Birefringent Fiber Research Articles

Highly birefringent and low loss anti-resonant hollow-core fiber with stadium-shaped nested structure

Abstract We propose a stadium-shaped nested anti-resonant hollow-core fiber (SSAF), designed to enable high birefringence and low loss in the near-infrared bands. A numerical investigation and simulation for variations in the parameters of the stadium-shaped nested structure were conducted, and the confinement loss (CL) was reduced by parameter optimization, while a birefringence of 10-4 was maintained. With optimized SSAF structure, the birefringence and CL are improved to 1.39 ×10−4 and 26.5 dB/km at 1.38 µm, 1.28 ×10−4 and 2.64 dB/km at
1.55 µm, respectively. Meanwhile, it exhibits favorable single-mode characteristics and achieves a high-order mode extinction ratio (HOMER) of up to 103, and the superior bending resistance characteristics were validated. Our work offers valuable guidance for designing and optimizing highly birefringent anti-resonant hollow-core fiber (ARF), and the proposed
SSAF has great application potential in polarization-dependent transmission and interferometric fiber gyroscopes.

Elliptical birefringence model for highly efficient study of SOP and DOP in complicated birefringent fiber

Optical chirality has recently let to many novel prospects and applications and this phenomenon also exists in twisting linear birefringent fiber. However, it has not been investigated when the birefringence is non-uniform, namely, both the spinning rate and linear birefringence vary along the fiber axis. Additionally, this non-uniformity brings dissatisfaction in terms of computational efficiency when using traditional methodologies, such as the coupled mode theory and the cascaded linear phase delayer matrix model. In order to study this kind of complicated birefringent fiber (CBF), this work introduces an innovative solution to this issue: the elliptical phase delayer model, specifically designed to analyze situations where the optical fiber experiences arbitrary spinning. The derivation of this model employs the Jones matrix, and its validity and computational efficiency are verified through numerical calculations. Furthermore, this work explores the State of Polarization (SOP) of CBF using the proposed model. It also investigates the Degree of Polarization (DOP) of the output light wave, which is indicative of the depolarization effect due to spinning. This study presents an elliptical phase delayer model that offers an efficient means of calculating the SOP and DOP of CBF, and is also applicable to other spun optical structures.

Broadband high birefringence and single-polarization hollow-core anti-resonant fibers with an elliptical-like core

Due to the light-guiding mechanism of hollow-core anti-resonant fibers (HC-ARFs), the low overlap between core modes and anti-resonant layers poses a challenge in achieving high birefringence. To address this issue, we propose three high-birefringence HC-ARFs with an elliptical core and varying cladding compositions and conduct a detailed optimization and analysis for structure (c). Simulation results demonstrate that structure (a) and structure (b) provide high birefringence, broadband, and low-loss transmission properties. Specifically, structure (a) achieves a birefringence greater than 1.3×10−4 over a 680 nm wavelength range, and structure (b) achieves a birefringence greater than 1.6×10−4 over a 580 nm wavelength range, both maintaining fundamental mode (FM) loss below 1 dB/m. Structure (c) enhances birefringence by an order of magnitude and offers excellent single-polarization properties by introducing high-refractive-index material. At 1.55μm, structure (c) achieves a birefringence of 0.98×10−3, with a low FM loss for x-polarization of 0.01 dB/m and a polarization extinction ratio (PER) of 57450. Additionally, structure (c) exhibits low bend loss in the x-direction, with only 0.06 dB/m for a bend radius of 6 cm.

Turning four-wave mixing on and off in elliptically birefringent fibers via narrow frequency detuning.

Controlling four-wave mixing (FWM) is vital for several applications, including fiber optical communication, optical signal processing, optical amplification, and frequency generation. This paper presents a novel, to our knowledge, approach to control unidirectional FWM in elliptically birefringent fibers. By leveraging the frequency-dependent polarization eigenmodes of these fibers and detuning the optical frequency of one of the pump fields by a few megahertz, we can turn the FWM interaction on and off, thus controlling the generation of signal and idler fields. Moreover, this approach allows us to turn off the FWM interaction at any desired frequency, enabling all-optical switching and narrowband filtering applications.

Design and error analysis of simple terahertz high birefringence microstructured fiber

Abstract High birefringence fibers are significant in the terahertz technology field, serving as waveguides for terahertz transmission. They are applicable in various fields such as communication, imaging. Integrating metal microstructures into polymer microstructured optical fibers can effectively modulate the transmission characteristics of the fiber, enhancing birefringence and reducing loss, thereby achieving better performance compared to traditional single-material fibers. This paper presents a structurally simple terahertz high birefringence microstructured fiber, where the introduction of gold microstructures enhances the birefringence of fiber, with a maximum birefringence of up to 1.089 × 10−2. We also discuss several manufacturing errors that may occur during the fiber fabrication process. The results indicate that the designed fiber exhibits significant manufacturing tolerance. Variations in the thickness and angle of the gold microstructures, as well as the angular offset of the elliptical cladding wall, peak-to-valley errors, and changes in the aspect ratio of the elliptical tube, have relatively minor effects on the overall transmission performance. The research findings provide insights for designing subsequent high birefringence terahertz fibers, thereby propelling advancements in this field. They offer a theoretical basis for the preparation of related microstructured fiber structures and provide valuable understanding for optimizing fiber manufacturing processes.

Effects of white noise on straddle and soliton dynamics in birefringent fibers using the novel Kaup-Newell equation approach

Effects of white noise on straddle and soliton dynamics in birefringent fibers using the novel Kaup-Newell equation approach

The dynamic behaviors between double-hump solitons in birefringent fibers

In this paper, we research the fractional coupled Hirota equations with variable coefficients describing the collisions of two waves in deep oceans and the propagation of ultrashort light pulses in birefringent fibers and successfully acquire the double-hump one-soliton, two-solitons and N-solitons solutions via the Hirota bilinear method. At the same time, the Bäcklund transformation and the corresponding soliton solutions are also obtained. Based on the precise forms of the solitons solutions, we gain double-hump solitons images with different shapes including U-shape, V-shape and wave-type by assigning proper functions to the group velocity dispersion and the third-order dispersion and analyze the interaction dynamics of double-hump solitons. It is worth noting that the Hirota bilinear operators involved here are fractional rather than integer, which has never appeared in previous literatures.

Stripe Soliton in All‐Fiber Lasers

AbstractStripe solitons (SSs), the special localized wavepackets exhibiting periodic modulations, are identified in condensed matter physics and nonlinear science. Here, giant‐chirp and chirp‐free SSs in all‐fiber lasers are demonstrated composed of single‐mode fiber and polarization‐maintaining fiber. The chirp property of SSs depends on the cavity dispersion while the stripe period relies on the fiber birefringence. Theoretical and numerical results coincide with experimental findings, revealing that the filtering and frequency shift of two vector modes is governed by the mode coupling related to birefringence and the nonlinear coupling induced by the phase modulation, respectively, which disrupts their complementarity and ultimately leads to modulation of the overall spectrum. With the aid of the saturable absorption and cross‐phase modulation effects, the multi‐color pulses synergistically overlap, giving rise to the unique SSs. These results present a simple approach for generating chirp‐controllable SSs in all‐fiber lasers, which is crucial for applications in difference frequency generation and soliton physics.

Highly birefringent hexagonal porous core photonic crystal fiber for polarization maintaining integrated THz-photonics applications

Highly birefringent hexagonal porous core photonic crystal fiber for polarization maintaining integrated THz-photonics applications

New Coupled Optical Solitons to Birefringent Fibers for Complex Ginzburg–Landau Equations with Hamiltonian Perturbations and Kerr Law Nonlinearity

In this study, we use an analytical method tailored for the in-depth exploration of coupled nonlinear partial differential equations (NLPDEs), with a primary focus on the dynamics of solitons. Traditional methods are quite effective for solving individual nonlinear partial differential equations (NLPDEs). However, their performance diminishes notably when addressing systems of coupled NLPDEs. This decline in effectiveness is mainly due to the complex interaction terms that arise in these coupled systems. Commonly, researchers have attempted to simplify coupled NLPDEs into single equations by imposing proportional relationships between various solutions. Unfortunately, this simplification often leads to a significant deviation from the true physical phenomena that these equations aim to describe. Our approach is distinctively advantageous in its straightforwardness and precision, offering a clearer and more insightful analytical perspective for examining coupled NLPDEs. It is capable of concurrently facilitating the propagation of different soliton types in two distinct systems through a single process. It also supports the spontaneous emergence of similar solitons in both systems with minimal restrictions. It has been extensively used to investigate a wide array of new coupled progressive solitons in birefringent fibers, specifically for complex Ginzburg–Landau Equations (CGLEs) involving Hamiltonian perturbations and Kerr law nonlinearity. The resulting solitons, with comprehensive 2D and 3D visualizations, showcase a variety of coupled soliton configurations, including several that are unprecedented in the field. This innovative approach not only addresses a significant gap in existing methodologies but also broadens the horizons for future research in optical communications and related disciplines.

Picosecond laser with Yb-doped tapered low birefringent double clad fiber

Abstract In this study, we present results of development fiber picosecond laser by using an active ytterbium tapered double clad optical fiber with mode field diameter of 35 μm and low intrinsic birefringence (1.45 * 10−8 rad m−1). We have demonstrated 1040 nm/50 ps optical source with tunable repetition rate (within range of 1–20 MHz) and an average power of 160 W (peak power 160 kW, 8 μJ per pulse) delivering Gaussian beam with excellent quality (M 2 ∼ 1.11/1.22).

Optical soliton solutions in birefringent fibers with multiplicative white noise: an analysis for the perturbed Chen–Lee–Liu model

Optical soliton solutions in birefringent fibers with multiplicative white noise: an analysis for the perturbed Chen–Lee–Liu model

Analyzing the influence of multiplicative white noise on optical solitons in birefringent fibers through the perturbed Gerdjikov–Ivanov model

Analyzing the influence of multiplicative white noise on optical solitons in birefringent fibers through the perturbed Gerdjikov–Ivanov model

Schrödinger-Hirota equation in birefringent fibers with cubic-quantic nonlinearity and multiplicative white noise in the ito sense: Nucci’s reductions and soliton solutions

This paper explores innovative solutions for the Stochastic Schrödinger-Hirota equation within the context of birefringent fibers with cubic-quintic nonlinearity, emphasizing incorporating multiplicative white noise in the Itô sense. Leveraging the Nucci reduction method, the study focuses on obtaining exact solutions, shedding light on the intricate interplay between quantum mechanics and stochastic processes. The Nucci reduction method is a powerful tool to facilitate the derivation of precise solutions, showcasing its efficacy in unravelling complex mathematical structures and providing valuable insights into the behaviour of quantum systems under the influence of diverse parameters. In addition, two effective and convenient procedures are employed to extract bright, dark, and unique soliton solutions, as well as their combination. Exploring these solutions contributes to a deeper understanding of the equation’s dynamics, particularly in real-world applications such as quantum optics and condensed matter physics. Additionally, this study incorporates graphical depictions of specific solutions to demonstrate the effect of white noise on solitons visually.

Stability and instability nature of solitons in an optical fiber with four wave mixing effect

The investigation into modulational instability (MI) within the Kundu-Eckhaus (KE) equation, governing optical solitons, involves a thorough examination of the effects of self-phase modulation, cross-phase modulation, and intermodal dispersion. Special attention is given to understanding the influence of the four-wave mixing effect. The KE equation, which models birefringent fiber and includes terms related to intermodal dispersion, cross-phase modulation, and self-phase modulation, serves as the fundamental framework for this analytical study. Employing conventional linear stability analysis, the gain within the KE equation is determined. To shed light on the role of four-wave mixing in various scenarios, the gain spectrum is utilized as a tool to analyze the behavior of the KE equation under different conditions. This methodology seeks to provide insightful information about the intricate interactions that impact the modulational instability of solitonic pulses in an optical systems. After that, we have investigated the soliton solution by implementing the Jacobian elliptical function approach. Finally, our focus here is on linear stability analysis, which employs eigenvalue spectra to study solitons’ stability via direct numerical simulation.

High pressure sensor based on intensity-variation using polymer optical fiber

Silica fiber under high pressure increases the risk of fiber breakage or permanent deformation, which may cause sensor failure due to mechanical strength limitations. High pressure can also induce birefringence in optical fiber. In this study, we present a simple design and low-cost high pressure sensor using polymer optical fiber (POF) based on the intensity-variation technique. A side-coupling mechanism in the sensor structure is adopted, which varies the intensity with applied pressure. Two POFs are twisted together to create a sensing region where the light is launched in the first fiber and measurement is taken from the second fiber. In sensing phenomena, cladding mode frustrated total internal reflection occurs when pressure increases. Silicone gel is used in the pressure chamber for sealing and preventing leakage. The sensor structure is able to detect high pressure in the MPa range, where we tested up to 4 MPa. For higher sensitivity, twisted and bend structure is analyzed, and sensitivity is achieved at about 432.21 nW/MPa. However, twisted helical structure is adopted to enhance sensing range which is about 50 cm. The proposed high-pressure sensor structure is easier to fabricate and has high stability because it doesn’t require any destructive method as compared to other conventional methods.

Various dynamic behaviors for the concatenation model in birefringent fibers

This study explores various wave phenomena related to the concatenation model, which is characterized by the inclusion of the Kerr law of nonlinearity in birefringent fibers. Several distinct auxiliary functions and logarithmic transformation are utilized to formulate various analytical solutions, including multi-wave solutions, two solitary wave solutions, breather waves, periodic cross kink solutions, Peregrine-like rational solutions, and three-wave solutions. To demonstrate the influence of different parameters on the interaction of the obtained solutions, some figures are provided to vividly display these transmission and interaction characteristics.

Discovering novel optical solitons of two CNLSEs with coherent and incoherent nonlinear coupling in birefringent optical fibers

Discovering novel optical solitons of two CNLSEs with coherent and incoherent nonlinear coupling in birefringent optical fibers

Birefringent optical fibers to decouple thermo-mechanical effects on FBG sensors

Optical fiber Bragg (FBG) sensors are gaining importance in structural health monitoring (SHM) systems due to their compact size and ability to be embedded into the lamination sequences of composite material elements. A significant challenge, widely discussed in the literature, concerns the decoupling of thermomechanical measurements made through these sensors. This work aims to solve this problem using birefringent optical fibers instead of conventional ones. The distinctive characteristics of birefringent fibers allow an FBG sensor, written in such fibers, to present not a single peak but two distinct peaks, each with different responses to changes in strain and temperature. This is due to the different refractive index distribution in the fiber core section, which allows for two axes on which the light signal propagates at different speeds. This property offers a significant advantage: by having two independent equations associated with the two peaks, it is possible to decouple the thermomechanical measurements using only the fiber itself, without the need to introduce additional components to achieve mechanical decoupling (capillaries with through or interrupted fiber). This would ensure that strain and temperature are measured at the same point. In the first phase of the work, an FBG sensor on a birefringent fiber was characterized and subsequently calibrated. Therefore, a dedicated experimental set-up was created to conduct thermal, mechanical, and thermomechanical characterization tests, in order to verify the feasibility and effectiveness of decoupling. In a second step, such sensor was embedded within a sample of composite material (unidirectional glass fibers), which was subsequently subjected to the same characterization tests conducted on the single fiber. The results highlight the ability of this new transducer to decouple the thermal effect from the mechanical effect, allowing this new technology to overcome the problems of FBG sensors made of standard fibers.

Highly birefringent anti-resonant hollow-core fiber with meniscoid nested structure.

We propose a meniscoid nested anti-resonant hollow-core fiber (MAF), wherein the fourfold rotational symmetry structure enables high birefringence and low loss in dual-wavelength range. Numerical investigation and simulation for variations in wall thickness along orthogonal directions are conducted, through which a formulated optimization criterion revealing the relationship between minimum difference in wall thickness and birefringence of 10-5 is obtained. A parameter of beat length to loss ratio η is defined to evaluate MAF performance with respect to birefringence and confinement loss (CL). With optimized MAF structure, the birefringence and CL are improved to 3.62 × 10-5 and 8.5 dB/km at 1.06 µm, 9.83 × 10-5 and 204.1 dB/km at 1.55 µm, respectively. Meanwhile, the bandwidths extend to 172 nm at 1.06 µm and 216 nm at 1.55 µm, and the superior bending resistance characteristics are validated. Our work offers valuable guidance for designing and optimizing highly birefringent anti-resonant hollow-core fiber (ARF), and the proposed MAF has great potential in polarization-dependent transmission and interferometric fiber gyroscopes.