High-bandwidth (2 GHz/spl middot/km) graded-index polymer optical fiber (GI POF) was successfully obtained by the new interfacial-gel polymerization technique in which the unreactive component was used in order to obtain the quadratic refractive-index distribution. This high-bandwidth GI POF makes it possible to transmit high-speed optical signals in the short range network which was not covered by the step-index type POF commercially available. The high bandwidth GI POF will open the way for great advantages in the high-speed multimedia network. >

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High-bandwidth graded-index polymer optical fiber

Low‐loss waveguides for integrated optical devices are formed by electrically induced migration of ions in glass plates. The guiding region is located beneath the substrate glass. The transmission loss of the waveguides is estimated to be less than 0.1 dB/cm.

Optical waveguide formed by electrically induced migration of ions in glass plates

Fused SiO2 has been used as a new noncrystalline host for the fabrication of two types of neodymium‐doped room‐temperature lasers, one of which operates at 1.06‐μm and the other at 1.08‐μm wavelength. The lasers have the geometry of clad optical fibers, with active cores as small as 15‐μm diameter by 1‐cm length. They are end pumped at 0.590 and 0.5145 μm with a pulsed dye laser and an argon ion laser, respectively. Thresholds as low as 1–2 mW of absorbed pump power in a 40‐μm‐diam core have been obtained, and eventual pumping with high‐radiance semiconductor optical sources appears feasible.

Neodymium‐doped silica lasers in end‐pumped fiber geometry

A method and apparatus are disclosed for high speed multiaccess data communication using guided wave components and angular division multiplexing for parallel optical signal transmission over a multimode optical fiber. A receiver at each station in the network comprises an optical coupler/demultiplexer, a pulse regenerator, an optical processor and detectors. The transmitter at each station comprises an array of lasers, a switching matrix for controlling emissions into the optical fiber and a multiplexer/coupler for coupling the laser emissions to the multimode optical fiber. The optical processor is directly coupled to the switching matrix. Preferably, the multiplexer/coupler comprises a graded-index planar lens, one major surface of which abuts the optical fiber and the other major surface of which is contacted by a plurality of single mode waveguides from the different lasers of the transmitter. As a result, the single mode signals introduced into the lens at different radial distances are coupled to different modal groups propagating in the optical fiber. The coupler/demultiplexer preferably comprises a graded-index lens and an array of concentric half-ring lasers. Annular cones of radiation propagating in the optical fiber are focused to an array of concentric rings near the half-ring lasers where they are converted into linear beams propagating in single mode guided wave structures.

Local area network optical fiber data communication

Glass optical waveguides with attenuations below 20 dB/km have made possible a new approach to optical communications. These glass fibers satisfy requirements for transmission over kilometer lengths with experimental systems utilizing existing devices for sources and detectors. The realization of material and fabrication advances necessary for this accomplishment are the topic of this paper. Basic theoretical principles are introduced in a review fashion. The application of these principles in choice of materials and fabrication is described. Results in fiber performance following this framework are given in a section on evaluation, which includes information capacity, attenuation, and some environmental requirements. Preliminary experiments in bundling and cabling are discussed, followed by concluding remarks.

Glass fibers for optical communications

Optical device for transmitting an image wherein a number of optical fibers are disposed in such a manner that they are arranged neatly in the same relative position among them, at least, both ends thereof, each of said fibers having such a refractive index distribution as to substantially satisfy the equation n = N (1 - ar2) IN A CROSS SECTION THEREOF, WHERE N is a refractive index at a center, n is a refractive index at a distance r from the center, and a is a positive constant, whereby light due to an object placed at one end of said fibers forms an image of the object at the other end thereof.

Image transmitter formed of a plurality of graded index fibers in bundled configuration

Glass fibers and rods with radially parabolic refractive-index distributions were produced by exchanging potassium ions from a salt bath or a lower-index cladding glass for thallium ions in the glass composition. A fiber 1 m long and 0.25 mm in diameter could be bent around a curve of radius 10 cm without deforming the Gaussian mode pattern; the depolarization of a laser beam was < −20 dB. The resolution of a rod 3.14 mm long and 1.0 mm in diameter with a focal length of 1.64 mm was of the order of 450 lines/mm. Attenuation (caused primarily by absorption induced by trace impurities) was 100 to 250 dB/km at 6328 A; since further improvement with respect to loss is expected, these fiber guides are promising materials for use in long-distance optical communications.

Light-Focusing Glass Fibers and Rods

A multiplexed optical communications system comprises a plurality of fibrous light guide elements which receive respective ones of a plurality of modulated light beam sources having predetermined phase differences therebetween. The output ends of the elements are formed into a bundle which communicates with one end of a light transmission path. Means positioned at the other end of the transmission path are provided for separating the modulated signals in accord with their respective phase separations.

Multiplexed optical communications system

Schalteinrichtung zur wahlweisen Verbindung von optischen Einrichtungen

A time-division, space-division multiplex system employing a fibrous converging light guide having a specific reflective index distribution. Beams of coherent modulated light spatially multiplexed (and if desired, also time-division multiplexed) are impinged upon one end of the guide, each beam having a specific incident angle and position from the axis. The modulated beams are emitted in a spatially multiplexed fashion from the other end of the guide where they are detected.

Teiji Uchida

Papers

Image transmitter formed of a plurality of graded index fibers in bundled configuration

Light-Focusing Glass Fibers and Rods

Multiplexed optical communications system

Schalteinrichtung zur wahlweisen Verbindung von optischen Einrichtungen

Multiplexed optical communication system