Characterization of highly birefringent optical fibers using interferometric techniques
04 Jun 1996-Vol. 46, Iss: 4, pp 903-907
TL;DR: In this paper, a method for measuring modal bireringence and polarization mode dispersion in highly birefringent fibers is presented, which employs the principle of white-light interferometry for dispersion measurement, and classical coherent interferometrical measurement.
Abstract: A method is presented for measuring modal birefringence and polarization mode dispersion in highly birefringent fibers. The method employs the principle of white-light interferometry for dispersion measurement, and classical coherent interferometry for birefringence measurement. The key parts of the measuring system are a Wollaston prism made of crystalline quartz used as a shearing type interferometer and a set of quartz delay plates for compensation of retardations up to 1000/spl lambda/ introduced by the tested fibers. The interferometer is combined with a CCD camera and with a processing system allowing for convenient measurement data acquisition and handling.
Citations
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TL;DR: The results of modeling show that the temperature and pressure sensitivity of elliptical-core fiber are associated primarily with variations in stress induced by these parameters.
Abstract: Modal birefringence and its sensitivity to temperature and hydrostatic pressure were measured versus wavelength in three elliptical-core fibers and one fiber with stress-induced birefringence. We carried out the measurements in the spectral range from 633 to 843 nm by using interferometric methods. In fibers with elliptical cores all the measured parameters showed high chromatic dependence, whereas in fibers with stress-induced birefringence this dependence was weak. We modeled the dispersion characteristics of two elliptical-core fibers by using the modified perturbation approach first proposed by Kumar. The modification consists of introducing into the expression for the normalized propagation constants an additional perturbation term that contains information about stress-induced birefringence. The results of modeling show that the temperature and pressure sensitivity of elliptical-core fiber are associated primarily with variations in stress induced by these parameters. The agreement between measured and calculated values of sensitivity in the worst case was equal to 20% for modal birefringence and temperature sensitivity and 50% for pressure sensitivity. Lower agreement between measured and calculated values of pressure sensitivity is most probably associated with uncertainties in the material constants used in modeling.
97 citations
TL;DR: In this article, the group-index difference and the refractive index difference between the fast and slow modes in polarization-maintaining optical fiber are measured in reflection, which enables a distributed measurement of the fiber's birefringence that is rapid and completely nondestructive.
Abstract: Optical-frequency-domain reflectometry is used to measure the group-index difference and the refractive-index difference (i.e., beat length) between the fast and slow modes in polarization-maintaining optical fiber. The Rayleigh scatter normally present in the fiber is measured in reflection. This measurement, in turn, enables a distributed measurement of the fiber's birefringence that is rapid and completely nondestructive
81 citations
Cites background from "Characterization of highly birefrin..."
...Low coherence interferometric techniques resulted in improved sensitivity [8], [9]....
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TL;DR: An exact analysis of the working parameters of a modified Wollaston prism is presented and an angle of incidence that causes the plane of the interference fringes to be perpendicular to the axis of the optical system is found.
Abstract: An exact analysis of the working parameters of a modified Wollaston prism is presented. Parameters include the output splitting angle, the retardation, and the location of the plane of the interference fringes (plane of apparent splitting). Results are presented for the entire range of optical axis inclinations and wedge angles. Approximate expressions from the literature are evaluated. An angle of incidence that causes the plane of the interference fringes to be perpendicular to the axis of the optical system is found for each configuration analyzed. This is then applied to the design of modified Wollaston prisms for Nomarski differential interference contrast microscopy.
33 citations
TL;DR: A new type of fiber-optic pressure sensor based on a specially developed side-hole fiber that allows for unambiguous and fast phase-shift measurements in the range from -/spl pi//2 to +/splpi//2 with a sampling rate of 5 kHz and resolution of about 1% of full scale.
Abstract: A new type of fiber-optic pressure sensor based on a specially developed side-hole fiber is presented. It allows for unambiguous and fast phase-shift measurements in the range from -/spl pi//2 to +/spl pi//2 with a sampling rate of 5 kHz and resolution of about 1% of full scale (2 /spl middot/ 10/sup -3/ atm).
30 citations
Cites methods from "Characterization of highly birefrin..."
...The pressure and temperature sensitivities of this fiber were measured using the low coherence interferometric method described in [10], which allows also for determining the sign of sensitivity....
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Patent•
10 Apr 2003
TL;DR: In this paper, the spectrally-resolved state of polarization (SOP) variation across each DWDM channel and using a polarization controller to deterministically extinguish the signal across narrow frequency subbands within each DWC channel.
Abstract: Methods and apparatus for rapid, accurate OSNR measurements by directly measuring the spectrally-resolved State of Polarization (SOP) variation across each DWDM channel and using a polarization controller to deterministically extinguish the signal across narrow frequency subbands within each DWDM channel. In-band ASE noise is subsequently measured as a function of frequency across the channel bandwidth.
17 citations
References
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TL;DR: In this article, single crystals of ZnSe have been prepared by the vapor growth technique and optical and electrical measurements on these crystals are reported, where the transverse optical phonon energy is 0.031 ev.
Abstract: Single crystals of ZnSe have been prepared by the vapor growth technique and optical and electrical measurements on these crystals are reported. Analysis of the reststrahlen reflection peak gives 0.026 ev for the transverse optical phonon energy. The longitudinal optical phonon energy is 0.031 ev as calculated from the transverse phonon energy, the static dielectric constant, e0=8.1±0.3, and the high‐frequency dielectric constant, e∞=5.75±0.1. The effective ionic charge calculated from the Szigetti formula is 0.7±0.1. Exciton absorption peaks associated with the valence and conduction bands in the vicinity of Γ were observed at liquid hydrogen temperature with the principal peak at 2.81±0.01 ev. The exciton reduced mass 0.1 m0 combined with the room temperature electron‐to‐hole mobility ratio of 12, obtained by preliminary transport measurements on n‐ and p‐type ZnSe gives tentative values of 0.1 m0 and 0.6 m0 for the electron and hole masses, respectively.Reflectance was determined by various methods in ...
172 citations
TL;DR: In this paper, the authors consider fiber-optic interferometric sensors with a short coherence length and find that the minimum detectable phase is limited by the noise associated with incoherent interference.
Abstract: If a number of fiber-optic interferometric sensors are arranged so that their outputs are returned to the user via a common optical bus, then some method of distinguishing the returns from different sensors must be used to recover individual signals. One such method involves using light with a short coherence length, so that returns from different sensors will be mutually incoherent. The interferometric signal associated with each sensor can then be recovered via appropriate optical processing. The author considers sensors multiplexed using this technique and calculates their noise performance. It is found that for systems with only a few sensors, the minimum detectable phase is limited by the noise associated with incoherent interference; this can be minimized by using light with as short a coherence length as is practical. The maximum number of sensors that can be multiplexed is limited by optical power loss. A ladder topology is tentatively found to give the best performance. >
140 citations
TL;DR: In this article, optical absorption measurements indicate two Jahn-Teller-split Fe2+ crystalline-field peaks and an absorption edge near 2.4 eV, independent of stoichiometry.
131 citations
TL;DR: A new method for precisely measuring the wavelength dependence of modal birefringence in highly bireFringent fibers is presented using an incoherent light source such as a fiber Raman laser.
Abstract: Modal birefringence of highly birefringent fibers can be measured nondestructively by the elastooptic modulation method. Based on this modulation method, a new method for precisely measuring the wavelength dependence of modal birefringence in highly birefringent fibers is presented using an incoherent light source such as a fiber Raman laser.
63 citations
Additional excerpts
...It is well known from the literature [12], [ 15 ] that a pointlike force applied laterally to the HB fiber causes coupling between polarization modes....
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TL;DR: A white-light interference phenomenon arising between polarization modes as a result of mode coupling induced by a pointlike lateral force applied in approximately one half the length of the tested fiber permits the use of a Wollaston prism without a delay line as an analyzing interferometer.
Abstract: A method for measuring modal birefringence and polarization mode dispersion in highly birefringent fibers is presented. It employs a white-light interference phenomenon arising between polarization modes as a result of mode coupling induced by a pointlike lateral force applied in approximately one half the length of the tested fiber. This permits the use of a Wollaston prism without a delay line as an analyzing interferometer. Results of measurements of modal birefringence and polarization mode dispersion at λ(0)= 826 nm are reported for four commercially available fibers: the York Bow-Tie, the Fujikura Panda, the Andrew E-type, and the Andrew D-type.
63 citations