Optical waveguide device, manufacturing method thereof, optical information processing apparatus, and electronic equipment

Disclosed herein is an optical waveguide device including a cladding having first and second surfaces opposite to each other, a core laminated to the first surface of the cladding for guiding light in a longitudinal direction thereof, the core having a pair of light incident and emergent portions at the opposite ends, and a pair of light collimating or focusing members bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese Patent Application JP 2004-352678 filed in the Japanese Patent Office on Dec. 6, 2004, the entire contents of which being incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an optical waveguide device suitable for a light source module, optical interconnection, optical communication, etc., and also to a manufacturing method for the optical waveguide device, an optical information processing device using the optical waveguide device, and electronic equipment using the optical information processing apparatus.

At present, signal transmission between semiconductor chips such as LSIs (large-scale integrated circuits) is generally made by electrical signals through board wiring. However, a data exchange amount required between the chips has remarkably increased with a recent higher functionality of MPU, resulting in the occurrence of various high-frequency problems. Such high-frequency problems typically include RC signal delay, impedance mismatch, EMC/EMI, and crosstalk.

To solve these problems, a packaging industry has mainly attempted to use various techniques such as optimization of wiring and placement and development of new materials.

However, the effects by the optimization of wiring and placement and the development of new materials have been blocked by physical limitations in recent years. Accordingly, for realization of higher functionality of a system in the future, it has now become necessary to reconsider the structure of a printed wiring board designed to simply package semiconductor chips. In recent years, various drastic measures against these problems have been proposed. Typical ones of the drastic measures are as follows:

(1) Finer Interconnection by Formation of a Multichip Module (MCM)

A high-performance chip is mounted on a precise mounting board such as a ceramic/silicon board, thereby realizing finer interconnection that cannot be formed on a motherboard (multilayer printed board). Accordingly, a wiring pitch can be reduced and a data exchange amount can therefore be greatly increased by increasing a bus width.

(2) Electrical Interconnection by Sealing and Integration of Various Semiconductor Chips

Various semiconductor chips are two-dimensionally sealed and integrated by using polyimide resin, and finer interconnection is made on such an integrated board. Accordingly, a wiring pitch can be reduced and a data exchange amount can therefore be greatly increased by increasing a bus width.

Through electrodes are formed in various semiconductor chips, and these semiconductor chips are attached together to form a multilayer structure. Accordingly, the interconnection between different kinds of semiconductor chips can be physically short-circuited, so that the problems including signal delay can be avoided. However, there arise other problems such as increased heating value due to the multilayering and thermal stress between the semiconductor chips.

Further, an optical transmission and coupling technique by optical wiring has been developed to realize high-speed and large-capacity signal exchange (e.g., “An Encounter with Optical Wiring”, Nikkei Electronics, pp. 122-125, FIGS. 4-7, (Dec. 3, 2001), and NTT R&D, vol. 48, no. 3, pp. 271-280 (1999)). Optical wiring is applicable to various places such as between electronic units, between boards in an electronic unit, and between chips on a board.FIG. 20shows optical wiring for signal transmission between chips spaced a short distance. As shown inFIG. 20, an optical waveguide51is formed on a printed wiring board57on which the chips are mounted. This optical waveguide51is used as a transmission line for laser light or the like modulated by a signal, thereby allowing the construction of an optical transmission and communication system.

FIG. 21shows the structure of the optical waveguide51. As shown inFIG. 21, the optical waveguide51is composed of two claddings54and55and a core56sandwiched between these claddings54and55. The core56has a pair of light incident and emergent portions59aand59bat the opposite ends. Each of the light incident and emergent portions59aand59bis formed as a 45° mirror surface. Further, the cladding54is integrally formed with a pair of lens portions52at positions respectively corresponding to the light incident and emergent portions59aand59bof the core56.

A manufacturing method for the optical waveguide51will now be described with reference toFIGS. 22A to 22F.

As shown inFIG. 22A, a cladding54is filled into the cavity defined between an upper mold53aand a lower mold53bhaving in combination a shape corresponding to the cladding54with the lens portions52, thus fabricating the cladding54by injection molding as shown inFIG. 22B. Accordingly, the lens portions52and the cladding54are integrally molded.

As shown inFIG. 22C, a core material56ais filled into a mold58. As shown inFIG. 22D, the cladding54with the lens portions52is attached to the upper surface of the mold58with the core material56ainterposed between the cladding54and the mold58, and UV light is next applied to cure the core material56a. As shown inFIG. 22E, the mold58is removed to obtain a laminated structure composed of the cladding54and the core56.

Finally, as shown inFIG. 22F, another cladding55previously fabricated by injection molding or the like is bonded to the cladding55of the above laminated structure, thus obtaining the optical waveguide51.

In the conventional optical waveguide and the manufacturing method therefor as shown inFIGS. 21 and 22Ato22F, the lens portions52and the cladding54are integrally molded by using the upper and lower molds53aand53b. Accordingly, the positions of the lens portions52are decided in this molding step, and the alignment between the light incident and emergent portions59aand59bof the core56and the lens portions52becomes difficult. As a result, there is a possibility of reduction in alignment accuracy and yield.

SUMMARY OF THE INVENTION

It is accordingly an embodiment of the present invention to provide an optical waveguide device which can improve the yield and can easily and precisely perform the alignment of lens portions for obtaining effective incidence and emergence of light.

It is another embodiment of the present invention to provide a manufacturing method for the optical waveguide device.

It is still another embodiment of the present invention to provide an optical information processing apparatus including the optical waveguide device.

It is a further embodiment of the present invention to provide electronic equipment including the optical information processing apparatus.

In accordance with a first embodiment of the present invention, there is provided an optical waveguide device including a cladding having first and second surfaces opposite to each other; a core laminated to the first surface of the cladding for guiding light in a longitudinal direction thereof, the core having a pair of light incident and emergent portions at the opposite ends; and a pair of lens portions bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core.

In accordance with a second embodiment of the present invention, there is provided an optical information processing apparatus including an optical waveguide device; a light emitting device for launching light into the optical waveguide device; and a light receiving device for receiving emergent light from the optical waveguide device; the optical waveguide device including a cladding having first and second surfaces opposite to each other; a core laminated to the first surface of the cladding for guiding light in a longitudinal direction thereof, the core having a pair of light incident and emergent portions at the opposite ends; and a pair of lens portions bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core; the light from the light emitting device entering the light incident portion of the core through one of the lens portions; the emergent light from the optical waveguide device emerging from the light emergent portion of the core and passing through the other lens portion to reach the light receiving device.

In accordance with a third embodiment of the present invention, there is provided a manufacturing method for an optical waveguide device including a cladding having first and second surfaces opposite to each other; a core laminated to the first surface of the cladding for guiding light in a longitudinal direction thereof, the core having a pair of light incident and emergent portions at the opposite ends; and a pair of lens portions bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core; the manufacturing method including the steps of forming the lens portions; bonding the lens portions to the cladding; and bonding the core and the cladding.

In accordance with a fourth embodiment of the present invention, there is provided electronic equipment including an optical information processing apparatus; a first circuit device provided on the input side of the optical information processing apparatus for supplying an input signal; and a second circuit device provided on the output side of the optical information processing apparatus for receiving an output signal; the optical information processing apparatus including an optical waveguide device; a light emitting device for launching light into the optical waveguide device; and a light receiving device for receiving emergent light from the optical waveguide device; the optical waveguide device including a cladding having first and second surfaces opposite to each other; a core laminated to the first surface of the cladding for guiding light in a longitudinal direction thereof, the core having a pair of light incident and emergent portions at the opposite ends; and a pair of lens portions bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core; the light from the light emitting device entering the light incident portion of the core through one of the lens portions; the emergent light from the optical waveguide device emerging from the light emergent portion of the core and passing through the other lens portion to reach the light receiving device.

The term of “core” used in the present invention means not only a single core, but also a plurality of core arrays.

According to the present invention, the pair of lens portions are bonded to the second surface of the cladding at the opposite ends corresponding to the light incident and emergent portions of the core. Accordingly, as compared with the case that the lens portions and the cladding are integrally molded as by the conventional manufacturing method for the optical waveguide as mentioned above, the alignment between the lens portions and the light incident and emergent portions of the core can be performed easily and precisely. Further, the yield can be improved.

The core serves to guide an incident optical signal, and the cladding serves to confine the optical signal in the core. The core is formed of a material having a high refractive index, and the cladding is formed of a material having a refractive index lower than that of the core.

Preferably, the cladding is formed from a flexible sheet, and each of the lens portions is bonded through a lens supporting portion to the second surface of the cladding.

The optical waveguide in the prior art as mentioned above is formed of resin in general, so that it has moisture absorbency and accordingly gradually expands. In the case of using such an optical waveguide, the gradual expansion of the optical waveguide results in gradual deviation of the optical axis.

Further, if the thickness of the optical waveguide is excessive, the deformation of the optical waveguide due to heat, external stress, etc. cannot be absorbed without the application of stress to the core. Accordingly, it is necessary to maintain a thickness of 0.5 mm or less at a central portion of the optical waveguide in the case where the optical waveguide has a length of about 50 mm to 30 mm (in a direction of propagation of light), thereby ensuring the flexibility of a module using the optical waveguide. In the conventional optical waveguide shown inFIG. 21, such a small thickness can be realized by using a state-of-the-art injection molding technique. However, a cost increase is invited.

According to the present invention, the cladding is formed from a flexible sheet, and each of the lens portions is bonded through the lens supporting portion to the second surface of the cladding. Accordingly, the optical waveguide device has high rigidity at the opposite ends of the cladding, so that a bonding strength between the optical waveguide device and a mounting board can be improved. As a result, stable incidence and emergence of light without optical axis deviation can be ensured.

Further, since the cladding is formed from a flexible sheet, the optical waveguide device can be made thin and flexible at a central portion thereof. Accordingly, the deformation of the optical waveguide device due to heat, external stress, etc. can be effectively absorbed without the application of stress to the core.

Further, each lens portion can be fabricated by a general injection molding technique, and an inexpensive sheet material can be used for the flexible sheet as the material of the cladding to thereby reduce the amount of use of an expensive optical resin, thus reducing the cost.

Preferably, the optical waveguide device according to the present invention further includes an additional cladding provided on the core opposite to the cladding, and the additional cladding is formed from a flexible sheet.

In the manufacturing method for the optical waveguide device according to the present invention, it is preferable that the lens portions are bonded to the second surface of the cladding, and the core is next bonded to the first surface of the cladding in the condition where the light incident and emergent portions of the core are respectively aligned to the lens portions. In the conventional manufacturing method for the optical waveguide as mentioned above, the cladding and the lens portions are integrally molded. Accordingly, in the case of changing the placement of each lens portion, the shapes of the upper and lower molds must be changed with difficulty. To the contrary, according to the manufacturing method of the present invention, the lens portions previously fabricated are bonded to the second surface of the cladding. Accordingly, the flexibility of placement of each lens portion can be increased and the alignment between each lens portion and the cladding can be easily performed.

In the manufacturing method for the optical waveguide device according to the present invention, it is also preferable that the core is bonded to the first surface of the cladding, and the lens portions are next bonded to the second surface of the cladding at positions respectively corresponding to the light incident and emergent portions of the core. According to this manufacturing method, the cladding is bonded to the core before bonding the lens portions to the cladding. Accordingly, the core can be formed more easily. Further, the lens portions are bonded to the cladding in the condition where the cladding and the core have been bonded together. Accordingly, the alignment between the lens portions and the light incident and emergent portions of the core can be performed more easily and precisely.

The optical waveguide device according to the present invention is suitably applicable to an optical information processing apparatus such as optical wiring including a light emitting device (e.g., laser) for launching light into the core and a light receiving device (e.g., optical wiring or photodetector) for receiving emergent light from the core.

Preferably, the optical information processing apparatus further includes a first converter connected through a driver amplifier to the light emitting device for converting a parallel input signal into a serial input signal; and a second converter connected through a transimpedance amplifier and an I/V conversion amplifier to the light receiving device for converting a serial output signal into a parallel output signal.

The optical information processing apparatus according to the present invention is suitably applicable to electronic equipment including a first circuit device provided on the input side of the optical information processing apparatus for supplying an input signal and a second circuit device provided on the output side of the optical information processing apparatus for receiving an output signal.

Other objects and features of the invention will be more fully understood from the following detailed description and appended claims when taken with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

FIG. 1Ais a schematic sectional view of an optical waveguide device1according to the present invention, andFIG. 1Bis an exploded view ofFIG. 1A.

As shown inFIGS. 1A and 1B, the optical waveguide device1has a laminated structure composed of a first cladding2, a second cladding5independent of the first cladding2, and a core4sandwiched between the first and second claddings2and5, wherein light is guided in the core4. The core4serves to guide an incident optical signal, and the claddings2and5serve to confine the optical signal in the core4. The core4is formed of a material having a high refractive index, and the claddings2and5are formed of a material having a refractive index lower than that of the core4.

The cladding2is formed from a flexible sheet, and a pair of light collimating or a focusing section3are bonded to the upper surface of the cladding2at its opposite ends corresponding to light incident and emergent portions7and8of the core4. Each light collimating or a focusing section3is an integral member independent of the cladding2and composed of a lens portion11and a lens supporting portion12for supporting the lens portion11. The lens supporting portion12of each light collimating or a focusing section3is bonded to the cladding2.

Thus, each light collimating or a focusing section3is an integral member composed of the lens portion11and the lens supporting portion12, and each lens supporting portion12is bonded to the cladding2. Accordingly, the optical waveguide device1has high rigidity at the opposite ends of the cladding2, so that a bonding strength between the optical waveguide device1and a mounting board (not shown) can be improved. As a result, stable incidence and emergence of light without optical axis deviation can be ensured.

Further, since the cladding2is formed from a flexible sheet, the optical waveguide device1can be made thin and flexible at a central portion thereof. Accordingly, the deformation of the optical waveguide device1due to heat, external stress, etc. can be effectively absorbed without the application of stress to the core4.

Further, each light collimating or a focusing section3as an integral member composed of the lens portion11and the lens supporting portion12can be fabricated by a general injection molding technique, and an inexpensive sheet material can be used for the flexible sheet as the material of the cladding2to thereby reduce the amount of use of an expensive optical resin, thus reducing the cost.

Each of the light incident and emergent portions7and8of the core4is formed as an inclined mirror surface, e.g., 45° mirror surface. The core4with such inclined mirror surfaces7and8can be formed by injection molding. Thus, the inclined mirror surfaces7and8can be formed by injection molding without direct processing to the core4. Accordingly, the surface condition of the inclined mirror surfaces7and8can be made smooth without damage in fabrication, so that the optical waveguide device1can be fabricated with good quality easily and precisely. Since the light incident and emergent portions7and8of the core4are formed as the inclined mirror surfaces, an optical signal output from a light emitting device can be made to efficiently enter the core4. The incident optical signal can be guided in the core4and can be made to efficiently emerge toward a light receiving device. The material of the core4may be selected from any materials known in the art, such as UV (ultra-violet) curable resin (e.g., fluorinated polyimide).

It is more preferable that a flexible sheet is also used as the second cladding5provided on the lower surface of the core4opposite to the upper surface thereof where each light collimating or a focusing section3as an integral member composed of the lens portion11and the lens supporting portion12is bonded.

According to the optical waveguide device1, the pair of light collimating or a focusing section3independent of the cladding2are bonded to the upper surface of the cladding2at its opposite ends corresponding to the light incident and emergent portions7and8of the core4, and each light collimating or a focusing section3is formed as an integral member composed of the lens portion11and the lens supporting portion12. Accordingly, as compared with the conventional manufacturing method for the optical waveguide mentioned above wherein each lens portion and the cladding are integrally molded, the alignment between the lens portions11and the light incident and emergent portions7and8of the core4can be performed easily and precisely, and the yield can be improved.

The optical waveguide device1can be suitably applied to an optical information processing apparatus such as optical wiring including a light emitting device (e.g., laser) for launching light into the core4of the optical waveguide device1and a light receiving device (e.g., optical wiring or photodetector) for receiving emergent light from the core4.

In this case, a converter for converting a parallel input signal into a serial input signal is preferably connected through a driver amplifier to the light emitting device, and a converter for converting a serial output signal into a parallel output signal is preferably connected through a transimpedance amplifier and an I/V conversion amplifier to the light receiving device.

The optical information processing apparatus such as optical wiring according to the present invention can be suitably applied to electronic equipment including a circuit device for supplying an input signal to the input side of the optical information processing apparatus and a circuit device for receiving an output signal from the output side of the optical information processing apparatus.

A manufacturing method for the optical waveguide device1will now be described with reference toFIGS. 2A to 2F.

As shown inFIG. 2A, a pair of upper and lower molds6aand6bhaving a shape in combination corresponding to the shape of each light collimating or a focusing section3are used, and a material3aof each light collimating or a focusing section3is filled into the cavity defined by the upper and lower molds6aand6b. Thereafter, the material3ais cured to fabricate each light collimating or a focusing section3. Thus, each light collimating or a focusing section3can be easily fabricated as an integral member composed of the lens portion11and the lens supporting portion12by a general injection molding technique.

As shown inFIG. 2B, the pair of light collimating or a focusing section3fabricated above are bonded to the upper surface of the first cladding2formed from a flexible sheet at its opposite ends. At this time, the lens supporting portion12of each light collimating or a focusing section3is bonded to the cladding2.

As shown inFIG. 2C, a core material4ais filled into a mold13. As shown inFIG. 2D, the cladding2having the pair of light collimating or a focusing section3fabricated above is attached to the upper surface of the mold13with the core material4ainterposed between the cladding2and the mold13, and UV light is next applied to thereby cure the core material4a. As shown inFIG. 2E, the mold13is removed to obtain a laminated structure composed of the cladding2and the core4.

In the step shown inFIG. 2D, the light incident and emergent portions7and8of the core4are formed as inclined mirror surfaces, e.g., 45° mirror surfaces by injection molding. Thus, the inclined mirror surfaces7and8can be formed without direct processing to the core4. Accordingly, the surface condition of the inclined mirror surfaces7and8can be made smooth without damage in fabrication, so that the optical waveguide device1can be fabricated with good quality easily and precisely.

As shown inFIG. 2F, the second cladding5(e.g., flexible sheet)5is bonded to the laminated structure composed of the first cladding2and the core4, more specifically, to the lower surface of the core4opposite to the upper surface thereof where each light collimating or a focusing section3is bonded.

Thus, the optical waveguide device1can be fabricated by the manufacturing method mentioned above. According to the manufacturing method for the optical waveguide device1as mentioned above, each light collimating or a focusing section3previously fabricated is bonded to the upper surface of the cladding2. Accordingly, the flexibility of placement of each light collimating or a focusing section3can be increased and the alignment between each lens portion11and the cladding2can be easily performed. In contrast, according to the conventional manufacturing method for the optical waveguide mentioned above, the cladding and each lens portion are integrally molded. Accordingly, in the case of changing the placement of each lens portion, the shapes of the upper and lower molds must be changed with difficulty.

Second Preferred Embodiment

FIGS. 3A to 3Eare schematic sectional views showing another manufacturing method for the optical waveguide device1.

As shown inFIG. 3A, a core material4ais filled into a mold13. As shown inFIG. 3B, the first cladding2formed from a flexible sheet is attached to the upper surface of the mold13with the core material4ainterposed between the cladding2and the mold13, and UV light is next applied to thereby cure the core material4a. As shown inFIG. 3C, the mold13is removed to obtain a laminated structure composed of the cladding2and the core4.

As shown inFIG. 3D, the pair of light collimating or a focusing section3(each formed as an integral member composed of the lens portion11and the lens supporting portion12) previously fabricated by injection molding as similar to the step ofFIG. 2Aare bonded to the upper surface of the cladding2opposite to the lower surface thereof where the core4is bonded, at the opposite ends corresponding to the light incident and emergent portions7and8of the core4.

As shown inFIG. 3E, the second cladding (e.g., flexible sheet)5is bonded to the laminated structure composed of the cladding2and the core4, more specifically, to the lower surface of the core4.

According to this manufacturing method, the cladding2is bonded to the core4before bonding each light collimating or a focusing section3to the cladding2. Accordingly, the core4can be formed more easily. Further, each light collimating or a focusing section3is bonded to the cladding2in the condition where the cladding2and the core4have been bonded together. Accordingly, the alignment between the lens portions11and the light incident and emergent portions7and8of the core4can be performed more easily and precisely.

Third Preferred Embodiment

FIGS. 4A to 4Cshow an optical information processing apparatus14according to the present invention which includes an optical waveguide device1according to the present invention, a plurality of light emitting devices (e.g., lasers)9for respectively launching light into a plurality of cores4of the optical waveguide device1, and a plurality of light receiving devices (e.g., photodetectors)10for respectively receiving emergent light from the plural cores4. More specifically,FIG. 4Ais a schematic sectional view of the optical information processing apparatus14,FIG. 4Bis a bottom plan view of the optical waveguide device1shown inFIG. 4Awith the second cladding5removed, andFIG. 4Cis a top plan view of the optical waveguide device1shown inFIG. 4A.

As shown inFIG. 4B, the plural cores4are arranged in parallel with a given pitch on the cladding2, and each core4has a pair of light incident and emergent portions7and8each formed as a 45° mirror surface. The light incident portions7of the plural cores4are aligned in position in the direction of arrangement of the plural cores4(i.e., in the transverse direction of the cladding2). Similarly, the light emergent portions8of the plural cores4are aligned in position in the direction of arrangement of the plural cores4.

The plural light emitting devices9are arranged at positions respectively corresponding to the light incident portions7of the plural cores4. Although not shown, the gap in each light emitting device9is provided with a through electrode for electrically connecting the light emitting device9and a semiconductor integrated circuit chip. Similarly, the plural light receiving devices10are arranged at positions respectively corresponding to the light emergent portions8of the plural cores4, and the gap in each light receiving device10is provided with a through electrode for electrically connecting the light receiving device10and another semiconductor integrated circuit chip.

Accordingly, in the optical information processing apparatus14shown inFIGS. 4A to 4C, the plural light emitting devices9are arranged with the same pitch as the arrangement pitch of the plural cores4, and the plural light receiving devices10are also arranged with the same pitch as the arrangement pitch of the plural cores4.

As shown inFIG. 4C, a pair of light collimating or a focusing section3are bonded to the upper surface of the cladding2at its opposite ends corresponding to the positions of the array of the light incident portions7and the array of the light emergent portions8of the plural cores4. That is, each light collimating or a focusing section3is formed as an integral member composed of a plurality of lens portions11and a lens supporting portion12for supporting the plural lens portions11, wherein the plural lens portions11are respectively aligned to the plural light incident and emergent portions7and8.

The operation mechanism of the optical information processing apparatus14will now be described. An electrical signal transmitted from one semiconductor integrated circuit chip (not shown) is converted into an optical signal in each light emitting device9, and the optical signal is output from each light emitting device9. The optical signal thus output is focused by the corresponding lens portion11of the light collimating or a focusing section3on the incident side to enter the light incident portion7of the corresponding core4. The incident light is reflected on the light incident portion7formed as a 45° mirror surface, and is then guided in the core4in its longitudinal direction to reach the light emergent portion8. The light thus guided is reflected again on the light emergent portion8formed as a 45° mirror surface to emerge from the core4. The emergent light is focused by the light collimating or a focusing section3on the emergent side, and is then received by the corresponding light receiving device10, in which the optical signal is converted into an electrical signal. The electrical signal is transmitted from the light receiving device10to another semiconductor integrated circuit chip (not shown). This operation mechanism is similarly performed in other preferred embodiments to be described later.

Fourth Preferred Embodiment

FIG. 5Ais a schematic plan view of an optical information processing apparatus14including an optical waveguide device1according to the present invention, a light emitting device array9a, and a light receiving device array10a.FIG. 5Bis a side view taken in the direction of arrow A inFIG. 5A, andFIG. 5Cis a schematic plan view of a cladding2on which a pair of light collimating or a focusing section3are bonded. Each light collimating or a focusing section3is formed as an integral member composed of a plurality of lens portions11and a lens supporting portion12for supporting the plural lens portions11. InFIGS. 5A to 5C, the cladding5as shown inFIGS. 1A and 1Bis not shown.

As shown inFIG. 5A, a plurality of cores4are arranged in parallel at a given pitch. Each core4has a pair of light incident and emergent portions7and8at the opposite ends. Each of the light incident and emergent portions7and8is formed as a 45° mirror surface. In any two adjacent ones of the plural cores4, the light incident and emergent portions7and8of one of the two adjacent cores4are shifted from the light incident and emergent portions7and8of the other core4in the longitudinal direction of the cores4.

The light emitting device array9aincludes a plurality of light emitting devices9arranged at positions respectively corresponding to the light incident portions7of the plural cores4. Although not shown, the gap in each light emitting device9is provided with a through electrode for electrically connecting the light emitting device9and a semiconductor integrated circuit chip. Similarly, the light receiving device array10aincludes a plurality of light receiving devices10arranged at positions respectively corresponding to the light emergent portions8of the plural cores4, and the gap in each light receiving device10is provided with a through electrode for electrically connecting the light receiving device10and another semiconductor integrated circuit chip.

As shown inFIG. 5C, the plural lens portions11of the light collimating or a focusing section3on the incident side are arranged at positions respectively corresponding to the light incident portions7of the plural cores4. Similarly, the plural lens portions11of the light collimating or a focusing section3on the emergent side are arranged at positions respectively corresponding to the light emergent portions8of the plural cores4. Each lens portion11is integral with the lens supporting portion12of each means3, and the lens supporting portion12of each means3is bonded to the cladding2.

In this preferred embodiment, the plural cores4are divided into a plurality of groups, and each group is composed of a given number of cores4shifted with a given pitch in the longitudinal direction of the cores4. Accordingly, in each group, the light incident portions7of the cores4are shifted with this given pitch in the longitudinal direction of the cores4, and the light emergent portions8of the cores4are shifted with the same pitch in the longitudinal direction of the cores4. Accordingly, the light emitting devices9respectively corresponding to these light incident portions7of the cores4in each group are shifted with the same pitch in the longitudinal direction of the cores4, and the light receiving devices10respectively corresponding to these light emergent portions8of the cores4in each group are shifted with the same pitch in the longitudinal direction of the cores4. For example, in the case that the pitch of the light incident portions7of the cores4in each group in the longitudinal direction of the cores4is 100 μm, the pitch of the corresponding light emitting devices9in the longitudinal direction of the cores4is 100 μm. Similarly, in the case that the pitch of the light emergent portions8of the cores4in each group in the longitudinal direction of the cores4is 100 μm, the pitch of the corresponding light receiving devices10in the longitudinal direction of the cores4is 100 μm.

On the other hand, the pitch of the light emitting devices9aligned in the transverse direction of the cladding2is equal to the sum of the distances between the cores4in each group. Similarly, the pitch of the light receiving devices10aligned in the transverse direction of the cladding2is equal to the sum of the distances between the cores4in each group. For example, in the case that the pitch of the cores4in the transverse direction of the cladding2is 20 μm, the pitch of the light emitting devices9aligned in the transverse direction of the cladding2is 100 μm. Similarly, in the case that the pitch of the cores4in the transverse direction of the cladding2is 20 μm, the pitch of the light receiving devices10aligned in the transverse direction of the cladding2is 100 μm.

With this longitudinally shifted arrangement of the cores4in each group, the light emitting and receiving devices9and10(which will be hereinafter referred to also as optical devices9and10) respectively corresponding to the light incident and emergent portions7and8of the cores4can be arranged two-dimensionally. For example, in the case that the optical devices9and10are arranged with a pitch of 100 μm in the transverse direction of the cladding2, the cores4can be arranged with a finer pitch of 20 μm.

In other words, the optical devices9and10are arranged with a relatively large pitch such that the influence of crosstalk due to interference of light or heat generation from the optical devices can be avoided, and the degree of integration of the cores4can be increased.

Since the cores4are arranged with a high degree of integration and the optical devices9and10are arranged two-dimensionally, any wasted space can be eliminated and the footprint of each optical device can be reduced. Accordingly, a further cost reduction can be expected.

Fifth Preferred Embodiment

FIG. 6Ais a schematic plan view of an optical information processing apparatus14including an optical waveguide device1according to the present invention, two light emitting device arrays9a-1and9a-2, and two light receiving device arrays10a-1and10a-2.FIG. 6Bis a side view taken in the direction of arrow A inFIG. 6A, andFIG. 6Cis a schematic plan view of a cladding2on which a pair of light collimating or a focusing section3are bonded. Each light collimating or a focusing section3is formed as an integral member composed of a plurality of lens portions11and a lens supporting portion12for supporting the plural lens portions11. InFIGS. 6A to 6C, the cladding5as shown inFIGS. 1A and 1Bis not shown.

As shown inFIG. 6A, a plurality of first and second cores4-1and4-2are alternately arranged in parallel at a given pitch in such a manner that the plural first cores4-1are shifted by a given amount from the plural second cores4-2in the longitudinal direction of the cores4-1and4-2. Accordingly, the light incident portion7of each first core4-1is shifted by the given amount from the light incident portion7of each second core4-2in the longitudinal direction of the cores4-1and4-2, and the light emergent portion8of each first core4-1is shifted by the given amount from the light emergent portion8of each second core4-2in the longitudinal direction of the cores4-1and4-2.

The light emitting device array9a-1includes a plurality of light emitting devices9arranged at positions respectively corresponding to the light incident portions7of the first cores4-1, and the light receiving device array10a-2includes a plurality of light receiving devices10arranged at positions respectively corresponding to the light emergent portions8of the second cores4-2. These arrays9a-1and10a-2are located near one longitudinal end of the cladding2.

Similarly, the light receiving device array10a-lincludes a plurality of light receiving devices10arranged at positions respectively corresponding to the light emergent portions8of the first cores4-1, and the light emitting device array9a-2includes a plurality of light emitting devices9arranged at positions respectively corresponding to the light incident portions7of the second cores4-2. These arrays10a-land9a-2are located near the other longitudinal end of the cladding2.

Thus, the light emitting devices9corresponding to the first cores4-1and the light receiving devices10corresponding to the second cores4-2are alternately arranged in zigzag. Similarly, the light receiving devices10corresponding to the first cores4-1and the light emitting devices9corresponding to the second cores4-2are alternately arranged in zigzag. Accordingly, light is guided in the first cores4-1in a first direction, and light is guided in the second cores4-2in a second direction opposite to the first direction.

As shown inFIG. 6C, the plural lens portions11of the light collimating or a focusing section3located near one longitudinal end of the cladding2are arranged in zigzag so as to correspond to the light emitting devices9of the array9a-1and the light receiving devices10of the array10a-2. Similarly, the plural lens portions11of the light collimating or a focusing section3located near the other longitudinal end of the cladding2are arranged in zigzag so as to correspond to the light emitting devices9of the array9a-2and the light receiving devices10of the array10a-1. Each lens portion11is integral with the lens supporting portion12of each means3, and the lens supporting portion12of each means3is bonded to the cladding2. Accordingly, incident light from each light emitting device9can be effectively launched into the corresponding core4-1or4-2, thereby ensuring efficient optical coupling. Similarly, emergent light from each core4-1or4-2can be effectively received by the corresponding light receiving device10.

As mentioned above, the light emitting devices9and the light receiving devices10are alternately arranged so as to correspond to the cores4-1and4-2alternately arranged in parallel. Accordingly, as shown by an enclosed portion C inFIG. 6A, the light emitting device9and the light receiving device10respectively corresponding to input/output pads connected to a specific circuit in a semiconductor integrated circuit chip can be located at positions close to each other, so that the length of electrical wiring can be shortened to thereby facilitate the protection from high-frequency problems.

Sixth Preferred Embodiment

FIG. 7Ais a schematic plan view of an optical information processing apparatus14including an optical waveguide device1according to the present invention, two light emitting device arrays9a-1and9a-2, and two light receiving device arrays10a-1and10a-2.FIG. 7Bis a side view taken in the direction of arrow A inFIG. 7A, andFIG. 7Cis a schematic plan view of a cladding2on which a pair of light collimating or a focusing section3are bonded. Each light collimating or a focusing section3is formed as an integral member composed of a plurality of lens portions11and a lens supporting portion12for supporting the plural lens portions11.FIG. 7Dis a plan view showing the arrangement of light receiving devices10in the light receiving device array10a-1and the arrangement of light emitting devices9in the light emitting device array9a-2. InFIGS. 7A to 7D, the cladding5as shown inFIGS. 1A and 1Bis not shown.

The configuration of this preferred embodiment is obtained by combining the configuration of the fourth preferred embodiment and the configuration of the fifth preferred embodiment. That is, as in the fifth preferred embodiment, the light emitting devices9and the light receiving devices10are alternately arranged so as to correspond to the cores4arranged in parallel. Accordingly, the direction of propagation of light in one of the adjacent cores4is opposite to that in the other core4.

Further, as in the fourth preferred embodiment, in each of the optical device arrays9a-1,9a-2,10a-1, and10a-2, the adjacent optical devices9are shifted from each other in the longitudinal direction of the cores4, and the adjacent optical devices10are similarly shifted from each other in the longitudinal direction of the cores4as shown inFIG. 7D.

As shown inFIG. 7C, the plural lens portions11of each light collimating or a focusing section3are arranged so as to correspond to the optical devices9and10in the arrays9a-1and10a-2(similarly in the arrays9a-2and10a-1). Each lens portion11is integral with the lens supporting portion12of each means3, and the lens supporting portion12of each means3is bonded to the cladding2. Accordingly, incident light from each light emitting device9can be effectively launched into the corresponding core4, thereby ensuring efficient optical coupling. Similarly, emergent light from each core4can be effectively received by the corresponding light receiving device10.

Further, as compared with the case where the optical devices in each optical device array are linearly arranged (aligned in the transverse direction of the cladding), the pitch of the optical devices in this preferred embodiment can be increased. Accordingly, the effect of the fifth preferred embodiment can be exhibited also in this preferred embodiment. Simultaneously, the optical devices9and10can be arranged with a relatively large pitch such that the influence of crosstalk due to interference of light or heat generation from the optical devices can be avoided, and the degree of integration of the cores4can be increased.

Seventh Preferred Embodiment

The optical waveguide device according to the present invention may be directly mounted on a printed wiring board. As another case, the optical waveguide device according to the present invention may be set in a socket to configure an opto-electric composite device, which may be mounted on a printed wiring board.

FIG. 8Ais a schematic perspective view of such a socket17as viewed from its upper side where the optical waveguide device is set, andFIG. 8Bis a schematic perspective view of the socket17as viewed from its lower side.

As shown inFIGS. 8A and 8B, the socket17is provided with positioning means having a recess/projection structure for positioning and fixing the optical waveguide device. More specifically, the recess/projection structure has a plurality of recesses18each for engaging the optical waveguide device to position it in its transverse direction and a plurality of projections19each for positioning the optical waveguide device in its longitudinal direction. The depth of each recess18is larger than the thickness of the optical waveguide device.

The recess/projection structure of the socket17further has a plurality of flat raised surfaces20. Each flat raised surface20is provided with conducting means for conducting the upper and lower surfaces of the socket17, such as terminal pins21. As will be hereinafter described, an interposer on which the light emitting devices and/or the light receiving devices are mounted is fixed to the flat raised surfaces20of the socket17.

The socket17is formed of any dielectric resin known in the art, such as glass-containing PES (polyethylene sulfide) resin and glass-containing PET (polyethylene terephthalate) resin. As to such a material of the socket17, there are numerous data on its kind, dielectric property, and reliability, and there are various manufactures handling the material. Accordingly, the socket17is a structure easy to accept in respect of function, cost, reliability, etc., and it is easy to merge this structure and an existing printed wiring board mounting process.

A manufacturing method for the socket17is not especially limited. For example, the socket17can be easily fabricated by molding with the use of a mold having the recess/projection structure mentioned above.

FIG. 9Ais a schematic perspective view of an opto-electric composite device22configured by setting the optical waveguide device1in a pair of sockets17, andFIG. 9Bis an exploded view ofFIG. 9A.

As shown inFIGS. 9A and 9B, the opto-electric composite device22includes the pair of sockets17and the optical waveguide device1set in these sockets17so as to connect these sockets17. The optical waveguide device1has any one of the structures mentioned in the previous preferred embodiments. The optical waveguide device1set in the sockets17is kept in noncontact with a printed wiring board to be hereinafter described, so that it is possible to effectively prevent breaking of the optical waveguide device1due to heat radiation from a semiconductor integrated circuit chip.

A pair of interposers24are fixed to the flat raised surfaces20of the pair of sockets17, respectively. A pair of semiconductor integrated circuit chips23aand23bare mounted on the pair of interposers24, respectively. Although not shown inFIGS. 9A and 9B, the light emitting devices and/or the light receiving devices as mentioned above are mounted on each interposer24.

FIG. 10Ais a schematic perspective view of each interposer24as viewed from the upper side thereof, andFIG. 10Bis a schematic perspective view of each interposer24as viewed from the lower side thereof. As shown inFIG. 10A, a semiconductor integrated circuit chip23is mounted on the upper surface of the interposer24. As shown inFIG. 10B, a plurality of light emitting device arrays9aeach for launching light into the optical waveguide device1and a plurality of light receiving device arrays10aeach for receiving emergent light from the optical waveguide device1are mounted on the lower surface of the interposer24near the center thereof. Further, a plurality of electrodes25for other signal wiring (e.g., power supply wiring and DC signal) are provided on the lower surface of the interposer24near the periphery thereof. Although not shown inFIGS. 10A and 10B, each light emitting device array9aincludes a plurality of light emitting devices arranged at positions respectively corresponding to the light incident portions of the optical waveguide device1, and each light receiving device array10includes a plurality of light receiving devices arranged at positions respectively corresponding to the light emergent portions of the optical waveguide device1. Further, the gap in each light emitting device is provided with a through electrode for electrically connecting the light emitting device and the semiconductor integrated circuit chip, and the gap in each light receiving device is provided with a through electrode for electrically connecting the light receiving device and the semiconductor integrated circuit chip.

In fixing the pair of interposers24and the pair of sockets17with the optical waveguide device1fitted in the recesses18, the lower surface of each interposer24on which the light emitting device arrays9aand/or the light receiving device arrays10aare mounted is brought into contact with the flat raised surfaces20of the corresponding socket17, and the electrodes25of each interposer24are electrically connected to the terminal pins21of the corresponding socket17.

As mentioned above, the depth of each recess18of each socket17is larger than the thickness of the optical waveguide device1. Accordingly, as shown in FIG.9A, a spacing27is defined between the upper surface26of the optical waveguide device1and the lower surface of each interposer24on which the light emitting device arrays9aand/or the light receiving device arrays10aare mounted.

As mentioned above, the semiconductor integrated circuit chip23is mounted on each socket17through each interposer24, and the spacing27is defined between the upper surface26of the optical waveguide device1and the lower surface of each interposer24on which the light emitting device arrays9aand/or the light receiving device arrays10aare mounted. Accordingly, even when the semiconductor integrated circuit chip23generates heat in using the opto-electric composite device22, it is possible to effectively prevent breaking of the optical waveguide device1due to the heat from the semiconductor integrated circuit chip23.

In operation, an electrical signal transmitted from the semiconductor chip23ais converted into an optical signal by each light emitting device of the light emitting device array9a, and the optical signal as laser light is output from each light emitting device. The optical signal thus output is collimated by the corresponding lens portion11of the light collimating or a focusing section3located under the light emitting device array9a, and then enters the light incident portion of the corresponding core4. The incident light is guided in this core4in its longitudinal direction, and then emerges from the light emergent portion of this core4. The optical signal thus output from the optical waveguide device1is received by the corresponding light receiving device of the light receiving device array10amounted on the other interposer24having the other semiconductor chip23b. This optical signal is converted into an electrical signal by this light receiving device, and this electrical signal is then transmitted to the semiconductor chip23b.

This opto-electric composite device22may be configured into an optical wiring system in which the optical waveguide device1according to the present invention is used as optical wiring. In this case, the opto-electric composite device22is fixed to a printed wiring board in the condition where electrical connection therebetween is established.

According to the opto-electric composite device22, it can be electrically connected to a printed wiring board in the condition where the optical waveguide device1is fitted in the recesses18of the sockets17. Accordingly, the mounting structure of an existing printed wiring board can be utilized in such a manner that an area for mounting the sockets17on the printed wiring board must be ensured and other general electrical wiring can be formed by a conventional process.

In the case that the optical waveguide device1is not resistant to a high-temperature process, the sockets17may be first fixed to the printed wiring board, and all of the mounting processes including a high-temperature process such as solder reflow and underfill resin sealing may be next completed. Thereafter, the optical waveguide device1may be fitted into the recesses18of the sockets17previously fixed to the printed wiring board. Thus, the optical waveguide device1can be mounted without suffering damage due to high temperature.

Further, each socket17can be formed of a resin having rigidity higher than that of the printed wiring board, and optical coupling between the optical devices and the optical waveguide device1can be established on this socket17. Accordingly, a mounting accuracy required for the optical coupling can be easily ensured. For example, an assembly accuracy on the order of several micrometers can be ensured by an existing molding technique. Accordingly, a higher density in an optical bus can be expected.

Further, since the semiconductor integrated circuit chip23and the optical device arrays9aand/or10aare mounted on the opposite surfaces of the interposer24in close relationship, the wiring length between the semiconductor integrated circuit chip23and the optical devices can be reduced. Accordingly, measures against noise and crosstalk of electrical signals can be easily taken, and an optical modulation rate can also be improved.

Further, since the opto-electric composite device22can be electrically connected to the printed wiring board in the condition where the optical waveguide device1is fitted in the recesses18of the sockets17, high-density wiring on the printed wiring board and the flexibility of design thereof can be ensured and an optical wiring system can be extended on the printed wiring board at a low cost with high flexibility. Accordingly, it is possible to expect high-speed distributed processing on the printed wiring board, high functionality of electronic equipment as a whole, and reduced TAT (turn around time) of development, for example.

A manufacturing method for the opto-electric composite device22will now be described with reference toFIGS. 11A to 13C.FIGS. 11A to 11CandFIGS. 12A and 12Bare schematic sectional views taken along the line A-A′ inFIG. 9A.

As shown inFIGS. 11A and 11B, a pair of sockets17are mounted on a printed wiring board28. At this time, the terminal pins21of each socket17are aligned to electrodes (not shown) on the printed wiring board28and are electrically connected with each other.

Although not shown, other electronic components are preliminarily mounted on the printed wiring board28, and electrical wiring is also preliminarily formed on the printed wiring board28.

As shown inFIG. 11C, the optical waveguide device1is fitted at its opposite end portions into the opposed recesses18of the sockets17so as to connect the sockets17. At this time, the optical waveguide device1can be easily positioned in its longitudinal direction by the opposed projections19of the sockets17, and can be easily positioned in its transverse direction by the opposed recesses18of the sockets17. Further, since the optical waveguide device1is fitted in the recesses18of the sockets17, the optical waveguide device1is kept in noncontact with the printed wiring board28.

The optical waveguide device1may be fixed to the sockets17by any bonding means such as adhesive resin.FIGS. 13A to 13Cshow a process of fixing the optical waveguide device1to each socket17by using adhesive resin. As shown inFIG. 13A, a groove30having an arbitrary shape is formed on the bottom surface of each recess18of each socket17. Both ends of the groove30are positioned near the corresponding projection19. As shown inFIG. 13B, the optical waveguide device1is fitted into the recess18of each socket17. As mentioned above, the optical waveguide device1can be easily positioned in its longitudinal and transverse directions by the projection19and the recess18. In this condition, both ends of the groove30positioned near the projection19are not covered by the optical waveguide device1. As shown inFIG. 13C, adhesive resin is filled into the groove30from its exposed both ends by using a dispenser31or the like, and is then cured to thereby fix the optical waveguide device1in the recess18of each socket17.

After setting the optical waveguide device1in the sockets17as described above, the interposers24are fixed to the flat raised surfaces20of the sockets17, respectively. Preliminarily mounted on the interposers24are the semiconductor integrated circuit chips23aand23b, e.g., MPU (micro processor unit) and DRAM (dynamic random access memory) and the light emitting device arrays9aand/or the light receiving device arrays10a. In fixing each interposer24to the corresponding socket17, the lower surface of the interposer24on which the light emitting device arrays9aand/or the light receiving device arrays10aare mounted is brought into contact with the flat raised surfaces20of the socket17, and the electrodes25formed on the lower surface of the interposer24are electrically connected to the terminal pins21(seeFIG. 8A) exposed to the flat raised surfaces20of the socket17.

As shown inFIG. 12B, aluminum fins29are set on the semiconductor integrated circuit chips23aand23b, respectively.

By using this opto-electric composite device22, an optical wiring system can be configured wherein the optical waveguide device1is used as optical wiring.

FIGS. 14A and 14Bshow an example of such an optical wiring system wherein the opto-electric composite device22is extended on the printed wiring board28. For example, by normalizing an optical waveguide module, the extension in four directions can be flexibly attained. Further, in the optical waveguide device1according to the present invention, the cladding2is formed from a flexible sheet, and each light collimating or a focusing section3is formed as an integral member composed of the lens portions11and the lens supporting portion12, wherein the lens supporting portion12is bonded to the cladding2. Accordingly, the optical waveguide device1has high rigidity at its opposite end portions except the intermediate portion, so that the opto-electric composite device22can be extended not only on the printed wiring board28, but also between a plurality of wiring boards. As a result, high-speed distributed processing on the printed wiring board28can be attained, and it is possible to expect high functionality of SET and reduced TAT of development, for example. In particular, since the cladding2is formed from a flexible sheet, the intermediate portion of the optical waveguide device1becomes flexible to thereby allow the absorption of mounting errors and deformation due to heat and external stress, for example. Accordingly, the effects as mentioned above can be realized more surely.

According to this preferred embodiment, the opto-electric composite device22can be electrically connected to the printed wiring board28in the condition where the optical waveguide device1is fitted in the recesses18of the sockets17. Accordingly, the mounting structure of the existing printed wiring board28can be utilized in such a manner that an area for mounting the sockets17on the printed wiring board28must be ensured and other general electrical wiring can be formed by a conventional process.

In the case that the optical waveguide device1is not resistant to a high-temperature process, the sockets17may be first fixed to the printed wiring board28, and all of the mounting processes including a high-temperature process such as solder reflow and underfill resin sealing may be next completed. Thereafter, the optical waveguide device1may be fitted into the recesses18of the sockets17previously fixed to the printed wiring board28. Thus, the optical waveguide device1can be mounted without suffering damage due to high temperature.

Further, each socket17can be formed of a resin having rigidity higher than that of the printed wiring board28, and optical coupling between the optical devices and the optical waveguide device1can be established on this socket17. Accordingly, a mounting accuracy required for the optical coupling can be easily ensured. For example, an assembly accuracy on the order of several micrometers can be ensured by an existing molding technique. Accordingly, a higher density in an optical bus can be expected.

Further, since each of the semiconductor integrated circuit chips23aand23band the optical device arrays9aand/or10aare mounted on the opposite surfaces of the corresponding interposer24in close relationship, the wiring length between each of the semiconductor integrated circuit chips23aand23band the optical devices can be reduced. Accordingly, measures against noise and crosstalk of electrical signals can be easily taken, and an optical modulation rate can also be improved.

Further, since the opto-electric composite device22can be electrically connected to the printed wiring board28in the condition where the optical waveguide device1is fitted in the recesses18of the sockets17, high-density wiring on the printed wiring board28and the flexibility of design thereof can be ensured and an optical wiring system can be extended on the printed wiring board28at a low cost with high flexibility. Accordingly, it is possible to expect high-speed distributed processing on the printed wiring board28, high functionality of electronic equipment as a whole, and reduced TAT (turn around time) of development, for example.

Further, the semiconductor integrated circuit chips23aand23bare mounted on the sockets17through the interposers24, and the spacing27is defined between the upper surface26of the optical waveguide device1and the lower surface of each interposer24on which the light emitting device arrays9aand/or the light receiving device arrays10aare mounted. Accordingly, even when the semiconductor integrated circuit chips23aand23bgenerate heat in using the opto-electric composite device22, it is possible to effectively prevent breaking of the optical waveguide device1due to the heat from the semiconductor integrated circuit chips23aand23b.

Eighth Preferred Embodiment

The electronic equipment according to the present invention includes the optical information processing apparatus according to the present invention, a circuit device for supplying an input signal to the input side of the optical information processing apparatus, and a circuit device for receiving an output signal from the output side of the optical information processing apparatus, wherein the optical information processing apparatus includes the optical waveguide device according to the present invention, a light emitting device for launching light into the core of the optical waveguide device, and a light receiving device for receiving emergent light from the core.

Further, a converter for converting a parallel input signal into a serial input signal is preferably connected through a driver amplifier to the light emitting device, and a converter for converting a serial output signal into a parallel output signal is preferably connected through a transimpedance amplifier and an I/V conversion amplifier to the light receiving device.

FIG. 15shows the configuration of a computer system200as an example of the electronic equipment according to the present invention. The computer system200includes a CPU (central processing unit)201, north bridge202as a memory controller, DRAM (dynamic random access memory)203, south bridge204as an I/O controller, bus205, network interface (network I/F)206, storage device207, and other input/output devices (I/O devices)208.

The north bridge202is connected to the CPU201through an optical information processing apparatus210aconfigured as optical wiring according to the present invention. The south bridge204is connected to the north bridge202through an optical information processing apparatus210bconfigured as optical wiring according to the present invention, and is further connected through the optical wiring210ato the CPU201. The DRAM203is connected to the north bridge202through an optical information processing apparatus210cconfigured as optical wiring according to the present invention. The CPU201controls each component according to an OS (operating system) and an application program. The north bridge202centrally controls the access to the memory203.

The bus205is connected through electrical wiring214to the south bridge204. All of the network interface206, the storage device207, and the other I/O devices208are connected to the bus205. The storage device207includes an HDD (hard disk drive), DVD (digital versatile disk) drive, and CD (compact disk) drive. The I/O devices208include a video input/output device and serial and parallel interfaces.

FIG. 16shows the configuration of each of the optical information processing apparatuses210a,210b, and210cshown inFIG. 15(which devices210a,210b, and210care represented by optical wiring210inFIG. 16). This optical wiring210has a plurality of optical transmission systems220-1to220-N corresponding to N channels. Each of the optical transmission systems210-1to220-N is composed of a first transmission system221for transmitting an optical signal from a first circuit to a second circuit and a second transmission system222for transmitting an optical signal from the second circuit to the first circuit. In the case of the optical wiring210ashown inFIG. 15, the first circuit corresponds to the CPU201, and the second circuit corresponds to the north bridge202. In the case of the optical wiring210bshown inFIG. 15, the first circuit corresponds to the north bridge202, and the second circuit corresponds to the south bridge204. In the case of the optical wiring210cshown inFIG. 15, the first circuit corresponds to the DRAM203, and the second circuit corresponds to the north bridge202. Further, the optical wiring210has a configuration having opposite waveguide directions as shown inFIGS. 6A to 6C.

The first transmission system221includes a parallel/serial converter (P/S converter)221a, driver amplifier221b, semiconductor laser221cas the light emitting device, optical waveguide device221daccording to the present invention, photodiode221eas the light receiving device, transimpedance amplifier (TIA)221f, I/V conversion amplifier (IVA)221g, and serial/parallel converter (S/P converter)221h. In this case, the P/S converter221a, the driver amplifier221b, and the semiconductor laser221care provided in the first circuit, and the photodiode221e, the ITA221f, the IVA221g, and the S/P converter221hare provided in the second circuit. The optical waveguide device221dhas such a structure as described in the first preferred embodiment, and it is positioned so that an optical signal transmitted from the semiconductor laser221ceffectively enters the device221dand an optical signal guided by the device221dis effectively received by the photodiode221e.

Similarly, the second transmission system222includes a P/S converter222a, driver amplifier222b, semiconductor laser222c, optical waveguide device222daccording to the present invention, photodiode222e, TIA222f, IVA222g, and S/P converter222h. In this case, the P/S converter222a, the driver amplifier222b, and the semiconductor laser222care provided in the second circuit, and the photodiode222e, the TIA222f, the IVA222g, and the S/P converter222hare provided in the first circuit. The optical waveguide device222dhas such a structure as described in the first preferred embodiment, and it is positioned so that an optical signal transmitted from the semiconductor laser222ceffectively enters the device222dand an optical signal guided by the device222dis effectively received by the photodiode222e.

Each of the P/S converters221aand222aconverts parallel data to be transmitted, e.g., 8-bit parallel data of b0to b76into serial data. The driver amplifiers221band222bdrive the semiconductor lasers221cand222caccording to the serial data obtained by the P/S converters221aand222a, respectively. The semiconductor lasers221cand222cgenerate optical signals corresponding to the serial data. The TIAs221fand222festablish impedance matching in supplying current signals generated by photoelectric conversion from the photodiodes221eand222eto the subsequent IVAs221gand222g, respectively. The IVAs221gand222gconvert the current signals as output signals from the ITAs221fand222finto voltage signals, respectively. The S/P converters221hand222hconvert the transmitted serial data as output signals from the IVAs221gand222ginto parallel data.

There will now be described the operation in transmitting data from the first circuit to the second circuit. The 8-bit parallel data to be transmitted from the first circuit is converted into serial data by the P/S converter221a, and this serial data is supplied to the driver amplifier221b. The semiconductor laser221cis driven by the driver amplifier221bto generate an optical signal corresponding to the serial data. The optical signal is next guided by the optical waveguide device221dand transmitted to the second circuit.

In the second circuit, the optical signal guided by the optical waveguide device221dand emerging therefrom is received by the photodiode221e. The optical signal is next converted into a current signal by the photodiode221e, and this current signal is supplied through the TIA221ffor impedance matching to the IVA221g, in which the current signal is converted into a voltage signal. The transmitted serial data as output signal from the IVA221gis next converted into parallel data by the S/P converter221h.

In this manner, data is transmitted from the first circuit to the second circuit. Although not described in detail, the operation in transmitting data from the second circuit to the first circuit is similarly performed. Since the optical wiring210shown inFIG. 16has the N optical transmission systems220-1to220-N corresponding to N channels, data transmission and reception corresponding to N channels can be performed in parallel.

In the computer system200, semiconductor chips constituting the CPU201, the north bridge202, the DRAM203, the south bridge204, and the bus205as electronic components are mounted on a printed wiring board (motherboard) not shown, and the optical information processing apparatus210configured as optical wiring according to the present invention is also mounted on this printed wiring board.

According to this preferred embodiment, the optical information processing apparatus as optical wiring according to the present invention is used between the chips in the electronic equipment. Accordingly, high-speed and large-capacity signal exchange can be realized.

Each of the optical waveguide devices221dand222din the optical wiring210has such a structure as shown inFIGS. 1A and 1B. That is, each light collimating or a focusing section3is formed as an integral member composed of the lens portion11and the lens supporting portion12, and the lens supporting portion12of each means3is bonded to the cladding2. Accordingly, each of the optical waveguide devices221dand222d(corresponding to the optical waveguide device1shown inFIGS. 1A and 1B) has high rigidity at the opposite ends of the cladding2, so that a bonding strength between the optical waveguide devices221dand222dand the printed wiring board can be improved. As a result, stable incidence and emergence of light without optical axis deviation can be ensured.

Further, since the cladding2is formed from a flexible sheet, the optical waveguide devices221dand222dcan be made thin and flexible at their central portions. Accordingly, the deformation of the optical waveguide devices221dand222ddue to heat, external stress, etc. can be effectively absorbed without the application of stress to the cladding2.

Further, each light collimating or a focusing section3as an integral member composed of the lens portion11and the lens supporting portion12can be fabricated by a general injection molding technique, and an inexpensive sheet material can be used for the flexible sheet as the material of the cladding2to thereby reduce the amount of use of an expensive optical resin, thus reducing the cost.

Thus, the optical waveguide device according to the present invention has such excellent effects as mentioned above, so that the electronic equipment using this optical waveguide device according to the present invention can exhibit an effect that stable incidence and emergence of light can be ensured without the influence of heat, external stress, etc. and the limitation of an installation environment.

Ninth Preferred Embodiment

FIG. 17shows the configuration of a game machine300as another example of the electronic equipment according to the present invention. The game machine300basically includes a main CPU301for performing signal processing and control of internal components according to various application programs such as a game application program, a graphic processor (GP)302for performing image processing, a network interface (network I/F)303for interfacing with a network such as the Internet, an IO processor (IOP)304for performing interface processing, an optical disk control section306for performing read control of an optical disk305such as DVD and CD and decoding data read from the optical disk305, a DRAM307as a main memory connected to the main CPU301, an IOP memory308for holding instructions and data to the IO processor304, an OS-ROM309in which a program for an operating system is mainly stored, a sound processor unit (SPU)310for performing sound signal processing, and a sound buffer311for storing compressed waveform data.

The main CPU301and the network I/F303are connected by optical wiring210d. The main CPU301and the graphic processor302are connected by optical wiring210e.

Each of the optical wirings210dand210eis configured as shown inFIG. 16, so that data transmission and reception by optical signals are performed between the main CPU301and the network I/F303and between the main CPU301and the graphic processor302.

The main CPU301and the IO processor304are connected by an SBUS314. The IO processor304is connected through an SSBUS315to the optical disk control section306, the OS-ROM309, and the second processor unit310.

The main CPU301executes a program stored in the OS-ROM309or various game application programs read from the optical disk305and loaded into the DRAM307or downloaded through a communication network. The graphic processor302performs rendering or the like in a video game to output a video signal to a display, for example.

Connected to the IO processor304are a controller port321to which a controller (not shown) is connected, a memory card slot322into which a memory card (not shown) is inserted, a USB connection terminal323, and an IEEE1394 connection terminal324. Accordingly, the IO processor304performs data exchange, protocol conversion, etc. between it and the controller connected through the controller port321, the memory card connected through the memory card slot322, or a mobile phone or personal computer (both not shown) connected through the USB connection terminal323.

The sound processor unit310reproduces compressed waveform data stored in the sound buffer311at a predetermined sampling frequency according to an instruction from the main CPU301, thereby synthesizing various sounds to output an audio signal to a speaker.

In the game machine300, semiconductor chips as basic electronic components including the main CPU301are mounted on a printed wiring board (motherboard) not shown, and the optical information processing apparatuses210dand210econfigured as optical wirings according to the present invention are also mounted on this printed wiring board.

According to this preferred embodiment, the optical information processing apparatus as optical wiring according to the present invention is used between the chips in the electronic equipment. Accordingly, high-speed and large-capacity signal exchange can be realized.

Further, the optical waveguide device according to the present invention used in each of the optical wirings210dand210ehas excellent effects similar to those of the eighth preferred embodiment, so that the electronic equipment using this optical waveguide device according to the present invention can exhibit a similar effect that stable incidence and emergence of light can be ensured without the influence of heat, external stress, etc. and the limitation of an installation environment.

Tenth Preferred Embodiment

FIG. 18shows the configuration of a server400as another example of the electronic equipment according to the present invention. The server400basically includes CPUs401and402, chip set403, network interface (network I/F)404, memory405, PCI bridge406, and router407.

The CPUs401and402are respectively connected through optical wirings210fand210gto the chip set403, and the network I/F404is connected through optical wiring210hto the chip set403. The network I/F404functions to interface with a network. The chip set403controls the CPUs401and402, the network I/F404, the memory405, and the PCI bridge406.

Each of the optical wirings210f,210g, and210his configured as shown inFIG. 16, so that data transmission and reception by optical signals are performed between the CPU401and the chip set403, between the CPU402and the chip set403, and between the chip set403and the network I/F404.

The memory405, the PCI bridge406, and the router407are connected through electrical wirings to the chip set403.

A plurality of PCI devices415to417such as storage devices are connected through a PCI bus414to the PCI bridge406. The router407is composed of a switch card421and line cards422to425, for example. The line cards422to425are processors for performing preprocessing of packets, and the switch card421is a switch for switching a destination of each packet according to an address.

In the server400, semiconductor chips as basic electronic components including the CPUs401and402and the chip set403are mounted on a printed wiring board (motherboard) not shown, and the optical information processing apparatuses210f,210g, and210hconfigured as optical wirings according to the present invention are also mounted on this printed wiring board.

According to this preferred embodiment, the optical information processing apparatus as optical wiring according to the present invention is used between the chips in the electronic component. Accordingly, high-speed and large-capacity signal exchange can be realized.

Further, the optical waveguide device according to the present invention used in each of the optical wirings210f,210g, and210hhas excellent effects similar to those of the eighth preferred embodiment, so that the electronic equipment using this optical waveguide device according to the present invention can exhibit a similar effect that stable incidence and emergence of light can be ensured without the influence of heat, external stress, etc. and the limitation of an installation environment.

While the specific preferred embodiments of the present invention have been described above, various modifications may be made without departing from the scope of the present invention.

In the first preferred embodiment shown inFIGS. 1Aand1B, the second cladding5is provided on the lower surface of the core4opposite to its upper surface where the lens portion11is bonded. As a modification, the second cladding5may be omitted.

As the lens portion11, a convex lens is applicable. However, the shape of the lens portion in the present invention is not especially limited. For example, a spherical lens, cylindrical lens, etc. are also applicable.

Further, as shown inFIG. 19, each flat raised surface20of the socket17may have a plurality of interposer positioning mechanisms32(e.g., fitting bosses). The shape, size, etc. of each positioning mechanism32are not especially limited. Further, the shape, size, etc. of each projection19are also not especially limited.

While the present invention is suitable for an optical wiring system for transmitting an optical signal carried by laser light as described above, the present invention is applicable also to a display by selecting a light source or the like.

The present invention can be suitably used as an optical information processing apparatus such as optical wiring configured so that signal light efficiently focused into a given flux by an optical waveguide device and then emerging from the optical waveguide device or signal light efficiently incident on the optical waveguide device and then emerging therefrom is received by a light receiving device (e.g., optical wiring or photodetector) located on the output side of the optical waveguide device.

While the invention has been described with reference to specific embodiments, the description is illustrative and is not to be construed as limiting the scope of the invention. Various modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.