High-birefringence Optical Fibers Research Articles

High birefringence and near‐zero dispersion control of nonlinear photonic crystal fibers with a double‐cladded coaxial core

AbstractOptical propagation characteristics of high birefringence (HB), near‐zero chromatic dispersion, and small effective mode area are first investigated along with simultaneously effective controllability for the new double‐cladded coaxial core photonic crystal fibers with the breakthrough air‐hole defects at the middle‐top, middle‐bottom, right‐top, and left‐bottom, as pairs, which enable the adaptation of novel systematic approach for design goals in the inner first hexagonal cladding layer. Compared with results (around 3.2 × 10−4) of well‐known HB optical fibers, superior performance for preserving the lightwave polarization state by about three times higher HB levels has been achieved with additive advantages of fabrication from only pure fused silica material and broadly unlimited stable single‐mode operation.

Proposal of high-birefringence twin-core hollow optical fiber

We propose a high-birefringence twin-core hollow optical fiber, which is composed of two rectangular Ge-doped cores, annular silica cladding, and a large central air hole. The rectangular cores are weakly coupled with the air hole and arranged in the same silica cladding. The mode birefringence in single-mode operation of 1.55 μm reaches 2.48 × 10 − 4, which is comparable with traditional panda polarization maintaining fiber. By introducing an extra stress zone, the mode birefringence can be improved further by two times. The high birefringence of the twin-core hollow fiber is induced by strong asymmetry of the waveguide structure. The characteristics of the guiding mode, birefringence, and evanescent field are analyzed numerically by full-vector finite-element method. The effect of geometric and material parameters is discussed. The proposed scheme of twin-core hollow fiber can overcome the polarization fading effect and signal cross talk occurring in traditional multicore fibers and is much desirable for improving the performance of in-fiber integrated interferometers and biochemical sensors.

Multimaterial polarization maintaining optical fibers fabricated with the powder-in-tube technology

We present the fabrication of multimaterial polarization maintaining optical fibers. We exploit the flexibility of the powder-in-tube process for fabricating silica-based optical fibers composed of two rods of glass material on the sides of the core. We demonstrate the capability of this process to use glass material with properties sorely different from the ones of silica for developing high-birefringence optical fiber. This proof-of-concept paves the way for the use of different materials with specific properties for improving the performances of polarization maintaining optical fibers.

Polarization Dependence of Modal Attraction in High Birefringence Bimodal Optical Fibers

We study nonlinear mode coupling among two intense and copropagating beams of different wavelength in bimodal and high birefringence optical fibers. With the proper design of the bimodal fiber, we show that this process may lead to modal attraction, where the modal distribution of light at a pump wavelength is replicated at the signal wavelength, independently of the input mode excitation conditions of the signal. We analyse the dependence of the efficiency of the modal attraction process upon the input state of polarization of both the signal and the pump beams.

A High-Temperature Fiber Sensor Using a Low Cost Interrogation Scheme

Regenerated Fibre Bragg Gratings have the potential for high-temperature monitoring. In this paper, the inscription of Fibre Bragg Gratings (FBGs) and the later regeneration process to obtain Regenerated Fiber Bragg Gratings (RFBGs) in high-birefringence optical fiber is reported. The obtained RFBGs show two Bragg resonances corresponding to the slow and fast axis that are characterized in temperature terms. As the temperature increases the separation between the two Bragg resonances is reduced, which can be used for low cost interrogation. The proposed interrogation setup is based in the use of optical filters in order to convert the wavelength shift of each of the Bragg resonances into optical power changes. The design of the optical filters is also studied in this article. In first place, the ideal filter is calculated using a recursive method and defining the boundary conditions. This ideal filter linearizes the output of the interrogation setup but is limited by the large wavelength shift of the RFBG with temperature and the maximum attenuation. The response of modal interferometers as optical filters is also analyzed. They can be easily tuned shifting the optical spectrum. The output of the proposed interrogation scheme is simulated in these conditions improving the sensitivity.

OSNR monitoring using fiber bragg grating in high birefringent optical fibers

This work presents a technique based on the application of a high birefringent (Hi-Bi) fiber Bragg grating (FBG) to monitor the optical signal to noise ratio (OSNR) of an optical channel.A Hi-Bi FBG produces reflection at two different spectral bands depending on the polarization of the incoming signal. The OSNR can be determined by decomposing, for a data channel, the polarized signal information and the depolarized noise. This work gathers the simulation and experimental results for a single channel system continuous wave signal and modulated at 10 Gb s−1. The results for a multichannel system are also presented. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:6–9, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27228

Temperature-independent torsion sensor based on “figure-of-eight” fiber loop mirror

An interrogation sensor system combining the “figure-of-eight” fiber loop mirror using a single directional 3×3 fiber optic coupler was proposed. One fiber loop mirror was formed by inserting a length of high birefringent optical fiber at the input ports of the 3×3 coupler. Splicing the output ports of the 3×3 coupler between them created the other fiber loop mirror. The introduction of this second loop gave rise to two polarization states of light with the same frequency but different optical phase. The mechanical torsion sensing head was located at the second loop and was exhibited an average modulus torsion sensitivity of 7.9×10−4 degree/dB. The performance of the sensor was not affected by environmental temperature variations.

Nonlinear polarizers based on four-wave mixing in high-birefringence optical fibers

Parametric amplification or four-wave mixing in high-birefringence optical fibers may be exploited to implement a novel type of nonlinear polarizer. Such a device leads to the simultaneous amplification, frequency conversion, and repolarization of both signal and idler waves along one of the principal birefringence axes of the fiber, independently of the pump, signal, and idler input state of polarization, power, and frequency detuning. We discuss the conditions for the observation of polarization attraction in fiber optics parametric amplifiers operating with a pump in either the normal or the anomalous dispersion regime.

Evolution of first-order sidebands from multiple FWM processes in HiBi optical fibers

The generation of two idler waves inside a high birefringent (HiBi) optical fiber through three four-wave mixing (FWM) processes is studied theoretically. The coupled-equations for the field amplitudes are derived and analytically solved, in the co-polarized and orthogonal polarization schemes. The obtained solutions take into account the delayed Raman response of the medium. The polarization sensitivity of the generation of the idler waves is analyzed. Results show that the stimulated Raman scattering does not change the efficiency of the idler wave generation in the co-polarized scheme, whereas in the orthogonal polarization scheme that nonlinear process decreases the efficiency of the four-wave mixing processes. Results also show that this set of multiple four-wave mixing processes is physically quite different from the typical single or dual pump four-wave mixing configurations. Findings show that the power transfer from the pumps to the idler fields can lead to a monotonous growth, or a periodic evolution of the sidebands along the fiber. Results show that the process efficiency varies greatly with the angle between the two pump polarizations.

Monitoring Method of Stray Current in Coal Mine on Optical Fiber Sensing Technique

In this work a novel monitoring method was developed to measure the underground stray current in coal mine with fiber current sensing technique. According to the theory of optical fiber current sensor based on Faraday magneto-optic effect, a fiber sensing system was designed and the relative experiments with current generator simulating stray current were completed. The results indicate that the measurement was influenced by birefringence and temperature change. The sensing heads with high cylindrical birefringence optical fiber had a good suppressing effect on linear birefringence and the polarization state of polarized light was also more stable than that with low birefringence optical fiber. The fiber current sensing method is doable in underground stray current monitoring system in coal mine.

Technology of high birefringent microstructured polymer optical fibers

Technology of high birefringent microstructured polymer optical fibers

Experimental evidence of Brillouin-induced polarization wheeling in highly birefringent optical fibers

We study the influence of Stimulated Brillouin Scattering on the polarization stabilization of a light beam propagating in a highly-birefringent optical fiber. In particular, due to a saturation effect, we find that the output polarization lies on a ring when the polarization is represented onto the Poincaré sphere.

Chiral polarization solitons in elliptically birefringent spun optical fibers

We obtain stable kink soliton solutions describing the nonlinear polarization evolution of counterpropagating optical beams in spun high-birefringence optical fibers. Applications to nonlinear polarizers for continuous waves are described.

背向切割法测量高双折射多孔光纤拍长

Based on the cutback method,an experimental system has been set up to measure the beat-length of high-birefringence(hi-bi) optical fiber. The least-square fitting is adopted to process data. The restriction to the cut length of fiber is relaxed and the measurement range of beat length is extended, so that the cutback method can be suitable for the short beat-length measurement of hi-bi holey optical fiber.

Filter of optical vortices: highly twisted high-birefringence optical fibers

Modes and bandgap structure of highly twisted high-birefringence weakly guiding fibers are studied in the scalar approximation. It is shown that within the gap the system can serve as a filter of circular optical vortices.

Analysis of optical Kerr effect induced coupling among polarization modes in high-birefringence optical fibers

We present a theoretical analysis of the mode coupling induced by the optical Kerr effect in a high birefringence fiber. Several pump-probe architectures which allow mapping of the birefringence along the fiber are studied. The application of nonlinearly induced coupling to distributed sensing is also discussed, showing its performance in terms of signal-to-noise ratio and also its potential for simultaneous measurement of several parameters.

Distributed sensing of polarization mode coupling in high birefringence optical fibers using intense arbitrarily polarized coherent light

A polarization diversity detection system for location of polarization mode coupling has been studied both theoretically and experimentally for use with high birefringence fibers. Two complementary detectors are found to be sufficient for reliable operation of a pump-probe method based on the optical Kerr effect. Such a system is capable of locating any mode coupling point with arbitrary pump and probe polarization states when pump and probe polarization switching techniques are used to avoid signal fading. Experimental results are in good agreement with theory.

Fiber optic distributed sensing scheme for monitoring structural strain and deformation

A fiber optic distributed sensing scheme used to monitor structural strain and deformation is presented. In the sensor system, a high-birefringent optical fiber is used as the sensing fiber, and the sensor units along the sensing fiber distribution are arrayed on a measured test structure. The structural deformation can be evaluated by detecting the polarization mode coupling effect in each sensor unit along the highbirefringent fiber. Interferometry and optical path scanning are used to determine the location and magnitude of the mode-coupling effects caused by structural strain or deformation.

An intrinsic optical-fiber position sensor with schemes for temperature compensation and resolution enhancement

This paper presents an optical fiber based position monitoring system, incorporating a high birefringent optical fiber and white-light interferometry. The effects of temperature variation are largely eliminated using a scheme of detecting the relative position within the stroke. A fringe-order identification technique employing two or more broad-band sources is described which can be used to enhance the resolution of the position detection.

A study of the optomechanical response of a diametrically loaded high-birefringent optical fiber

This paper describes an experimental and finite-element study of the optomechanical response of a diametrically loaded Bow-Tie high-birefringent optical fiber. The thermomechanical finite-element analysis performed in this study uses PATRAN as the solid modeler and ABAQUS as the analysis package. The purpose of this study is to determine the effect of a diametrical load on the optical phase generated by polarimetric sensors as a function of polar angle. This is done in order to understand the behavior of structurally embedded polarimetric sensors, and to determine the effect of load-induced rotation of principal optical axis in a Bow-Tie fiber in order to assess the response of the lead-sensitivity of lead-insensitive embedded polarimetric sensor configurations. The results indicate that the stress concentrations produced by the stress-applying parts are responsible for a polarimetric phase sensitivity that is a function of the applied load direction. The results further indicate that the diametric loads do not significantly alter the principal optical axes in the lead-in fiber.