JPH10197756A - Optical bus and signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the optical bus which is increased in the efficiency of use of incident signal light and the signal processor which adopts the optical bus and has its circuit board detached and attached freely with ease according to the extension of a system. SOLUTION: The directions of diffraction type unit optical elements 51, 52, 53... constituting a diffraction optical element 50 in specific directions are determined according to the mean quantities of incident light, made incident on the diffraction type unit optical per unit area elements 51, 52, 53..., per unit area so that the quantities of signal light traveling to signal light projection parts are made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like optical bus for transmitting an optical signal, and a signal processing device for performing signal processing including transmission and reception of a signal using the optical bus.

[0002]

2. Description of the Related Art With the development of very large scale integrated circuits (VLSI), circuit functions of circuit boards (daughter boards) used in data processing systems have been greatly increased. As the number of signal connections to each circuit board increases as circuit functions increase, a data bus board (mother board) that connects each circuit board (daughter board) with a bus structure requires a large number of connectors and connection lines. Parallel architecture has been adopted. The operation speed of the parallel bus has been improved by increasing the parallelism by increasing the number of connection lines and miniaturization, but the processing speed of the system has been reduced due to the signal delay caused by the capacitance between the connection lines and the resistance of the connection lines. It may be limited by the operating speed of the bus. In addition, electromagnetic noise (E
MI: Electro Magnetic Interf
issue) is also a significant constraint on improving the processing speed of the system.

In order to solve such a problem and improve the operation speed of the parallel bus, use of an optical connection technique in a system called an optical interconnection has been studied. The outline of the optical interconnection technology is described in “Sadaji Uchida, Academic Lecture Meeting on Circuit Packaging, 15C01, pp. 146-64”. 201
-202] and [H. Tomimiuro et al. ,
“Packaging Technology for
Optical Interconnects ", I
EEE Tokyo No. 33 pp. 81-86,
As described in "1994", various forms are proposed depending on the configuration of the system.

[0004]

SUMMARY OF THE INVENTION Among the various types of optical interconnection technologies that have been proposed in the past,
No. 41042 discloses an example in which an optical data transmission method using a high-speed, high-sensitivity light-emitting / light-receiving device is applied to a data bus, in which a light-emitting / light-receiving device is provided on both front and back surfaces of each circuit board. A serial optical data bus for loop transmission between circuit boards has been proposed, in which light emitting / receiving devices on adjacent circuit boards incorporated in a system frame are spatially coupled by light. . In this method, signal light sent from a certain circuit board is subjected to optical / electrical conversion on an adjacent circuit board, and is further subjected to electrical / optical conversion on that circuit board, and then transmitted to the next adjacent circuit board. As in the case of transmitting light, the circuit boards are sequentially arranged in series and transmitted between all the circuit boards incorporated in the system frame while repeating photoelectric conversion and electric / optical conversion on each circuit board. For this reason, the signal transmission speed depends on the optical / electrical conversion / electrical / optical conversion speed of the light receiving / light emitting device arranged on each circuit board, and at the same time is restricted. In addition, since data transmission between each circuit board uses optical coupling via a free space by a light receiving / light emitting device arranged on each circuit board, it is arranged on both front and back sides of an adjacent circuit board. It is necessary that the light emitting / receiving devices are optically aligned and all circuit boards are optically coupled. Further, since the optical data transmission paths are coupled via free space, interference (crosstalk) between adjacent optical data transmission paths occurs, and data transmission failure is expected. In addition, it is expected that data transmission failure occurs due to scattering of signal light due to an environment in the system frame, for example, dust or the like. Furthermore, since the circuit boards are arranged in series, if any one of the boards is removed, the connection is interrupted there, and an extra circuit board is required to compensate for the disconnection. That is, there is a problem that the circuit board cannot be freely inserted and removed, and the number of circuit boards is fixed.

Another technique for data transmission between circuit boards is disclosed in Japanese Patent Application Laid-Open No. 61-196210. The technology disclosed herein has two parallel surfaces,
In this method, a circuit board is provided opposite to a light source, and circuit boards are optically coupled to each other through an optical path using free space, which is configured by a diffraction grating and a reflection element arranged on the surface of the plate. In this system, light emitted from one point can be connected to only one fixed point, and it is not possible to connect all circuit boards comprehensively like an electric bus. In addition, since the light is repeatedly propagated a plurality of times by the diffraction grating and the reflection element, data transmission failure due to the displacement of the optical element is expected.

An optical bus has been considered as a configuration that has high resistance to environmental changes such as temperature changes and dust and allows easy attachment and detachment of a circuit board according to the expandability of the system. The optical bus has an extremely thin sheet-shaped optical transmission layer, and diffuses and propagates signal light incident from the end face of the optical transmission layer. The signal light incident from the signal light input / output unit is reliably transmitted to any signal light input / output unit, and the number of circuit boards and the like optically coupled to the optical bus in the signal light input / output unit is determined. Can be freely increased or decreased within the maximum number, and a system that is strong against environmental changes and highly scalable is constructed. However, as described above, the optical bus diffuses and propagates the incident signal light, and thus has a problem that the light use efficiency is low.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides an optical bus in which the utilization efficiency of incident signal light is enhanced, and the use of the optical bus makes it easy to freely attach and detach a circuit board according to the expandability of the system. It is an object to provide a signal processing device.

[0008]

According to the present invention, there is provided an optical bus according to the present invention, comprising: a sheet-like optical bus for transmitting signal light; (1-1) transmitting signal light from the surface of the optical bus; (1-2) a plurality of signal light emitting portions for emitting signal light propagating in the optical bus from an end face of the optical bus (1-3) a plurality of signal light emitting portions A diffractive optical element for diffracting the signal light incident on the optical bus from the optical signal and directing the signal light to each of the plurality of signal light emitting units, and equalizing the amount of the signal light traveling toward each of the plurality of signal light emitting units. A signal light diffracting section having a diffractive optical element having a structure is provided.

In the optical bus according to the present invention, the signal light incident from the signal light incident portion is made uniform by the diffractive optical element of the signal diffraction portion toward each of the plurality of signal light emitting portions. Thus, even if the incident signal light has an intensity distribution within the spot, a uniform amount of light can be propagated to each of the plurality of signal light emitting portions.
Therefore, the incident signal light can be used effectively,
The use efficiency of signal light increases.

The diffractive optical elements are arranged in a predetermined direction, each of the diffractive optical elements being composed of a plurality of diffractive unit optical elements for diffracting light toward the plurality of signal light emitting portions, respectively. The width in the predetermined direction of each of the diffractive unit optical elements, according to the average light amount per unit area of the signal light incident on each of the plurality of diffractive unit optical elements,
It is preferable that the light amount of the signal light traveling toward each of the plurality of signal light emitting portions is determined to be uniform.

When the width of each of the plurality of diffractive unit optical elements in a predetermined direction is determined in accordance with the average light amount per unit area of the signal light incident on each of the plurality of diffractive unit optical elements, It is possible to easily equalize the light amount of the signal light going to each of the plurality of signal light emitting units.
In addition, the diffractive optical elements are arranged in a predetermined direction, and are repeatedly arranged plural times within the spot of the incident signal light in order of arrangement to diffract light toward each of the plurality of signal light emitting portions. It is also a preferred embodiment that the optical element comprises the diffractive unit optical element.

When the diffractive optical element is configured as described above, the light amounts of the signal lights going to the respective signal light emitting portions can be easily averaged and uniformized. Also,
The signal processing device of the present invention employing the optical bus includes: (2-1) a base; (2-2) a signal light emitting portion for emitting the signal light; and a signal carried by the signal light emitted from the signal light emitting portion. A plurality of electronic circuits, each of which includes at least one of an electronic circuit that generates a signal light, and an electronic circuit that performs signal processing based on a signal carried by the signal light incident portion that receives the signal light and the signal light that is incident from the signal light incident portion. (2-3) a signal light incident portion for receiving the signal light from the surface;
A plurality of signal light emitting portions that emit the signal light propagating through the inside from the end face, and a diffractive optical element that diffracts the signal light incident from the signal light incident portion and directs the signal light toward each of the plurality of signal light emitting portions. And a signal light diffracting section having a diffractive optical element having a structure for equalizing the amount of signal light traveling toward each of the plurality of signal light emitting sections. (2-4) The circuit board having the signal light emitting portion, the signal light emitting portion of the circuit board having the signal light emitting portion is optically coupled to the signal light incident portion of the optical bus, and the signal light emitting portion is provided. A circuit board supporting member for supporting the substrate in a state where the signal light incident portion of the circuit board is optically coupled to the signal light emitting portion of the optical bus;

According to the signal processing device of the present invention, the optical bus of the present invention is employed as described above, the utilization efficiency of incident signal light is good, the resistance to environmental changes such as temperature change and dust is high, and the circuit A scalable system with easy attachment and detachment of substrates is constructed.

[0014]

Embodiments of the present invention will be described below. FIG. 1 is a diagram illustrating a signal processing according to the present invention including a sheet-like optical data bus, which is an embodiment of the optical bus of the present invention, and a plurality of circuit boards optically connected to each other by the sheet-like optical data bus. It is a schematic structure figure of one embodiment of a device.

A supporting substrate 1 which is an example of the substrate according to the present invention
A sheet-shaped optical data bus 20 in which optical transmission layers 21 and clad layers 22 are alternately stacked on top of each other and a part of which is formed in a stepped manner so that signal light is easily incident is fixed. The optical transmission layer 21 is a layer responsible for propagation of signal light,
A signal light diffracting unit (not shown in FIG. 1) for diffracting the incident signal light, which will be described in detail later, is provided. The cladding layer 22 is a layer that functions to suppress light in the light transmission layer 21 from leaking in the thickness direction of the layer, and a material having a refractive index lower than the refractive index of the optical transmission path is selected. I have. Although omitted in FIG. 1, the cladding layer 2 is formed to prevent signal light from entering the adjacent optical transmission line beyond the cladding layer 22.
It is also possible to provide a light-shielding layer that absorbs light so as to be sandwiched between the two. The same effect can be obtained even when a black pigment is dispersed in a part of the cladding layer 22.

, 30 are fixed on the supporting board 10, and each of the board connectors 3
The circuit boards 40,..., 40 are detachably mounted on 0,. A power supply line and electrical wires 11 for transmitting electric signals are provided on the support substrate 10, and the electrical wires 11 are connected to the board connectors 30,.
, 30 are electrically connected to the electronic circuits 41 on the circuit boards 40,..., 40 mounted on the board connectors 30,.

Each of the circuit boards 40,..., 40 has a light emitting / receiving element 42, which is a pair of a light emitting element and a light receiving element.
, 42 are provided, and when the circuit board 40 is mounted on the board connector 30, each of the light emitting and receiving elements 42,.
2 is optically coupled to the optical bus 20, and the signal light emitted from the light emitting element in a certain light emitting and receiving element 42 enters the optical transmission layer 21 of the optical data bus 20, The light of the quantity of light that has been diffracted and uniformed by the signal light diffraction unit is received by the light receiving elements in the other plurality of light emitting and receiving elements 42.

Next, the signal light diffraction portion of the light transmission layer 21 will be described. FIG. 2 is a diagram illustrating a light intensity distribution of the signal light emitted from the light emitting element in the light emitting and receiving element in the signal light diffracting portion of the optical transmission layer. The signal light emitted from the light projecting element in the light projecting and receiving element 42 reaches the signal light diffracting portion of the optical transmission layer 21. In the signal light diffracting portion, the horizontal direction shown in FIG. It has a relative light emission intensity represented by the horizontal mode a and the vertical horizontal mode b.

FIG. 3 is a schematic diagram of a diffractive optical element included in the signal light diffraction section. The spot A of the signal light having a predetermined light intensity distribution and emitted from the light projecting element is incident on the diffractive optical element 50 shown in FIG. This diffractive optical element 50 has a plurality of diffractive unit optical elements 51, 52, 53,... Which are arranged in the horizontal direction of FIG. It is composed of These plurality of diffractive unit optical elements 51, 5
Each of 2, 53,... Has a diffraction grating having a predetermined grating interval. Plural diffraction unit optical elements 5
1, 52, 53,..., In the horizontal direction in FIG.
.. According to the average light quantity per unit area of the signal light incident on each of the diffractive unit optical elements 51, 52, 53,.
It is set so that the light amounts of the signal lights directed toward the respective signal light emitting portions are made uniform. The number of the diffractive unit optical elements 51, 52, 53,... Matches the number of light receiving elements on the same common signal path. As described above, in the case of the diffractive optical element shown in FIG.
The areas of 2, 53,... Are adjusted in accordance with the light intensity distribution, whereby the signal light propagating to each light receiving element is made uniform.

FIG. 4 is a schematic view of a diffractive optical element different from the diffractive optical element shown in FIG. The diffractive optical elements 50 shown in FIG. 4 are arranged in a predetermined direction, cyclically repeated in the arrangement order in the spot A of the incident signal light, and directed toward the plurality of signal light emitting units one by one. It is composed of a plurality of diffractive unit optical elements 51, 52, 53,... For diffracting light. Here, the diffractive unit optical element 51,
Are divided at least twice as many as the light receiving elements on the same common signal path, and the diffracting unit in which the traveling direction of the signal light propagating to each light receiving element by diffraction is sequentially repeated. The configuration of the optical elements 51, 52, 53,... For example, as will be described later in detail, the diffractive unit optical element 51 of the diffractive optical element 50 diffracts light toward the first signal light emitting unit, and the diffractive unit optical element 52 modulates the second signal. The light is diffracted toward the light emitting unit, the diffractive unit optical element 53 diffracts the light toward the third signal light emitting unit, and the diffractive unit optical element 54 is further diffracted toward the first signal light emitting unit. Diffracts light cyclically, such as diffracting light. Even with such a configuration, the signal light can be made uniform. In this configuration, the area of the diffractive unit optical elements 51, 52, 53,... Is the same. Also, by setting the total area of the diffractive unit optical elements 51, 52, 53,..., That is, the signal light diffracting portion to be equal to or larger than the spot diameter of the incident signal light, the displacement at the time of mounting the light projecting element can be prevented. A configuration having a wide allowable range can be obtained.

FIG. 5 is a schematic diagram showing the direction of propagation of diffracted light in the optical transmission layer shown in FIG. The signal light enters the signal light incident portion 24 of the optical transmission layer 21 shown in FIG. 5 from above. The incident signal light is diffracted by the diffractive optical element 50 provided in the signal light diffracting section 60, and the amount of the signal light traveling toward each of the plurality of signal light emitting sections 25 is made uniform. Further, the signal light emitted from each signal light emitting unit 25 is input to a light receiving element 42 a in each light emitting and receiving element 42. Here, the traveling direction of the diffracted light propagating to the light receiving element 42a in each light emitting / receiving element 42 is determined by the emission wavelength of the light emitting element, the distance from the signal light diffraction unit 60 to each light receiving element 42a, and the diffraction type unit. It is determined by the lattice spacing of the optical element. The relationship between the lattice spacing and the emission wavelength is shown in the following equation (1).

D · sin θ ₁ = mλ (1) where d is the lattice spacing, m is the first-order diffracted light (m = 1), λ
Represents the emission wavelength, and θ ₁ represents the diffraction angle of the incident signal light. Therefore, the elevation angle x (where x = π / 2−θ ₁ ) from the signal light diffraction unit 60 to the light receiving element 42a is calculated from the size of the optical transmission layer 21 and the distance from each light receiving element 42a.
By substituting into the equation (1), the lattice spacing d can be obtained.

FIG. 6 is a schematic diagram showing the propagation direction of the diffracted light different from the propagation direction of the diffracted light shown in FIG. FIG. 6 shows a state where the first-order diffracted light is totally reflected and propagated in the light transmission layer 21. In this case, the lattice spacing d may be determined so as to satisfy the total reflection condition determined by the refractive indexes of the light transmission layer 21 and the cladding layer 22. If the critical angle is φ _C ,
In the equation (1), the lattice spacing d can be determined under the condition of θ ₁ = π / 2−φ _{C to} π / 2. The critical angle φ _C is as follows: φ _C = sin ^-1 (n ₂ / n ₁ ) (2) where n
₁ is the refractive index of the clad layer, n ₂ is the refractive index of the light transmission layer.

FIG. 7 is a schematic view showing a tilted diffractive unit optical element. By providing an inclination to each of the diffractive unit optical elements, the traveling directions of the first-order diffracted light and the specularly reflected light can be made to coincide with each other, thereby increasing the utilization efficiency of the incident light. Assuming that the inclination angle is θ ₂ and the elevation angle from the signal light diffraction section to the light receiving element is x, θ ₂ = (π / 2−x) / 2.

Here, if θ ₁ = 2 · θ ₂ is satisfied, the traveling directions of the first-order diffracted light and the specularly reflected light in the signal light diffraction section can be matched. Further, the inclination angle θ ₂ may be determined so that the specularly reflected light is totally reflected and propagated in the light transmission layer 21. In this case, θ ₂ = (π / 2−φ _C ) / 2 to π /
The inclination angle is determined under the condition of 4.

Next, some conditions for propagating the signal light incident on the light transmission layer 21 to the light receiving element will be described with reference to FIG. FIG. 8 is a schematic side view of the light transmission layer, a schematic plan view of the light transmission layer, and a detailed schematic view of a diffractive optical element in the light transmission layer. As shown in FIG. 8B, the light transmission layer 21 includes three signal light incident portions 24-1, 24-2, 24-3 and three signal light emitting portions 25-1, 25-2, 25-. 3 Each signal light incidence section 24-1, 24-2, and 24-3 is provided with each signal light diffraction section 60, and each signal light diffraction section 60 is provided with each diffraction optical element 50. . Further, each light receiving element 42a is provided corresponding to each signal light emitting section 25-1, 25-2, 25-3. Here, as shown in FIG. 8A, the length of the perpendicular from the signal light diffraction portion 60 of the optical transmission layer 21 to the side of the optical transmission layer 21 where the light receiving element 42a is attached is L1, The thickness of the light transmission layer 21 is D
(The light receiving element 42a is attached at the center (D / 2) in the thickness direction). The mounting pitch of each light receiving element 42a is L2. Further, the pitch of the grating width of the diffractive unit optical element is p. Here, attention is paid to the diffractive optical element 50 surrounded by a broken line shown in FIG. 8B, and the diffractive unit optical element 51 of the diffractive optical element 50 is directed toward the signal light emitting unit 25-1. Diffracts light,
The diffractive unit optical element 52 diffracts light toward the signal light emitting unit 25-2, the diffractive unit optical element 53 diffracts light toward the signal light emitting unit 25-3, and further diffracts the unit optical element. It is assumed that the light is diffracted cyclically, such as 54 diffracting the light toward the signal light emitting unit 25-1. Hereinafter, three diffractive unit optical elements 51, 52, and 53 of the diffractive optical element 50 will be described.

First, conditions for directly transmitting the first-order diffracted light to the light receiving element 42a will be described. In order to directly propagate the first-order diffracted light to the light receiving element 42a, the lattice spacing d of each of the diffractive unit optical elements 51, 52, 53 is defined as follows. However, each diffraction type unit optical element 51, 5
The directions of the gratings 2 and 53 are formed toward the direction of each light receiving element 42a.

The grating interval d of the diffractive unit optical element 51 is

[0029]

(Equation 1)

The grating interval d of the diffractive unit optical element 52 is

[0031]

(Equation 2)

The grating interval d of the diffractive unit optical element 53 is

[0033]

(Equation 3)

Second, conditions for totally reflecting the first-order diffracted light in the light transmission layer 21 and propagating it to the light receiving element 42a will be described. In order to totally reflect the first-order diffracted light in the light transmission layer 21 and propagate it to the light receiving element 42a, the lattice spacing d is defined as follows. λ <d <λ / sin (π / 2−φ _C ) Third, conditions for directly transmitting specularly reflected light to the light receiving element 42a will be described.

In order to directly transmit the specularly reflected light to the light receiving element 42a, the inclination angle θ ₂ between the gratings is defined as follows. However, the inclination angle theta ₂ shown here is an illustration of one of the tilt angle of the diffractive unit optical element, in the same diffractive unit optical element, it is necessary to adjust each inclination angle. It is assumed that the direction of each diffraction grating is formed toward the direction of each light receiving element 42a.

The inclination angle θ ₂ between the gratings of the diffractive unit optical element 51 is

[0037]

(Equation 4)

The inclination angle θ ₂ between the gratings of the diffractive unit optical element 52 is

[0039]

(Equation 5)

The inclination angle θ ₂ between the gratings of the diffractive unit optical element 53 is

[0041]

(Equation 6)

Fourthly, conditions for totally reflecting specularly reflected light in the light transmission layer 21 and propagating the light to the light receiving element 42a will be described. In the light transmission layer 21, the specular reflected light is totally reflected and the light receiving element 4
In order to propagate the light to 2a, the inclination angle θ ₂ between one grating of the diffractive unit optical element is defined as follows. (Π / 2−φ _C ) / 2 <θ ₂ <π / 4 Next, a method for manufacturing the optical transmission layer 21 in the present embodiment will be described.

As an example, an ultra-high sensitivity positive type resist TSMR-8800 (manufactured by Tokyo Ohka) is applied to a glass substrate or the like, and exposure is performed based on predetermined diffraction grating configuration conditions. When an inclination is provided for the lattice spacing, the amount of light transmitted through the resist is adjusted using a mask for adjusting the exposure energy. The original substrate is plated with Ni or the like to produce a stamper. Next, polymethyl methacrylate (P
An optical transmission substrate having a predetermined diffraction grating structure is transferred by heating and softening a thermoplastic resin such as MMA, refractive index: 1.49) above the glass transition point, and pressing it against a stamper to solidify it by cooling. A reflective surface is formed by depositing Al or the like on the surface of the diffraction grating portion of the obtained optical transmission substrate. The clad layer 22 can be formed by applying or printing a solution material (for example, made of Florad FC-722 3M, refractive index: 1.36) on the light transmission layer 21, and has already been formed into a sheet. A shaped material can be formed by thermocompression bonding or the like.

In addition to PMMA, a plastic material having similar optical characteristics such as polystyrene (PS) and polycarbonate (PC) can be used for the light transmission layer 21. There is no problem if the material has a lower refractive index than the light transmission layer. Also, regarding the film thickness of the light transmission layer 21 and the cladding layer 22,
It is optional as long as the optical characteristics are not impaired.

[0045]

As described above, according to the present invention,
The signal light incident from the signal light incident portion is diffracted by the diffractive optical element of the signal diffraction portion toward each of the plurality of signal light emitting portions so that the light amount of the signal light is equalized. Even if the signal light has an intensity distribution within the spot, a uniform amount of light can be propagated to each of the plurality of signal light emitting portions. Accordingly, the incident signal light can be effectively used, the utilization efficiency of the signal light can be increased, and the driving voltage of the light emitting / receiving element can be suppressed to reduce power consumption.

Further, even if there is a temperature change or the like, the incident signal light is surely propagated to each of the plurality of signal light emitting sections, and a system which is strong against environmental changes and has a good expandability is constructed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an optical bus according to an embodiment of the present invention, which includes a sheet optical data bus and a plurality of circuit boards optically connected to each other by the sheet optical data bus. It is a schematic structure figure of one embodiment of a device.

FIG. 2 is a diagram showing a light intensity distribution of signal light emitted from a light emitting element in the light emitting and receiving element in a signal light diffracting portion of an optical transmission layer.

FIG. 3 is a schematic diagram of a diffractive optical element included in a signal light diffraction unit.

FIG. 4 is a schematic view of a diffractive optical element different from the diffractive optical element shown in FIG.

FIG. 5 is a schematic diagram showing a propagation direction of diffracted light in the light transmission layer shown in FIG.

FIG. 6 is a schematic diagram showing a direction of propagation of diffracted light different from the direction of propagation of diffracted light shown in FIG.

FIG. 7 is a schematic view showing a tilted diffractive unit optical element.

8A is a schematic side view of the light transmission layer, FIG. 8B is a schematic plan view of the light transmission layer, and FIG. 8C is a detailed schematic view of a diffractive optical element in the light transmission layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Support substrate 11 Electric wiring 20 Sheet-shaped optical data bus 21 Optical transmission layer 22 Cladding layer 24,24-1,24-2,24-3 Signal light incidence part 25,25-1,25-2,25-3 Signal light emitting unit 30 Board connector 40 Circuit board 41 Electronic circuit 42 Light emitting / receiving element 42a Light receiving element 50 Diffractive optical element 51, 52, 53 Diffractive unit optical element 60 Signal light diffracting unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Gowa Shiotani 430 Nakaicho Sakai, Ashigagami-gun, Kanagawa Green Tech Nakai Inside Fuji Xerox Co., Ltd. Inside the company (72) Inventor Masao Funada 430 Sakai Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture Inside Fuji Xerox Fuji Xerox Co., Ltd.

Claims (4)

[Claims] 1. A sheet-like optical bus for transmitting signal light, comprising: a signal light incident portion for inputting signal light from a surface of the optical bus to the optical bus; and a signal light propagating in the optical bus. A plurality of signal light emitting portions emitting from an end face of the optical bus, and a diffractive optic for diffracting the signal light incident on the optical bus from the signal light incident portion and directing the signal light toward each of the plurality of signal light emitting portions. An optical bus, comprising: a signal light diffracting element having a diffractive optical element having a structure for equalizing the amount of signal light traveling toward each of the plurality of signal light emitting parts. 2. The diffractive optical elements are arranged in a predetermined direction, each of the diffractive optical elements being composed of a plurality of diffractive unit optical elements for diffracting light toward each of the plurality of signal light emitting units, and The width of each of the diffractive unit optical elements in the predetermined direction is determined by the average amount of signal light per unit area of the signal light incident on each of the plurality of diffractive unit optical elements. 2. The optical bus according to claim 1, wherein the optical bus is determined so that the amount of light is made uniform. 3. The diffractive optical elements are arranged in a predetermined direction, cyclically repeat in the order of arrangement within a spot of the incident signal light a plurality of times, and emit light toward each of the plurality of signal light emitting units. 2. The optical bus according to claim 1, comprising a plurality of diffractive unit optical elements for diffracting. 4. A base, a signal light emitting portion for emitting signal light, an electronic circuit for generating a signal to be carried by the signal light emitted from the signal light emitting portion, a signal light incident portion for receiving the signal light, and A plurality of circuit boards mounted with at least one of an electronic circuit that performs signal processing based on a signal carried by the signal light incident from the signal light incident unit; a signal light incident unit that receives the signal light from the surface; A plurality of signal light emitting portions that emit the signal light propagating through the inside from the end face, and a diffractive optical element that diffracts the signal light incident from the signal light incident portion and directs the signal light toward each of the plurality of signal light emitting portions. And a signal light diffracting section having a diffractive optical element having a structure for equalizing the amount of signal light directed toward each of the plurality of signal light emitting sections. , And the circuit board, wherein the signal light emitting portion of the circuit board having the signal light emitting portion is optically coupled to the signal light incident portion of the optical bus, and the circuit board having the signal light incident portion. In a state where the signal light incident portion is optically coupled to the signal light emitting portion of the optical bus,
A signal processing device comprising: a circuit board supporting member supported by the base.