Bell System Technical Journal, The (Volume:53 , Issue: 4 ), pages 675 – 696, April 1974
ABSTRACT
The number of modes that can propagate without radiation loss in oversized waveguides is sharply reduced if the waveguide is coupled to a structure supporting radiation modes, the loss mechanism being analogous to Cerenkov radiation. The coupling formula derived in Part I1 is used to evaluate the loss for a specific configuration: a reactive surface (e.g., a thin dielectric slab) acting as a waveguide, coupled to a semi-infinite dielectric acting as a mode sink. The method consists in first assuming that the substrate is finite in size and lossy and adding the losses associated with each substrate mode. The substrate dimensions are subsequently made infinite and the dissipation loss is made to vanish. The expression obtained for the radiation loss coincides with an expression obtained by solving the boundary value problem. The method is then applied to the problem of mode selection for dielectric rods coupled to dielectric slabs, which is of particular importance for optical communications and integrated optics. A 2-dB/m radiation loss is calculated for the first higher order mode when the rod radius is 10 µm, λ = 1 µm, n = 1.41, and the rod-to-slab spacing is 0.15 µm.
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.
Optics communications, vol 7, number 4, april 1973
ABSTRACT
It is shown that the force exerted by plane electromagnetic waves on multilayer media can be evaluated in terms of the changes in momentum flow that take place at the planes of discontinuity. The expression obtained is relevant to radiation pressure experiments.
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.
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.
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.