JP2018087840A - Light sum arithmetic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light sum arithmetic unit capable of shortening an optical path length and being downsized.SOLUTION: A light sum arithmetic unit includes: a plurality of light output units for outgoing respective plurality of light signals in parallel; a light focusing unit for reflecting and focusing the plurality of light signals; and a current output unit for converting the focused light signal to an electric current to output it. The light output unit includes a plurality of optical fiber for propagating light intensity corresponding to respective plurality of light signals, and a plurality of collimator lenses for adjusting the light signal output from respective plurality of optical fiber into parallel light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical sum arithmetic apparatus that performs an arithmetic operation on optical signals.

  In recent years, as an environment for acquiring a large amount of data from the Internet and various sensors is constructed, research and business for analyzing the data and performing highly accurate knowledge processing and future prediction are actively performed. One of the analysis techniques that has attracted particular attention in this trend is called deep learning.

  Deep learning is a machine learning technique based on a neural network, and has a function of discriminating and judging by learning data in an artificial neural network in which neurons are arranged in multiple layers. An analog optical computing unit has attracted attention as an element for increasing the computation speed of deep learning.

  When speeding up the learning of a neural network using an analog optical computing unit, it should be noted that the apparatus is miniaturized in order to shorten the light propagation time.

  The configuration of the conventional optical sum calculation device is that the optical fiber array is bundled, the light beam is emitted from each optical fiber to the space, and the position of the light beam of the optical fiber array is precisely adjusted so that the light receiving element is flush with the same plane. In general, the light beam is focused on (for example, Patent Document 1).

JP 2011-28235 A

  However, the conventional optical sum calculation apparatus has a problem that the apparatus becomes large. The reason for the increase in size will be briefly explained.

  In order to reduce the loss when propagating in the space as much as possible, strong directivity is required for the light used for the optical calculation. In addition, since the clock frequency in the optical calculation is in the order of MHz to GHz, the size of the light receiving element needs to be 3 mm or less. The light receiving element has a dependency between the angle at which light enters the light receiving surface and the sensitivity. Therefore, in order to make the sensitivity to all the light beams the same, it is necessary to keep the incident angle on the light receiving surface within a predetermined range. In other words, it is necessary to increase the distance from the light receiving element so that the incident angle of light does not change greatly depending on the light beam. Therefore, there is a problem that the optical path length becomes long and the apparatus becomes large.

  The present invention has been made in view of this problem, and an object of the present invention is to provide an optical sum calculation device capable of configuring an optical system compactly.

  An optical sum calculation apparatus according to an aspect of the present embodiment includes a light output unit that emits a plurality of optical signals in parallel, a light collecting unit that reflects and collects the plurality of optical signals, and condensed light. The gist of the present invention is to provide a current output unit that converts a signal into a current and outputs the current.

  ADVANTAGE OF THE INVENTION According to this invention, the optical sum calculating apparatus which can comprise an optical system compactly can be provided.

It is a figure which shows the function structural example of the optical sum calculating apparatus which concerns on 1st Embodiment. It is a perspective view of the optical sum operation device concerning a 1st embodiment. It is a front view of the optical sum operation device concerning a 1st embodiment. It is a side view of the light output part of the optical sum arithmetic unit which concerns on 1st Embodiment. It is the front view which looked at the light output part of the optical sum operation device concerning a 1st embodiment from the front. It is a top view of the optical sum operation device concerning a 1st embodiment. It is a figure which shows the example of the focus of a concave mirror. It is a figure which shows the relationship between a light-receiving surface and a focus, (a) is a figure which shows the example which has a light-receiving surface in the light output part side rather than a focus, (b) is a light-collecting part side from a focus. It is a figure which shows a certain example. It is a figure which shows typically the relationship between the incident angle of the optical signal which injects into the light-receiving surface of an electric current output part, and a focus. It is a front view of the condensing part of the optical operation apparatus which concerns on 2nd Embodiment. It is a side view of FIG. It is a figure which shows the AA sectional drawing (refer FIG. 3) of the optical sum calculating apparatus which concerns on 2nd Embodiment. It is a figure which shows typically the optical path length of the optical sum calculating apparatus of the comparative example provided with the fiber folder. It is a top view which shows the specific example of arrangement | positioning of the main structure part of the optical sum calculation apparatus 1 which concerns on this embodiment. It is a figure which shows the optical path length of the optical sum calculating apparatus shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same components in a plurality of drawings, and the description will not be repeated.

[First Embodiment]
FIG. 1 shows a functional configuration example of the optical sum calculation apparatus 1 according to the first embodiment, FIG. 2 shows a perspective view of the optical sum calculation apparatus 1, and FIG. 3 shows a front view of the optical sum calculation apparatus 1. The configuration of the optical sum calculation device 1 will be described with reference to FIGS.

  The optical sum calculation device 1 includes a light output unit 10, a light collecting unit 20, and a current output unit 30. The light collecting unit 20 and the current output unit 30 are accommodated in the space 100.

  As shown in FIG. 2, the light output unit 10 emits a plurality of optical signals in parallel to the light collecting unit 20 disposed in the space 100. The optical signal in this example is shown as an example of 100 (10 × 10).

The optical signal is, for example, a signal for performing parallel computation of learning of a hierarchical neural network. 100 optical signals are arranged in an array of 10 α _{11 to} α _A1 in the x-axis direction on the xy plane in the space 100 and 10 α _{11 to} α _{1A in} the y-axis direction ( FIG. 3). The notation of the optical signals α _A1 and α _1A is omitted because the drawing becomes complicated. Details of the light output unit 10 will be described later.

In this example, the condensing unit 20 reflects and collects 100 optical signals α _{11 to} α _AA . The condensing unit 20 is disposed to face the xy plane on the space 100 side of the light output unit 10.

  The current detection unit 30 converts the collected optical signal into a current and outputs the current. The current detection unit 30 is disposed between the light output unit 10 and the light collection unit 20. In addition, the current detection unit 30 is disposed in the central portion of the xy plane on the space 100 side of the light output unit 10.

  In FIG. 1 to FIG. 3, a configuration for supporting the light collecting unit 20 and the current detection unit 30 and an electric wire for extracting the converted current to the outside are omitted.

  According to the optical sum calculation apparatus 1 of the present embodiment, since the optical signal is reflected and collected, the distance between the light output unit 10 and the light collecting unit 20 can be shortened. Therefore, the optical system of the optical sum calculation device 1 can be configured compactly.

(Light output part)
The light output unit 10 will be described in detail with reference to FIGS. 4 and 5. FIG. 4 is a side view of the light output unit 10. FIG. 5 is a front view of the light output unit 10 as viewed from the light collecting unit 20 side.

The optical output unit 10 is connected to each of the plurality of optical fibers 11 _{11 to} 11 _AA and the plurality of optical fibers 11 _{11 to} 11 _AA that propagate the light intensities of the plurality of optical signals, and generates optical signals of parallel light. A plurality of collimator lenses 12 _{11 to} 12 _AA and a bundling fixing unit 13 that arranges the collimator lenses 12 _{11 to} 12 _AA on a plane (xy plane) orthogonal to the direction of the optical signal. In the following, when there is no need to clarify the position of each component, the notation of the subscript is omitted.

  The wavelength of the optical signal propagating through the optical fiber 11 is 1550 nm, for example. The optical signal is input from the outside via the optical fiber 11.

  The optical fiber 11 and the collimator lens 12 may be an integrated optical fiber with a collimator lens. For example, an optical fiber with a collimator lens manufactured by THORLAB can be used.

  The binding fixing part 13 is made of a metal block, for example. The metal block is suitable for fixing the collimator lens 12 and the optical fiber 11 because drilling and the like can be performed with high accuracy. As the material, for example, aluminum can be used.

  A hole in the z-axis direction is formed in the binding fixing portion 13, and the collimator lens 12 and the optical fiber 11 are inserted into the hole and fixed. The optical fiber 11 and the binding fixing part 13 are fixed with an adhesive, for example.

As shown in FIG. 5, the collimator lenses 12 can be arranged by bringing adjacent collimator lenses 12 into contact with each other. In FIG. 5, -y-axis direction of a point of the outer periphery of the collimator lens 12 ₁₁ located in the corner of the x-y plane is in contact with one point of the outer periphery of the adjacent collimator lenses 12 _12. Further, one point of the outer periphery of the x-axis direction of the collimator lens 12 ₁₁ is in contact with one point of the outer periphery of the adjacent collimator lenses 12 _21.

one point of the outer periphery of the y-axis direction of the collimator lens 12 _65, located near the center of the x-y plane is in contact with one point of the outer periphery of the adjacent collimator lenses 12 _64. One point of the outer periphery of the -y-axis direction of the collimator lens 12 ₆₅ is in contact with one point of the outer periphery of the adjacent collimator lenses 12 _66. One point of the outer periphery of the x-axis direction of the collimator lens 12 ₆₅ is in contact with one point of the outer periphery of the collimator lens 12 ₇₅ adjacent. One point of the outer periphery of the -x-axis direction of the collimator lens 12 ₆₅ is in contact with one point of the outer periphery of the adjacent collimator lenses 12 _55.

  In this way, the collimator lens 12 is arranged with adjacent collimator lenses in contact with each other. This arrangement can be easily realized by a combination of the collimator lens 12 processed with high accuracy and the bundling fixing portion 13 that can be processed with high accuracy.

  The collimator lens 12 is a lens whose aberration has been corrected so as to obtain parallel light as is well known. Therefore, by fixing the collimator lens 12 in parallel to the surface orthogonal to the direction of the optical signal of the binding fixing unit 13, a plurality of parallel lights can be easily generated.

  Further, according to the light output unit 10 of the present embodiment, since the respective collimator lenses 12 are arranged in contact with each other, the interval between the optical signals on the xy plane can be shortened. By shortening the interval between the optical signals, an effect of shortening the optical path length between the collimator lens 12 and the current output unit 30 can also be obtained. That is, there is an effect of speeding up the sum calculation time. Detailed description including a quantitative value for shortening the optical path length will be described later.

(Condenser)
The condensing part 20 is demonstrated in detail with reference to FIG. FIG. 6 is a diagram showing a top view of the optical sum calculation apparatus 1 according to the present embodiment.

The condensing unit 20 includes a concave mirror 21 that reflects the plurality of optical signals emitted from the light output unit 10 and condenses the reflected plurality of optical signals on the light receiving surface 31 of the current output unit 30. In FIG. 6, only the optical signals α ₁₁ , α ₁₂ , α ₁₃ , α ₁₄ , and α _{1A out of} 100 optical signals are shown, and other notations are omitted.

The light receiving surface 31 of the current output unit 30 is disposed at the focal point of the concave mirror 21. The focus of the concave mirror 21 will be described with reference to FIG. FIG. 7 represents the parabola of the concave mirror 21 in the x-axis direction as z = cx ² , and the parabola in the y-axis direction as z = cy ² .

In this case, the distance z _F from the bottom O of the concave mirror 21 to the focal point F can be expressed by the following equation. c is a secondary coefficient.

つまり、凹面鏡２１の底Ｏの座標を次式としたときに、

That is, when the coordinate of the bottom O of the concave mirror 21 is expressed by the following equation:

電流出力部３０の受光面３１は、次式で表せる座標に配置する。

The light receiving surface 31 of the current output unit 30 is arranged at coordinates that can be expressed by the following equation.

電流出力部３０の受光面３１を底Ｏから距離ｚ_Ｆの位置に配置すれば、集光部２０で反射した光信号のすべてを電流に変換することができる。つまり、電流出力部３０の受光面３１を焦点Ｆに配置すれば、すべての光信号の和を求めることができる。

By arranging the light-receiving surface 31 of the current output unit 30 from the bottom O at a distance z _F, it is possible to convert all of the optical signal reflected by the condensing unit 20 to the current. That is, if the light receiving surface 31 of the current output unit 30 is disposed at the focal point F, the sum of all the optical signals can be obtained.

  The light receiving surface 31 of the current output unit 30 is disposed within the focal point F on an axis (z axis) orthogonal to the bottom O of the concave mirror 21. The reason why the light receiving surface 31 is disposed within the focal point F of the concave mirror 21 will be described with reference to FIG.

  FIG. 8 is a diagram schematically illustrating the positional relationship between the focal point F and the light receiving surface 31 in the z-axis direction. FIG. 8A shows a case where the light receiving surface 31 is arranged at a position separated by the focal point F or more. FIG. 8B shows a case where the light receiving surface 31 is disposed within the focal point F.

  In the case of FIG. 8A, the optical signal is collected before the light receiving surface 31. In that case, if the phases of the respective optical signals do not match, attenuation or increase (interference) of the optical signal occurs in the condensed portion, and the correct sum of the optical signals cannot be obtained. In the case of FIG. 8B, since the optical signal is not condensed before the light receiving surface 31, a correct sum of the optical signals can be obtained.

  Note that since there is a dependency between the angle at which the optical signal enters the light receiving surface 31 and the sensitivity, it does not mean that the light receiving surface 31 should be close to the bottom O. When the light receiving surface 31 is close to the concave mirror 21, the incident angle formed by the perpendicular of the light receiving surface 31 and the optical signal is increased, and the sensitivity of the current output unit 30 is deteriorated. Therefore, the light receiving surface 31 needs to be arranged at a position where the sensitivity of the current output unit 30 can be obtained.

  The arrangement of the light receiving surface 31 will be described in more detail with reference to FIG. FIG. 9 is a diagram schematically illustrating the relationship between the incident angle of the optical signal incident on the light receiving surface 31 of the current output unit 30 and the focal point F. FIG.

  FIG. 9 shows an example in which the center of the light receiving surface 31 is arranged on the bottom O side of the focal point F. P represents a perpendicular line of the light receiving surface 31, and θ represents an incident angle formed by the perpendicular line P and the optical signal.

In FIG. 9, the incident angle θ is the largest for the optical signal reflected at the position farthest from the bottom O of the concave mirror 21. In the present embodiment, the collimator lenses 12 ₁₁ , 12 _1A , 12 _A1 , 12 _AA arranged at the four corners of the collimator lenses 12 _{11 to} 12 _AA arranged in an array form are reflected by the concave mirror 21. The incident angle θ of the optical signals α ₁₁ , α _1A , α _A1 , α _AA is the largest. Hereinafter, the optical signals α ₁₁ , α _1A , α _A1 , α _AA are represented as the optical signal α ₁₁ as a representative of them.

The optical signal α ₁₁ is incident on the end of the light receiving surface 31. Therefore, it is necessary to keep the incident angle θ of the optical signal α ₁₁ incident on the end of the light receiving surface 31 within a range where the sensitivity of the current output unit 30 can be obtained.

The incident angle θ of the optical signal alpha ₁₁ is the light receiving surface 31 becomes larger the closer to the bottom O. Therefore, the distance from the focal point F at which the light receiving surface 31 can be brought closer to the bottom O side can be obtained by the maximum incident angle θ allowed by the size of the light receiving surface 31 and the sensitivity of the current output unit 30.

  The center of the light receiving surface 31 of the current output unit 30 is defined such that the length from the center of the light receiving surface 31 to one end portion is a, and the incident angle with respect to the perpendicular P of the light receiving surface incident on the one end portion is θ. It is arranged within the range from the focal point F on the z axis orthogonal to the bottom O to the position near the concave mirror 21 in the length b shown by the following equation.

つまり、受光面３１は、焦点Ｆからｂの長さ凹面鏡２１側の位置の範囲に配置すれば良い。このように配置することで、電流出力部３０は光信号を集光した正しい電流値を出力することができる。

That is, the light receiving surface 31 may be disposed in the range of the position from the focal point F to the length b on the concave mirror 21 side. By arranging in this way, the current output unit 30 can output a correct current value obtained by condensing the optical signal.

In the description with reference to FIG. 9, the beam diameter of the optical signal α ₁₁ is set to 0. Beam diameter of the actual optical signal alpha ₁₁ has a finite value. Therefore, in practice it is necessary to consider the beam diameter of the light signal alpha _11. When considering the beam diameter, the beam diameter may be subtracted from the length a.

[Second Embodiment]
FIG. 10 is a front view of the light collecting unit 20 according to the second embodiment, and FIG. 11 is a side view of the light collecting unit 20. FIG. 12 is a cross-sectional view of the AA cross section (see FIG. 3) of the optical sum calculation apparatus 2 according to the second embodiment.

As shown in FIGS. 10 and 11, the concave mirror 21 is formed only on the outer annular portion 22 except the central portion 23, and a plurality of collimator lenses 12 _{16 to} 12 of the light output unit 10 as shown in FIG. 12. _A6 is arranged at a position facing the annular portion 22 (mirror).

As shown in FIG. 12, the collimator lenses 12 ₅₆ and 12 ₆₆ and the optical fibers 11 ₅₆ and 11 ₆₆ of the light output unit 10 facing the mirrorless portion of the central portion 23 of the concave mirror 21 do not exist. Instead, the optical sum calculation device 2 includes a support unit 14.

  The support unit 14 extends from the central portion of the surface of the light output unit 10 facing the concave mirror 21 in the direction of the concave mirror 21, and supports the current output unit 30 with the light receiving surface 31 facing the concave mirror 21. The current output unit 30 outputs a current via an electric wire (not shown) arranged along the support unit 14.

  By supporting the current output unit 30 in this way, the current output unit 30 does not block the optical signal. Further, by leading an electric wire that outputs an electric current converted from the optical signal to the outside along the support portion 14, interference between the electric wire and the optical signal can be prevented. Illustration of the electric wire is omitted.

  The optical sum calculation device 2 of the present embodiment has an effect of facilitating the arrangement of the current output unit 30. In addition, since it is not necessary to finely adjust the position of the electric line so as not to interfere with the optical signal, the cost of the optical sum calculation device 2 can be reduced. In addition, since the interference between the electric line and the optical signal can be completely eliminated, the reliability of the optical sum calculation device 2 can be improved.

(Comparative example optical path length)
In FIG. 13, the optical path length of the optical sum calculation apparatus of the comparative example which is not provided with the condensing part 20 is shown typically. FIG. 13 shows only two optical fibers 11 ₁₅ and 11 ₁₆ arranged to face the current output unit 30.

As the optical fibers 11 ₁₅ and 11 ₁₆ , an optical fiber with a collimator (manufactured by THORLABS: CFS2-1550-APC) was used. Optical signal alpha ₁₅ emitted from each of the optical fibers ₁₁ 15, _{11 16,} the direction of the alpha ₁₆ is adjusted by the fiber folder ₁₅ 15, _{15 16} for holding the optical fiber ₁₁ 15, _{11 16.}

The fiber folders 15 ₁₅ and 15 ₁₆ adjust the incident angle θ of the optical signals α ₁₅ and α ₁₆ on the light receiving surface 31 of the current output unit 30 to, for example, 4 °. As the fiber folders 15 ₁₅ and 15 ₁₆ , for example, KM100V / M manufactured by THORLABS can be used. Its size is a square with a side of 50 mm.

From the center of the light receiving surface 31, for example, five of the center of the optical fiber 11 ₁₁ at one end of the case of arranging the optical fibers, 225 mm in the x-axis direction (50 × 5-25mm) is away. In order to set the incident angle of the optical signal emitted from the light receiving surface 31 to 4 °, it is necessary to separate the light receiving surface 31 from the collimator lens by 3217 mm (3217 = 225 × sin 4 °).

(Optical path length of this embodiment)
In FIG. 14, the example of the specific optical path length of this embodiment is shown. FIG. 14 is a top view showing the arrangement of the main components when the secondary coefficient c of the concave mirror 21 of the optical sum calculation device 1 is set to c = 0.926 × 10 ⁻³ , for example.

The focal point F of the concave mirror 21 when c = 0.926 × 10 ⁻³ is 270 mm from the equation (1). Therefore, the light receiving surface 31 of the current output unit 30 is disposed at a position of 270 mm from the bottom O on the z axis orthogonal to the bottom O of the concave mirror 21.

Five optical fibers with a collimator having a diameter of 4 mm (11 _{11 to} 11 ₁₅ ) are arranged in the x-axis direction around the z axis, and five (11 _{16 to} 11 _1A ) are arranged in the −x direction. The diameter of the collimator lens omitted from the reference numerals connected to each optical fiber is the same as the diameter of the optical fiber. The collimator-equipped optical fibers 11 _{11 to} 11 _1A are arranged by bringing adjacent collimator lenses into contact with each other.

When the optical fibers 11 _{11 to} 11 _1A are thus arranged, the centers of the optical fibers 11 ₁₁ and 11 _{1A on} both outer sides in the x-axis direction are 18 mm and -18 mm. In other words, the optical fiber 11 ₁₁ disposed (x = 18, y = 0 , Z ≧ 270). The optical fiber _111A is disposed at (x = -18, y = 0, Z ≧ 270).

  Here, Z ≧ 270 mm represents a position where the collimator lens 12 does not block the optical signal reflected by the light collecting unit 20. In this example, it is arranged at z = 300 mm.

The optical signals α ₁₁ and α _1A have the largest incident angle θ of the optical signal on the light receiving surface 31 of the current output unit 30. The optical signal α _{11 is used} for verification.

Optical signal alpha ₁₁ needs to be emitted from the x-coordinate represented by the following formula.

例えば、入射角度θ=4°とするとX≒18.88mmである。この例では光信号α_１１の出射位置の座標は、（x=18, y=0, Z=300）であるので式（５）の条件を満たす。光信号α_１Ａについても条件を満たす。

For example, when the incident angle θ = 4 °, X≈18.88 mm. The coordinates of the exit position of the optical signal alpha ₁₁ in this example satisfies the condition of (x = 18, y = 0 , Z = 300) and is therefore equation (5). The condition is also satisfied for the optical signal α _1A .

FIG. 15 shows the optical path length of a specific example of this embodiment. The horizontal axis is the distance from the bottom O of the concave mirror 21 (x or y), the vertical axis is the optical path length (z), and each unit is mm. The horizontal axis of each plot represents the coordinates of the centers of the optical fibers 11 _{11 to} 11 _1A (4 mm intervals of −18 to 18 mm).

  The optical path length of the optical sum calculation apparatus 1 of this embodiment is 570 mm. This optical path length is obtained when the distance between the concave mirror 21 and the light signal emission position is 300 mm. Therefore, the remaining 30 mm (difference from the focal point) can be further shortened.

  Thus, the optical sum calculation apparatus 1 of this embodiment can reduce the optical path length to 1/5 or less of the comparative example. Therefore, the speed of the sum operation can be increased to 5 times or more.

  As described above, according to the optical sum calculation devices 1 and 2 of the present embodiment, the optical system can be made compact and the sum calculation time can be shortened.

  The optical sum calculation device 1 has been described with an example in which the number of collimator lenses 12 and optical fibers 11 is 100 × 10 × 10, but the present invention is not limited to this example. There can be any number of optical signals.

  Further, the example in which the incident angle θ of the optical signal to the light receiving surface 31 of the current output unit 30 is 4 ° has been described, but the present invention is not limited to this example. The incident angle θ depends on the size of the light receiving element. Depending on the light receiving element used, the angle may be larger (or smaller).

  The concave mirror 21 of the light collecting unit 20 may use an offset type. By using the offset type, the focal point can be arranged outside the range facing the light output unit 10, and the arrangement of the current output unit 30 can be facilitated. Thus, the present invention is not limited to the above-described embodiment, and can be modified within the scope of the gist thereof.

  The present embodiment can be applied to, for example, a learning device for a hierarchical neural network, and can be used in fields such as optical computing.

1,2: Kowa arithmetic unit 10: light output portion _{11, 11} 11 _{to 11 AA:} optical fiber _{12, 12} 11 _{to 12 AA:} collimating lens 13: bundling fixing unit 14; supporting portion _{15, 15} 15, _{15 16:} Fiber folder 20: Condensing part 21: Concave mirror 22: Ring part 23: Center part 30: Current output part 31: Light receiving surface

Claims (6)

A light output unit for emitting a plurality of optical signals in parallel;
A light collecting unit that reflects and collects the plurality of optical signals;
And a current output unit for converting the collected optical signal into a current and outputting the current. The optical sum calculation device according to claim 1,
The light output unit is
A plurality of optical fibers that propagate the light intensity of each of the plurality of optical signals;
A plurality of collimator lenses connected to each of the plurality of optical fibers to generate optical signals of parallel light;
An optical sum calculation device, comprising: a plurality of collimator lenses arranged in contact with adjacent collimator lenses on a surface orthogonal to the direction of the optical signal. In the optical sum calculation device according to claim 1 or 2,
The condensing part is
An optical sum calculation apparatus comprising: a concave mirror that reflects a plurality of optical signals emitted from the light output unit and collects the reflected plurality of optical signals on a light receiving surface of the current output unit. In the optical sum calculation device according to claim 3,
The center of the light receiving surface of the current output unit is defined as follows: the length from the center of the light receiving surface to one end portion is a, and the incident angle with respect to the normal of the light receiving surface incident on the one end portion is θ. An optical sum calculation device, which is arranged within a range from a focal point on an axis orthogonal to the bottom to a position of a length b concave mirror side represented by the following equation.

In the optical sum calculation device according to claim 3 or 4,
The concave mirror, the mirror is formed only in the outer annular portion excluding the central portion,
A plurality of collimator lenses of the light output unit are arranged at positions facing the mirror. The optical sum calculation device according to claim 5,
The light output portion includes a support portion that extends in a direction of the concave mirror from a central portion of the surface facing the concave mirror, and supports the current output portion with the light receiving surface facing the concave mirror. Kowa arithmetic unit.

Images