Results 161 to 170 of about 57,281 (193)

The dynamic birefringence of high polymers

Journal of Polymer Science Part B: Polymer Physics, 1962
AbstractThe simultaneous measurement of the birefringence and strain of a sample subjected to sinusoidal strain is proposed as a means for elucidating the molecular mechanism of the response of high polymers to mechanical deformation. A linear phenomenological theory is proposed in which strain‐optical coefficient distribution functions are assigned to
Richard S. Stein, Shigeharu Onogi, Daniel A. Keedy   +2 more
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Dynamic Birefringence of High Polymers II

Journal of Applied Physics, 1963
The time-dependence of birefringence was investigated in experiments involving relaxation at constant strain, extension at constant rate of strain, and periodically varying strain. The results of constant strain relaxation are calculated from the other two types of experiments using the linear phenomenological theory of birefringence relaxation. Strain-
R. S. Stein, S. Onogi, K. Sasaguri, D. A. Keedy   +3 more
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Dodecagonal photonic quasi-crystal fiber with high birefringence

Journal of the Optical Society of America A, 2016
A photonic quasi-crystal fiber (PQF) with high birefringence is proposed. A dodecagonal Stampfli quasi-periodic lattice of air holes constitutes the cladding of the PQF. The PQF maintains the properties of high birefringence and single-mode operation regime in a wide wavelength range from 1.2 to 2.0 μm by optimizing the size of the air holes around the
Weicheng, Cai, Exian, Liu, Bo, Feng, Wei, Xiao, Hongfei, Liu, Ziming, Wang, Shuo, Wang, Taiyuan, Liang, Jianqiang, Liu, Jianjun, Liu   +9 more
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High Frequency Polarization Modulation Method for Measuring Birefringence

Applied Optics, 1975
A high frequency modulation method utilizing a photoelastic polarization modulator for the measurement of optical birefringence is described and discussed. Although the apparatus has the high sensitivity required to measure very small retardations, the accurate measurement of larger retardations is emphasized and a particularly simple null detection ...
F A, Modine, R W, Major, E, Sonder
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High birefringence in tension-coiled single-mode fibers

Optics Letters, 1980
Coiling a single-mode fiber of radius r under tension onto a cylinder of radius R produces a linear birefringence of βtc ≃ 28 × 107∊2r/R deg/m in the fiber at λ = 0.63 μm, where ∊z is the relative fiber elongation. Polarization beat lengths down to 2.5 cm have been realized this way, providing excellent polarization holding.
S C, Rashleigh, R, Ulrich
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Zero dispersion with high birefringence photonic crystal fibre

2014 International Conference on Electronics and Communication Systems (ICECS), 2014
In this paper we have proposed some new photonic crystal fiber structures whose geometries are derived from the polynomials of Pascal's Triangle (PT). The simulation of the proposed structures are carried out using OptiFDTD simulator with full vector mode solver using finite difference time domain (FDTD).
Pranaw Kumar, Naikatmana Pani, Chandrani Paul, Amlan Datta   +3 more
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High Resolution Photoelastic Pressure Sensor Using Low-Birefringence Fiber

SPIE Proceedings, 1986
The effect of birefringence induced in a single-mode fiber by a lateral force has been applied to measure the absolute value of force or pressure with high resolution. A sensor configuration with an extended detecting surface has been investigated by means of calibrated weights.
A, Bertholds, R, Dändliker
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Measurement of polarization mode dispersion in high-birefringence fibers

Optics Letters, 1983
A broadband superluminescent diode at 0.84 microm is used to measure the group-delay difference in four high-birefringence single-mode fibers. Measured values range from 0.6-0.9 nsec/km for the stress-induced birefringence fibers to 3.6 nsec/km for the elliptical-core fiber.
W K, Burns, R P, Moeller
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An analysis of high birefringence fibers

Journal of Lightwave Technology, 1987
A fiber is birefringent if it has a non-circular core and/or cladding, or is subjected to anisotropic stress. As a result of anisotropic stress, the fibers become biaxial. In this work, a theoretical study on the fields and dispersion of polarization modes in biaxial fibers is presented. The analysis is based on a perturbation method.
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High Frequency Enhancement By Birefringent Lens

Journal of Optics, 1980
The present paper reports the experimental realisation of the high frequency enhancement technique by utilising a birefringent lens suggested by Chakraborty and Mandal Adhikari (1). It is shown that the subtraction of a focussed and a defocussed image of binary objects reveals their edges.
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