Birefringent Fiber Research Articles

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

This paper is devoted to the investigation of phase portraits analysis of a vector short pulse equation describing propagation of short light pulses in birefringent optical fiber. Indeed, we introduce transformations that are helpful in decoupling this equation and following the fourth order runge–kutta scheme, we construct phase portraits of the system under interest. The analysis of the phase portrait shows that the system possesses soliton solutions and periodic solutions. We derive Hamiltonian like energy of the system and show that the system is conservative. By double integration, we construct some expressions of the solutions to the system by direct integration which differ from the solutions previously obtained in the literature by the fact that they are difficult to be expressed explicitly as functions of the phase of the wave.

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

In this paper, coupled conformable fractional Fokas-Lenells equation with spatio-temporal dispersion is introduced, which is usually used to simulate the propagation model of pulses’ temporal evolution in birefringent fibers. Firstly, the traveling wave transformation is applied to convert the conformable time–space fractional Fokas-Lenells model into two-dimensional planar dynamic system. Secondly, the qualitative analysis of the coupled conformable fractional Fokas-Lenells equation with spatio-temporal dispersion is discussed by using the plane dynamics system. Moreover, two-dimensional phase portraits, three-dimensional phase portraits, Poincaré sections and sensitivity analysis of its perturbed system are drawn by using the Maple mathematical software. Finally, the optical soliton solutions of the coupled conformable fractional Fokas-Lenells equation with spatio-temporal dispersion are obtained by using planar dynamical system method.

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

This paper describes a novel compact fiber sensor with high sensitivity for the simultaneous measurement of underwater salinity and temperature by simulation. The structure is based on a highly birefringent, asymmetric, full-circular hole photonic crystal fiber (HB-A-FCH PCF), which achieves the birefringence value of 2.83 × 10-3 at the wavelength of 2.2 µm. In addition, with ethanol-filled specific air holes, the temperature sensitivity of HB-A-FCH PCF is remarkably improved. Therefore, considering the high birefringence property, we simulate a Michelson interferometer-based sensor setup with air holes as fluid microchannels and simultaneously measure salinity and temperature through the spectral responses of the x- and y-polarization state. Theoretical analysis shows the sensor can achieve the salinity and temperature sensitivity up to 5.1472 nm/% and −0.8987 nm/°C in x-polarized fundamental mode, respectively, whereas the salinity and temperature sensitivity up to 4.5386 nm/% and −0.8000 nm/°C in y-polarized fundamental mode, respectively.

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

Object:The objective of this article is to study the stochastic Schrödinger–Hirota equation with parabolic law nonlinearity and spatiotemporal dispersion (STD) in birefringent fibers having multiplicative white noise in the Itô sense. Method:The Jacobi-elliptic expansion approach and the extended auxiliary equation algorithm are utilized. Result:The Jacobi-elliptic solutions, bright solitons, dark solitons, singular solitons and periodic solutions of the given system are introduced.

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.

Binary solvent-exchange-induced self-assembly of silk fibroin birefringent fibers for optical applications

To generate birefringence in artificial materials has attracted increasing attention in terms of their potential for applications in sensor, tissue engineering and optical devices. Silk materials with patterned structures presented unique optical features, however, effectively fabricating of structural anisotropy in silk materials to directly tailor their birefringence is still challenging. Silk fibroin birefringent fibers (SBFs) with tunable birefringence were obtained in this study via a strategy that combined injection technique and binary solvent-exchange-induced self-assembly (BSEISA). The structural deformation of these SBFs that introduced by external stimulus such as tensile and solvent swelling was critical to their birefringence. As a result, pink, yellow, green, cyan, and purple were successfully achieved in the interference color of the SBFs with an exchanging solvent of 25, 55, 75, 90 wt% ethanol aqueous solution, and methanol respectively. Moreover, we respectively exchanged these SBFs against with Congo red (SBF-CR), methyl orange (SBF-MO), methylene blue (SBF-MB) and rhodamine B (SBF-RhB) solutions to produce fibers with diversity in their birefringent performance. Two types of patterns were designed and thereafter constructed by (1) SBF\\SBF-CR\\SBF-RhB, and (2) SBF\\SBF-MB\\SBF-CR. Interestingly, the patterns both displayed a letter of “A” in natural light, while displayed different letters of (1) “H” and (2) “U” in polarized light. This study demonstrated that these SBFs with unique optical and birefringent performances are anticipated to act as sensors and code labels for optical applications.

Phase portrait, bifurcation, chaotic pattern and optical soliton solutions of the Fokas-Lenells equation with cubic-quartic dispersion in optical fibers

The main purpose of this paper is to study the Fokas-Lenells equation with cubic-quartic dispersion describing the propagation of birefringent fibers and polarization preserving fibers. Firstly, using traveling wave transformation and homogeneous balance principle, the Fokas-Lenells equation with cubic-quartic dispersion is simplified into ordinary differential equation. Secondly, the dynamic properties of two-dimensional system and its perturbed system are studied. Finally, by using the trial method of polynomial of rank homogeneous equation, the optical soliton solutions of the Fokas-Lenells equation with cubic-quartic dispersion can be obtained. Moreover, three-dimensional diagram, two-dimensional diagram, density plot and contour plot of the obtained solutions are drawn by explaining the propagation of optical solitons.

Highly Dispersive Optical Solitons in Birefringent Fibers of Complex Ginzburg–Landau Equation of Sixth Order with Kerr Law Nonlinear Refractive Index

In this paper, we derived optical soliton solutions with a highly dispersive nonlinear complex Ginzburg–Landau (CGL) equation in birefringent fibers that have Kerr law nonlinearity. We applied two mathematical methods, namely the addendum Kudryashov’s method and the unified Riccati equation expansion method. Straddled solitary solutions, bright soliton, dark soliton and singular soliton solutions were obtained.This model represents the propagation of a dispersive optical soliton through a birefringent fiber. This happens when pulses propagating through an optical fiber split into two pulses.

Polarization-maintaining large-mode-area solid-core anti-resonant fiber for high-power fiber lasers

A polarization-maintaining large-mode-area solid-core anti-resonant fiber is investigated in this work with double-layer anti-resonant elements for improved capability on fundamental mode guidance and higher order mode suppression, and structural and material asymmetry on inner-layer cladding tubes for high birefringence. Mode coupling between fundamental core mode in one polarization direction and mode on two high-index inner cladding tubes is used to enhance the fiber birefringence under large core diameter. Eventually, an optimized design of polarization-maintaining large-mode-area solid-core anti-resonant fiber with the currently largest mode field area of 3026 μm2 and birefringence of 1.20 × 10−5 can be anticipated with the confinement losses for all the higher order modes exceeding 10 dB/m. Moreover, confinement loss below 0.1 dB/m can still be obtained for the fundamental core mode in both polarization direction even under the mode-coupling effect. Active polarization-maintaining anti-resonant fiber is analyzed and the refractive index of the central rare-earth-doped region is optimized for the first time for both well guided signal and pump laser. Large pump absorption coefficient can thus be anticipated from the multimode laser core-pumped active large-mode-area fiber, which facilitates short active fiber length needed for sufficient laser gain. The fiber proposed here offers great potential for the development of high-performance fiber laser sources including high-power single-frequency fiber amplifiers and high-peak-power ultrashort pulsed fiber amplifiers.

Customized Optical Fiber Birefringent Sensors to Multipoint and Simultaneous Temperature and Radial Strain Tracking of Lithium‐Ion Batteries

AbstractBatteries are seen as a vital piece for actual carbon‐neutral world needs. However, as they basically operate through extremely exothermic electrochemical events, special attention must be paid to their thermal and volumetric constraints, where continuous and accurate monitoring is of great importance. Considering it, customized optical sensors, based on fiber Bragg gratings recorded in birefringent PANDA fibers (FBG‐PANDA), are developed and instrumented in a coiled configuration into a cylindrical Li‐ion battery (LiB) to simultaneously track temperature and radial strain during galvanostatic cycles, in three different battery locations, for the first time. The maximum temperature and radial strain variations are achieved in the middle and at the end of the discharge steps. This thermal behavior is correlated with the internal heat generation and transfer of thermal energy processes, with a tendency to accumulate in the LiB central zone.Good feasibility and reproducibility are observed in the optical sensor's performance and demonstrated that by operating as a multiparameter decouple system, they can decrease the complexity and intrusiveness in batteries, by using only one optical fiber line. The reported results are in accordance with the literature, indicating that such sensors could be consistently used for future applications regarding battery safety parameters sensing.

Optical solitons in birefringent fibers with the generalized coupled space–time fractional non-linear Schrödinger equations

The nonlinear Schrödinger (NLS) equation is an ideal model for describing optical soliton transmission. This paper first introduces an integer-order generalized coupled NLS equation describing optical solitons in birefringence fibers. Secondly, the semi-inverse and fractional variational method is used to extend the integer‐order model to the space–time fractional order. Moreover, various nonlinear forms of fractional NLS equations are discussed, including the Kerr, power, parabolic, dual-power, and log law. The exact soliton solutions, such as bright, dark, and singular solitons, are given. Finally, the behavior of the solution is shown by three-dimensional figures with different fractional orders, which reveals the propagation characteristics of optical solitons in birefringence fibers described by the generalized coupled space–time fractional NLS equation.

Wave structures and the chaotic behaviors of the cubic-quartic nonlinear Schrödinger equation for parabolic law in birefringent fibers

Wave structures and the chaotic behaviors of the cubic-quartic nonlinear Schrödinger equation for parabolic law in birefringent fibers

A comparative study of nonlinear fractional Schrödinger equation in optics

The optical soliton solutions to the fractional nonlinear Schrödinger (NLS) equation in the presence of nonlinear oscillating coefficient with Beta and M-truncated derivatives are studied by applying a complex wave transformation that converts the fractional NLS equation to an ordinary differential equation. The optical solution structures are attained with the use of the Sardar sub-equation (SSE) method. The NLS equation is an important nonlinear complex model which governs the propagation of an optical pulse in a birefringent optical fiber. The fractional NLS equation is used in optical telecommunication, high-energy physics, gas dynamics, electrodynamics and ocean engineering. The graphical presentation of the attained results is also discussed in detail.

Blind SOP recovery of eigenvalue communication system based on a nonlinear Fourier transform.

Owing to the random birefringence of optical fibers, the recovery of the state of polarization (SOP) is urgently needed, especially in the nonlinear spectrum division multiplexing transmissions. Based on the variance of the polarization power ratio among symbols as the cost function, we propose a novel algorithm for the blind SOP recovery of eigenvalue communications. In the single eigenvalue transmissions with phase-shift keying or 16-ary amplitude and phase-shift keying constellations, at least 25.3 dB polarization extinction ratio can be achieved by using a block length of 30, even under 7 dB OSNR condition. It also shows that the proposed algorithm can be employed in multi-eigenvalue NFDM transmissions and full-spectrum modulated NFDM system. In the experiment, our proposed algorithm performs the same as the training symbol based method in back-to-back and less than 3000 km fiber link conditions; a maximum performance gain of 1.6 dB was obtained in ultra-long-haul condition (4300 km). It also shows that the impact of the polarization mode dispersion of a single-mode fiber on the algorithm is negligible.

Dispersive Optical Solitons with Differential Group Delay Having Multiplicative White Noise by Itô Calculus

The current paper recovers dispersive optical solitons in birefringent fibers that are modeled by the Schrödinger–Hirota equation with differential group delay and white noise. Itô Calculus conducts the preliminary analysis. The G′/G-expansion approach and the enhanced Kudryashov’s scheme gave way to a wide spectrum of soliton solutions with the white noise component reflected in the phase of the soliton.