mixing in a nonuniform media is derived analytically and demonstrated numerically. It is shown that due to the medium nonuniformity, a stable phase-locked evolution is automatically established. For a weak nonuniformity, the efficiency of the energy conversion between the interacting waves can reach almost 100%. One of the potential applications of our theory is the design of highly-efficient optical parametric amplifiers.
TL;DR: In this paper, the authors report the generation of a squeezed vacuum state of light whose noise ellipse rotates as a function of the detection frequency, and use a theoretical model based on the Heisenberg-Langevin formalism to describe this effect.
Abstract: We report the generation of a squeezed vacuum state of light whose noise ellipse rotates as a function of the detection frequency. The squeezed state is generated via a four-wave mixing process in a vapor of ${}^{85}$Rb. We observe that rotation varies with experimental parameters such as pump power and laser detunings. We use a theoretical model based on the Heisenberg-Langevin formalism to describe this effect. Our model can be used to investigate the parameter space and potentially to tailor the ellipse rotation in order to obtain an optimum squeezing angle, for example, for coupling to an interferometer whose optimal noise quadrature varies with frequency.
TL;DR: The parametric amplification gain and bandwidth in highly nonlinear tellurite hybrid microstructured optical fiber are simulated based on four wave mixing process and a broad gain bandwidth can be realized in the near infrared window by using aTellurite HMOF as short as 25 cm.
Abstract: The parametric amplification gain and bandwidth in highly nonlinear tellurite hybrid microstructured optical fiber (HMOF) are simulated based on four wave mixing process. The fiber core and cladding materials are made of TeO2–Li2O–WO3–MoO3–Nb2O5 and TeO2–ZnO–Na2O–P2O5 glass, respectively. The fiber has four zero-dispersion wavelengths and the chromatic dispersion is flattened near the zero-dispersion wavelengths. A broad gain bandwidth as wide as 1200 nm from 1290 to 2490 nm can be realized in the near infrared window by using a tellurite HMOF as short as 25 cm.
TL;DR: In this paper, a numerical model of Semiconductor Optical Amplifiers (SOA) is experimentally validated in terms of the Alpha Factor (αH) and the Four-Wave Mixing (FWM).
Abstract: In this paper, a numerical model of Semiconductor Optical Amplifiers (SOA) is experimentally validated in terms of the Alpha Factor (αH) and the Four-Wave Mixing (FWM). Besides, a Coherent Optical-Orthogonal Frequency Division Multiplexing (CO-OFDM) simulation platform is used to confirm the good agreement between the measured and the simulated Error Vector Magnitude (EVM) of a received signal amplified by the studied SOA in an optical transmission link. In addition, the performance of the SOA on the amplification of a 10.94 Gb/s QPSK CO-OFDM signal is numerically analyzed with respect to the Amplified Spontaneous Emission (ASE) noise, the Alpha Factor, the output saturation power of the SOA and the bit rate.
TL;DR: In this paper, a 250 GHz Er-doped fiber laser with a silicon micro-ring resonator (SMRR) is proposed to achieve passive mode-locking through the dissipative four-wave mixing effect induced by a piece of high nonlinear fiber.
Abstract: We propose and demonstrate a 250-GHz high-repetition-rate mode-locked Er-doped fiber laser, which utilizes a silicon micro-ring resonator (SMRR). The SMRR acts as an optical comb filter to help achieve passive mode-locking through the dissipative four-wave-mixing effect induced by a piece of high nonlinear fiber. A short section of polarization-maintaining fiber is inserted in the cavity to induce birefringence filtering to significantly enhance the stability of the proposed laser through the combined effects of optical filtering and nonlinear spectral broadening. The laser can operate about 2 and 6 nm in the case of 1.48-ps and 875-fs output pulsewidth, with 3-dB bandwidth, respectively. The laser can remain mode locked, during our measurement time, without any cavity length or temperature feedback control.
TL;DR: In this article, the design, implementation and performance analysis of four wave mixing (FWM) in optical communication system for different number of input channels is presented using various values of channel spacing.