Four-wave Mixing Generation Research Articles

A Brief Look Into Nonlinear Optical Properties Of MXenes (M2X) Ti2C, Nb2C, And V2C Through Four Wave Mixing Generation In 2 µm Fiber Laser

Generation of four wave mixing (FWM) effect in MXenes with chemical ratio of M2X, particularly Ti2C, Nb2C, and V2C were reported in this work. The setup was operated at 2 µm wavelength region with tapered fiber as the material host. The experiment managed to show conversion efficiencies of −43.93 dB, −42.60 dB, and −41.20 dB and idlers’ SNR of 7.73 dB, 9.10 dB, and 9.80 dB for Ti2C, Nb2C, and V2C, respectively. The relation of nonlinear optical properties such as nonlinear absorption coefficient and nonlinear refractive index to FWM generation were explored. The result of the investigation successfully showed the relationship of third order nonlinear optical properties and FWM effect in the specified MXenes with comparisons.

Ultrafast Four‐Wave Mixing Phase‐Matched by Transient Nonlinear Phase Modulation in a MAPbBr3 Single Crystal

AbstractA degenerated four‐wave‐mixing (FWM) process in single‐crystal (CH3NH3)PbBr3 (MAPbBr3) is reported, where 150‐fs laser pulses at 1.33 µm are employed as the pump. Two pump photons interact with a single crystal, producing another two photons with higher and lower energies, respectively. One of the FWM‐generation sidebands is tuned from ∼1.23 to 1.21 µm and the other from ∼1.43 to 1.48 µm for the center wavelength, as the pump fluence is increased from 2.6 to 11.69 mJ cm−2. The self‐phase modulation induced by the strong pump pulses through the optical Kerr effect is responsible for the tuning dynamics. Transient spectroscopy not only verifies the FWM scheme for the interacting waves but also reveals the interference dynamics between the FWM‐generated sidebands and the probe pulse. In particular, the angular dependence of the FWM generation supplies direct evidence for the phase‐matching geometry. Using experimental data, a nonlinear refractive index coefficient of 1.19 × 10−14 cm2 W−1 at 1.33 µm for single‐crystal MAPbBr3 is determined.

Nonlinear optical signatures of topological Dirac fermion.

Dirac fermion in topological materials exhibits intriguing nonlinear optical responses. However, their direct correlation with the linearly dispersed band remains elusive experimentally. Here, we take topological semimetal ZrSiS as a paradigm, unveiling three unique nonlinear optical signatures of Dirac fermion. These signatures include strong quadrupolar response, quantum interference effect, and exponential divergent four-wave mixing (FWM), all of which are described by the prominent third-order nonlinear optical susceptibility. Resonantly enhanced by linear bands, quadrupolar second harmonic generation in centrosymmetric bulk overwhelms the electric-dipole contribution at the surface with inherent inversion symmetry breaking. Furthermore, owing to the interference between multiple resonant transition pathways within linear bands, difference-frequency FWM is several orders of magnitude stronger than sum-frequency FWM and third harmonic generation. The difference-frequency FWM further displays an inverse-square divergence toward degenerate excitation, whose scaling law perfectly matches with the long-sought behavior of Dirac fermion. These signatures lay the solid foundation toward the practical applications of topological materials in nonlinear optoelectronics and photonics.

Cascaded degenerate four-wave mixing generation in thin-film lithium tantalate microdisk cavity

Cascaded degenerate four-wave mixing generation in thin-film lithium tantalate microdisk cavity

Efficient four-wave mixing wavelength conversion in a hybrid silicon slot and polymer microring resonator.

We present a silicon slot microring resonator for efficient frequency conversion via four-wave mixing (FWM). The slot consists of a narrow silicon waveguide pair with a gap of 80 nm, which is filled with a nonlinear optical polymer. The group velocity dispersion for the microring is controlled by engineering the geometry of the slot structure. Because of the large buildup factor of the slot microring, an FWM conversion efficiency of -27.4 dB is achieved with an optical pump power of less than 1.0 mW. From the measured power dependence of FWM generation, a nonlinear refractive index coefficient of 1.31 × 10-17 m2 W-1 is obtained at a wavelength of 1562 nm. This work presents a hybrid silicon slot and polymer microring as a potential nonlinear device for applications in integrated photonic devices.

Generation of four-wave mixing with nonlinear Vanadium-carbide (V2C)-deposited side-polished fiber (SPF) in 1.5- and 2.0-µm wavelength operation

In this work, we report the use of V2C-deposited SPF as a nonlinear device for the generation of four-wave mixing (FWM) effect in 1.5- and 2.0-µm wavelength operation. The FWM-based system was able to generate idlers at 1.5- and 2.0-µm with a peak conversion efficiency of –44 dB and –41 dB and had a maximum tuning range of 5.5 nm and 12 nm respectively. The nonlinear optical properties of V2C MXene were studied by Z-scan analysis, where V2C had a nonlinear absorption coefficient, β and nonlinear refractive index, n2 of (5.95 ± 5.18)×10-8 m/W and (-2.43 ± 4.93)×10-20 m2/W. The experimental results demonstrated that V2C-deposited SPF was effectively employed as a nonlinear device to induce the FWM effect.

Generation of four-wave mixing in molybdenum ditelluride (MoTe2)-deposited side-polished fibre

In this work, we report the effect of four-wave mixing (FWM) in MoTe2 deposited on a side-polished fibre (SPF). The MoTe2 layer has a nonlinear coefficient of 17.368 W−1 km−1 at 1550 nm, while the coated SPF has a conversion efficiency of – 38 dB and output tuning range of 5 nm. The generated idlers from the induced FWM effect were observed to be highly stable with minimal peak fluctuations and only minor changes in their measured conversion efficiency. The proposed MoTe2 based SPF is thus a suitable device for inducing the FWM effect in an optical fibre laser cavity and could also serve to induce other non-linear optical effects for use in optical communications networks.

Wideband tuning of four-wave mixing in liquid-filled photonic crystal fiber

A wideband tuning of parametric four-wave mixing generation in a liquid-filled photonic crystal fiber is theoretically demonstrated, and influence of its temperature is investigated. The broadband spectrum is generated via a supercontinuum generation process induced by degenerate four-wave mixing (DFWM), for which the thermo-optic coefficient of the oil (the refractive index matching fluid) is considered. The signal band tuning from 734 nm to 923 nm, and the idler band from 1931 nm to 1255 nm, are observed when the temperature increases from 30°C to 90°C. The findings can be applied in many fields, such as CARS.

Dispersive wave and four-wave mixing generation in noninstantaneous nonlinear fiber solitons.

This paper presents a detailed analysis regarding the generation of a dispersive wave (DW) and four-wave mixing in the noninstantaneous, nonlinear response of solvents using a commercial photonic crystal fiber filled with carbon disulfide (CS2) where the beam is pumped in the anomalous dispersion domain. The main finding is the fact that the output spectrum changes from coherent DW to incoherent modulation instabilities just by changing from constant to variable nonlinear parameters. This study can be extended to other solvents including ethanol, methanol, and butanol.

Half panda waveguide structure in the generation of four-wave mixing

By simulating the structure of half Panda waveguide base on nonlinear material, it was able to generate the four-wave mixing base on 3 picks which the highest pick was pump and the lowest power goes to converted. In this research the high Qfactor showing the optimization for the waveguide was successful which was 2.58 × 103 in drop port. better power transferring occurred with the nonlinear material has been used. It has been found that signal and pump intensity were higher than the converted values. Finite different time domain (FDTD) is the simulation that has been used in this modeling.

Closed-form FWM expressions accounting for the impact of modulation format

Four Wave Mixing (FWM) is one of the main transmission impairments in coherent optical systems and a broad gamut of analytical expressions calculating its power already exists in the literature. Most of these expressions, such as the GN-model, assume that due to the large values of accumulated dispersion, each transmitted signal behaves as stationary circular Gaussian noise, ignoring the dependence of FWM on the employed modulation format. This assumption leads to significant error especially in the case of quadrature-phase-shift keying (QPSK), in systems with small number of spans and in the dispersion managed case. In addition, the GN-model is inaccurate when applied to metro networks, due to the low accumulated dispersion. In this paper, we derive closed-form expressions which incorporate the impact of modulation format on FWM generation, extending and improving the accuracy compared to existing closed-form FWM expressions. Moreover, the proposed method includes terms that make it applicable to systems with small span lengths (<30 km), which is the case in metro networks. The accuracy of the proposed formulas is benchmarked against a numerical method, where the signal transmission is modeled using the split step fourier method (SSFM), for a wide range of system configurations and parameters.

Panda resonator structure to generate four-wave mixing by nonlinear effect

Finite-difference time domain (FDTD) simulation has been used for modeling of nonlinear optical interaction in a modified microring resonator as Panda structure. By proposing the Panda structure which has been modeled using both silicon and material (Chi2) with nonlinear effect, generation of four-wave mixing is feasible. Due to the nonlinear interaction between the two input waves as pump and signal within the microring resonators the results show the generation of three picks including the pump, signal and converted wave. In the case, if the silicon has been utilized as the core waveguide, the resonance interferences occur, where the high Qfactor of the resonance frequencies was obtained as 3.87 × 103 in the drop port outputs. Compared to silicon material, the nonlinear material shows a better power transferring performances. In the results showing the four-wave mixing, the converted wave has a lower power than the signal and pump.

Raman-Kerr frequency combs in Zr-doped silica hybrid microresonators.

Resonant cavity-enhanced Kerr frequency combs have been demonstrated using a range of cavity materials. Regardless of cavity type, one fundamental challenge is achieving low or flat dispersion while maintaining high-efficiency four-wave mixing (FWM). Here we demonstrate a Raman-Kerr frequency comb using a Zr-doped silica hybrid toroidal microcavity. The Zr-doped layer both flattens the dispersion and increases the stimulated Raman scattering efficiency. This enhancement enables the generation of FWM around both the Stokes and anti-Stokes Raman scattering emissions. As a result, the Raman-Kerr frequency comb spans more than 300nm in the near-IR region with less than 5.2mW of input power.

Stimulated emission from ladder-type two-photon coherent atomic ensemble.

We investigated the stimulated emission from a ladder-type two-photon coherent atomic ensemble, for the 5S1/2 - 5P3/2 - 5D5/2 transition of 87Rb atoms. Under the ladder-type two-photon resonance condition obtained using pump and coupling lasers, we observed broad four-wave mixing (FWM) light stimulated from two-photon coherence induced by the seed laser coupled between the ground state of 5S1/2 and the first excited state of 5P3/2. A dip in the FWM spectrum was obtained for three-photon resonance due to V-type two-photon coherence using the pump and seed lasers. From the FWM spectra obtained for varying frequency detuning and seed-laser power, we determined that the seed laser acts as a stimulator for FWM generation, but also acts as a disturber of FWM due to V-type two-photon coherence.

Generation of four-wave mixing with highly sharp idlers using 2 mm home-made side-polished fiber deposited by ZnO nanorod

A side-polished fiber with embedded zinc oxide nanorods (ZnO-NRs) is proposed, fabricated, and tested to generate four-wave-mixing (FWM). The side-polished fiber is manufactured by polishing a conventional single mode fiber to completely remove 2 mm of its cladding and its core partially, after which the fiber is simply immersed into a solution consisting of ZnO-NRs and allowing it to dry. A pump and a signal wavelength of 1550 and 1551 nm are injected into the fiber and generate idlers at 1549 and 1552 nm which agree well with theoretical values. Our experimental results show that the optimum FWM range is determined to be a 6 nm shifted away from the pump wavelength and occurs in the pump and wavelength spacing as narrow as 0.1 nm. The proposed system allows for the easy integration of optically active materials into a fiber.

Resonant intracavity four-wave mixing in a composite atom–cavity system

We experimentally study intracavity four-wave mixing (FWM) using Λ-type, three-level electromagnetically induced transparency (EIT) atoms confined in an optical ring cavity. The original dark-state peak disappears accompanying the generation of intracavity FWM when the coupling light is changed from traveling-wave to standing wave. Additionally, this FWM signal is on resonance with the optical cavity only when the coupling laser is detuned from the atomic resonance center, where the absorption is drastically reduced for both the probe and FWM fields. At last, we do theoretically analysis for the susceptibility of this composite atom–cavity system.

Generation of Four-Wave Mixing in a Highly Non-Linear Optical Fiber Using a Tunable Dual Wavelength Fiber Laser Source

In this paper, we demonstrate a Four Wave Mixing (FWM) effect in a highly nonlinear single mode optical fiber. A tunable dual-wavelength fiber laser is used to provide the pump and signal probe to generate partially degenerate FWM. Calculations using coupled differential equations and experimental results in the generation of FWM were analyzed. We observed that FWM conversion efficiency depends more significantly on the wavelength detuning between pump and signal wavelength as compared to zero-dispersion wavelength. The tunability is achieved using an arrayed waveguide grating which provides different wavelength combinations of the dual-wavelength fiber laser output and can be tuned from 1530.47nm to 1548.61nm with a spacing of 100GHz. The highly nonlinear fiber has a nonlinear coefficient, γ of 10.8 W-1km-1. Hence, to achieve higher FWM output power the pump power of the dual wavelength fiber laser has to be higher than that of the signal probe. The optimum measured values of pump and signal power are +13.3dBm and +5dBm respectively, limited buy the current experimental setup.

Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by generated free electrons. Developed expressions validated by order of magnitude estimations and available experimental data allow us to identify the area for the operation under high input laser intensities avoiding the onset of full-scale discharge, loss of efficiency and inhibition of generated L-α radiation. Calculations made reveal an opportunity for scaling up the output energy of the experimentally generated pulsed L-α radiation without significant enhancement of photoionization.

Wideband tuning of four-wave mixing in solid-core liquid-filled photonic crystal fibers.

We present an experimental study of parametric four-wave mixing generation in photonic crystal fibers that have been infiltrated with ethanol. A silica photonic crystal fiber was designed to have the proper dispersion properties after ethanol infiltration for the generation of widely spaced four-wave mixing (FWM) bands under 1064nm pumping. We demonstrate that the FWM bands can be tuned in a wide wavelength range through the thermo-optic effect. Band shifts of 175 and over 500nm for the signal and idler bands, respectively, are reported. The reported results can be of interest in many applications, such as CARS microscopy.

Influence of four-wave mixing in short- and medium-range 1310 nm dense wavelength division multiplexing systems

In this paper, we demonstrate a comprehensive analysis of the impact of four-wave mixing (FWM) on the quality of transmission in short- and medium-range dense wavelength division multiplexing (DWDM) systems in the 1310 nm wavelength domain. The presented analysis proves that, for the system with uniform power per channel assignment, setting proper input channel power can substantially reduce the influence of the FWM effect on bit error rate in low channel spaced short-range systems, despite the position of the DWDM grid around the zero-dispersion wavelength. Simulations and experimental analysis of the possibility of FWM suppression have been provided. The power penalty measurements show that the influence of FWM on system performance may be as low as 0.3 dB with reasonable input power (i.e., -11 dBm per channel), making possible the transmission of data by fiber over distances of 25 km. Finally, we demonstrate that, for channel spacing as low as 120 GHz, error-free transmission in the 1310 nm wavelength domain is possible, despite high efficiency of FWM generation. The results prove that utilization of the 1310 nm wavelength domain in a system with low channel spacing, i.e., with better bandwidth allocation, is an interesting solution for data storage and processing center applications.