Optical Soliton Pulses Research Articles

Bright-dark and dark-dark solitons for the coupled cubic-quintic nonlinear Schrödinger equations in a twin-core nonlinear optical fiber

In this paper, we investigate the coupled cubic-quintic nonlinear Schrödinger equations, which can describe the effects of quintic nonlinearity on the ultrashort optical soliton pulse propagation in a twin-core nonlinear optical fiber. Through the Kadomtsev-Petviashvili hierarchy reduction, we present the bright-dark and dark-dark soliton solutions in terms of the Grammian for such equations. With the help of analytic and graphic analysis, head-on and overtaking elastic interactions between the two solitons are presented, as well as the bound-state solitons. Particularly, we find the inelastic interaction between the bright-dark two solitons. One of the electromagnetic fields presents the V-shape profile, while the other one presents the Y-shape profile.

Higher-order interaction-induced effects between strong dispersion-managed solitons with dissimilar powers

We address one of the major penalties associated with the transmission of optical solitons in fiber-optic networks: the intrachannel interactions between pulses in a single channel strong dispersion-managed transmission link. We calculate the interaction length between sets of two and three pulses as a function of the ratio of dissimilar peak powers of interacting solitons by means of a variational approach to the generalized nonlinear Schrodinger equation describing the evolution of optical soliton pulses. We find a maximum of this colliding length for specific values of pulse energies. The effect of higher-order perturbation terms, such as third-order dispersion, Raman scattering, and self-steepening, shows an enhancement of the interaction distance in a broad range of dispersion difference values. We conclude that the transmission characteristics of soliton trains may be improved by means of using specific values of unequal energies and taking into account higher-order correction terms.

TEMPORAL SOLITON: GENERATION AND APPLICATIONS IN OPTICAL COMMUNICATIONS

In general, the temporal and spectral shape of a short optical soliton pulse does not change during propagation in a nonlinear medium due to the Kerr effect which balances the chromatic dispersion. Microring resonators (MRRs) can be used to generate chaotic signals. The smaller MRR is used to form the stopping and filtering system. The employed optical material was InGaAsP/InP, which is suitable for use in the practical devices and systems. The tuning and manipulation of the bandwidth of the soliton signals is recommended to control the output signals. The MRRs can be applied to produce ultra-short pulses, where the medium has a nonlinear condition, thus, using of soliton laser becomes an interesting subject. Therefore, an ultra-short pulse in the scope of pico and femtoseconds soliton pulses can be utilized for many applications in engineering communications. In order to obtain smaller bandwidth of the optical soliton pulses, we propose integrating series of MRRs. In this study, 5 fs soliton pulse could be generated using a series of five MRRs. The soliton signals experience less loss during the propagation, where they are more stable compared to normal conventional laser pulses. Using the series of MRRs connected to an add/drop system, shorter soliton bandwidth and highly multi soliton pulses can be obtained. Therefore, generation of ultra-short multi picosecond (1.2 and 1.3 ps), could be performed, where the radius of the add/drop system has been selected to 50 and 300 µm respectively.

OPTICAL BISTABILITY CONTROLLED USING ADD-DROP MOBIUS MICRORING RESONATOR SYSTEM

The theoretical investigation has been performed on the implementation of optical Mobius shape in add-drop microring resonator. The modified add-drop Mobius configuration is used to investigate the optical bistability and the spectral transmission. The optical bright soliton pulse is used as the input source of the resonator system. The pulses propagation of the resonator system is modelled using the iterative programming based on the transfer matrix analysis equations. The enhancement of nonlinear effect of the resonator system is achieved by the add-drop Mobius resonator configuration. The system has been modelled for a variation of coupling coefficient for increase the bistable signal properties. The Add-drop Mobius MRR generated a bistable signal with 6.01 mW hysteresis width, and 9.47 mW output switch power with optimized radius of 5 µm outer and 4.5 m inner ring parts with 50 mW controlled power and input power. Mobius configuration is found as the better shape of resonator cavity that capable of optical switching application.

2 × 2 MIMO-OFDM-RoF generation and transmission of double V-Band signals using a microring resonator system

Multi-input multi-output (MIMO) signals have been all-optically generated via orthogonal frequency division multiplexing, and transmitted over a 50 km single mode fibre (SMF) optical link and also a 5 m 2 × 2 MIMO wireless link. The series of constituent single and multi-carrier optical soliton pulses, at frequencies of f1 = 192.6988, f2 = 192.7588, f3 = 192.79 and f4 = 192.84 THz that are applicable for radio over fibre (RoF) systems, were created using a microring resonator system. Sixty four multi-carriers with specific free spectral range of 109.37 MHz across a selected range of 192.7553–192.7623 THz were produced for the purpose of establishing two MIMO V-Band RF signals, and single carriers operating at f3 and f4 optically transported two separate MIMO signals over an RoF link. The optical single sideband with carrier modulation technique has been implemented so as to overcome RF power degradation. The resultant bit error rate (BER) calculation of overall system performance is discussed, and power penalties of 1.7 and 4.7 dB in 25 and 50 km SMF transmissions at the BER threshold respectively have been identified. The results of this research show that transmission of MIMO signals is feasible for up to a 50 km SMF path length and wireless distance of 3 m.

Kuznetsov–Ma soliton and Akhmediev breather of higher-order nonlinear Schrödinger equation**Project supported by the Key Project of Scientific and Technological Research in Hebei Province, China (Grant No. ZD2015133).

In terms of Darboux transformation, we have exactly solved the higher-order nonlinear Schrödinger equation that describes the propagation of ultrashort optical pulses in optical fibers. We discuss the modulation instability (MI) process in detail and find that the higher-order term has no effect on the MI condition. Under different conditions, we obtain Kuznetsov–Ma soliton and Akhmediev breather solutions of higher-order nonlinear Schrödinger equation. The former describes the propagation of a bright pulse on a continuous wave background in the presence of higher-order effects and the soliton’s peak position is shifted owing to the presence of a nonvanishing background, while the latter implies the modulation instability process that can be used in practice to produce a train of ultrashort optical soliton pulses.

Self-similar soliton-like solution for coupled higher-order nonlinear Schrödinger equation with variable coefficients

Self-similar soliton-like solution of a kind of coupled higher-order nonlinear Schrödinger equation with variable coefficients describing the optical soliton pulses propagating in inhomogeneous optical fiber media is investigated in this paper. The balance principle and the F-expansion technique are used to obtain the exact bright and dark self-similar soliton-like solutions analytically. As an example, we present a periodic distributed amplification system to investigate the pulse evolution characteristics by using the split-step Fourier method and the Runge–Kutta method. It is found that the self-similar soliton-like optical pulses can propagate stably in the given coupled system.

Optical Amplification of Tweezers and Bright Soliton Using an Interferometer Ring Resonator System

System of optical soliton amplification which consists of an add/drop multiplexer system is presented. Optical dark and bright soliton pulses can be amplified significantly. Dark soliton and Gaussian laser beam are input into the configured system and travel within the waveguide. Continuous soliton pulse will be sliced into smaller pulses by the nonlinear effect known as chaos, thus large bandwidth of optical signals can be obtained. Amplification occurs when the soliton propagates along the add/drop multiplexer system. Amplified optical tweezers signals with power of 487 W and FWHM of 6.8 nm are simulated. The amplified bright soliton could be obtained with maximum power of 360 W and FWHM of 1.5 nm. Therefore amplification of soliton pulses can be used to perform the long distance optical communication.

Optical Quantum Generation and Transmission of 57–61 GHz Frequency Band Using an Optical Fiber Optics

An optical panda ring resonator connecting to two microring resonators (MRRs) can be used to generate a high frequency optical soliton. The optical soliton pulse of 57-61 GHz can be generated and transmitted via an optical quantum transmission link. This system uses a Gaussian laser pulse propagating within a nonlinear MRRs system. The ultra-short single and multi soliton pulses within the range of 57-61 GHz can be generated and seen at the through and drop ports of the system. The transmission link consists of MRRs system, optical transmitter, connector, fiber optics, erbium doped fiber amplifier (EDFA), receiver and antenna which provide transmission of optical soliton via the wired/wireless communications. The fiber optic has a length of 1 km, where the wireless link covers a short distance optical communication of 10 m. Here, the transmitted optical soliton pulses can be received, detected and used by the users.

W-Band OFDM Transmission for Radio-Over-Fiber Link Using Solitonic Millimeter Wave Generated by MRR

A system comprises of a W-band (75-110 GHz) optical millimeter (mm)-wave generation using microring resonators (MRRs) and radio-over-fiber (RoF) link architectures is presented for multigigabit data rates demand. The MRRs are used to generate optical mm-wave soliton pulses for W-band applications. To achieve faster transmission speed wirelessly, higher spectral efficiency (SE) and better transmission performance, orthogonal frequency-division multiplexing (OFDM) is used. The results show that the MRRs support W-band optical soliton pulses, which can be used in an OFDM transmission/receiver system. Localized narrow bandwidth soliton pulses within frequencies of 92.2-93.2 GHz can be seen in the throughput port of the Panda system with respect to the full width at half maximum and free spectrum range of 3.5 and 184 MHz, respectively. The error vector magnitude of the system was measured and the viability of the solitonic OFDM-based system for RoF link over 25-Km fiber link and 2-m wireless link was confirmed. The data rate of the system with 16-quadrature amplitude modulation is measured as 43.6 Gb/s and with 10 GHz of bandwidth, the SE is obtained as 4.36 bit/s/Hz.

Transmission of data with orthogonal frequency division multiplexing technique for communication networks using GHz frequency band soliton carrier

Microring resonators (MRRs) can be used to generate optical millimetre-wave solitons with a broadband frequency of 40-60 GHz. Non-linear light behaviours within MRRs, such as chaotic signals, can be used to generate logic codes (digital codes). The soliton signals can be multiplexed and modulated with the logic codes using an orthogonal frequency division multiplexing (OFDM) technique to transmit the data via a network system. OFDM uses overlapping subcarriers without causing inter-carrier interference. It provides both a high data rate and symbol duration using frequency division multiplexing over multiple subcarriers within one channel. The results show that MRRs support both single-carrier and multi-carrier optical soliton pulses, which can be used in an OFDM based on whether fast Fourier transform or discrete wavelet transform transmission/receiver system. Localised ultra-short soliton pulses within frequencies of 50 and 52 GHz can be seen at the throughput port of the panda system with respect to full-width at half-maximum (FWHM) and free spectrum range of 5 MHz and 2 GHz, respectively. The soliton pulses with FWHMs of 10 MHz could be generated at the drop port. Therefore, transmission of data information can be performed via a communication network using soliton pulse carriers and an OFDM technique.

Optical Stretcher of Biological Cells Using Sub-Nanometer Optical Tweezers Generated by an Add/Drop Microring Resonator System

The design system consists of a nonlinear modified add/drop Microring Resonators (MRR) to build up optical tweezers in the form of potential wells is presented. The optical tweezers can be used for sub-nanometer objects trapping to form an optical stretcher used to deform the biological cells. The fabricated material used is InGaAsP/InP, which provide the required output signals. The optical tweezers can be formed by the dark soliton pulses and can be tuned and amplified using the Gaussian laser beam input. The optical dark soliton pulses with the central wavelengths range 1.4 to 1.55-m are fed into the system, collide with the input Gaussian laser beam at the add port and finally the optical tweezers with bandwidth of 4, 12 and 18 nm could be generated and used to trap sub-nanometer objects using a molecular buffer system. Interacting the tweezers holding the subnanometer objects with human tissue, influence the cellular surface of the cells by the generated forces. Therefore an optical stretcher can be formed to deform the biological cells of human tissue using optical tweezers.

Effect of Raman gain on the characteristic of soliton transmission in birefringence optical fiber

The coupled nonlinear Schrödinger (CNLS) equation including Raman gain has been utilized for birefringence fiber. Evolution process of the optical soliton pulse has been simulated by the fractional Fourier method when the optical soliton pulse transmission in a birefringence fiber has a different nature. Results show that the drift of soliton caused by nonlinear coupling effect can be suppressed by Raman gain, at the same time, the soliton pulse peak in the transmission is enhanced. The interaction between optical solitons can be effectively restrained by Raman gain in the birefringence fiber.

IEEE 802.15.3c WPAN Standard Using Millimeter Optical Soliton Pulse Generated by a Panda Ring Resonator

A system of microring resonators (MRRs) connected to an optical modified add/drop filter system known as a Panda ring resonator is presented. The optical soliton pulse of 60 GHz frequency band can be generated and used for Wireless Personal Area Network (WPAN) applications such as IEEE 802.15.3c. The system uses chaotic signals generated by a Gaussian laser pulse propagating within a nonlinear MRRs system. The chaotic signals can be generated via a series of microring resonators, where the filtering process is performed via the Panda ring resonator system wherein ultrashort single and multiple optical soliton pulses of 60 GHz are generated and seen at the through and drop ports, respectively. The IEEE 802.15.3c standard operates at the 60 GHz frequency band, and it is applicable for a short distance optical communication such as indoor systems, where the higher transmission data rate can be performed using a high frequency band of the output optical soliton pulses. The single and multi-soliton pulses could be generated and converted to logic codes, where the bandwidths of these pulses are 5 and 20 MHz, respectively. Thus, these types of signals can be used in optical indoor systems and transmission link using appropriate components such as transmitter, fiber optics, amplifier, and receiver.

Soliton propagation with cross-phase modulation in silicon photonic crystal waveguides

An effort was conducted to numerically determine, using the Nonlinear Schrodinger Split-Step Fourier method, if using cross phase modulation could cause temporal soliton pulse propagation in a silicon slow-light photonic crystal waveguide shorter than a millimeter. The simulations demonstrated that due to the higher powers and shorter scales of photonic crystals, two-photon absorption would cause an optical soliton pulse to be extremely dissipative. The model demonstrated, however, that by utilizing cross-phase modulation, it is possible to sustain a compressed soliton pulse within a silicon photonic crystal waveguide subjected to two-photon absorption over longer relative distances.

Disturbance of soliton pulse propagation from higher-order dispersive waveguides

Optical soliton pulses offer many applications within optical communication systems, but by definition a soliton is only subjected to second-order anomalous group-velocity-dispersion; an understanding of higher-order dispersion is necessary for practical implementation of soliton pulses. A numerical model of a waveguide was developed using the nonlinear Schrödinger equation, with parameters set to ensure the input pulse energy would be equal to the fundamental soliton energy. Higher-order group-velocity-dispersion was gradually increased, for various temporal widths and waveguide dispersions. A minimum pulse duration of 100 fs was determined to be necessary for fundamental soliton pulse propagation in practical photonic crystal waveguides.

Optical quantum transmitter with finesse of 30 at 800-nm central wavelength using microring resonators

A microring resonator (MRR) system incorporating an add/drop system is presented. The finesse of the proposed system can be determined using the full width at half maximum (FWHM) and free spectrum range (FSR) of the generated multiple soliton pulses. The central wavelength of the bright input soliton pulse has been selected as 800 nm, at which a ring system with better sensitivity shows high finesse that is suitable for applications to many optical communication systems such as optical transmitters and sensors. Simulation results show that FSR of 0.3 nm and 1.1 ns and FWHM of 10 pm and 36.6 ps could be obtained. Therefore, a system with finesse of 30 can be obtained; in such a system, the MRR system shows high performance. This system can be used in optical communication networks as a transmitter system for optical soliton pulses with finesse of 30, and theses pulses can be detected via an optical receiver.

Ultra-Short of Pico and Femtosecond Soliton Laser Pulse Using Microring Resonator for Cancer Cells Treatment

A system of microring resonators (MRRs) incorporating with an add/drop filter system is presented in which ultra-short single and multi temporal and spatial optical soliton pulses can be simulated and used to thermalbased killing of abnormal cells, tumor and cancer, applicable in nanomedical treatments. This proposed system uses chaotic signals generated by a bright soliton pulse within a nonlinear MRRs system. Interaction between gold nanoparticles and ultra-short femtosecond and picosecond laser pulses holds great interest in laser nanomedicine. By using the appropriate soliton input power and MRRs parameters, required spatial and temporal signals are generated spreading over the spectrum. Results obtained show that smallest single temporal and spatial soliton pulse with FWHM = 712 fs and FWHM = 17.5 pm could be generated respectively. The add/drop filter system is used to generate high capacity ultra-short soliton pulses in the range of nanometer/second and picometer/second.

Symbolic computation on soliton dynamics and Bäcklund transformation for the generalized coupled nonlinear Schrödinger equations with cubic-quintic nonlinearity

In this paper, we study the generalized coupled nonlinear Schrödinger equations with the cubic-quintic nonlinearity and arbitrary coupling parameters which describe the effects of the quintic nonlinearity on the ultrashort optical soliton pulse propagation in the non-Kerr media. Dark–dark N- and bright–dark two-soliton solutions are derived with symbolic computation. The bilinear Bäcklund transformation and the corresponding one-soliton solution are also given. Interactions of the dark–dark solitons including the repulsive and coherent interactions are investigated analytically and graphically, which are different from those in previous studies. The relationship between the amplitude and the velocity of the dark soliton is studied, especially the soliton with the small amplitude catches up with the one with the large amplitude. Head-on and overtaking interactions of dark–dark solitons are presented. Interactions between a stationary dark soliton and another dark one are shown. The asymptotic analysis shows that the interaction of dark–dark two solitons is elastic. The periodic attraction and repulsion of the bright–dark two solitons in the bound state are also analyzed, which are in accordance with those in the bright–dark vector soliton studies but different from the asymmetric and symmetric stationary bound states of Manakov bright–dark solitons.

Ultra-short Laser Pulse Generated by a Microring Resonator System for Cancer Cell Treatment

A microring resonator (MRRs) system incorporated with a add/drop filter is proposed in which ultra-short single, multi-temporal, and spatial optical soliton pulses are simulated and used to kill abnormal cells, tumors, and cancer. Chaotic signals are generated by a bright soliton pulse within a nonlinear MRRs system. Gold nanoparticles and ultra-short femtosecond/picosecond laser pulses’ interaction holds great interest in laser nanomedicine. By using appropriate soliton input power and MRRs parameters, desired spatial and temporal signals can be generated over the spectrum. Results show that short temporal and spatial solitons pulse with FWHM = 712 fs and FWHM = 17.5 pm could be generated. The add/drop filter system is used to generate the high-capacity, ultra-short soliton pulses in the range of nanometer/second and picometer/second.