Dark Soliton Pair Research Articles

Observation of spin-wave dark soliton pairs in yttrium iron garnet thin films

The formation of a pair of dark solitons from a single nonlinear black spin-wave pulse was observed. The experiments were carried out with a long and narrow magnetic yttrium iron garnet film strip in a surface spin-wave configuration. The black spin-wave pulses were excited by the use of microwave black pulses---large-amplitude microwaves with narrow squarelike dips. Pairs of black solitons were observed in certain input power and input black pulse width ranges. For each pair, the two solitons show opposite $\ensuremath{\pi}$ phase jumps and an overall phase change of zero. Beyond those power and width ranges, one also observed pairs of gray solitons that showed opposite phase jumps and a zero total phase change. The formation of a single black soliton was also observed, but only for an input black pulse that was very narrow. The experimental observations were reproduced by numerical simulations based on the complex Ginzburg-Landau equation.

Coupled tapering/uptapering of dark soliton pair in nonlinear media

Tapering/uptapering of coupled dark solitons of two coaxially co-propagating mutually incoherent beams in a nonlinear medium in presence of small gain or loss has been investigated in this paper using Beam Propagation Method (BPM), i.e., by direct simulations of the underlying Nonlinear Schrödinger Equation (NLSE). The results are compared with the earlier published results of tapering/uptapering of coupled bright solitons. It is found that in contrast to uptapering of bright solitonic pair, dark solitonic pair tapers in presence of losses. Moreover, in contrast to the possibility of tapering as well as uptapering of a bright solitonic pair, a dark solitonic pair never undergoes uptapering.

基于耦合Ginzburg-Landau方程的石墨烯锁模光纤激光器的暗暗孤子解及其稳定性

基于耦合Ginzburg-Landau方程的石墨烯锁模光纤激光器的暗暗孤子解及其稳定性

Molecular transport network security using multi-wavelength optical spins

Multi-wavelength generation system using an optical spin within the modified add-drop optical filter known as a PANDA ring resonator for molecular transport network security is proposed. By using the dark-bright soliton pair control, the optical capsules can be constructed and applied to securely transport the trapped molecules within the network. The advantage is that the dark and bright soliton pair (components) can securely propagate for long distance without electromagnetic interference. In operation, the optical intensity from PANDA ring resonator is fed into gold nano-antenna, where the surface plasmon oscillation between soliton pair and metallic waveguide is established.

Peregrine solitons and algebraic soliton pairs in Kerr media considering space–time correction

Abstract Exact unified rational solutions describing a family of Peregrine solitons as well as related algebraic soliton pairs in either self-focusing or self-defocusing Kerr media are presented, with distinct defining regimes and an explicit relationship for those of opposite nonlinearity. The active role of the space–time correction effect that plays in these soliton species is highlighted, leading to unique dynamics such as the persistence of Peregrine solitons in a defocusing Kerr medium, the availability of giant peak amplitude for the bright–bright soliton pair, and the existence of so-called bright–dark soliton pair. The evolution dynamics of the algebraic two-soliton state toward a spliced single soliton is also discussed.

Drug Delivery System Model using Optical Tweezer Spin Control

A new concept of molecular motor using optical tweezers within a modified optical add–drop filter known as PANDA ring resonator is proposed. In simulation, dark and bright solitons are input into the system. The orthogonal tweezers can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the optical tweezers generated by dark and bright soliton pair corresponding to the left-hand and right-hand rotating solitons (tweezers) can be generated. In application, the trapped molecules can be moved and rotated to the required destinations, which can be useful for healthcare applications, especially, in drug delivery, medical diagnosis and therapy.

Optical Capsule and Tweezer Array for Molecular Motor Use

A generation of optical capsules and tweezers within a modified optical add-drop filter known as PANDA ring resonator with a new concept is proposed. By using dark and bright solitons, the orthogonal tweezers can be formed within the system and observed simultaneously at the output ports. Under the resonant condition, the optical capsules and tweezers generated by dark and bright soliton pair corresponding to the left-hand and right-hand rotating solitons (tweezers) can be generated. When a soliton is interacted by an object, an angular momentum of either bright or dark tweezers is imparted to the object, in which two possible spin states known as tweezer spins are exhibited. Furthermore, an array of molecular capsules and spins, i.e., trapped molecules can be generated and detected by using the proposed system, which can be used to form large scale tweezer or capsule spins. In application, the trapped molecules can be moved and rotated securely to the required destinations, which can be useful for many applications, especially, in medical diagnosis, therapy and surgery.

Temperature effects of Hamiltonian dark solitons on the stability of holographic solitons in a separate holographic–Hamiltonian soliton pair

We investigate theoretically the temperature effects on the evolution and stability of a separate holographic–Hamiltonian dark–dark or bright–dark soliton pair formed in an unbiased serial photorefractive crystal circuit. Our numerical results show that, for a stable dark–dark or bright–dark soliton pair originally formed in a crystal circuit at given temperatures, when the crystal in which formed a Hamiltonian dark soliton changes, the holographic dark or bright soliton supported by the other crystal tends to evolve into another stable soliton or experiences larger cycles of compression or breaks up into beam filaments or exhibit a common decaying process. The holographic dark soliton is more sensitive to the temperature change than the holographic bright one.

Evolution of dark–dark soliton pairs in a dispersion managed erbium-doped fiber ring laser

The evolution of dark–dark soliton pairs is numerically investigated in a dispersion managed erbium-doped fiber ring laser. It is found that the fluctuation of the background, the sideband intensity of the optical spectrum, the distance and the width of dark–dark soliton pairs are related to the orientation of the polarization controllers and the pump power of the fiber ring laser. The evolution of dark–dark soliton pairs is caused by the modulation instability and the balance between gain and loss in the fiber ring laser.

Beam splitters in inhomogeneous nonlocal media

We numerically investigate the dark soliton interaction in an inhomogeneous nonlocal medium and find that the variation of the longitudinal nonlocality disturbs the pair of dark solitons and splits them into two separate dark solitons with the same escape angle but opposite deflection directions. In particular, the escape angle monotonically increases with an increase of the inhomogeneous variation rate. We show that the waveguide induced by the dark soliton interaction yields a complete family of beam splitters for trapped linear beams. Interestingly, a weak probe signal is split into two beams in this waveguide, and the two beams have different powers, which could be controlled by adjusting the nonlocality variation rate.

Multifunction Sensors Using Coincidence Dark-Bright Soliton Pair in a MZI

A new system of multifunction sensors using dark and bright solitons in a Mach-Zehnder interferometer (MZI) is proposed. In this concept, the coincidence dark and bright soliton pair within the MZI can be arranged by using the phase controller, in which (|D)) and (|B)) states represent the orthogonal dark and bright solitons, respectively. We assume that both solitons are input into the MZI ports simultaneously (coincidently). The randomly input dark and bright soliton states into the MZI ports can perform the change in phase after propagating through a phase shifter/sensing unit, in which the phase change recovery using the phase related measurement device can be provided. By using the orthogonal soliton behaviors, a sensing application using a soliton(photon) pair can be formed. Moreover, the soliton power can be reduced to a single photon power (10-6 W), where finally the single photon sensor can be operated. The self calibration concept between signal and referencing arms of a MZI can also be established, which is discussed in details.

The temperature characteristics of unbiased separate spatial soliton pairs due to two-photon photorefractive effect

We investigate theoretically the temperature effects on the intensity profile and spatial evolution of separate spatial soliton pairs formed in a serial two-photon photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright–dark soliton pair, when the temperature of the dark soliton crystal changes, the intensity profiles of the dark and the bright soliton will all change. When the temperature of the bright soliton crystal changes, only change the intensity profiles of the bright soliton will. For a bright–bright soliton pairs, the intensity profiles of the soliton determined only by the parameters of the corresponding crystal, whereas the intensity profiles of the soliton determined by the parameters of two crystals for the dark–dark soliton pairs. Finally, we discuss the temperature of dark solitons effects on the dynamical evolution of bright–dark soliton pairs.

Optical spin generated by a soliton pulse in an add–drop filter for optoelectronic and spintronic use

A new concept of an optical spin generation using bright and dark soliton conversion behaviors within a modified optical add–drop filter known as PANDA ring resonator is proposed. The orthogonal solitons can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the dark and bright soliton pair corresponding to the left-hand and right-hand rotating solitons (photons) can be generated. When a soliton is absorbed by an object, an angular momentum of either +ħ or −ħ is imparted to the object, in which two possible spin states known as optoelectronic(soliton) spins are exhibited. Furthermore, an array of soliton spins, i.e. particles can be generated and detected by the proposed system, which can be used to form large scale spin generation.

Stability of incoherently coupled bright–dark spatial soliton pairs in biased two-photon photovoltaic photorefractive crystals

This paper investigated numerically the stability of bright–dark soliton pairs in biased two-photon photovoltaic photorefractive crystals. Our analysis indicates that these soliton pairs exist irrespective of the polarity of photovoltaic field and external bias field and they are stable only in the particular range of negative polarity. That is to say, the modulational instability emerges for the positive polarity. In range of negative polarity, there exist a characteristic value of photovoltaic field and external bias field. When the values are less than the characteristic value, these bright–dark soliton pairs are stable. If the values are large than the characteristic value, the modulational instability will still emerge.

Novel communication security scheme using dark-bright soliton conversion behaviors

We propose a novel scheme of communication security using dark-bright soliton conversion behaviors in which the transmission signals can be secured by using the random codes generated by dark-bright soliton conversion within the system. The system consists of two parts, where first, an optical Mach Zhender interferometer (MZI) is used to generate the coincidence dark and bright soliton pair by using the (π/2) phase retarder (i.e., a coupler), in which |D〉 and |B〉 states represent the orthogonal dark and bright soliton pulses. The signals from through (Th) port are formed and transmitted via the transmission line to the end user. Second, the add/drop filter is used to separate(filter) the required signal form the transmission link, in which the Th and drop port signals are formed as a reference and signal, respectively. In this case, we assume that both solitons are input into the MZI ports simultaneously (coincidently), in which the binary codes are randomly formed and used to present the transmission data, in which the states 0 and 1 are represented by |DB〉 and |BD〉, respectively. Finally, the eavesdropper and signal accuracy are also described.

Evolution and self-deflection of separate holographic-Hamiltonian soliton pairs

We present a numerical investigation of the dynamical evolutions, stabilities and self-deflections of both solitons in a separate dark–dark or bright–dark holographic– Hamiltonian soliton pair supported by an unbiased series photorefractive crystal circuit. The results obtained show that the Hamiltonian dark soliton can affect the evolution and stability of the holographic dark and bright solitons by the light-induced current, but not vice versa. For a dark–dark soliton pair, increasing the input intensity of the Hamiltonian dark soliton can increase the bending angle of the holographic dark soliton.

One-dimensional optical dark screening photovoltaic–photorefractive solitons, soliton pairs and incoherent interaction between them in BaTiO 3 crystal

We studied the theory of the optical solitons and introduced the nonlinear equations governed by the screening photovoltaic–photorefractive dark solitons. By the use of the numerical methods, the intensity profile, refractive index change of the media and also stability under propagation are investigated. Also, we investigated incoherent coupled dark–dark soliton pairs and incoherent interaction between them.

Incoherently coupled bright–dark photovoltaic soliton pairs based on two-photon photorefractive effect

The coupling of two mutually incoherent optical beams with the same polarization and wavelength in two-photon photovoltaic photorefractive crystal is studied, it is predicted theoretically that incoherently coupled bright–dark photovoltaic spatial soliton pairs are possible due to two-photon photorefractive effect. The existing conditions of these soliton pairs in the crystal are discussed in detail. The intensity profile of these soliton pairs is shown by numerical calculation under the parameters of relevant crystal.

INCOHERENTLY COUPLED SCREENING-PHOTOVOLTAIC SPATIAL SOLITON PAIRS IN BIASED TWO-PHOTON PHOTOVOLTAIC PHOTOREFRACTIVE CRYSTALS

The incoherently coupled dark–dark, bright–bright, bright–dark screening-photovoltaic spatial soliton pairs are predicted in biased two-photon photovoltaic-photorefractive crystals under steady-state conditions. The result shows that these soliton pairs are established by the solitary beams which have the same polarization, wavelength, and are mutually incoherent. The screening-photovoltaic soliton pairs can be considered as the united form of screening soliton pairs and open or closed-circuit photovoltaic soliton pairs. They reduce to screening soliton pairs in the absence of photovoltaic effect, whereas they become photovoltaic soliton pairs under the open or closed-circuit conditions when the bias field is not applied. Moreover, the stability of these solitons has been investigated.

Incoherently coupled soliton pairs in nonlocal nonlinear media

We show that incoherently coupled soliton pairs can exist in nonlocal Kerr-type nonlinear media. Such solitons can propagate in bright–bright, dark–dark, and gray–gray configurations. When the nonlocal nonlinearity is absent, these bright–bright and dark–dark soliton pairs are those observed previously in local Kerr-type nonlinear media. Our analysis indicates that for a self-focusing nonlinearity the intensity full width half maximum (FWHM) of the bright–bright pair components increases with the degree of nonlocality of the nonlinear response, whereas for a self-defocusing nonlinearity the intensity FWHM of the dark–dark and gray–gray pair components decreases with the increase in the degree of nonlocality of the nonlinear response. The stability of these soliton pairs has been investigated numerically and it has been found that they are stable.