Birefringent Optical Fiber Research Articles

All-Optical Nonlinear Control of Circularly Polarized Light in Birefringent Fibers

Polarization state manipulation and tunability are two highly desirable objectives of utmost importance for the development of many applications, especially in optical fiber-based systems. In this article, we present in detail a comprehensive theory for describing and controlling the nonlinear polarization conversion of circularly polarized light in birefringent optical fibers (BOFs). We use our theory to provide a nonlinear model that allows obtaining the accurate input powers with which we can tune the most common continuous-wave polarization states at the BOF output. To analyze the polarization instability of the output optical signals, we define a parameter that gives a magnitude of the polarization instability as a function of the input power. The analytical results we provide agree accurately with the results obtained through numerical techniques. Our theory opens up new perspectives and provides considerable physical insight on the all-optical polarization control with BOFs.

Survey of third- and fourth-order dispersions including ellipticity angle in birefringent fibers on W-shaped soliton solutions and modulation instability analysis

In this work, the modified Sardar sub-equation method is used to construct optical soliton solutions to the coupled nonlinear Schrodinger equation (CNLSE) having third-order and fourth-order dispersions describing short-pulse propagation in two-core fibers. Several solutions are determined including W-shaped bright, dark soliton solutions, singular soliton solutions, periodic function solutions and the combined complex soliton solutions. It should be noted that this integration scheme is very powerful mathematical tools for obtaining exact optical soliton solutions of nonlinear evolution equations. Under suitable values for the physical parameters, some representative wave structures are graphically displayed. In addition, the linear stability technic is used to analyze the modulation gain spectra in the birefringence associated with an ellipticity angle. In our knowledge, these obtained results are new in the context of nonlinear birefringent optical fibers.

Transmission stability of chirped dark vector quasi-solitons in birefringent fiber system with nonlinear gain

In this article, we consider the coupled Ginzburg–Landau equation with variable coefficients including the nonlinear gain and obtain the exact solutions of chirped dark vector quasi-solitons via the ansatz method. Next, the propagation of chirped dark vector quasi-solitons is discussed to verify whether they can be transmitted stably in the birefringent optical fiber system. The numerical simulation shows that this can be achieved. We deeply add the small perturbation to the transmission of dark vector quasi-solitons to make the results above more general. The results further prove the correctness of our solutions.

Demonstration of a Duplex Microwave Photonic Filter and Its Reconfigurability in a Frequency Range of 0–10 GHz

In this paper, we have demonstrated a duplex microwave photonic filter system. The reconfigurability of a microwave passband filter by using a birefringent optical filter has also been demonstrated experimentally. The effect of filtering normally depends on the intermodal separation of a multimode laser diode (MLD), as well as the chromatic dispersion parameter and the length of a Single Mode-Standard Fiber (SM-SF). However, in this work, the intermodal separation of the MLD is altered by an optical filter which consists of a section of birefringent optical fiber (BOF) placed between crossed polarizers. Using this filter, six passbands in the frequency range of 0–10 GHz are obtained. Our duplex Microwave Photonic Filter (MPF) system is driven by only a single optical source. Performance evaluation for the filtered passband is also given in terms of the Signal-to-Noise-Ratio (SNR). On average, an SNR of 13.87 dB is obtained for all the passbands generated by our duplex Microwave Photonic Filter (MPF) system. For potential applications, the generated passbands may be used as radio frequency (RF) carriers to transmit analog or digital data in an optical communications system.

Theoretical analysis on polarization characteristics of spun birefringent optical fiber based on an analytical Jones matrix model

In practical applications, the analysis and control on polarization state are important. The spun birefringent optical fiber has diverse polarization characteristics. It can be used to manufacture linear polarization maintaining (PM) fibers, polarization rotators, retarders, and arbitrary state of polarization maintaining fibers. To understand the diversity of fiber, an analytical model of spun birefringent optical fiber based on the Jones matrix is established. The model is a general model which could explain why the fiber has so many polarization behaviors. A deep analysis shows two key parameters control the model of the spun birefringent optical fiber. When we change the two parameters, the model will degenerate into a fiber-optic rotator, a retarder, or a polarization maintaining device. According to the approximate models, the property of devices based on spun birefringent optical fiber can be analyzed and optimized exactly. The new theoretical model has a clear physical meaning and brings conveniences for the designing sensors, filters, polarization rotators, wave plates, and new polarization maintaining fibers.

Optical solitons of Biswas–Arshed equation in birefringent fibers using improved modified extended tanh-function method

In this paper, the optical solitons in birefringent optical fibers without four-wave mixing is addressed with the Biswas–Arshed equation. Dark, bright and singular solitons are obtained by using improved extended tanh-function method. Varieties of other traveling wave solutions are also formulated with this method. These solutions include singular periodic solutions, rational solutions, exponential solutions, Jacobi elliptic periodic type solutions and Wieierstrass elliptic doubly periodic type solutions. Moreover, for the physical illustration of the obtained solutions, the graphs are presented.

Generalized Darboux transformation, solitonic interactions and bound states for a coupled fourth-order nonlinear Schrödinger system in a birefringent optical fiber

The optical fiber communication system is one of the components of a supporting system in the modern Internet fields. Under investigation in this paper is a coupled fourth-order nonlinear Schrödinger system, which describes the ultrashort optical pluses in a birefringent optical fiber. By virtue of the existing Lax pair, generalized Darboux transformation, two- and three-soliton solutions are derived, with respect to the polarization components of the electric field. Based on such solutions, we graphically display (1) the elastic interactions between/among the two/three solitons on a zero-intensity background, where amplitudes of the solitons remain unchanged; (2) the inelastic interactions between/among the two/three solitons, where amplitudes of the solitons change; (3) the bound state among the three solitons; (4) the higher-order linear and nonlinear effects, represented by β, on the polarization components of the electric field: The interval between two peaks becomes smaller and the numbers of the peaks increase when the value of β increases; The three solitons move along the positive time direction when the value of β decreases; The distances between the adjacent peaks become smaller when the value of β increases.

Induction of dispersive wave and supercontinuum generation in a birefringent optical fiber under normal and anomalous dispersion

The effect of the sign of the dispersion parameter on nonlinear pulse propagation in a birefringent optical fiber is analyzed via numerical analysis. First, the concept of effective cross-dispersion is introduced to demonstrate the simultaneous existence of positive dispersions of opposite polarizations within the same waveguide, leading to the generation of a dispersive wave and supercontinuum. Then, a general set of equations is deduced to calculate the dispersive waves corresponding to x and y polarizations considering a birefringence-dependent wavelength. Using this, it is established that solitons and dispersive waves can be induced corresponding to each polarization even if the dispersions are normal. Finally, we demonstrate that spectral broadening can also be induced corresponding to one polarization despite the existence of positive dispersion, i.e., in the complete absence of solitons for the entire duration of pulse propagation.

Birefringence and Polarization Mode Dispersion Phenomena of Commercial Optical Fiber in Telecommunication Networks

The development of optical fibers from attenuation and absorption of fiber material for efficiency and quality has produced several positive results. However, several natural negative factors and environmental errors cause problems such as birefringence and dispersion mode variations. This article therefore proposed a simulation of birefringence and polarization mode dispersion (PMD) to investigate the emergence of interference and efforts towards finding a solution to the problem of optical fiber. Moreover, a single-mode fiber was investigated at the core refractive index and cladded with a core radius and fixed sample for a wavelength of infrared regimes. The performance of fibers was also evaluated through the determination of the PMD value of the fibers. The simulation results showed the difference observed in birefringence produced the power affecting the output. Meanwhile, the PMD also produced the light waves discovered to be experiencing widening pulses in the cladding.

Soliton solutions of Kundu-Eckhaus equation in birefringent optical fiber with inter-modal dispersion

We study the dynamics of optical soliton in birefringent optical fiber with the effect of inter-modal dispersion. We consider the model of the Kundu-Eckhaus (KE) equation for birefringent optical fiber with the inclusion of inter-modal dispersion. Multisoliton solutions of KE equation with the presence of inter-modal dispersion are found analytically by using mapping method and a symbolic computation system. Initially, the solutions are expressed in terms of the Jacobi elliptic function which is also recovered by the use of limiting case of modulus of ellipticity. With the help of graphical illustrations of our solutions, we understand the effect of inter-modal dispersion on the soliton evolution in optical birefringent optical fiber.

Polarization Dynamics of Light Propagating in Bent Spun Birefringent Fiber

A comprehensive theoretical study of the light propagation in a bent spun birefringent optical fiber is presented. We consider the wave equation for a birefringent medium with rotation of the principal axes in the presence of additional linear birefringence and then find an approximate solution being reasonable over a wide range of birefringence parameters. Using this solution, the polarization modes of a bent spun fiber are introduced as a generalization of the modes of a straight spun fiber, allowing one to predict the polarization parameters of light throughout the bent spun fiber. Moreover, it is established that the introduced modes are resistant to coupling if the bending radius varies smoothly making it practically easy to convert the modes of the straight spun fiber to the modes of the bent spun fiber. The polarization peculiarities of non-monochromatical light propagating in a spun fiber is also studied.

Full polarization control of fiber-delivered light in a dilution refrigerator.

Birefringence in optical fibers poses a challenge to controllably delivering polarized light. Strain-induced birefringence caused by bends in the fiber, vibrations, or a large temperature gradient can significantly alter the polarization, making it particularly difficult to deliver polarization states to low-temperature environments by fiber. In this paper, we investigate the transmission of polarized light through a fiber and discuss a method we have developed for delivering arbitrarily polarized light to the base stage of a dilution refrigerator using a standard optical fiber. We have created a compact, cryogenic optical system to identify the polarization of the delivered light, while room-temperature waveplates and a mathematical fiber model are used to fully characterize and compensate for the fiber's birefringent effects. We show here that we are able to deliver horizontal, vertical, diagonal, anti-diagonal, right circular, and left circular polarization states to milli-Kelvin temperatures, with state fidelities of greater than 0.96 being achieved in all cases. Additionally, we demonstrate that we can deliver randomly selected elliptical states through a standard fiber to the refrigerator. This opens up new opportunities for fiber-based optical experiments using polarized light, such as quantum information experiments using quantum states encoded in the polarization of single photons.

Effect of external relative pressure on phase shift in Sagnac interferometer

Subject of Research. The paper considers the effect of a relative pressure change on the H-parameter value in a birefringent optical fiber with ESC-4 elliptical straining cladding and in Sagnac coil with 140 mm diameter and 700 m length. We analyze the effect of a relative pressure change on the phase shift in Sagnac interferometer. Method. The broadband interferometry method was used for the H-parameter estimation. Michelson polarizing scanning interferometer with a broadband source with a 1560 nm central wavelength and a 45 nm bandwidth was applied. The relative pressure was varied in a special pressure chamber in the range from –80 kPa to +300 kPa. Main Results. It is found out that when the relative pressure changes, random phase jumps occur in Sagnac interferometer. Such random phase jumps are not observed under normal conditions. It is also shown that the effect of increased relative pressure on Sagnac phase shift is more pronounced than the effect of reduced relative pressure; the frequency of phase jumps is greater in case of increased relative pressure. Practical Relevance. Analysis of research results is focused on the problem of high-quality winding and laying of birefringent optical fiber in Sagnac coil, which will improve the accuracy characteristics of fiber- optic sensors based on Sagnac interferometers.

Production process monitoring and post-production strain measurement on a full-size carbon-fibre composite aircraft tail cone assembly using embedded optical fibre sensors

Multiplexed optical fibre sensors were embedded into a carbon-fibre-reinforced-preform during the industrial production of a full-sized, one-piece tail cone assembly for a regional jet aircraft. Optical fibre Fresnel sensors monitored both the infusion of the resin, via measurement of the refractive index-dependent attenuation in the reflected light signal, and the degree of cure of the resin, via measurement of the chemical cure reaction-dependent change in refractive index. The resin cure was also monitored by optical fibre Bragg gratings (FBGs) fabricated in high linearly birefringent optical fibre, which measured through-thickness strain development, while FBGs in standard single mode optical fibre measured longitudinal strain development. The magnitudes and profiles of the transverse and longitudinal strains developed during the curing process were consistent across different locations on the tail cone. Typical transverse and longitudinal strains, related to cure reaction-induced shrinkage, were −1500 ± 17 μϵ and −500 ± 5 μϵ, respectively. Post-production, the same embedded FBG sensors were used subsequently to monitor structural strains when the tail cone was subjected to vacuum pressure loading. The longitudinal strains measured using the embedded FBG sensors were generally in good agreement with the longitudinal strains measured by the surface-bonded resistance foil strain gauge (RFSG) sensors, both qualitatively and quantitatively. The in-plane transverse and circumferential strains, oriented collinearly, were measured by the embedded FBGs and appropriately oriented surface-bonded RFSG sensors, respectively, and were, qualitatively, in good agreement.

Simple method for the characterization of birefringence of single-mode optical fibers

Over the past few decades, various laboratories have worked on non-destructive methods for the evaluation of residual birefringence of single-mode optical fibers. Among them, polarimetric methods allowing the measurement of polarization eigenmodes represent the best option when it is necessary either to understand or to control the evolution of the state of polarization of light along the fiber. In this work, we present a polarimetric technique based on the use of Mueller calculus and the Poincaré sphere. This is a simple, precise, and non-destructive method allowing the measurement of the azimuth and ellipticity angles of the polarization eigenmode, as well as the total retardation angle modulus-π.

Lax pair, Darboux-dressing transformation and localized waves of the coupled mixed derivative nonlinear Schrödinger equation in a birefringent optical fiber

Under investigation in this paper is a coupled mixed derivative nonlinear Schrödinger equation, which can describe the pulse propagation in the femtosecond or picosecond regime of a birefringent optical fiber. Based on a Lax pair, we provide a Darboux transformation, and obtain the breather wave solutions. Then, a novel vector rogue wave solution is constructed by using Darboux-dressing transformation and asymptotic expansion. Those solutions exhibit some elastic and collision behaviors between a localized wave and a bright–dark soliton. Our works can be of importance in the theoretical experiments of the rogue wave generation mechanism and propagation trajectory.

Single-pulse, Kerr-effect Mueller matrix LiDAR polarimeter.

We present a novel light detection and ranging (LiDAR) polarimeter that enables measurement of 12 of 16 sample Mueller matrix elements in a single, 10 ns pulse. The new polarization state generator (PSG) leverages Kerr phase modulation in a birefringent optical fiber, creating a probe pulse characterized by temporally varying polarization. Theoretical expressions for the Polarization State Generator (PSG) Stokes vector are derived for birefringent walk-off and no walk-off and incorporated into a time-dependent polarimeter signal model employing multiple polarization state analyzers (PSA). Polarimeter modeling compares the Kerr effect and electro-optic phase modulator-based PSG using a single Polarization State Analyzer (PSA) and a scattering sample yielding similarly good performance for both. We include results from an experimental demonstration of the Kerr effect PSG.

Performance improvement of an optoelectronic oscillator by modifying the optical characteristics of a multimode laser diode

This paper presents a substantial improvement on the electrical performance of a microwave optoelectronic oscillator (OEO) by modifying the intermodal separation of a multimode laser diode (MLD). The Free Spectral Range (FSR) of the OEO is controlled by implementing an optical filter that allows manipulating the optical spectrum of an MLD. For this goal, a section of birefringent optical fiber is placed between two crossed polarizers as an optical filter. The intermodal separation of the MLD is varied using a suitable length of birefringent optical fiber. A set of stable microwave signals in the frequency range of 0–12 GHz is obtained. The performance evaluation for the microwave signal centered at 2.93 GHz shows a phase noise as low as −118.06 dBc/Hz at 10 kHz offset frequency and a Q factor of 1.40 × 109 for an optical delay line of 13 km.

Singular and bright-singular combo optical solitons in birefringent fibers to the Biswas-Arshed equation

In this paper, the dynamics of optical solitons in birefringent optical fibers without four-wave mixing is addressed with the advocacy of Biswas-Arshed equation in media with Kerr type nonlinearity. Singular solitons and bright-singular combo optical solitons are obtained by using exp-function method. Variety of other traveling wave solutions are also formulated with this integration scheme. These solutions include rational function solutions, mixed hyperbolic function solutions and combination of trigonometric function solutions. Some restraint conditions pop out naturally from the mathematical analysis that must be gratified to guarantee the existence of solitons. Moreover, for the physical illustration of the obtained solutions, 3D and 2D graphs are presented.

Spectrally pure single photons at telecommunications wavelengths using commercial birefringent optical fiber.

We report a bright and tunable source of spectrally pure heralded single photons in the telecom O-Band, based on cross-polarized four wave mixing in a commercial birefringent optical fiber. The source can achieve a purity of 85%, heralding efficiency of 30% and a coincidence-to-accidentals ratio of 108. Furthermore, through the measurements of joint spectral intensities, we find that the fiber is homogeneous over at least 45 centimeters and thus can potentially realize 4 sources that can produce identical quantum states of light. This paves the way for a cost-effective fiber-optic approach to implement multi-photon quantum optics experiments.