Solving Generalized Nonlinear Schrödinger Equation by Adomian Decomposition Technique

In this paper, using a suitable change of variable and applying the Adomian decomposition method to the generalized nonlinear Schr¨odinger equation, we obtain the analytical solution, taking into account the parameters such as the self-steepening factor, the second-order dispersive parameter, the third-order dispersive parameter and the nonlinear Kerr effect coefficient, for pulses that contain just a few optical cycle. The analytical solutions are plotted. Under influence of these effects, pulse did not maintain its initial shape.

Observation of spatial nonlinear self-cleaning in a few-mode step-index fiber for special distributions of initial excited modes

In this paper, we experimentally demonstrate that a nonlinear Kerr effect in suitable coupling conditions can introduce a spatially self-cleaned output beam for a few-mode step-index fiber. The impact of the distribution of the initial excited modes on spatial beam self-cleaning has been demonstrated. It is also shown experimentally that for specific initial conditions, the output spatial pattern of the pulsed laser can be reshaped into the LP11 mode due to nonlinear coupling among the propagating modes. Self-cleaning into LP11 mode required higher input powers with respect to the power threshold for LP01 mode self-cleaning. Our experimental results are in agreement with the results of numerical calculations.

Nonlinear optical decoder based on photonic quasi crystal ring resonator structure

Using two nonlinear photonic crystal ring resonators we proposed and designed an all optical decoder. 2D 12 fold quasicrystal was used as the core section of the resonant rings. In order to make use of advantages of nonlinear Kerr effect, we put 24 dielectric rods between the core and outer shell of the resonant ring. The linear refractive index and nonlinear Kerr coefficient of these rods are n 0 = 1.4 and n 2 = 10−14 m2/W. In the proposed structure port I was used to switch the optical beams coming from BIAS between O1 and O2 output ports. The optical intensity required for performing the switching task is about 0.1 kW/μm2.

Instantaneous Frequency Representation Used for CPA Laser Simulation

In the current study, we present a novel intuitive graphical method for the simulation of nonlinear effects on stretched pulses, characterized by a large time-bandwidth product. By way of example, this method allows precise determination of effects occurring in CPA (chirped pulse amplification) laser chains, such as the pre-pulse generation by the nonlinear Kerr effect. This method is not limited to first-order dispersion and can handle all resulting distortions of the generated pre-pulse.

Impact of Nonlinear Kerr Effect on the Focusing Performance of Optical Lens with High-Intensity Laser Incidence

The rapid development of high-energy and high-power laser technology provides an important experimental means for the research of extreme physical state in the laboratory and for the design of large laser facilities for realizing inertial confinement fusion. However, when the incident laser field is very strong, the Kerr effect of materials affects the nominal performance of optical elements. In this work, the impact of Kerr effect on the focusing performance of an optical lens is studied by calculating and comparing the filed patterns of focal spots for three different incident laser beams together with three different levels of light intensities. The traditional transfer function of an optical lens is firstly modified according to the theory of nonlinear Kerr effect. We use the two-dimensional fast Fourier transform algorithm and angular spectrum algorithm to numerically calculate the field distributions of focal spots in the nominal focal plane of lens and its adjacent planes based on the Fresnel diffraction integral formula. The obtained results show that the Kerr effect affects the focusing characteristics of lens, especially for the incidence of high-order Gaussian beams, such as Hermite-Gaussian beams and Laguerre-Gaussian beams. At the same time, the focal length and refractive index of lens also change the field patterns of focal spots. The presented methodology is of great value in engineering applications where the practical problem with beam size up to 100 mm can be calculated using a common laptop computer. The work provides an efficient numerical technique for high-intensity incident laser beams focused by lens that takes Kerr effect into consideration, which has potential applications in high energy density physics and large laser facilities for inertial confinement fusion.

Modeling of Ultra-Long Span Bidirectional Raman Transmission Link Using Three-Segment Hybrid Fiber Core Structure

Ultra-long span unrepeatered systems using distributed Raman amplification are cost-effective solutions for bridging moderate transmission distances. However, there are two major limiting factors: nonlinear Kerr effect-induced nonlinear signal distortion and optical signal-to-noise ratio degradation due to spontaneous Raman noise. In this report, we proposed a model of three-segment hybrid fiber effective core area structure and developed a model covering: (1) generalized mathematical formulations, (2) analysis of three-segment Raman amplified link, and (3) simulation model of data transmission. The proposed model showed an improvement of the Raman gain profile, a reduction of the negative impact of the nonlinear Kerr effect, and an enhancement of the optical signal-to-noise ratio. A numerical simulation of the transmission performance of the three-segment hybrid structure was compared to conventional single-segment single fiber core structure on 80 Gb/s differential quadrature phase-shift keying (DQPSK) modulated data signals over a propagation distance of 390 km. The required optical signal-to-noise ratio was reduced by 2.71 dB to achieve the target error rate without using forward error correction. The numerical model and simulation of various data rates up to 100 Gb/s consistently showed that an improvement in transmission performance could be achieved by using three-segment hybrid fiber effective core area structure.

Soliton Pulse Generation for WDM-Based Free Space Optics Communication Using Microring Resonators

A microring resonator (MRR) and an add/drop devices are presented to generate picosecond solitonic pulse and signal as multichannel localized wavelengths, applicable for WDM-based free space optics (FSO) communication. A Gaussian pulse is inputted to the first ring resonator of the proposed system. Because of the nonlinear Kerr effect, chaotic signals are created. The second MRR filters the generated signals and shape solitonic pulses, where the accurate FWHM of 20 ps with intensity of 2.45 W are obtained. The add/drop device is applied for tuning the solitonic pulses. Results indicate that a range of solitonic wavelengths from 1550 nm to 1600 nm are obtained, where FSR and FWHM are 144 pm and 5 pm, respectively. Finally, performance of the proposed MRR system is evaluated in terms of bit error rate (BER) and Q factor. In the analysis, the proposed solitonic pulse is compared to conventional counterparts. Using the proposed MRR system, BER and Q factor of WDM-based FSO are considerably improved.