Information processing device and information processing method

Abstract

This information processing device satisfactorily determines whether or not receiving characteristic are within an allowable range.　A position adjusting unit adjusts the position at which output light is condensed in a receiving device. A transmitting unit transmits the output light to the receiving device. An information processing unit calculates, on the basis of at least the coupling efficiency of the output light, information for determining whether or not to perform a determination of whether or not the receiving characteristics of the receiving device are within the allowable range.

Description

Information processing device and information processing method

[0001] This technology relates to an information processing device and an information processing method, and more specifically, to an information processing device used to determine whether or not the reception characteristics are within an acceptable range.

[0002] In optical communication (see, for example, Patent Document 1), the receiving characteristics are affected by the eccentricity and misalignment of the optical components on the receiving side (Rx side), and as a result, the optical coupling efficiency between the transmitting side (Tx side) and the receiving side (hereinafter simply referred to as "coupling efficiency") may fluctuate. When there is a large variation in the receiving characteristics, it is necessary to select a receiver whose receiving characteristics are within an acceptable range in order to achieve a coupling efficiency above the standard value.

[0003] International Publication No. 2017 / 056889

[0004] The purpose of this technology is to accurately determine whether or not the reception characteristics are within an acceptable range.

[0005] The concept of this technology is an information processing device comprising: a transmitting unit that transmits output light to a receiving device; a position adjustment unit that can adjust the position at which the output light is focused in the receiving device to a plurality of positions including a first position and a second position different from the first position; and an information processing unit that determines whether the receiving characteristics of the receiving device are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency when the output light is focused to the second position.

[0006] Another concept of this technology is an information processing method comprising: a procedure for adjusting the position at which the output light is focused in a receiving device from a first position to a second position different from the first position; a procedure for transmitting the output light, which is focused in the receiving device to the second position different from the first position, to the receiving device; and a procedure for determining whether the receiving characteristics of the receiving device are within an acceptable range, or for calculating determination information for the determination, based at least on the coupling efficiency when the output light is focused to the second position.

[0007] Another concept of this technology is an information processing device comprising a transmitting unit that transmits output light to a receiving device that is more critical to the receiving device in terms of coupling efficiency than light from an ideal transmitting device, and an information processing unit that determines whether the receiving characteristics of the receiving device are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency of the output light.

[0008] Exemplary embodiments of this technology will be described based on the following drawings. Figure 1 is a diagram showing an example of an optical communication system. Figure 2 is a graph showing the relationship between the normalized frequency V and the normalized propagation constant b. Figure 3A is a diagram for explaining the first determination. Figure 3B is a diagram showing an example of the intensity distribution at the output end of an optical fiber. Figures 3C to 3E are diagrams showing examples of coupling efficiency characteristics, respectively. Figure 4A is a diagram showing the simulation results of the intensity distribution. Figures 4B to 4D are diagrams showing examples of the intensity distribution at the output end of an optical fiber, respectively. Figure 5A is a diagram for explaining the second determination. Figure 5B is a diagram showing an example of the intensity distribution at the output end of an optical fiber. Figure 5C is a diagram showing an example of the intensity distribution at the input end of an optical fiber. Figure 6 is a diagram showing an example of a transmitting and receiving structure. Figure 7 is a diagram showing an example of the refractive index distribution of an optical fiber. Figure 8 is a diagram showing the simulation results of the coupling efficiency. Figure 9A is a diagram showing the intensity distribution of light having only the fundamental mode component. Figure 9B is a diagram showing the intensity distribution of light having both the fundamental mode and the first mode component. Figure 9C is a diagram for explaining the direction in which light output from an optical fiber propagates. Figure 10A is a graph showing the near-field pattern according to the position of the output end. Figure 10B is a diagram showing the position of the output end. Figures 11A to 11D are graphs showing near-field patterns corresponding to the output terminal position when the mode ratios are 20:80, 40:60, 60:40, and 80:20, respectively. Figure 12A is a graph showing the far-field pattern. Figure 12B is a diagram to explain the far-field pattern. Figure 13 is a graph showing the result of applying the first variable transformation to the far-field pattern. Figure 14 is a graph showing the result of applying the second variable transformation to the far-field pattern. Figure 15A is a graph showing the far-field pattern according to the output terminal position. Figure 15B is a graph showing the result of applying the first and second variable transformations to that far-field pattern. Figure 16 is a graph to explain the correlation between far-field pattern features and worst-case coupling efficiency. Figure 17 is a graph with an increased sample size to explain the correlation between far-field pattern features and worst-case coupling efficiency.Figure 18 is a diagram illustrating the normalized far-field pattern features. Figure 19A is a diagram showing the assumed transmit / receive structure in a simulation to determine the worst-case coupling efficiency. Figure 19B is a diagram illustrating the worst-case scenario. Figure 20 is a diagram showing an example of the hardware configuration of an information processing system. Figure 21A is a diagram showing an example of the configuration of a classifier. Figures 21B and 21C are diagrams showing examples of the operation of a movable mirror, respectively. Figures 22A to 22D are diagrams showing examples of the configuration of the intensity distribution adjustment unit. Figures 23A and 23B are diagrams showing other examples of the configuration of the intensity distribution adjustment unit. Figure 24A is a diagram showing an example of an intensity distribution image. Figure 24B is a contour map corresponding to Figure 24A. Figure 24C is a graph showing the intensity distribution on the A-B line in Figure 24B. Figure 24D is a graph showing an example of an intensity distribution. Figure 25 is a flowchart showing an example of a processing procedure in an information processing system. Figure 26 is a block diagram showing an example of the hardware configuration of a computer.

[0009] The following describes embodiments for carrying out the invention. The description will be in the following order: 1. Optical communication system 2. Judgment principle 2-1. First judgment 2-2. Second judgment 2-3. Characteristics of optical fiber 3. Information processing system 4. Processing procedure 5. Example of computer hardware configuration 6. Modified examples

[0010] "1. Optical Communication System" Figure 1 shows an example of a double-mode optical communication system 10. The transmitter 100 has an optical fiber 101, a gradient-index lens 102, and a lens 103. These are arranged in series in this order. Symmetrically, the receiver 200 has a lens 203, a gradient-index lens 202, and an optical fiber 201, all arranged in series in this order. The optical fibers 101 and 201 have a core in the center that forms the optical path and a cladding that surrounds it. The refractive index of the core is n １ The refractive index of the cladding is high, n ２ Because the intensity is low, light is trapped in the core and propagates from there.

[0011] The refractive index distribution lenses 102 and 202 are cylindrical lenses. The refractive index of the refractive index distribution lenses 102 and 202 is, for example, the refractive index n of the core of the optical fiber 101 and 201 along the optical axis. １ It is equivalent to [another value], and the value decreases as you move away from the optical axis.

[0012] In the transmitter 100, light is output from the optical fiber 101, and this light is transformed into collimated light by lens 103 via refractive index distribution lens 102. In the receiver 200, this collimated light is focused by lens 203, and this focused light (convergent light) is input to the optical fiber 201 via refractive index distribution lens 202.

[0013] The distributed refractive index lens 202 provided at the input end of the optical fiber 201 of the receiver 200 can return light that has shifted from the optical axis towards the center, thereby reducing coupling loss due to optical axis misalignment. Furthermore, if the receiver 200 is equipped with a distributed refractive index lens 202, providing a similar lens (distributed refractive index lens 102) in the transmitter 100 can suppress aberrations. Therefore, in this example, the transmitter 100 is also equipped with a distributed refractive index lens 102.

[0014] When a single-mode optical fiber, designed to propagate light of a first wavelength, is input with light of a second wavelength different from the first, first-order mode light may be generated in addition to the fundamental mode light within the optical fiber. In double-mode optical communication, which utilizes this principle, power loss can be reduced because the first-order mode component, generated by optical axis misalignment, propagates along with the fundamental mode component within the optical fiber.

[0015] Figure 2 is a graph showing the relationship between the normalized frequency V and the normalized propagation constant b. Here, the optical fiber is a step-index optical fiber. The normalized propagation constant b on the vertical axis is defined for each mode and indicates how much light of that mode propagates. b=0 indicates full cutoff, and b=1 indicates full propagation. The normalized frequency V on the horizontal axis can be expressed by the following formula (1): where d is the core diameter, NA is the numerical aperture, and λ is the wavelength of light. V = πdNA / λ ... (1)

[0016] When V < 2.405, LP 01 Other modes are blocked (single mode). LP 01 This is the fundamental mode, also called the zeroth-order mode. In single-mode optical communication, when λ = 1310 nm, d = 8 μm, and NA = 0.1, V = 1.92 < 2.405 is obtained from equation (1). Here, 1310 nm is an example of the first wavelength.

[0017] On the other hand, when λ = 850 nm, V = 2.96 > 2.405. Therefore, LP 01 The basic mode and LP 11 The first mode can propagate (double mode). Here, 850 nm is an example of a second wavelength.

[0018] This technology is for determining whether the reception characteristics of a receiver 200 are within an acceptable range in an optical communication system 10 as shown in Figure 1. The reception characteristics of the receiver 200 are affected by the eccentricity and misalignment of optical components such as the lens 203, the refractive index distribution lens 202, and the optical fiber 201.

[0019] "2. Determination Principle" Figure 3A shows an example of the information processing system 30. In this information processing system 30, the transmitter 100 in the communication system 10 shown in Figure 1 is replaced by the determination device 300. The determination device 300 has optical fibers 301, refractive index distribution lenses 302 and lenses 303 arranged in series in the same order as the transmitter 100 in the aforementioned communication system 10.

[0020] In the detector 300, similar to the transmitter 100, light is output from the optical fiber 301, and this light is transformed into collimated light by lens 303 via refractive index distribution lens 302. In the receiver 200, this collimated light is focused by lens 203, and this focused light is input to the optical fiber 201 via refractive index distribution lens 202.

[0021] The optical fiber 301 of the detector 300 is an optical fiber compatible with double-mode optical communication, similar to the optical fibers 101 and 201 in the communication system 10 described above, and propagates the fundamental mode and primary mode. Therefore, the light in the optical fiber 301 has fundamental mode and primary mode components, similar to the light in the optical fibers 101 and 201.

[0022] "2-1. First Determination" The first determination will now be explained. The determination device 300 makes the intensity distribution at the output end of the optical fiber 301 substantially point-symmetric (unbiased) as shown in Figure 3B. This intensity distribution at the output end of the optical fiber 301 is called the regular distribution. Since the intensity distribution hardly changes in the refractive index distribution type lens 302, the intensity distribution at the output end of the refractive index distribution type lens 302 can be considered identical to the intensity distribution at the output end of the optical fiber 301. Furthermore, the determination device 300 moves the focusing point p in the receiver 200 to the regular position. In this way, an ideal transmitter 100, free from eccentricity and misalignment, is reproduced by the determination device 300. However, it goes without saying that, due to the considerations of processing, control, and measurement accuracy, it is sufficient if the ideal transmitter 100 is substantially reproduced. An ideal transmitter 100 is compatible with an ideal receiver 200 (the optical axes of the transmitter and receiver coincide), but the transmitter 100 that is best suited in terms of coupling efficiency for a non-ideal receiver 200 may not be the ideal transmitter 100. In other words, the transmitter 100 that is best suited for a receiver 200 with eccentricity or misalignment may be a transmitter 100 with complementary eccentricity or misalignment.

[0023] Figure 4A shows the intensity distribution of light with fundamental mode and first-order mode components in a cross-section along the axial direction of an optical fiber. It can be seen that high-intensity spots appear alternately in the upper and lower directions along the core. Hereafter, the high-intensity spots will be referred to as hot spots, and the axis (up and down direction) along which the hot spots alternate will be referred to as the intensity deviation axis.

[0024] Figures 4B, C, and D show the intensity distributions in sections P1, P2, and P3, respectively, as shown in Figure 4A. In Figures 4B, C, and D, the dashed circles represent the outer circumference of the core. The hotspot in section P1 is (most) offset from the center of the core in a first direction (upward) along the intensity deviation axis, and the hotspot in section P3 is (most) offset from the center of the core in a second direction (downward), opposite to the first direction. In section P2, two hotspots are distributed symmetrically on either side of the center of the core. While all intensity distributions are substantially symmetric with respect to the intensity deviation axis, the intensity distribution in section P2 (the reference distribution) is also substantially symmetric with respect to the axis perpendicular to the intensity deviation axis (vertical direction) (horizontal direction). Therefore, the intensity distribution in section P2 is substantially point-symmetric with respect to the intersection of these axes. Hereafter, the axis perpendicular to the intensity deviation axis will be referred to as the reference axis (regular axis).

[0025] As described above, the detector 300 uses the intensity distribution at the output end of the optical fiber 301 (refractive index distribution lens 302) as the reference distribution, and then moves the focusing point p along the intensity deviation axis from the reference position within a predetermined range including, for example, -6 μm to +6 μm. Here, 6 μm is an example of the maximum axial misalignment of the optical fiber 201 (optical fiber 301 allowed by the transmitter 100) that is permitted by the receiver 200. When the optical fiber 301 is moved in the first direction (upward), the focusing point p moves in the second direction (downward), and when the optical fiber 301 is moved in the second direction, the focusing point p moves in the first direction. Since lenses 303 and 203 are collimators, ideally, the focusing point p moves only in the direction of movement of the optical fiber 301 (up and down).

[0026] In the first determination, the determination device 300 determines whether the receiving characteristics of the receiver 200 in the regular transmission environment are within an acceptable range, based on the relationship between the position x of the focusing point p and the coupling efficiency η (coupling efficiency characteristics). At this time, the determination device 300 calculates the coupling efficiency, for example, based on information indicating the transmission strength and information indicating the received strength sent from the receiver 200.

[0027] When the coupling efficiency characteristic satisfies a predetermined condition (the first condition), the determiner 300 determines that the reception characteristic of the receiver 200 in the reference transmission environment is within the allowable range. For example, the first condition is that both the coupling efficiency η at x = -6 μm and the coupling efficiency η at x = +6 μm are equal to a predetermined value η １ (e.g., 0.6) or more.

[0028] FIG. 3C shows an example of the coupling efficiency characteristic. In this example, the coupling efficiency characteristic (curve) is substantially an even function (without bias), and the first condition is satisfied. Therefore, the determiner 300 determines that the reception characteristic is within the allowable range. FIG. 3D shows another example of the coupling efficiency characteristic. In this example, although the coupling efficiency characteristic is somewhat biased in the first direction (rightward), the first condition is satisfied. Therefore, the determiner 300 determines that the reception characteristic is within the allowable range. FIG. 3E shows another example of the coupling efficiency characteristic. In this example, the coupling efficiency characteristic is largely biased in the first direction, and the coupling efficiency η at x = -6 μm is less than the predetermined value η １ is less than. Therefore, the first condition is not satisfied, and the determiner 300 determines that the reception characteristic is not within the allowable range. Whether the coupling efficiency characteristic is biased in the first direction can be determined (or estimated) based on various mathematical methods, assuming that the coupling efficiency characteristic is symmetric near the maximum point. For example, whether argmax η(x) > 0 holds, whether the x-coordinate of the centroid of η(x) > 0 holds, whether the derivative coefficient of η(x) at x = 0 > 0 holds, whether η(-x １ ) < η(x １ ) for some x １ exists, or whether η(-x １ ) < η(x １ ) holds for a certain x １ (e.g., 6 μm). Conversely, whether the coupling efficiency characteristic is biased in the second direction (leftward) can also be determined based on a similar method. By the first determination, the receiver 200 whose reception characteristic in the reference transmission environment is within the allowable range, that is, the receiver 200 whose reception characteristic may be within the allowable range can be selected.

[0029] The first condition may also be that the binding efficiency in the range of x = -6 μm to +6 μm is greater than or equal to a predetermined value (e.g., 0.6), or that the binding efficiency characteristic is substantially an even function. The determination machine 300 also determines the position x (e.g., -x) necessary for evaluating the first condition or determining the direction of the bias in the binding efficiency characteristic. １ and +x １ , or 0 and +x １ The binding efficiency η(x) may be measured only in the case of ).

[0030] "2-2. Second Determination" Next, the second determination will be explained. If the determination device 300 determines that the receiving characteristics of the receiver 200 in the reference transmission environment are within the acceptable range, it then performs the second determination.

[0031] The detector 300 moves the focusing point p by a predetermined distance (e.g., 6 μm) from the reference position in the opposite direction to the bias of the coupling efficiency characteristics determined when performing the first determination described above.

[0032] For example, if the coupling efficiency characteristics shown in Figure 3D are obtained, the judging device 300 moves the optical fiber 301 by a predetermined distance in the first direction (upward), as shown in Figure 5A, thereby moving the focusing point p by a predetermined distance in the second direction (downward). This predetermined distance is an example of the maximum axial misalignment of the optical fiber 101 that is allowed by the transmitter 100 (see Figure 1). The position of the focusing point p at this time is called the severe position. In this way, the transmitter 100 having eccentricity or misalignment is reproduced by the judging device 300. Note that if there is no bias in the coupling efficiency characteristics, the focusing point p may be moved in either the first or second direction.

[0033] Furthermore, the detector 300 sets the intensity distribution at the receiver 200 (focusing point p) to the intensity distribution that is most biased in the opposite direction to the bias of the coupling efficiency characteristics. This intensity distribution is called the severe distribution. For example, if the coupling efficiency characteristics shown in Figure 3D are obtained, the detector 300 sets the intensity distribution at the output end of the optical fiber 301 (refractive index distribution lens 302) to be most biased in the first direction (upward) as shown in Figure 5B, and sets the intensity distribution at the input end of the optical fiber 201 (refractive index distribution lens 202) to be most biased in the second direction (downward) as shown in Figure 5C.

[0034] In this way, by moving the position of the focusing point p and the hotspot at the focusing point p in the opposite direction to the bias of the coupling efficiency characteristics, the most severe transmission environment for the receiver 200 is reproduced. The determination device 300 measures the coupling efficiency η under these conditions. In the second determination, the determination device 300 determines that the receiving characteristics of the receiver 200 in a severe transmission environment are within an acceptable range when the coupling efficiency η satisfies a predetermined condition (second condition). The second condition is, for example, when the coupling efficiency η is a predetermined value η ２ (For example, it must be 0.6) or higher. For the receiver 200, the severe transmission environment is more demanding than the standard transmission environment in terms of coupling efficiency. The second determination allows for the selection of receivers 200 whose receiving characteristics in the severe transmission environment are within an acceptable range, that is, receivers 200 whose receiving characteristics are within an acceptable range.

[0035] Furthermore, the determination device 300 does not need to determine whether the direction of the bias in the coupling efficiency characteristics is in the first direction or the second direction. That is, by determining whether the smaller of the coupling efficiency η measured under a severe transmission environment based on the assumption that the direction of the bias in the coupling efficiency characteristics is in the first direction, and the coupling efficiency η measured under a severe transmission environment based on the assumption that the direction of the bias in the coupling efficiency characteristics is in the second direction satisfies the second condition, the second determination can be made without the first determination.

[0036] "2-3. Characteristics of Optical Fibers" Note that the severe transmission environment may include optical fiber 301, which is critical in terms of coupling efficiency. Such optical fibers will be described below.

[0037] Figure 6 shows an example of a transmission / reception structure for double-mode optical communication. The transmitting side has a connector body 401. This connector body 401 is made of a light-transmitting material such as synthetic resin or glass. A lens (collimator) 402 and an optical fiber insertion hole 403 are integrally formed on the connector body 401. Lens 402 corresponds to lens 103 in Figure 1. An optical fiber 404, corresponding to optical fiber 101 in Figure 1, is inserted into the optical fiber insertion hole 403. A refractive index distributed lens 405 is provided at the output end of the optical fiber 404. The refractive index distributed lens 405 is a cylindrical lens. The refractive index of the refractive index distributed lens 405 is equivalent to, for example, the refractive index of the core of the optical fiber 404 on the optical axis, and decreases as it moves away from the optical axis.

[0038] Since the structure of the receiving side is the same as (symmetrical) as that of the transmitting side, a detailed explanation will be omitted. The refractive index distribution lens 505 provided at the input end of the optical fiber 504 on the receiving side can return light that has shifted from the optical axis towards the center, thereby reducing coupling loss due to optical axis misalignment.

[0039] Furthermore, if a distributed refractive index lens 505 is provided on the receiving side, aberrations can be suppressed more effectively by providing a similar lens (distributed refractive index lens 405) on the transmitting side as well. Therefore, in this example, a distributed refractive index lens 405 is also provided on the transmitting side.

[0040] The optical fiber 404 is, for example, a graded-index optical fiber and has the refractive index distribution shown in Figure 7. The characteristics of the optical fiber 404 can be expressed by three parameters: the core diameter, which indicates the width of the refractive index distribution; α, which indicates the shape (steepness) of the refractive index distribution; and the central dip, which indicates the depth of the central depression. Due to manufacturing constraints, it is difficult to make the central dip zero.

[0041] Figure 8 shows the simulation results of the coupling efficiency when four parameters—the three parameters of the transmitting optical fiber 404 mentioned above, and the ratio of the fundamental mode and first mode of light propagating through this optical fiber 404—are randomly selected 120 times in the transmitting / receiving structure of Figure 6. If the baseline coupling efficiency is set to, for example, 0.6, it can be seen that the results include trials (experiments) that do not meet the baseline value. In cases where there is such a large variation in the characteristics of optical fibers, it is necessary to select optical fibers with characteristics within an acceptable range in order to achieve a coupling efficiency above the baseline value. Note that the coupling efficiency here refers to the worst-case coupling efficiency η, which will be discussed later. Ｗ That is the case.

[0042] This section explains the principle for determining whether the characteristics of an optical fiber are within acceptable limits. This principle enables highly accurate determination without the need for expensive equipment such as optical fiber refractive index meters, even when determination based on three parameters is difficult.

[0043] Figure 9A shows the intensity distribution of light containing only the fundamental mode components in a cross-section along the axial direction of an optical fiber. It can be seen that the intensity is high on the core side (center side) of the optical fiber and low on the cladding side (outside side). The graph on the right shows the near-field pattern (NFP). Here, the NFP is the intensity distribution at the output end of the optical fiber, depending on the position x from the center in the radial direction of the optical fiber.

[0044] Figure 9B shows the intensity distribution of light with fundamental mode and first-order mode components in a cross-section along the axial direction of an optical fiber. The ratio of fundamental mode to first-order mode is 50:50. It can be seen that hotspots appear alternately above and below the core. The graph on the right shows NFP. When the hotspot is located below the core at the output end, as shown in Figure 9C, the light emitted from the output end travels diagonally downwards. Conversely, when the hotspot is located above the core at the output end, the light emitted from the output end travels diagonally upwards.

[0045] Figure 10A is a graph showing NFP according to the position of the output terminal. The position of the output terminal is shown in Figure 10B, q １ ~q ６ The horizontal axis corresponds to the vertical direction in Figure 10B, and the vertical axis shows the normalized intensity I, with a maximum value of 1.

[0046] There is a hotspot on the upper side of the output terminal (q １ ~q ３ In this case, the intensity is maximum at one point in the region x < 0 (hereinafter referred to as the first peak) (argmax I(x) < 0), and the intensity is local rather than maximum at one point in the region x > 0 (hereinafter referred to as the second peak). Conversely, if there is a hotspot below the output terminal (q ４ ~q ６ In this case, we can see that the first peak is in the region x > 0 (argmax I(x) > 0), and the second peak is in the region x < 0.

[0047] This is also true when the ratio of the basic mode to the primary mode is changed from 50:50. Figures 11A to 11D are graphs showing NFP when the mode ratios are 20:80, 40:60, 60:40, and 80:20, respectively.

[0048] Figure 12A is a graph showing the simulation results of the far-field pattern (FFP) of light output from an optical fiber when the four parameters described above are randomly selected 24 times. Here, as shown in Figure 12B, the FFP is the distribution of intensity at a location far from the output end of the optical fiber, corresponding to the angle θ from the axial direction of the optical fiber. In Figure 12A, the intensity I is normalized.

[0049] For each of the 24 FFPs, a variable transformation (change of variables) from θ to φ (hereinafter referred to as the first variable transformation) is performed. Specifically, θ ０ Let = argmaxI(θ), then θ ０ When > 0, φ = θ - θ ０ On the other hand, θ ０ When < 0, φ = -(θ - θ)０ Therefore, the first variable transformation is to set the horizontal axis θ such that the first peak is located on the vertical axis I (φ=0). ０ The first variable transformation involves shifting the graph to the right and, if necessary, inverting the horizontal axis φ so that the second peak is located to the left of the vertical axis I (φ < 0). The 24 intensity distributions I(φ) shown in Figure 13 are obtained through the first variable transformation. Note that the condition "the second peak is located to the left of the vertical axis I" can be replaced with a condition such as "the intensity distribution I(φ) decreases monotonically to the right of the vertical axis I (φ > 0)."

[0050] Furthermore, for each of the 24 I(φ), a variable transformation from φ to γ ​​(hereinafter referred to as the second variable transformation) is performed. Specifically, I(φ) = I １ φ satisfying the condition φ １ gamma １ Let be any positive real number, then γ = (γ １ / φ １ )φ. For example, I １ = 1 / e ２ (This value is often used in the definition of beam diameter, etc.), γ １ = 30. The second variable transformation is the desired point (γ １ , I １ The horizontal axis φ is set to γ ​​so that the graph passes through ) １ / φ １ This involves doubling. The second variable transformation yields the 24 intensity distributions I(γ) shown in Figure 14. Note that γ = (γ １ / φ １ )φ and φ = ±(θ - θ) ０ ) From this, γ = ±(γ １ / φ １ ) (θ - θ) ０ Therefore, the variable transformation from θ to γ ​​is a one-dimensional affine transformation. Also, if i(θ) is the unnormalized intensity, then I(θ) = i(θ) / maxi(θ). Therefore, the transformation from i(θ) to I(γ) is a two-dimensional affine transformation.

[0051] Furthermore, the conversion result from I(θ) to I(γ) described above does not depend on the position of the output terminal. This can be confirmed by the fact that the six I(γ) obtained by converting the six I(θ) shown in Figure 15A are identical, as shown in Figure 15B. Here, the six I(θ) are obtained by fixing the four parameters mentioned above to one value and positioning the output terminal q shown in Figure 10B. １ ~q ６ These were selected from the following.

[0052] For each of the 24 I(γ) obtained in this way, I(γ) = I ２ γ that satisfies (hereafter referred to as FFP feature γ) ２ We will find the following: ２ ≠I １ For example, I ２ = 0.4. Figure 16 shows the γ obtained from 24 I(γ). ２ and worst-case coupling efficiency η Ｗ This graph shows the relationship between γ. Figure 17 is a graph in which the number of samples is increased from 24 to 128, instead of omitting the transformation process. In both graphs, γ ２ and η Ｗ A positive correlation can be observed between them. Therefore, γ ２ From the value of η Ｗ It is possible to calculate an estimated value of γ and determine whether the coupling efficiency is above a certain threshold value based on whether the FFP features are above a predetermined value. For example, if the threshold value for coupling efficiency is 0.6, ２ You should select an optical fiber with a value of approximately 19.1 or higher.

[0053] Note that this correlation is γ １ It does not depend on the value of γ. １ If we multiply the value by k, we get γ ２ The value of γ is also multiplied by k, and the slope of the regression line becomes 1 / k, but the correlation coefficient does not change. Therefore, the normalized FFP feature γ is used as the FFP feature. ２ / γ １ (Calculating this value means γ １ Let γ be set to = 1 ２ You may also use (which is equivalent to calculating ). If φ(I) is the inverse function of I(φ) for φ≧0, then γ ２ / γ １ = φ(I ２ ) / φ(I １ ) is. Also, if the inverse function of I(θ) at θ≧θ ０ ≧0 or θ≦θ ０ <0 is θ(I), then γ ２ / γ １ = (θ(I ２ ) - θ ０ ) / (θ(I １ ) - θ ０ ). Therefore, the FFP feature amount is the angle ratio of two points on the FFP to which an affine transformation is applied, and is θ ２ / θ １ shown in FIG. 18. For example, when the reference value of the coupling efficiency is 0.6, an optical fiber with γ ２ / γ １ of about 0.638 or more may be selected.

[0054] The worst-case coupling efficiency η Ｗ is the coupling efficiency η under the most severe conditions from the viewpoint of the coupling efficiency. The coupling efficiency η does not depend only on the characteristics of the optical fiber. Therefore, by assuming severely other than the characteristics of the optical fiber, an optical fiber capable of achieving a desired coupling efficiency even under severe conditions can be selected. The simulation for obtaining the coupling efficiency η Ｗ is performed assuming the transmission and reception structure shown in FIG. 19A. This transmission and reception structure and the transmission and reception structure shown in FIG. 6 are different in the shape of the connector bodies 401 and 501, but this difference does not affect the FFP or the coupling efficiency. Therefore, the two transmission and reception structures can be regarded as the same (even if the shapes of the connector bodies 401 and 501 are simplified for convenience in FIG. 19A, it does not matter).

[0055] The worst case is realized by, for example, two conditions. The first condition is that the axes of the receiving optical fiber 504 and the refractive index distribution type lens 505 are deviated from the axes of the transmitting optical fiber 404 and the refractive index distribution type lens 405. The deviation width here is, for example, 6 μm. The second condition is that, as shown in FIG. 19B, the FFP is most deviated in the direction opposite to the deviation (downward) of the first condition (upward) (q １ and q ６) Furthermore, while the binding efficiency changes depending on the bias of the FFP, the FFP features themselves do not change, as mentioned earlier.

[0056] A critical optical fiber 301 in terms of coupling efficiency can be defined, for example, as an optical fiber with coupling efficiency or (normalized) FFP features that barely exceed a reference value (where the difference or ratio from the reference value falls within a predetermined range).

[0057] "3. Information Processing System" Figure 20 shows an example of the hardware configuration of the information processing system 30. In Figure 20, parts corresponding to those in Figure 3A are denoted by the same reference numerals.

[0058] The receiver 200 includes a connector 204, an optical fiber 201, a light-receiving unit 205, and a control unit 206. The light-receiving unit 205 is equipped with a light-receiving element such as a photodiode. The light-receiving unit 205 converts the optical signal that has passed through the connector 204 and the optical fiber 201 into an electrical signal and supplies that electrical signal to the receiving circuit and the control unit 206. The control unit 206 generates information indicating the received signal strength from the electrical signal and sends it to the determination unit 300. The control unit 206 also controls the operation of each part of the receiver 200.

[0059] The detector 300 includes a light source 304, an optical fiber 301, an intensity distribution adjustment unit 305, a half mirror 306, an intensity distribution measurement unit 307, a moving mirror 308, a connector 309, a control unit 310, and a display unit 311.

[0060] Figure 21A shows a more detailed configuration example of the detector 300. A refractive index distribution lens 302 is provided at the output end of the optical fiber 301. Light is output from the optical fiber 301, and this light is transformed into collimated light by a lens (collimator) 312 via the refractive index distribution lens 302. This collimated light is incident on a half mirror 306 and reflected by a movable mirror 308. This reflected light is focused by a lens (focusing lens) 313, and this focused light is input to a connector 309.

[0061] The control unit 310 controls the operation of each part of the determination device 300. The light source 304 is equipped with light-emitting elements such as a vertical-cavity surface-emitting laser (VCSEL) or a light-emitting diode (LED). The light output from the light source 304 is input to the input terminal of the optical fiber 301. As mentioned above, the optical fiber 301 is an optical fiber compatible with double-mode optical communication and propagates the fundamental mode and the primary mode. Therefore, the light in the optical fiber 301 has components of the fundamental mode and the primary mode.

[0062] The intensity distribution adjustment unit 305 adjusts the intensity distribution at the output end of the optical fiber 301 based on the control signal from the control unit 310. When performing the first determination, the intensity distribution adjustment unit 305 adjusts the intensity distribution at the output end of the optical fiber 301 to a reference distribution. When performing the second determination, the intensity distribution adjustment unit 305 adjusts the intensity distribution at the receiver 200 (focusing point p) to a severe distribution by adjusting the intensity distribution at the output end of the optical fiber 301.

[0063] The intensity distribution adjustment unit 305 adjusts the intensity distribution at the output end of the optical fiber 301 by, for example, controlling the bending state of the optical fiber 301. It is known that the bending state of the optical fiber affects the phase of each mode (fundamental mode and first-order mode). By applying this, the intensity distributions shown in Figures 4B to 4D can be selectively realized.

[0064] Figures 22A to 22D show examples of the configuration of the intensity distribution adjustment unit 305. The intensity distribution adjustment unit 305 includes a fixed plate 321, a shaft 322 standing on the fixed plate 321, a cylindrical fiber support 323 inserted into the shaft 322, a rail 324 fixed to the fixed plate 321, a shaft 325 that stands movable along the rail 324, a cylindrical fiber support 326 inserted into the shaft 325, and cylindrical fiber supports 327 and 328. Figures 22A and 22C are side views of the intensity distribution adjustment unit 305, respectively, and Figures 22B and 22D are front views of the intensity distribution adjustment unit 305, respectively.

[0065] As shown in Figures 22A and 22C, the optical fiber 301 extends to the half-mirror 306 via the left side of the fiber branch 323 and to the light source 304 via the right side of the fiber branch 326. In this way, the optical fiber 301 is supported by the fiber branch 323 and the fiber branch 326. The curvature of the optical fiber 301 can be changed by moving the fiber branch 326 (axis 325) along the rail 324. At this time, damage to the optical fiber 301 is suppressed as the fiber branch 326 rotates (passively) around the axis 325.

[0066] The movement of the shaft 325 can be achieved, for example, by driving a stepper motor based on a control signal from the control unit 310. In Figures 22A and 22B, the fiber branch 326 is in the lower position and the curvature of the optical fiber 301 is small. In Figures 22C and 22D, the fiber branch 326 is in the upper position and the curvature of the optical fiber 301 is large.

[0067] Furthermore, the cylindrical fiber supports 327 and 328, like the fiber support column 326, move based on control signals from the control unit 310 to change the twisting state of the optical fiber 301. For example, by changing the twisting state of the optical fiber 301, the direction of the strength deviation axis can be adjusted.

[0068] Figures 23A and 23B show other configuration examples of the intensity distribution adjustment unit 305. The intensity distribution adjustment unit 305 has a fiber support 331 that fixedly holds the input end of the optical fiber 301 and a fiber support 332 that fixedly holds the output end of the optical fiber 301. The optical fiber 301 includes a bend between the fiber support 331 and the fiber support 332.

[0069] Furthermore, the intensity distribution adjustment unit 305 has a rail 333 and a fiber branch 334 that can move along the rail 333 between the fiber branches 331 and 332. The rail 333 is arranged on a straight line connecting the fiber branches 331 and 332. The fiber branch 334 grips a portion of the optical fiber 301.

[0070] The degree of curvature of the optical fiber 301 can be changed by moving the fiber branch 334 along the rail 333. The movement of the fiber branch 334 can be achieved, for example, by driving a stepping motor based on a control signal from the control unit 310. In Figure 23A, the fiber branch 334 is in the right position, and the deflection of the optical fiber 301 is between the fiber branch 334 and the fiber branch 332. In Figure 23B, the fiber branch 334 is in the left position, and the deflection is between the fiber branch 334 and the fiber branch 331.

[0071] Furthermore, the intensity distribution adjustment unit 305 has cylindrical fiber branches 335 and 336. The fiber branches 335 and 336, like the fiber branches 327 and 328, move to change the degree of twist of the optical fiber 301 based on control signals from the control unit 310.

[0072] As shown in Figure 20, the half-mirror 306 splits the light output from the optical fiber 301 into transmitted light and reflected light. The transmitted light is incident on the intensity distribution measuring unit 307, and the reflected light is incident on the movable mirror 308.

[0073] The intensity distribution measurement unit 307 evaluates the intensity distribution at the output end of the optical fiber 301 by measuring the intensity distribution of the transmitted light from the half mirror 306. The intensity distribution measurement unit 307 is equipped with a photodetector and obtains an image of the intensity distribution of the collimated light from the optical fiber 301 incident on this photodetector. The evaluation result of the intensity distribution at the output end of the optical fiber 301 is transmitted from the intensity distribution measurement unit 307 to the control unit 310.

[0074] The intensity distribution measurement unit 307 (or control unit 310) processes an image of the intensity distribution, for example, using the technology previously proposed by the applicant (see International Publication No. 2018 / 131700), to determine the position and diameter of the optical axis of the collimated light from the optical fiber 301, and evaluates the intensity distribution at the output end of the optical fiber 301. Furthermore, the intensity distribution measurement unit 307 (control unit 310) evaluates whether this intensity distribution is biased in a first direction, a second direction (or whether there is no bias).

[0075] Figure 24A shows an example of an intensity distribution image. Figure 24B is a contour map corresponding to Figure 24A. Figure 24C shows the intensity distribution along the A-B line in Figure 24B. Figure 24D shows an example of an unbiased intensity distribution corresponding to Figure 4C with a solid line c, an example of a biased intensity distribution corresponding to Figure 4B with a dashed line b, and an example of a biased intensity distribution corresponding to Figure 4D with a dashed-dotted line d.

[0076] As shown in Figure 20, the movable mirror 308 reflects the light reflected from the half-mirror 306 to the connector 309. The movable mirror 308 is, for example, a micro-electromechanical system (MEMS) mirror. Based on a control signal from the control unit 310, the movable mirror 308 rotates as shown in Figure 21B or translates as shown in Figure 21C (or a combination thereof) to adjust the input position of light to the connector 309. This makes it possible to move the focusing point p along the intensity deviation axis.

[0077] When performing the first determination, the movable mirror 308 moves the focusing point p along the intensity deviation axis within a predetermined range. When performing the second determination, the total reflection movable mirror 308 moves the focusing point p to a critical position.

[0078] Connector 309 is connected to connector 204 of receiver 200. This optical connector 309, together with the movable mirror 308, is included in the optical output adjustment unit. When connector 309 is connected to connector 204, lens 303 faces lens 203, as shown in Figure 3A above.

[0079] When the control unit 310 performs the first determination, it controls the intensity distribution adjustment unit 305 based on information from the intensity distribution measurement unit 307 to adjust the intensity distribution at the output end of the optical fiber 301 to a reference distribution, and controls the movable mirror 308 to move the focusing point p along the intensity deviation axis within a predetermined range, and determines whether the receiving characteristics of the receiver 200 in the reference transmission environment are within an acceptable range.

[0080] Further, when the control unit 310 determines that the reception characteristics of the receiver 200 in the reference transmission environment are within the allowable range, the control unit 310 then makes a second determination. When making the second determination, the control unit 310 controls the movable mirror 308 to move the condensing point p to the severe position, controls the intensity distribution adjustment unit 305 to adjust the intensity distribution at the output end of the optical fiber to the severe distribution, and determines whether the reception characteristics of the receiver 200 in the severe transmission environment are within the allowable range.

[0081] Note that the predetermined value η of the coupling efficiency η in the first determination １ and the predetermined value η of the coupling efficiency η in the second determination ２ do not have to be the same value. For example, the value η １ may be a value larger than the value η ２ This is because in the second determination, the most severe transmission environment for the receiver 200 is reproduced, so the coupling efficiency η in the second determination decreases compared to the coupling efficiency η in the first determination.

[0082] Thus, by setting the value η １ to a value larger than the value η ２ it is possible to determine at the first determination stage that the receiver 200 for which it is determined that the reception characteristics are not within the allowable range in the second determination. In this case, it is not necessary to perform the second determination, and efficient determination becomes possible.

[0083] The control unit 310 may perform the above-described first or second determination on a plurality of intensity deviation axes. The intensity deviation axis can be adjusted, for example, as described above, by changing the degree of twist of the optical fiber 301 in the intensity distribution adjustment unit 305. For example, after making a determination on a certain intensity deviation axis, the control unit 310 may make a determination on an intensity deviation axis rotated by 90 degrees. Also, while discretely or continuously rotating the intensity deviation axis, the most severe or mild intensity deviation axis may be specified from the viewpoint of the coupling efficiency, and the determination may be made on that intensity deviation axis.

[0084] The control unit 310 determines whether the receiving characteristics of the receiver 200 are within an acceptable range based on the first and second determinations on one or more intensity deviation axes. For example, the control unit 310 determines that the receiving characteristics of the receiver 200 are within an acceptable range when it determines that the receiving characteristics of the receiver 200 are within an acceptable range on all the intensity deviation axes that have been inspected or on the most severe intensity deviation axis. Alternatively, the control unit 310 may determine that the receiving characteristics of the receiver 200 are within an acceptable range when it determines that the receiving characteristics of the receiver 200 are within an acceptable range on at least one intensity deviation axis or on the mildest intensity deviation axis.

[0085] The display unit 311 displays the judgment result output from the control unit 310 on the display and informs the user. It is also conceivable that the control unit 310 may display judgment information in addition to the judgment result on the display unit 311. Here, the judgment information may include the coupling efficiency (characteristics) measured in the first judgment and the coupling efficiency measured in the second judgment. The display unit 311 is an example of a notification unit. Alternatively, instead of displaying the judgment result on the display, or in conjunction with displaying it, it is also conceivable that the judgment result could be informed to the user using voice, buzzer sounds, lights, haptics, or a combination thereof.

[0086] Alternatively, the display unit 311 may display judgment information output from the control unit 310, and the user may determine whether or not the receiving characteristics of the receiver 200 are within an acceptable range based on that judgment information.

[0087] "4. Processing Procedure" The flowchart in Figure 25 shows an example of the processing procedure on the receiver 200 side and the determination device 300 side in the information processing system 30 shown in Figure 20.

[0088] In step ST1, the receiver 200 starts operating, for example, in response to a power-on operation by the user. Meanwhile, in step ST11, the determination device 300 starts the determination process in response to a start operation by the user.

[0089] Next, in step ST12, the light source 304 starts emitting light. Then, in step ST13, the control unit 310 controls the intensity distribution adjustment unit 305 based on information from the intensity distribution measurement unit 307, thereby adjusting the intensity distribution at the output end of the optical fiber 301 to the reference distribution.

[0090] Next, in step ST14, the control unit 310 controls the movable mirror 308 so that the focusing point p in the receiver 200 moves within a predetermined range along the intensity deviation axis.

[0091] In step ST2, the receiver 200 generates information indicating the coupling efficiency characteristics and transmits it to the determination device 300.

[0092] Next, in step ST15, the determination device 300 makes a first determination based on the information from the receiver 200.

[0093] If it is determined that the receiving characteristics of the receiver 200 in the reference transmission environment are within an acceptable range, in step ST16, the control unit 310 controls the movable mirror 308 so that the focusing point p in the receiver 200 moves to a critical position.

[0094] Next, in step ST17, the control unit 310 controls the intensity distribution adjustment unit 305 based on information from the intensity distribution measurement unit 307, thereby adjusting the intensity distribution at the output end of the optical fiber 301 to a severe distribution.

[0095] In step ST3, the receiver 200 receives the light transmitted from the determination device 300 in the most severe transmission environment described above. The control unit 206 generates information indicating the received intensity from the electrical signal obtained by the light receiving unit 205 and transmits it to the determination device 300.

[0096] Next, in step ST18, the determination device 300 makes a second determination based on the information from the receiver 200.

[0097] If the receiver 200's receiving characteristics in a severe transmission environment are determined to be within an acceptable range, the determination device 300 displays such determination result on the display unit 311 in step ST19. On the other hand, if the receiver 200's receiving characteristics in a severe transmission environment are determined to be outside an acceptable range, or if the receiver 200's receiving characteristics in a standard transmission environment are determined to be outside an acceptable range in step ST15, the determination device 300 displays such determination result on the display unit 311 in step ST20.

[0098] After the processing in step ST19 or step ST20, the light emission of the light source 304 ends in step ST21, and the determination process ends in step ST22. Also, after the processing in step ST3, the receiver 200 ends its operation in step ST4, for example, in response to a power-off operation by the user.

[0099] Note that the processing procedure shown in the flowchart of Figure 25 shows an example in which the judging device 300 performs the first and second judgments on one intensity deviation axis. When performing judgments on multiple intensity deviation axes, the judging device 300 may, for example, first perform the first judgment on multiple intensity deviation axes, and then perform the second judgment on multiple intensity deviation axes. Alternatively, the judging device 300 may first perform the first and second judgments on one intensity deviation axis, and then perform the first and second judgments on another intensity deviation axis.

[0100] "5. Example of Computer Hardware Configuration" The processing in the determination device 300 shown in Figure 25 above can be executed by hardware, but it can also be executed by software. When a series of processes are executed by software, the programs that make up the software are installed from a recording medium on a computer that is built into dedicated hardware, or on a general-purpose computer that can perform various functions by installing various programs.

[0101] Figure 26 is a block diagram showing an example of the hardware configuration of computer 600. Computer 600 includes a CPU 601, ROM 602, RAM 603, bus 604, input / output interface 605, input unit 606, output unit 607, storage unit 608, drive 609, connection port 610, and communication unit 611. Note that the hardware configuration shown here is just one example, and some of the components may be omitted. Furthermore, it may include components other than those shown here.

[0102] The CPU 601 functions, for example, as an arithmetic processing unit or control unit, and controls the overall operation or part thereof of each component based on various programs recorded in the ROM 602, RAM 603, storage unit 608, or removable recording medium 701.

[0103] ROM 602 is a means for storing programs loaded into the CPU 601 and data used for calculations. RAM 603 temporarily or permanently stores, for example, programs loaded into the CPU 601 and various parameters that change as needed when executing those programs.

[0104] The CPU 601, ROM 602, and RAM 603 are interconnected via the bus 604. Meanwhile, various components are connected to the bus 604 via the input / output interface 605.

[0105] The input unit 606 can be, for example, a mouse, keyboard, touch panel, button, switch, or lever. Furthermore, the input unit 606 may also be a remote controller (hereinafter referred to as a remote control) capable of transmitting control signals using infrared rays or other radio waves.

[0106] The output unit 607 may be a device capable of visually or audibly notifying the user of the acquired information, such as a display device like a CRT (Cathode Ray Tube), LCD, or organic EL; an audio output device like a speaker or headphones; a printer, a mobile phone, or a facsimile.

[0107] The storage unit 608 is a device for storing various types of data. Examples of storage units 608 include magnetic storage devices such as hard disk drives (HDDs), semiconductor storage devices, optical storage devices, or magneto-optical storage devices.

[0108] The drive 609 is a device that reads information recorded on a removable recording medium 701, such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, or writes information to the removable recording medium 701.

[0109] The removable recording medium 701 may be, for example, DVD media, Blu-ray® media, HD DVD media, or various semiconductor storage media. Of course, the removable recording medium 701 may also be, for example, an IC card equipped with a contactless IC chip, or an electronic device.

[0110] The connection port 610 is a port for connecting external devices 502, such as a USB (Universal Serial Bus) port, an HDMI (High-Definition Multimedia Interface) port, an IEEE 1394 port, a SCSI (Small Computer System Interface), an RS-232C port, or an optical audio terminal. The external devices 702 are, for example, a printer, a portable music player, a digital camera, a digital video camera, or an IC recorder.

[0111] The communication unit 611 is a communication device for connecting to the network 703, and is, for example, a communication card for wired or wireless LAN, Bluetooth®, or WUSB (Wireless USB), a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various types of communication.

[0112] The programs executed by the computer may be programs that are processed chronologically in the order described herein, or they may be programs that are processed in parallel or at necessary times, such as when a call is made.

[0113] As explained above, this technology makes it possible to accurately determine whether the receiver's reception characteristics are within an acceptable range.

[0114] "6. Modifications" In the above explanation, the intensity distribution at the output end of the optical fiber 301 was adjusted by changing the curvature of the optical fiber 301. However, the method of adjusting the intensity distribution is not limited to this. For example, the intensity distribution at the output end of the optical fiber 301 may be adjusted by changing the intensity distribution at the input end of the optical fiber 301. Here, as a method of changing the intensity distribution at the input end of the optical fiber 301, for example, the relative position between the light source (light-emitting element) 304 and the input end of the optical fiber 301 can be adjusted by changing the position of the light source (light-emitting element) 304.

[0115] Furthermore, in the explanation above, the first wavelength was 1310 nm and the second wavelength was 850 nm. However, since lasers and LEDs can be considered as light sources, the first wavelength could be, for example, between 300 nm and 5 μm, a wavelength in the 1310 nm band including 1310 nm, 1550 nm, or a wavelength in the 1550 nm band including 1550 nm. Also, the second wavelength could be a wavelength in the 850 nm band including 850 nm.

[0116] Furthermore, in the above-mentioned explanation regarding the first determination, we considered the bias of the coupling efficiency characteristics along the intensity deviation axis (vertical direction in Figure 3A). However, the component of the bias along the reference axis (depth direction in Figure 3A) may also be considered. In that case, in order to determine the direction of the two-dimensional bias, in addition to the coupling efficiency characteristics along the intensity deviation axis, the coupling efficiency characteristics in the direction including the component along the reference axis (for example, the direction along the reference axis) may be measured, or instead of the coupling efficiency characteristics along the intensity deviation axis (two-dimensional graph as shown in Figures 3C to 3E), the coupling efficiency characteristics along the plane formed by the intensity deviation axis and the reference axis (three-dimensional graph) may be measured. Subsequently, the second determination may be made based on the direction of the two-dimensional bias (similar to the case where the second determination is made with the most severe intensity deviation axis), or the second determination may be made based on each component of the direction of the two-dimensional bias (similar to the case where the second determination is made with multiple intensity deviation axes). In the latter case, for example, the first and second determinations may be made by first considering only the components along the intensity deviation axis, and then the first and second determinations may be made by then considering only the additional components.

[0117] While preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art of the present disclosure that various modifications or alterations may be conceived within the scope of the technical idea set forth in the claims, and these will naturally also fall within the technical scope of the present disclosure.

[0118] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0119] Furthermore, this technology can also be configured as follows: (1) An information processing apparatus comprising: a transmitting unit that transmits output light to a receiving device; a position adjustment unit that can adjust the position at which the output light converges in the receiving apparatus to a plurality of positions including a first position and a second position which is different from the first position; and an information processing unit that, at least on the basis of coupling efficiency where the output light converges at the second position, performs determination as to whether the receiving characteristics of the receiving apparatus are within an acceptable range or not, or calculates information for the determination. (2) The information processing apparatus according to (1), wherein the first position is the position in which light transmitted from the transmitting unit of the information processing apparatus, which corresponds to an ideal transmitting device, is collected in the receiving device. (3) The information processing apparatus according to (2), wherein the distance between the first position and the second position corresponds to a maximum permissible limit of misalignment of an optical fiber in the receiving apparatus.(4) An information processing apparatus according to any one of (1) to (3), further comprising a distribution adjustment unit capable of adjusting the intensity distribution of input light input to the transmitting unit to a plurality of distributions including a first distribution and a second distribution which is different from the first distribution. (5) An information processing apparatus according to (4), wherein the first and second distributions are different in position of a hot spot, which is a region of high intensity. (6) An information processing apparatus according to (4) or (5), wherein the first distribution is a substantially point-symmetric distribution. (7) An information processing apparatus according to any one of (1) to (6), wherein the information processing unit determines that the receiving characteristics are not within an acceptable range when the coupling efficiency falls below a reference value. (8) The information processing device according to (6), wherein the information processing device performs the determination or calculates the information based at least on a first coupling efficiency when the output light having the first distribution is focused at the first position and a second coupling efficiency when the output light having the first distribution is focused at the second position. (9) The information processing device according to (8), wherein the information processing device determines that the receiving characteristics are not within an acceptable range when the first or second coupling efficiency falls below a reference value. (10) The information processing device according to any one of (4) to (7), wherein the second position is shifted in a first direction from the first position, the second distribution is biased in the first direction, and the information processing device performs the determination or calculates the information based at least on the coupling efficiency when the output light having the second distribution is focused at the second position.(11) The plurality of positions includes a third position, and the information processing unit further determines a first direction at least on the basis of first coupling efficiency where the output light having the first distribution converges at the first position and second coupling efficiency where the output light having the first distribution converges at the second position, and the information processing unit performs the determination or calculates the information at least on the basis of third coupling efficiency where the output light having the second distribution based on the first direction converges at the third position based on the first direction. (12) The information processing apparatus according to (11), wherein the first orientation corresponds to the orientation of the bias of the coupling efficiency characteristics in the receiving device.(13) The information processing apparatus according to (11) or (12), wherein the third position is shifted in a second direction, which is opposite to the first direction, from the position where light transmitted from the transmitting unit of the information processing apparatus corresponding to an ideal transmitting device is focused in the receiving device. (14) The information processing apparatus according to any one of (11) to (13), wherein the second distribution is biased toward the first direction. (15) The information processing apparatus according to any one of (11) to (14), wherein the third coupling efficiency is smaller than the first and second coupling efficiencies. (16) The information processing apparatus according to any one of (11) to (15), wherein the information processing unit determines that the receiving characteristics are not within an acceptable range when the first, second, or third coupling efficiency falls below a reference value. (17) The information processing apparatus according to any one of (1) to (16), wherein input light is input to the transmitting unit via an optical fiber, and the input light in the optical fiber has a fundamental-mode component and a first-order-mode component. (18) The information processing apparatus according to (17), further comprising a distribution adjustment unit that adjusts the intensity distribution of the input light by changing the curvature of the optical fiber.(19) An information processing method comprising: a step of adjusting the position at which output light converges in a reception apparatus from a first position to a second position, which is different from the first position; a step of transmitting the output light that converges at the second position to the reception apparatus to the reception apparatus; and a step of determining whether the receiving characteristics of the reception apparatus are within an acceptable range or calculating determination information for the determination, at least based on the coupling efficiency when the output light converges at the second position.(20) An information processing apparatus comprising: a transmitting unit configured to transmit, to a reception apparatus, output light that is more severe to the reception apparatus than light from an ideal transmission apparatus in terms of coupling efficiency; and an information processing unit that determines whether the reception characteristics of the reception apparatus are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency of the output light. (21) An information processing system comprising a reception apparatus and an information processing apparatus, wherein the information processing apparatus comprises: a transmitting unit that transmits output light to the reception apparatus; a position adjustment unit that can adjust the position at which the output light is focused in the reception apparatus to a plurality of positions including a first position and a second position different from the first position; and an information processing unit that determines whether the reception characteristics of the reception apparatus are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency when the output light is focused to the second position.

[0120] 10... Optical communication system 30... Information processing system 100... Transmitter 101, 201, 301, 404, 504... Optical fiber 102, 103, 203, 302, 303, 312, 313, 402, 405, 502, 505... Lens 200... Receiver 204, 309... Connector 205... Light receiving unit 206, 310... Control unit 300... Detector 304... Light source 305... Intensity distribution adjustment unit 306... Half mirror 307... Intensity distribution measurement unit 308... Movable mirror 311... Display unit 321... Fixing plate 322, 325... Axis 323, 326, 327, 328, 331, 332, 334, 335, 336... Fiber optic branch 324, 333... Rail 401, 501... Connector body 403, 503... Optical fiber insertion hole 600... Computer

Claims

1. An information processing device comprising: a transmitting unit that transmits output light to a receiving device; a position adjustment unit that can adjust the position at which the output light is focused in the receiving device to a plurality of positions including a first position and a second position different from the first position; and an information processing unit that determines whether the receiving characteristics of the receiving device are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency when the output light is focused to the second position.

2. The information processing apparatus according to claim 1, wherein the first position is the position in which light transmitted from the transmitting unit of the information processing apparatus corresponding to an ideal transmitting device is collected by the receiving device.

3. The distance between the first position and the second position corresponds to the permissible limit of the optical fiber displacement in the receiving device, as described in Invoice 2.

4. The information processing apparatus according to claim 1, further comprising a distribution adjustment unit capable of adjusting the intensity distribution of input light input to the transmitting unit to a plurality of distributions including a first distribution and a second distribution different from the first distribution.

5. The information processing apparatus according to claim 4, wherein the first and second distributions differ at the location of the hotspot, which is a high-intensity region.

6. The information processing apparatus according to claim 4, wherein the first distribution is a substantially point-symmetric distribution.

7. The information processing device according to claim 1, wherein the information processing device determines that the receiving characteristics are not within an acceptable range in response to the coupling efficiency falling below a reference value.

8. The information processing device according to claim 6, wherein the information processing device performs the determination or calculates the information based at least on a first coupling efficiency when the output light having the first distribution is focused at a first position and a second coupling efficiency when the output light having the first distribution is focused at a second position.

9. The information processing device according to claim 8, wherein the information processing device determines that the receiving characteristics are not within an acceptable range in response to the first or second coupling efficiency falling below a reference value.

10. The information processing apparatus according to claim 4, wherein the second position is shifted from the first position in a first direction, the second distribution is biased in the first direction, and the information processing unit performs the determination or calculates the information based at least on the coupling efficiency when the output light having the second distribution is focused at the second position.

11. The information processing apparatus according to claim 6, wherein the plurality of positions include a third position, the information processing unit further determines a first orientation based at least on a first coupling efficiency when the output light having the first distribution is focused at the first position and a second coupling efficiency when the output light having the first distribution is focused at the second position, and the information processing unit performs the determination or calculates the information based at least on a third coupling efficiency when the output light having the second distribution based on the first orientation is focused at the third position based on the first orientation.

12. The information processing apparatus according to claim 11, wherein the first orientation corresponds to the orientation of the bias in the coupling efficiency characteristics of the receiving device.

13. The information processing apparatus according to claim 11, wherein the third position is shifted in a second direction opposite to the first direction from the position where light transmitted from the transmitting unit of the information processing apparatus corresponding to an ideal transmitting device is focused in the receiving device.

14. The information processing apparatus according to claim 11, wherein the second distribution is biased toward the first direction.

15. The information processing apparatus according to claim 11, wherein the third coupling efficiency is smaller than the first and second coupling efficiencies.

16. The information processing device according to claim 11, wherein the information processing device determines that the receiving characteristics are not within an acceptable range in response to the first, second, or third coupling efficiency falling below a reference value.

17. The information processing apparatus according to claim 1, wherein input light is input to the transmitting unit via an optical fiber, and the input light in the optical fiber has a fundamental mode component and a first-order mode component.

18. The information processing apparatus according to claim 17, further comprising a distribution adjustment unit for adjusting the intensity distribution of the input light by changing the curvature of the optical fiber.

19. An information processing method comprising: a step of adjusting the position at which the output light is focused in a receiving device from a first position to a second position different from the first position; a step of transmitting the output light, which is focused in the receiving device to the second position different from the first position, to the receiving device; and a step of determining whether the receiving characteristics of the receiving device are within an acceptable range, or calculating determination information for the determination, at least based on the coupling efficiency when the output light is focused to the second position.

20. An information processing device comprising: a transmitting unit that transmits output light to a receiving device that is more critical to the receiving device in terms of coupling efficiency than light from an ideal transmitting device; and an information processing unit that determines whether the receiving characteristics of the receiving device are within an acceptable range or calculates information for the determination, at least based on the coupling efficiency of the output light.

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