Showing papers on "Photonic-crystal fiber published in 1973"
TL;DR: In this paper, fundamental optical scattering and absorption mechanisms have been identified which limit light transmission in fiber optical waveguide materials, which are intimately associated with the random structure in the liquid and glassy state.
Abstract: Fundamental optical scattering and absorption mechanisms have been identified which limit light transmission in fiber optical waveguide materials. These mechanisms, which are intimately associated with the random structure in the liquid and glassy state, are described and then used as a basis for comparing fiber optical waveguide materials. It is concluded that pure fused silica is a preferred waveguide material, having ultimate total losses of 1.2 dB/km at the Nd : YAG laser wavelength of 1.06 μ, 3.0 dB/km at the GaxAl1−xAs emission wavelength of approximately 0.8 μ, and 4.8 dB/km at the GaP : Zn, O emission wavelength centered at 0.7 μ.
188 citations
TL;DR: The acceptance angle of a fiber is increased remarkably by forming the fiber end spherically as discussed by the authors, and the coupling efficiency increased in this way is observed to be 5.2 times as high as that of a previous method.
Abstract: The acceptance angle of a fiber is increased remarkably by forming the fiber end spherically. It was demonstrated with light coupling into a fused‐silica‐core glass fiber from a mesa‐stripe‐geometry GaAs diode laser. The coupling efficiency increased in this way is observed to be 5.2 times as high as that of a previous method. The proper design of a fiber in this manner will lead to a light coupling efficiency higher than 90%.
131 citations
TL;DR: In this paper, the chemical composition of the core glass differs from that of the cladding glass, leading to undesired effects at the core-cladding interface and perhaps limiting the minimum fiber losses achievable.
Abstract: Currently there is strong interest in optical fibers for use as a transmission medium, analogous to the use of coaxial or wire pairs in the low-frequency region. Most work is devoted to a fiber structure consisting of a central glass core surrounded by a cylindrical glass cladding having a slightly lower index of refraction. This in turn requires that the chemical composition of the core glass differs from that of the cladding glass, leading to undesired effects at the core-cladding interface and perhaps limiting the minimum fiber losses achievable.
102 citations
01 Oct 1973
TL;DR: In this paper, the authors measured the refractive index profile and impulse response of three low-loss multimode optical fibers, each 1 km long, and found that pulse dispersion of about 1.5 ns or less was observed in two of the fibers.
Abstract: The refractive-index profile and impulse response of three low-loss multimode optical fibers have been measured. Pulse dispersion of about 1.5 ns or less was observed in two of the fibers, each 1 km long.
79 citations
TL;DR: In this paper, a new type of glass fiber is discussed, which is pure fused silica, and the cladding is a high silica content glass, and a light attenuation of approximately 20 dB/km was measured at a 632.8nm wavelength in the preliminary work.
Abstract: A new type of glass fiber is discussed. The core of the fiber is pure fused silica, and the cladding is a high‐silica‐content glass. This type of glass fiber has potentially the lowest attenuation of light propagation. A light attenuation of approximately 20 dB/km was measured at a 632.8‐nm wavelength in the preliminary work.
35 citations
Patent•
15 Aug 1973TL;DR: In this article, a method for monitoring and controlling the refractive index profile and diameter of optical fibers is presented, based on an analysis of the backscattered radiation produced when an optical beam impinges upon the fiber.
Abstract: A method is disclosed for monitoring and controlling the refractive index profile and the diameter of optical fibers The technique is based upon an analysis of the backscattered radiation produced when an optical beam impinges upon the fiber It can be shown, by a geometrical optical analysis, that the position of a sharp cutoff in the radiation pattern is a function of the refractive index profile while the distance between two successive minima (or maxima) is a function of the fiber diameter For certain simple fiber configurations, this data can be translated directly into a number for the fiber core index and a number for the fiber core diameter For more complicated fiber configurations, such as fibers having graded-index cores, the resulting radiation pattern can be compared to that of a reference fiber, and any unusual deviations noted The method is advantageously used in conjunction with a feedback system for monitoring fibers as they are drawn, and for controlling the drawing machinery so as to maintain the fiber parameters within specified tolerances
29 citations
TL;DR: In this paper, a simple one-dimensional geometrical theory with which to calculate losses introduced at a connection by alignment errors or fiber-end separation is presented. But it assumes that the fibers to be illuminated uniformly across the diameter of the core and within the acceptance angle.
28 citations
TL;DR: In this article, the authors used a ray-vector approach to reconstruct the behavior of a hollow glass fiber in the presence of a plane-polarized laser source, by which the incident wavefront is decomposed into the component interactions of reflection and refraction with the fiber to give the emergent wavefronts.
Abstract: Irradiation of a hollow glass fiber, normal to its axis, by a plane-polarized laser source produces a coaxial interference pattern with distinctive features that can be related to the cross-sectional geometry of the fiber, providing a sensitive means of non-destructive monitoring of the outer radius and the ratio of inner and outer radii. The phenomena involved in this interpretation are explained and reconstructed by use of a ray-vector approach, by which the incident wavefront is decomposed into the component interactions of reflection and refraction with the fiber to give the emergent wavefronts. A number of measurements made on some samples demonstrate the proposals.
17 citations
12 citations
TL;DR: In this paper, the authors consider the dispersion effects of the refractive index of glass fibers in the visible and near-infrared spectrum and show that the effect of dispersion can be significant and requires equalization.
Abstract: The transparency of glass fibers in the visible and near infrared—improved beyond all expectations by recent breakthroughs—seems now sufficient to transmit optical signals unprocessed over miles. No wonder that efforts have intensified all over the world to utilize fibers in future communication systems. Materials research and fabrication are the fields where present progress is most rapid. New ways of preform preparation by deposition, doping, or diffusion are being studied and found to offer improvements and versatility. As far as materials are concerned, fused silica has shown the lowest bulk losses and hence receives the most interest, but many glasses are being studied as well. As new processes become available and record lows in fiber loss are being reached, propagation theory is finding new challenges as well. On the one hand, multimode fibers seem desirable with respect to transmitter compatibility, splicing, and fabrication tolerances. On the other hand, the signal distortion caused by mode delay differences in multimode fibers can be considerable and requires equalization—inherent in the fiber or at the fiber end. Beyond that, the wavelength dependence of the refractive index produces dispersion effects serious enough to be of importance. Thinking ahead, one is confronted with the question of fiber handling, strength, and life. The technology of making cables and splices from a brittle material like glass is in its infancy, and we can only indicate the extent of these difficult problems ahead.
9 citations
TL;DR: In this article, the specific function of these modulators is to impress signal information, up to 50 Mb/s, on the CW emission of Nd:YAG lasers.
Abstract: Broad-band acoustooptic modulators have been designed and developed for fiber optical-communication applications. The specific function of these modulators is to impress signal information, up to 50 Mb/s, on the CW emission of Nd:YAG lasers.
01 Jan 1973
01 Jan 1973
TL;DR: In this chapter the development of optical communications systems is of great current technological interest, and a system operating at the frequency of visible or near infrared light would have a capacity that is exceedingly large.
Abstract: The development of optical communications systems is of great current technological interest. A system operating at the frequency of visible or near infrared light would have a capacity that is exceedingly large, and this is of course a principal reason for interest in such systems. Others include freedom from electromagnetic interference and the potentiality of achieving small size in the transmission medium. There would be many elements in such a system, including a source of light, a means for modulating the light beam, a transmission system, and a detector, as well as other components, perhaps; in this chapter we will be concerned only with the transmission aspects.