Birefringent Fiber Research Articles

Reverse-time type nonlocal Sasa–Satsuma equation and its soliton solutions

In this work, we study the Riemann–Hilbert problem and the soliton solutions for a nonlocal Sasa–Satsuma equation with reverse-time type, which is deduced from a reduction of the coupled Sasa–Satsuma system. Since the coupled Sasa–Satsuma system can describe the dynamic behaviors of two ultrashort pulse envelopes in birefringent fiber, our equation presented here has great physical applications. The classification of soliton solutions is studied in this nonlocal model by considering an inverse scattering transform to the Riemann–Hilbert problem. Simultaneously, we find that the symmetry relations of discrete data in the special nonlocal model are very complicated. Especially, the eigenvectors in the scattering data are determined by the number and location of eigenvalues. Furthermore, multi-soliton solutions are not a simple nonlinear superposition of multiple single-solitons. They exhibit some novel dynamics of solitons, including meandering and sudden position shifts. Also, they have the bound state of multi-soliton entanglement and its interaction with solitons.

Rocking filter in a highly birefringent fiber for resonant coupling between different LP11 modes and generation of cylindrical vector beams.

We present a rocking filter in a highly birefringent two-mode fiber that enables resonant coupling between different modes in the LP11 group. Our simulations and experimental results prove that such a filter allows for resonant coupling between orthogonally polarized LP11 modes of the same spatial structure, as well as between modes of the same polarizations and orthogonal spatial distributions. Furthermore, we demonstrate that such rocking filters can be used to generate pure TE01, TM01 and HE21 beams or their coherent superposition.

Investigating Families of Soliton Solutions for the Complex Structured Coupled Fractional Biswas–Arshed Model in Birefringent Fibers Using a Novel Analytical Technique

This research uses a novel analytical method known as the modified Extended Direct Algebraic Method (mEDAM) to explore families of soliton solutions for the complex structured Coupled Fractional Biswas–Arshed Model (CFBAM) in Birefringent Fibers. The Direct Algebraic Method (DAM) is extended by the mEDAM’s methodology to compute more analytical solutions that would otherwise be difficult to acquire. We use this method to derive several families of soliton solutions and examine their characteristics. We also look at how different model parameters, such as amplitude, width, and propagation speed, affect the dynamics of soliton. Our use of 2D and 3D graphics to illustrate the soliton solutions also makes it possible to see the soliton dynamics more clearly. The outcomes also demonstrate that the method suggested has proven successful in producing soliton solutions for intricate structures such as the CFBAM.

Birefringence analysis of collagen supraorganization in cat corneas with tropical keratopathy.

To evaluate the birefringent properties of the cornea and examine the supraorganizational aspects of collagen fibers in cats with tropical keratopathy. In this study, 10-micrometer-thick sections of corneal tissue from cats with tropical keratopathy were examined, both in the opaque and transparent areas of the anterior stroma. Control samples were obtained from healthy cat corneas. Polarized light microscopy was employed to evaluate the birefringent properties using two distinct methods. The first method involved measuring the optical retardation associated with corneal birefringence, while the second method assessed the alignment/waviness of the birefringent collagen fibers. Differences were significant when p < .05. Tropical keratopathy resulted in a significant rise (p < .05) in optical retardation in both opaque and transparent regions of the cat cornea. In the anterior stroma, both the opaque zones and transparent tissue exhibited a higher degree of collagen fiber packing than the control corneas. However, no significant differences (p > .05) in alignment were observed between the transparent tissue of the diseased cornea and the healthy corneas. Supraorganizational changes in collagen fiber packing are not restricted to lesion zones in cat corneas affected by tropical keratopathy. Such alterations also occur in the corneal tissue of the anterior stroma adjoining the lesions. Therefore, it is plausible that the transparent tissue of the anterior stroma in corneas affected by the disease may have functional abnormalities, despite its macroscopic healthy appearance. Additional investigations are required to clarify the implications of these potential defects and their conceivable contribution to tropical keratopathy.

Stability analysis and novel optical pulses to Kundu–Mukherjee–Naskar model in birefringent fibers

The concern of this study is to investigate the optical solitons pluses. The [Formula: see text]-dimensional Kundu–Mukherjee–Naskar (KMN) mathematical model in birefringent fibers is taken under consideration for this sake because this model has great importance in optics and delineate the propagation of soliton dynamics in optical fiber communication system and the rogue waves in the oceans and the bending of the light beam. Two newly developed approaches first extended rational sinh-Gordon method which is formulated from the well-known sinh-Gordon equation and second [Formula: see text]-expansion function method are manipulated for the construction of optical solitons in distinct formats. Bright, dark, and singular along their combined forms, periodic and plane wave solutions are extracted with the aid of proposed methods. Moreover, the modulation instability of investigated model is also carried out via linear stability theory. To endorse the physical compatibility of the results, the 2D, 3D, contour, and density plots have been delineated using appropriate parametric values. According to our literature research, these two methods that we are working on have not been applied to the KMN equation in birefringent fibers before, and we believe that the new solutions we have obtained will be useful to researchers working in modeling in this field. The evaluated results suggested that the techniques employed in this research to recover inclusive and standard solutions are approachable, efficient, and speedier in computing and can be considered a handy tool in solving more complex phenomena with the assistance of symbolic computation.

Measurement-Device-Independent Quantum Key Distribution Based on Decoherence-Free Subspaces with Logical Bell State Analyzer.

Measurement-device-independent quantum key distribution (MDI-QKD) enables two legitimate users to generate shared information-theoretic secure keys with immunity to all detector side attacks. However, the original proposal using polarization encoding is sensitive to polarization rotations stemming from birefringence in fibers or misalignment. To overcome this problem, here we propose a robust QKD protocol without detector vulnerabilities based on decoherence-free subspaces using polarization-entangled photon pairs. A logical Bell state analyzer is designed specifically for such encoding. The protocol exploits common parametric down-conversion sources, for which we develop a MDI-decoy-state method, and requires neither complex measurements nor a shared reference frame. We have analyzed the practical security in detail and presented a numerical simulation under various parameter regimes, showing the feasibility of the logical Bell state analyzer along with the potential that double communication distance can be achieved without a shared reference frame.

Polarization bases compensation towards advantages in satellite-based QKD without active feedback

Long-distance photonic implementations of quantum key distribution protocols have gained increased interest due to the promise of information-theoretic security against unauthorized eavesdropping. However, a significant challenge in this endeavor is photon-polarization getting affected due to the birefringence of fibers in fiber-based implementations, or variation of reference frames due to satellite movement in long-haul demonstrations. Conventionally, active feedback-based mechanisms are employed for real-time polarization tracking. Here, we propose and demonstrate an alternative approach via a proof-of-principle experiment over an in-lab entanglement-based (BBM92) protocol. In this approach, we perform a quantum state tomography to arrive at optimal measurement bases for any one party resulting in maximal (anti-)correlation in measurement outcomes of both parties. Our polarization-entangled bi-photons have 94% fidelity with a singlet state and a Concurrence of 0.92. By considering a representative 1 ns coincidence window span, we achieve a quantum-bit-error-rate (QBER) of ≈5%, and a key rate of ≈35 Kbps. The performance of our implementation is independent of any local polarization rotation. Finally, using optimization methods we achieve the best trade-off between the key rate, QBER, and balanced key symmetry. Our approach obviates the need for active polarization tracking. It is also applicable to such demonstrations with non-maximally entangled states and prepare-and-measure-based protocols with partially polarized single-photon sources.

Soliton Dynamics in a Birefringent Optical Fiber

Long-distance solitons maintain their form and speed. Single mode optical fiber exhibits birefringence as a result of its asymmetric core's effect on the refractive index. The soliton pulse is broadened and chirped as it travels through a birefringent optical fiber due to many features of the fiber. Therefore, it is necessary to strike a balance between the elements influencing the transmission to guarantee minimal data loss. This work uses OptiSysten software to strike a balance between the length, effective area, soliton period, and attenuation effects that affect the performance of the soliton while employing optical fiber as a birefringent optical fiber. Based on this research, a set of values for these parameters that minimizes widening and chirping was determined. The simulation findings are compared to the mathematical and analytical combination of soliton, which is based on the coupled non-linear Schrodinger equation. Although previous works on soliton had demonstrated the impact of GVD and SPM on the transmission, this paper aids comprehension by including additional performance-affecting characteristics.

Solitons behavior of Sasa-Satsuma equation in birefringent fibers with Kerr law nonlinearity using extended F-expansion method

Optical soliton solutions in birefringent fibers and other analytic solutions for Sasa-Satsuma equation with Kerr law nonlinearity are investigated using extended F-expansion method. Bright, dark, singular, combo bright-singular, combo dark-singular and combo singular soliton solutions are extracted. Also, periodic, rational and Jacobi elliptic functions solutions are derived. Finally, we offer some 3D, 2D and contour plots to illustrate the nature of the provided solutions.

Soliton interactions and Yang–Baxter maps for the complex coupled short‐pulse equation

AbstractThe complex coupled short‐pulse equation (ccSPE) describes the propagation of ultrashort optical pulses in nonlinear birefringent fibers. The system admits a variety of vector soliton solutions: fundamental solitons, fundamental breathers, composite breathers (generic or nongeneric), as well as so‐called self‐symmetric composite solitons. In this work, we use the dressing method and the Darboux matrices corresponding to the various types of solitons to investigate soliton interactions in the focusing ccSPE. The study combines refactorization problems on generators of certain rational loop groups, and long‐time asymptotics of these generators, as well as the main refactorization theorem for the dressing factors that leads to the Yang–Baxter property for the refactorization map and the vector soliton interactions. Among the results obtained in this paper, we derive explicit formulas for the polarization shift of fundamental solitons that are the analog of the well‐known formulas for the interaction of vector solitons in the Manakov system. Our study also reveals that upon interacting with a fundamental breather, a fundamental soliton becomes a fundamental breather and, conversely, that the interaction of two fundamental breathers generically yields two fundamental breathers with a polarization shifts, but may also result into a fundamental soliton and a fundamental breather. Explicit formulas for the coefficients that characterize the fundamental breathers, as well as for their polarization vectors are obtained. The interactions of other types of solitons are also derived and discussed in detail and illustrated with plots. New Yang–Baxter maps are obtained in the process.

Highly Birefringent and Low-Loss Hollow-Core Anti-Resonant Fiber Based on a Hybrid Guidance Mechanism

A highly birefringent and low-loss hollow-core anti-resonant fiber (HC-ARF) based on a hybrid guidance mechanism is proposed and investigated by using a finite element method. The hybrid guidance mechanism is caused by the anti-resonance effect and the total internal reflection effect. The proposed HC-ARF is obtained by employing twin symmetrical and mutually tangential elliptical arc anti-resonance layers (EA-ARLs) in a conventional 8-tube HC-ARF. Because of the anti-resonance mechanism and the total internal reflection mechanism in the EA-ARL, mode coupling appears between the core mode and the cladding mode. Simulation results indicate that the proposed HC-ARF can achieve birefringence as high as 10−2 in a near-infrared range of 1400 nm to 1600 nm and a low confinement loss (CL) of 7.74 × 10−4 dB/m (9.26 × 10−4 dB/m) for x- and y-polarization components of the fundamental mode (FM) at 1550 nm. In addition, the existence of the 8-tube anti-resonance structure in the cladding significantly suppresses the CL of the x-polarization component of the FM significantly, but the impact on the CL of the y-polarization FM can be ignored, which is determined mainly by the twin EA-ARLs. Furthermore, the performance of the birefringence and CL are also investigated by changing the values of other fiber structure parameters. Our proposed structure successfully shows the ability of the hybrid guidance mechanism in the application of CL manipulation of orthogonal polarization components.

Application of Crossed Polarizer Method in the Measurement of Differential Group Delay of Optical Fibers

In this paper, we report the use of crossed polarizer technique to measure the differential group delay (DGD) of few-mode optical fiber (FMF). The windowed Fourier transform (WFT) is applied in the analysis of beat length measurement in the spectral domain to obtain the dependence of DGD as a function of wavelength. The birefringence of polarization-maintaining fiber (PMF) and the DGD of FMF are measured by applying our method. We discuss the noise background, the width of DGD peaks, and the possible errors introduced in the optical path in the modified crossed polarizer technique.

Optical Solitons for the Concatenation Model with Differential Group Delay: Undetermined Coefficients

In the current study, the concatenation model of birefringent fibers is explored for the first time, and we present optical soliton solutions to the model. The integration algorithm used to achieve this retrieval is the method of undetermined coefficients, which yields a wide range of soliton solutions. The parameter constraints arise naturally during the derivation of the soliton solutions, which are essential for such solitons to exist.

Nonlinear dynamics of short light pulse in birefringent optical fiber

Nonlinear dynamics of short light pulse in birefringent optical fiber

All-fiber low threshold tunable multimode Q-switched mode locked fiber laser using a few mode Er-doped fiber

We report an all-fiber low threshold (70 mW) multimode Q-switched mode-locked (QML) fiber laser at 1.5 m. Nonlinear polarization rotation and a few mode Er-doped fiber (FM-EDF) were both adopted to achieve a low threshold QML operation initially, and the later experimental results showed and verified that the FM-EDF was the key factor of the QML pulses generation. A multimode QML state at 70 mW pump power was obtained with an 18 μs Q-switched pulse width and a 7.41 kHz repetition rate. The repetition rate and pulse width of the mode-locked pulses within the Q-switched envelope were 16.9 MHz and ∼910 ps respectively. The multimode QML fiber laser can be turned from 1561.8 nm to 1575.1 nm owing to the multimode interference and the fiber birefringence filtering effect. The QML pulses with dual-wavelength and three-wavelength were also observed by manipulating the polarization controllers and increasing the pump power. The experimental results showed that multimode QML pulses can be achieved with a short FM-EDF at a lower pump power in an all-fiber multimode cavity. The generated low threshold and tunable QML multimode fiber laser has potential application in measuring and mode-division multiplexed system.

Chaotic pattern, phase portrait, sensitivity and optical soliton solutions of coupled conformable fractional Fokas-Lenells equation with spatio-temporal dispersion in birefringent fibers

Chaotic pattern, phase portrait, sensitivity and optical soliton solutions of coupled conformable fractional Fokas-Lenells equation with spatio-temporal dispersion in birefringent fibers

Highly sensitive sensor for simultaneous underwater measurement of salinity and temperature based on highly birefringent asymmetric photonic crystal fiber

Highly sensitive sensor for simultaneous underwater measurement of salinity and temperature based on highly birefringent asymmetric photonic crystal fiber

Research on Magnetic-Induced Error of Small-Sized Fiber Optic Gyro Fiber Coil in Space Environment

Spacecraft is severely limited in weight and volume, resulting in a small bending radius of the fiber coil used by IFOG (Interference Fiber Optic Gyroscope). The fiber coil has such a size that the influence of bending on fiber birefringence cannot be ignored. In this paper, we research magnetic-induced errors of small-sized IFOG working in low orbit space. Firstly, we use the Jones matrix to analyze the effects of radial magnetic field and axial magnetic field on IFOG. Secondly, we establish a three-dimensional model for the radial magnetic-induced errors and magnetic-induced errors of minor radius fiber coil. Using the finite element method, we analyze the magnetic-induced error between different levels of the fiber coil. Combined with the birefringence distribution of the minor radius fiber coil, an accurate three-dimensional magnetic-induced error model is established. Thirdly, in the experiment, we design the magnetic-induced error test platform that includes the Fluke standard current source, transconductance amplifier, and Helmholtz coil. The experimental results show that, compared with the traditional calculation method, the three-dimensional magnetic-induced error model reduces the RMSE (Root Mean Square Error) of the radial magnetic field by 56.9% and the RMSE of the axial magnetic field by 35.7%, respectively.

Dispersive optical solitons in birefringent fibers for stochastic Schrödinger–Hirota equation with parabolic law nonlinearity and spatiotemporal dispersion having multiplicative white noise

Dispersive optical solitons in birefringent fibers for stochastic Schrödinger–Hirota equation with parabolic law nonlinearity and spatiotemporal dispersion having multiplicative white noise

Effect of core ellipticity and core-induced thermal stress on the conversion of LP11 modes to vector vortex modes in gradually twisted highly birefringent fibers.

We study the effect of the core ellipticity and core-induced thermal stress on the conversion of LP11 modes to vortex modes in gradually twisted highly birefringent PANDA fibers using an improved perturbation-based modeling method. We show that these two technologically unavoidable factors have a significant impact on the conversion process, which manifests itself in shortening the conversion length, altering the assignment between the input LP11 modes and output vortex modes, and modifying the vortex mode structure. In particular, we demonstrate that for certain fiber geometries, it is possible to obtain output vortex modes with parallel and antiparallel spins and orbital angular momenta. The simulation results obtained using the modified method are in good agreement with recently published experimental data. Furthermore, the proposed method provides reliable guidelines for choosing fiber parameters that ensure a short conversion length and the desired polarization structure of the output vortex modes.