Optical waveguides – Integrated optical circuit
Reexamination Certificate
2002-11-27
2004-07-06
Dunn, Drew (Department: 2872)
Optical waveguides
Integrated optical circuit
C385S043000, C385S049000
Reexamination Certificate
active
06760500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to optical wiring devices for use in mounting thereon integrated high speed circuitry.
2. Discussion of the Background
Large Scale Integrated circuits (LSIs) are currently capable of operating at remarkably increased speeds due to the increased performance of bipolar transistors and field effect transistors, for example.
However, while the speed of internal operations of LSIs have increased, operation speeds at the level of printed circuit boards including mounted LSI chips and/or racks including printed circuit boards remain less than the LSI operation speeds. When operation frequencies of the printed circuit boards and racks are increased, signal transfer losses of electrical leads, noises and electromagnetic interference are also increased. Thus, it is necessary to lower the operation frequency with an increase in length of the leads used therein to prevent degradation of signals transmitted. Accordingly, currently available electrical wiring devices are incapable of improving the operation speeds, even when the operation speeds of the active LSIs elements are increased, due to the problems at the printed circuit boards and/or racks.
Several approaches have been proposed to avoid the above-noted problems. One approach uses an optical wiring device for optically connecting LSIs. With such an optical wiring/connection, frequency dependency characteristics (such as loss) hardly occur in certain frequency regions ranging from direct current (DC) up to several tens of giga-hertz (GHz). Thus, the lead wiring may offer transfer rates of several tens of gigabits per second (Gbps) because of the absence of any electromagnetic interference and/or ground potential variation noises occurring along signal transmission paths.
To achieve this optical wiring device, leads using optical guide paths or waveguides are required. Generally, connection of optical waveguides is performed through flat plate-like optical waveguide substrates or optical fibers, which can result in a decrease in general-purpose properties or flexibilities compared to electrical lead wiring methodology. Due to this, optical wiring devices are used less in general-purpose applicability than in electrical wiring devices, and are generally only used in special-purpose equipment.
SUMMARY OF THE INVENTION
Accordingly one object of the present invention is to provide a novel optical wiring device capable of optically connecting LSI chips, while retaining general-purpose features.
To attain the above object, the present invention provides an optical wiring device including a substrate having a first surface and a second surface on an opposite side of the first surface, and having a hole through the substrate between the first and second surfaces, an integrated circuit disposed on the first surface of the substrate, and an electrical wiring provided on the first surface of the substrate and connected to the integrated circuit. Also included is a photoelectric conversion element provided on the first surface of the substrate and configured to convert between electrical signals and optical signals, and an optical terminal disposed in contact with the hole on a side of the second surface of the substrate. The electrical signals are transmitted between the photoelectric conversion element and the integrated circuit, and the optical signals are transmitted to and from the photoelectric conversion element or through the optical terminal.
In addition, the through-hole in the substrate has a slant side surface for use in performing position alignment of the optical terminal.
It is preferable the optical wiring device has structures as described below.
(1) The optical terminal has a curved plane opposing the photoelectric conversion element.
(2) The hole is provided in a tapered form, and the curved plane of the optical terminal contacts a side surface of the substrate surrounding the hole.
(3) The curved plane of the optical terminal is a part of a spherical surface.
(4) The hole in provided in a tapered form, and the spherical surface of the optical terminal is in contact with a side surface of the substrate surrounding the hole.
The present invention also provides an optical wiring device including a first substrate having a first surface and a second surface on an opposite side of the first surface of the substrate, and having a hole provided through the first substrate between the first and the second surfaces, an integrated circuit disposed on the first surface of the first substrate and a photoelectric conversion element provided on the first surface of the first substrate for conversion between electrical signals and optical signals. Also included is an optical terminal disposed in contact with the hole on the side of the second surface of the first substrate and a second substrate having an optical wiring, and being attached to the first substrate with the optical terminal therebetween. The electrical signals are transmitted between the photoelectric conversion element and the integrated circuit, and said optical signals are transmitted between the photoelectric conversion element and the optical wiring through the optical terminal.
It is preferable the optical wiring device has structures as described below.
(1) The optical wiring runs within the second substrate.
(2) The optical terminal has a curved plane opposing the optical wiring, and an optical focusing point due to the optical terminal being positioned at a portion of the optical wiring.
(3) The second substrate has a concave portion, and the optical terminal has a curved plane in contact with the concave portion of the second substrate so as to be optically coupled to the optical wiring.
(4) The concave portion is provided in a tapered form, and the curved plane of the optical terminal is a part of a spherical surface in contact with a side surface of the concave portion.
(5) The optical focusing point due to the optical terminal is positioned at a portion of the optical wiring deeper than a bottom surface of the concave portion.
(6) An electrical wiring is provided on the first surface of the first substrate and is connected to the integrated circuit.
(7) The optical terminal has a curved plane opposing the photoelectric conversion element.
(8) The hole is provided in a tapered form, and the curved plane of the optical terminal contacts with a side surface of the first substrate surrounding the hole.
(9) The optical terminal has a spherical shape.
(10) The optical terminal has a curved plane opposing the photoelectric conversion element.
(11) The hole is provided in a tapered form, and the curved plane of the optical terminal contacts with a side surface of the first substrate surrounding the hole.
(12) The concave portion is provided in a tapered form, and the optical terminal has a spherical shape.
(13) There is provided an optical connector for optically connecting the optical wiring to another optical wiring, in which the optical connector allows optical signals to be transmitted therein upon application of a pressure thereto.
(14) The optical connector includes a matrix portion and holes dispersed in the matrix portion, and the longest diameter of each of the holes extends in a direction perpendicular to a direction in which the optical signals are transmitted.
(15) The optical connector includes a matrix portion and particles dispersed in the matrix portion, and the refractive index of the particles is higher than the refractive index of the matrix portion.
A principal concept of the invention lies in providing within an integrated circuit (LSI) package structure a package substrate mounting thereon one or more LSI and optical semiconductor element(s) with at least one through-hole provided in the package substrate for alignment in optical axes between an optical semiconductor element and optical input/output terminal having its distal end as formed in either a hemispherical shape or spherical tapered shape.
Another important concept of the invention lies in that a concave por
Kabushiki Kaisha Toshiba
Lavarias Arnel C.
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