Archives par mot-clé : Carnot

TRANSVERSE COUPLING IN FIBER OPTICS PART I : COUPLING BETWEEN TRAPPED MODES

J. A. Arnaud

Bell System Technical Journal, The  (Volume:53 ,  Issue: 2 ), pages 217 – 224, Feb. 1974

ABSTRACT

Two perturbation formulas have been proposed to evaluate the coupling between parallel optical waveguides, one involving a line integral and the other a surface integral. They are shown to be identical. The former expression is preferred because of its greater simplicity. The case of two parallel lossy dielectric slabs is discussed as an example.

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CLASSROOM DEMONSTRATION OF THE LAW OF PROPAGATION OF GAUSSIAN BEAMS

J. A. Arnaud American

American Journal of Physics, vol 41/4, avril 1973, pp. 549-552

ABSTRACT

A method for simulating the propagation of coherent optical beams with Gaussian irradiance patterns in free space and through unaberrated lenses is described. This method is based on the skew-ray representation of Gaussian beams. The rotation in space of a collimated laser beam with skew axis generates a Gaussian beam profile. The phase of the optical fiels is given by the angular position of the laser-beam center.

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VI HAMILTONIAN THEORY OF BEAM MODE PROPAGATION

Jacques Arnaud

Progress in Optics, Volume 11, 1973, Pages 247-304,

ABSTRACT

This paper considers the propagation and diffraction of coherent light beams through nonorthogonal optical systems such as sequences of astigmatic lenses oriented at oblique angles to each other. The fundamental (gaussian) mode has elliptical light spots in each beam cross section and ellipsoidal (or hyperboloidal) wavefronts near the axis. It is found that the orientation of the light spot differs from that of the wavefront, and changes continuously by as much as π radians as the beam propagates through free space. A theory of these general astigmatic beams is given and simple experimental observations are described. The coupling factor between two such beams is also given.

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MODES IN HELICAL GAS LENSES

J. A. Arnaud

Applied Optics, vol 11, numeber 11, november 1972

ABSTRACT

Helical gas lenses incorporate four coaxial helices at temperatures +T, -T, +T, and -T, respectively. Because of the resulting change in refractive index of the gas filling the space inside the helices, optical beams can be guided by this system over long distances. A general expression for the modes of propagation is given; it involves Hermite polynomials in two complex variables. For small temperature differences the mode fields reduce to Laguerre-Gauss functions. Calculated irradiance patterns are shown for various mode numbers and various values of T.

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FOCUSING OF 52-GHZ BEAMS BY CYLINDRICAL MIRRORS (SHORT PAPERS)

J. A. Arnaud, J. T. Ruscio, D. C. Hogg

Microwave Theory and Techniques, IEEE Transactions on  (Volume:20 ,  Issue: 5 ), 344 – 345, May 1972

ABSTRACT

The possibility of using inexpensive commercial glass mirrors for refocusing and redirecting millimeter-wave beams has already been investigated; such beams would be useful for distributing large quantities of information in cities. Interference is expected to be minimal as a result of the close confinement of the beams. We report preliminary experiments made in the 50-55-GHz band, using a swept backward-wave oscillator (BWO) as a source.

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