Interferometric determination of induced birefringence due to bending in single-mode optical fibres
TL;DR: In this article, multiple beam Fizeau fringes in transmission have been used to demonstrate and to measure the radial change of the refractive index and the related induced birefringence in the cladding of bent singlemode fibres to an accuracy of.
Abstract: Multiple beam Fizeau fringes in transmission have been used to demonstrate and to measure the radial change of the refractive index and the related induced birefringence in the cladding of bent single-mode fibres to an accuracy of .
Citations
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TL;DR: A digital holographic microscope that permits one to image polarization state and the birefringence induced by internal stress in an optical fiber is measured and compared to a standard method, which had been developed to obtain high-resolution bireFringence profiles of optical fibers.
Abstract: We present a digital holographic microscope that permits one to image polarization state. This technique results from the coupling of digital holographic microscopy and polarization digital holography. The interference between two orthogonally polarized reference waves and the wave transmitted by a microscopic sample, magnified by a microscope objective, is recorded on a CCD camera. The off-axis geometry permits one to reconstruct separately from this single hologram two wavefronts that are used to image the object-wave Jones vector. We applied this technique to image the birefringence of a bent fiber. To evaluate the precision of the phase-difference measurement, the birefringence induced by internal stress in an optical fiber is measured and compared to the birefringence profile captured by a standard method, which had been developed to obtain high-resolution birefringence profiles of optical fibers.
128 citations
TL;DR: A concise and effective model based on coupled mode theory to describe mode evolution in long tapered active fiber is presented and can provide instructive suggestions when designing long Tapered fiber based laser and amplifiers.
Abstract: A concise and effective model based on coupled mode theory to describe mode evolution in long tapered active fiber is presented in this manuscript. The mode coupling due to variation of core radius and slight perturbation have been analyzed and local gain with transverse spatial hole burning (TSHB) effect, loss and curvature have been taken into consideration in our model. On the base of this model, the mode evolution behaviors under different factors have been numerically investigated. Our model and results can provide instructive suggestions when designing long tapered fiber based laser and amplifiers.
35 citations
TL;DR: Digital holographic microscopy is demonstrated for quantifying a polarization-sensitive map of an object with a single-shot measurement that will facilitate the high-precision measurements for fast dynamics of the polarization properties of biological specimens.
Abstract: Field-based polarization measurements are essential for the completeness of information when exploiting the complex nature of optical responses of target objects. Here, we demonstrate digital holographic microscopy for quantifying a polarization-sensitive map of an object with a single-shot measurement. Using the image-splitting device generating four different copies of an object image and a separate reference beam of an off-axis configuration enables single-shot and multi-imaging capability. With the use of two polarization filters, four complex field images containing an object’s polarization response are obtained simultaneously. With this method, we can construct a complete set of 2-by-2 Jones matrix at every single point of the object’s images, and thus clearly visualize the anisotropic structures of biological tissues with low level of birefringence. This method will facilitate the high-precision measurements for fast dynamics of the polarization properties of biological specimens.
35 citations
TL;DR: A novel application of quantitative phase imaging under linearly polarized light is introduced for studying unstained anisotropic live cells and the experimental retardation measurements are in very good agreement with the established Brace-Köhler method.
Abstract: A novel application of quantitative phase imaging under linearly polarized light is introduced for studying unstained anisotropic live cells. The method is first validated as a technique for mapping the two-dimensional retardation distribution of a well-characterized optical fiber and is then applied to the characterization of unstained isolated cardiac cells. The experimental retardation measurements are in very good agreement with the established Brace-Kohler method, and additionally provide spatially resolved cell birefringence and phase data.
30 citations
TL;DR: In this paper, the theoretical and experimental considerations of the transverse two-and multiple-beam Fizeau fringes techniques used to resolve and infer the structure and the index profiles of the optical fibers with high index and spatial resolution are discussed.
29 citations
References
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TL;DR: In twisted single-mode optical fibers the polarization of light is affected by an elastooptically induced optical activity and by a modification of any linear birefringence present.
Abstract: In twisted single-mode optical fibers the polarization of light is affected by an elastooptically induced optical activity and by a modification of any linear birefringence present. These effects are discussed theoretically and demonstrated experimentally. The activity/twist ratio is α/τ ≃ 0.13 … 0.16 universally in weakly guiding silica fibers. Twisted fibers may be used as polarization rotators. A fiber with a ±68° double twist operates as a fast/slow mode interchanger, suitable for delay equalization.
760 citations
TL;DR: In a bent optical fiber, lateral internal stress induces a birefringence, betab, where r is the fiber radius and R is the bending radius.
Abstract: In a bent optical fiber, lateral internal stress induces a birefringence, betab. At lambda = 0.633 microm in a silica fiber, betab = 7.7 X 10(7) r2 /R2 deg/m, where r is the fiber radius and R is the bending radius.
543 citations
TL;DR: In this article, the phase difference between the two polarisation states of the fundamental mode on a slightly elliptical, weakly guiding fibre is derived using both an exact analysis and perturbation theory.
Abstract: The phase difference between the two polarisation states of the fundamental mode on a slightly elliptical, weakly guiding fibre is derived using both an exact analysis and perturbation theory. Deficiences in some earlier calculations are also discussed.
71 citations
TL;DR: A mathematical expression is derived for the shape of multiple-beam Fizeau fringes crossing a graded-index optical fiber inserted in a silvered liquid wedge.
Abstract: A mathematical expression is derived for the shape of multiple-beam Fizeau fringes crossing a graded-index optical fiber inserted in a silvered liquid wedge. Formulas are obtained for calculating both α and Δn from fringe shifts. A formula is deduced for step-index fiber. Experimental results have been obtained from microinterferograms.
42 citations
TL;DR: It is found that the temperature sensitivity of a fiber polarimeter can be significantly reduced by UV irradiation of the fiber.
Abstract: It is found that the temperature sensitivity of a fiber polarimeter can be significantly reduced by UV irradiation of the fiber. A stress-relief model is proposed to explain the mechanism, which is proposed to be a consequence of the breakage of oxygen-deficient bonds (wrong bonds) in the glass network through single-photon or multiphoton absorption, with a subsequent relaxation of the tensile stresses in the fiber core.
39 citations