ISSN:0048-6604    

DOI:10.1029/RS017i001p00001

年代:1982

数据来源: WILEY

摘要:

An asymptotic theory is developed for vector modes of inhomogeneous circular waveguides, by means of which closed form expressions for the propagation characteristics of modes can be obtained. Basically, the theory is an extension of WKB's asymptotic theory based on scalar wave or geometric optical considerations to the coupled equations describing the basic properties of vector waves, and, therefore, the leading terms are the well‐known lowest‐order WKB solutions. The major part of the paper is offered on the theoretical foundations of the method. However, the formulas derived here are shown to be applicable for general classes of refractive index prof

ISSN:0048-6604    

DOI:10.1029/RS017i001p00003

年代:1982

数据来源: WILEY

摘要:

Reflection and excitation problems of circularly symmetric surface waves occurring at an abrupt discontinuity in a homogeneous core‐type optical fiber are analyzed using the Fourier transform and Wiener‐Hopf techniques. The frequency characteristics of reflection and transmission coefficients are revealed with numerical examp

ISSN:0048-6604    

DOI:10.1029/RS017i001p00011

年代:1982

数据来源: WILEY

摘要:

Bending losses in a radially inhomogeneous profile fiber were studied, taking into account bend‐induced field deformation to the first‐order perturbation. Analytical bending loss formulas are given for arbitrary mode numbers in step‐index fibers. Polarization degeneracy in bending loss still exists even when field deformation effects are taken into account. The bending loss in a step‐index single‐mode fiber increases by 36% at υ = 2.4 and ℜ =RΔ/a = 10 as compared with that without fiel

ISSN:0048-6604    

DOI:10.1029/RS017i001p00021

年代:1982

数据来源: WILEY

摘要:

The waveguide and material dispersion are investigated for various silica‐based single‐mode optical fibers with arbitrary refractive‐index profiles. It is shown that in the case of the doubly clad optical fiber with an index difference between the core and the outer cladding Δ1= 1.0% and that between the inner and the outer cladding Δ2= −1.0%, where the diameter of the core 2a= 7.2 μm and the thickness of the inner claddingt= 1.1 μm, the total dispersion is reduced to within ±1 ps km−1nm−1over a wide spectral range of

ISSN:0048-6604    

DOI:10.1029/RS017i001p00031

年代:1982

数据来源: WILEY

摘要:

A vector wave analysis is proposed for analyzing the propagation characteristics of the guided modes of the graded‐index fibers. Two pairs of the vector wave equations with respect to the transverse components of the electromagnetic fields are derived and solved by the perturbation method in which we use the scalar wave equation as an unperturbed one. As an example, we calculate the eigenvalues and the eigenfunctions of the vector modes of a graded‐index fiber with an even polynomial‐profile core, and for the eigenvalues we obtain the analytic solutions. Moreover, the result coincides with that obtained by a more sophisticated m

ISSN:0048-6604    

DOI:10.1029/RS017i001p00037

年代:1982

数据来源: WILEY

摘要:

The cutoff condition of HE, EH, TE, and TM modes is formulated in an integral equation by using a Sturm‐Liouville‐type boundary problem. A formula for calculating the cutoff frequencies of the TM01and HE21modes is derived in addition to the TE01cutoff by calculating the eigenvalue of this integral equation. The cutoff frequencies of the TM01and HE21modes are calculated and compared with those of the TE01mode for various index profiles. As a result, the cutoff frequency of the TM01mode is dominant for the single‐mode limit over frequencies of the TE01, TM01, and HE21modes for the α‐power law index profile. However, in the case of an index profile including a center dip, the cutoff frequency of the TE01mode dominates the single‐mode

ISSN:0048-6604    

DOI:10.1029/RS017i001p00043

年代:1982

数据来源: WILEY

摘要:

The field distribution in the elliptical optical fiber is theoretically analyzed and its polarization stability to the bending and the twist is discussed by using Poincaré sphere representation

ISSN:0048-6604    

DOI:10.1029/RS017i001p00051

年代:1982

数据来源: WILEY

摘要:

The effects of random bends on the baseband frequency response of the multimode optical fiber are very important in practical communication systems. But their theoretical investigation has not been fully carried out. Therefore in this paper we theoretically investigate the baseband frequency characteristics of the multimode fiber whose axis suffers from random bends with the help of the variational method. As a result, we obtain the phase characteristics as well as the amplitude characteristics and indicate that the phase distortion can be neglected within the bandwidth. Also, we confirm the existence of the quasi‐steady state, in which the transmission characteristics are fairly stabilized, although the bandwidth is not always proportional to the inverse square root of the fiber lengt

ISSN:0048-6604    

DOI:10.1029/RS017i001p00057

年代:1982

数据来源: WILEY

摘要:

General transmission theory of transient coherence of optical fields in dispersive fibers is shown. Temporal and spatial coherence properties of optical waves in random gradient fibers excited by partially coherent sources are studied by stochastic process theory for irregularities along fibers. Generalized coupling equations concerned with transient mutual correlation functions of random fields are derived. Using transient mutual correlation functions, exact spectral transfer functions for base band power responses are discussed with dispersive effects. Based on this theory, optical pulse signals in gradient fibers with radially inhomogeneous refractive index and lossy cladding that gives excellent filtering properties are studied. Scattering, pulse broadening, and base band power response are discussed.

ISSN:0048-6604    

DOI:10.1029/RS017i001p00065

年代:1982

数据来源: WILEY