Beam and Fiber Optics discusses the concepts of wave and geometrical optics that are most relevant to a deeper understanding of beam optics. This book is organized into five chapters that provide the necessary algebraic details, particularly the laws of beam propagation through unaberrated optical systems.
The first chapter presents a broad view of the subject matter and a comparison between the laws of mechanics and the laws of optics. Chapter 2 explores the laws of propagation of Gaussian beams through freespace, unaberrated lenses, or lenslike media and resonators. The simplest configurations (two-dimensional with isotropic media) are first considered, but a few advanced problems are also treated. This chapter also discusses the use of Gaussian beams at millimeter wavelengths. In Chapter 3, various wave equations relevant to beam optics are given, and their relationship is examined. This text also emphasizes the importance of the Lorentz reciprocity theorem for problems of coupling between beams or fibers. The geometrical optics limit of wave equations is addressed in Chapter 4. This chapter also considers the propagation of optical pulses in dispersive inhomogeneous (graded-index) fibers based on the point of view of Hamiltonian optics. The final chapter is devoted to piecewise homogeneous dielectric waveguides, such as the dielectric slab and the dielectric rod. A method to evaluate the bending loss of open waveguides is described.
This book will be useful to students, professors, and research engineers in the field of electromagnetic communication.
The identification, medium refractive indexn = nonrelativistic particle velocityv, in the analogy of geometrical optics with nonrelativistic particle mechanics is physically correct and useful, but can easily be misinterpreted. The conditions under which the analogy holds are outlined. The significance of Descartes’s mechanical models is also discussed.
Electronics Letters, Volume 11, Issue 23, 13 November 1975, p. 554 – 556
ABSTRACT
A formulation of ray optics that takes the polarisation of electromagnetic waves into account shows that the maximum difference in time delay between corresponding HE and EH modes is, for almost any multimode graded-index fibre, of the order of 10 000 (Δn/n)2/V ns/km, where V is the V-number of the fibre and Δn is the variation of the refractive index between axis and cladding. The effect of polarisation on pulse broadening is found to be negligible if the V-number of the fibre is much larger than about 20.
Microwave Theory and Techniques, IEEE Transactions on (Volume:23 , Issue: 11), pages 935 – 936, Nov. 1975
ABSTRACT
In the above paper, Lewin gave an expression for the bending loss of a dielectric fiber with circular cross section. I have shown that the bending loss of arbitrary optical guides can be obtained in a simple manner when the field of the straight guide is known. The purpose of this letter is to show that the results of the two theories are in agreement, except for a factor of 2.
IEEE Transactions on Microwave Theory and Techniques, (Volume:23, Issue: 11), Pages 927–929, Nov 1975
ABSTRACT
The integral of the square of the Airy function from one of its zeros to infinity is equal to the square of the first derivative of the Airy function at the zero considered. Two important applications of this result to fiber optics are discussed.
Bell System Technical Journal, The (Volume:54 , Issue: 8 ), pages 1431 – 1450, Oct. 1975
ABSTRACT
We evaluate the crosstalk between adjacent cores in an optical fiber that results from electromagnetic coupling. Means of reducing it are discussed. We find that a 0.5-μm-thick layer of silver can, in principle, reduce the crosstalk from −20 to −130 dB without significant increase of the loss. These theoretical results are obtained for two identical single-mode dielectric slabs. In reality, the slabs are not rigorously identical. Longitudinal fluctuations of slab thickness reduce the crosstalk by at least 40 dB. The slab spacing can accordingly be reduced from, typically, 11 to 6 μm for a constant crosstalk. If the slabs are made dissimilar with a relative difference in thickness of 10 percent, the spacing can be reduced further, to approximately 1.5 times the slab thickness. For example, a 15-μm spacing is required between single-mode dissimilar slabs if the nominal slab thickness is 10 μm, provided scattering can be neglected.
Bell System Technical Journal, The (Volume: 54 , Issue: 7 ), pages 1179 – 1205, Sept. 1975
ABSTRACT
Closed-form expressions are obtained for the impulse response of graded-index fibers whose relative permittivity is a homogeneous function of the two transverse coordinates x, y, and for the impulse width in graded-index fibers whose profile departs slightly, but otherwise arbitrarily, from a square law. The inhomogeneous dispersion of the material is taken into account. Pulse broadening can be reduced by a factor of 12 from the value obtained for square-law fibers. Simple expressions are found for the acceptance of highly oversized fibers.
Electronics Letters, Volume 11, Issue 18, 4 September 1975, p. 447 – 448
ABSTRACT
A closed-form expression for pulse broadening in graded-index fibres that have small and circularly symmetric, but otherwise arbitrary, deviations from a square-law, and arbitrary dn/dλ, is applied to germania-doped fibres. The range of validity of the theoretical expression is defined by comparison with the results of numerical integration.
Microwave Theory and Techniques, IEEE Transactions on (Volume:23 , Issue: 4 ), pages 377 – 379, Apr 1975
ABSTRACT
Microwave beams can be kept confined by sequences of pairs of cylindrical mirrors, each pair acting as a lens. At 100 GHz, with 1.2-m x 1.2-m focusers spaced 80 m apart, a loss of the order of 2 dB/km has been measured in clear weather. The use of this beam-guiding arrangement, called a « Hertzian cable, » for distribution of information in cities is discussed.
Journal of Optical Society of America, vol. 65, n° 2, February 1975
ABSTRACT
The motion of charged particle in a space- and time – dependent potential and the motion of an optical pulse in an inhomogeneous anisotropic medium coincide when the dispersion surfaces are the same.