Optical waveguides – Integrated optical circuit
Reexamination Certificate
2002-08-06
2004-12-07
Ullah, Akm Enayet (Department: 2874)
Optical waveguides
Integrated optical circuit
C385S129000, C385S130000
Reexamination Certificate
active
06829398
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical waveguide apparatus that includes an optical waveguide sheet and an optical device. In this specification, an optical waveguide sheet or optical sheet is a waveguide which permits light transmission form a light transmitting unit toward a direction different from a direction oriented from the light transmitting unit to a light receiving unit, as well as light transmission form the light transmitting unit to the light receiving unit, for example.
2. Description of the Related Background Art
In recent years, performances of portable apparatuses, such as personal computers, cellular phones and personal digital assistants (PDAs), and digital audio-visual apparatuses have been increasingly improved, and their interconnections are being developed using all kinds of frequency bands in both of wireless and wire forms. Therefore, appropriate prompt measures are needed to cope with malfunctions of digital equipment due to electromagnetic interference from electric substrates (electromagnetic interference: EMI), immunity from intervention of external electric waves (immunity), and signal errors resulting from defective connections (signal integrity (SI)). With those electromagnetic-wave problems, products prior to shipment are required to clear regulation magnitudes prescribed in the electric-wave regulation law, and development costs for taking those measures continuously increase. In this situation, the optical wiring without any electromagnetic induction is expected to radically solve the above bottleneck.
Further, in the near future the high-speed interconnect environment will be surely established also in homes, so that there is a need to prevent the malfunction and noise intervention even when high-speed electronic equipment is freely connected in a variety of ground environments. Also in this respect, the optical interconnection is an effective means that can readily achieve an electric isolation from the ground.
Various methods of the optical wiring interconnection have been proposed.
FIG. 1
illustrates an optical wiring structure
1100
disclosed in Japanese Patent Application Laid-Open No. 9(1997)-270751. In
FIG. 1
, reference numeral
1120
designates an electric circuit board. Reference numeral
1130
designates an emitting end of optical signals S
1
, S
2
and S
3
. Reference numeral
1133
designates an optical-signal input portion. Reference numeral
1101
designates an optical bus. Reference numeral
1134
designates an optical-signal output portion. Reference numeral
1140
designates a receiving end of optical signals S
1
, S
2
and S
3
. Optical devices
1132
and
1142
driven by driver circuits
1131
and
1141
are mounted at the output and input ports
1130
and
1140
, respectively. The optical device
1132
is optically coupled to the waveguide sheet
1101
through a 45-degree mirror (optical-path converting unit)
1133
s.
In the structure of
FIG. 1
, the positioning or alignment between the optical device
1132
and the optical bus (waveguide sheet)
1101
, more specifically, between the optical device
1132
and the mirror
1133
s
, is critically important when light from the optical device
1132
is to be coupled to the optical bus
1101
.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical waveguide apparatus that facilitates the alignment between an optical device and an optical path converting unit, an optical device, and an opto-electric mixture wiring substrate.
According to one aspect of the present invention, there is provided an optical waveguide apparatus that includes an optical waveguide sheet, and an optical device integrated with an optical-path converting unit. The optical sheet can include a guide unit for setting the optical device therein.
According to another aspect of the present invention, there is provided an optical waveguide apparatus that includes an optical waveguide sheet, an optical device, and a guide unit for setting the optical device therein, which is formed on the optical sheet or a layer on the optical sheet. An optical-path converting unit can be provided at a place in the optical sheet immediately below the guide unit.
According to another aspect of the present invention, there is provided an optical device that is a surface optical device integrated with an optical-path converting unit, which is to be mounted on an optical waveguide sheet. The surface optical device is a surface optical device in a broad sense which includes an end emitting semiconductor laser connected to a 45-degree mirror that can emit light perpendicularly to a substrate, as well as a vertical cavity surface emitting laser (VCSEL) and a surface photodiode. The optical-path converting unit changes a propagation direction of light emitted from the optical device from a direction perpendicular to the optical sheet to a direction parallel to the optical sheet, or changes a propagation direction of light directed to the optical device from a direction parallel to the optical sheet to a direction perpendicular to the optical sheet.
The above optical device is integrated with the optical-path converting unit, such as a conical mirror, a semispherical mirror, and a prism. The prism has a reflective and refractive surface, while the mirror has a reflective surface. With such an optical device, no special means needs to be formed in the optical waveguide sheet on which the optical device is to be mounted. The optical device with the optical-path converting unit can be set at a desired location of the optical sheet at which a guide hole or the like is formed, so that the optical device can be positioned at a location corresponding to an appropriate electrode pad formed on the electric circuit board.
Therefore, the above optical device is more advantageous than the case where a mirror or the like is formed in the optical waveguide sheet in the following point. There is no need to align the optical device with the mirror when the optical device is mounted on the optical sheet, and no special processing of the optical sheet is needed. Thus, an optical waveguide apparatus for the optical wiring can be achieved with excellent productivity.
When a two-dimensional slab waveguide is used as the optical sheet, the conical mirror enables signal transmission and receiving to be performed in all directions parallel to the slab waveguide. When the 45-degree mirror is also used, signal transmission and receiving along a desired direction can be executed together with the signal transmission and receiving in all directions. Where one two dimensional slab waveguide is used, signal multiplexing will be basically performed using the time division sharing, i.e., parallel-serial conversion. However, when a line waveguide (a linear waveguide) is formed in the two-dimensional slab waveguide, parallel transmission with independent channels can be employed for necessary lines as well.
More specifically, the following specific constructions are possible. The optical device can be mounted on a mounting substrate, and the optical-path converting unit can be formed of a polymer. Alternatively, the optical device can be in a bare-chip form, and the optical-path converting unit can be formed of a polymer.
The optical-path converting unit can be a device that coverts the optical path by its reflecting action. In this case, the optical-path converting unit can include a conical reflective surface an apex of which is directed toward the center of a functional portion of the optical device, such as a surface emitting device, such that light from the optical device can be reflected in all directions around the apex and distributed over 360 degrees about the apex. The optical-path converting unit also can include a conical reflective surface an apex of which is directed toward the center of a functional portion of the optical device, such as a surface light-receiving device, such that light travelling from all directions around the apex can be reflected toward th
Lin Tina
Ullah Akm Enayet
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