JP2023169689A - Light beam diameter measurement device, method, program, and storage medium - Google Patents

Abstract

To measure the diameter (mode field diameter) of a light beam emitted from an optical device without rotating the optical device.SOLUTION: A light beam diameter measurement device 1 comprises: a light reception section (lens-attached fiber) 12 that receives a light beam B; a moving section 14 that moves the light reception section 12 along a plurality of straight lines X1, X2, X3, X4, and X5, which are parallel to one another on a surface S1 to which a direction of travel of the light beam B is normal; a power meter 16 that measures the power of the light beam received by the light reception section 12; and a light beam diameter derivation section 18 that derives the diameter (mode field diameter) of the light beam B as 4λZ/(πdx) (when a wavelength of the light beam B is λ and a distance between an emission end surface 2E of the light beam B and the surface S1 is Z) on the basis of length dx of a first range in which a measurement result is a first predetermined ratio 1/e2 or more, with respect to a maximum value 1 in the straight line X3 that has the highest maximum value of measurement results from the power meter 16 among the plurality of straight lines X1, X2, X3, X4, and X5.SELECTED DRAWING: Figure 1

Description

The present invention relates to measurement of light beam diameter.

Various techniques are known for measuring the mode field diameter (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). For example, while rotating an optical device such as an optical fiber or optical waveguide, an optical power meter receives the light beam output from the optical device and obtains the light intensity distribution (correspondence between the rotation angle of the light source and the optical power). , techniques for calculating the mode field diameter are known.

JP 2019-15584 Publication JP2014-9956A Japanese Patent Application Publication No. 2018-97012

However, there are problems with conventional techniques for rotating optical devices. For example, because it is necessary to increase the distance between the optical device and the power meter (for example, about 20 cm), the power of the optical beam received by the power meter becomes weaker, making it more susceptible to noise and less accurate. In some cases, it becomes impossible to measure the mode field diameter.

Therefore, an object of the present invention is to measure the diameter of a light beam output from an optical device without rotating the optical device.

A light beam diameter measuring device according to the present invention includes a light receiving section that receives a light beam, and a light receiving section that moves the light receiving section along a plurality of straight lines parallel to each other on a plane normal to the traveling direction of the light beam. a moving unit, a power measuring unit that measures the power of the light received by the light receiving unit, and a power measuring unit that measures the power of the light received by the light receiving unit; and a light beam diameter deriving section that derives the diameter of the light beam based on a first range in which the measurement result is equal to or greater than a first predetermined ratio.

In the light beam diameter measuring device configured as described above, the light receiving section receives the light beam. A moving section moves the light receiving section along a plurality of mutually parallel straight lines on a plane normal to the traveling direction of the light beam. A power measuring section measures the power of light received by the light receiving section. The light beam diameter deriving section determines that the measurement result is at least a first predetermined ratio with respect to the maximum value on a straight line in which the maximum value of the measurement result by the power measurement section is the maximum among the plurality of straight lines. Based on the range, derive the diameter of the light beam.

In the light beam diameter measuring device according to the present invention, the first predetermined ratio may be 1/e ² (where e is the base of the natural logarithm).

In addition, in the light beam diameter measuring device according to the present invention, when the length of the first range is dx, the wavelength of the light beam is λ, and the distance between the emission end surface of the light beam and the surface is Z, The light beam diameter deriving section may derive the diameter as 4λZ/(πdx).

In addition, in the light beam diameter measuring device according to the present invention, the moving section further moves the light receiving section along a plurality of orthogonal straight lines that are orthogonal to the straight line and parallel to each other, and the light beam diameter deriving section Furthermore, based on a second range in which the measurement result is greater than or equal to a second predetermined ratio with respect to the maximum value of the orthogonal straight line in which the maximum value of the measurement result by the power measuring unit is the maximum among the plurality of orthogonal straight lines. , the diameter of the light beam may be derived.

In the light beam diameter measuring device according to the present invention, the second predetermined ratio may be 1/e ² (where e is the base of the natural logarithm).

In addition, in the light beam diameter measuring device according to the present invention, the length of the first range is dx, the length of the second range is dy, the wavelength of the light beam is λ, and the output end face of the light beam and the face When the distance from You may also do so.

Note that the light beam diameter measuring device according to the present invention may have a plurality of planes parallel to each other.

In addition, in the light beam diameter measuring device according to the present invention, the light receiving section may be a spherical fiber.

In addition, in the light beam diameter measuring device according to the present invention, the light beam may be emitted from an optical waveguide.

Note that the light beam diameter measuring device according to the present invention further includes a light beam reflected from an optical waveguide, and a reflectance derivation that derives the reflectance of the optical waveguide based on the measurement result by the power measurement section. It may be made to have a section.

The present invention includes a light receiving section that receives a light beam, a moving section that moves the light receiving section along a plurality of straight lines parallel to each other on a plane whose normal is the traveling direction of the light beam, and the light receiving section A method for performing a light beam diameter measurement process in a light beam diameter measuring device having a power measurement unit that measures the power of light received by a light beam diameter derivation for deriving the diameter of the light beam based on a first range in which the measurement result is greater than or equal to a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the unit is the maximum; This is a method for measuring the diameter of a light beam, which includes steps.

The present invention includes a light receiving section that receives a light beam, a moving section that moves the light receiving section along a plurality of straight lines parallel to each other on a plane whose normal is the traveling direction of the light beam, and the light receiving section A program for causing a computer to execute a light beam diameter measurement process in a light beam diameter measurement device having a power measurement unit that measures the power of light received by the plurality of straight lines. Deriving the diameter of the light beam based on a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the power measurement unit is the maximum. This is a program that includes a process for deriving the diameter of a light beam.

The present invention includes a light receiving section that receives a light beam, a moving section that moves the light receiving section along a plurality of straight lines parallel to each other on a plane whose normal is the traveling direction of the light beam, and the light receiving section A computer-readable recording medium having recorded thereon a program for causing a computer to execute a light beam diameter measurement process in a light beam diameter measuring device having a power measuring section for measuring the power of light received by the light beam. The beam diameter measurement process includes a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on a straight line in which the maximum value of the measurement result by the power measurement unit is the maximum among the plurality of straight lines. This recording medium includes a light beam diameter deriving step of deriving the diameter of the light beam based on the above.

FIG. 1 is a functional block diagram showing the configuration of a light beam diameter measuring device 1 according to a first embodiment of the present invention. 3 is a diagram showing a cross section of the light beam B in a plane S1 whose normal is the traveling direction (Z direction) of the light beam B. FIG. It is a diagram showing a plurality of straight lines X1, X2, X3, X4, and X5 along which (the tip of) the light receiving section 12 moves. It is a graph showing the measurement results by the power meter 16 on the straight line X3. FIG. 3 is a diagram showing a plurality of orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 along which (the tip of) the light receiving section 12 moves. It is a graph showing the measurement results by the power meter 16 on the orthogonal straight line Y3. FIG. 2 is a functional block diagram showing the configuration of a light beam diameter measuring device 1 according to a modification of the first embodiment. FIG. 2 is a functional block diagram showing the configuration of a light beam diameter measuring device 1 according to a second embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a functional block diagram showing the configuration of a light beam diameter measuring device 1 according to a first embodiment of the present invention. The light beam diameter measuring device 1 according to the first embodiment includes a light receiving section 12, a moving section 14, a power meter 16, and a light beam diameter deriving section 18.

The light receiving section 12 receives the light beam B. The light receiving section 12 is, for example, a spherical fiber. Moreover, the light beam B is emitted from the optical device 2 and travels in the Z direction (rightward in FIG. 1). The light beam B expands as it travels. The optical device 2 is, for example, an optical waveguide. Note that in FIG. 1, a direction perpendicular to the Z direction and perpendicular to the paper surface is the X direction, and a direction perpendicular to the X and Z directions is the Y direction (upward in FIG. 1).

FIG. 2 is a diagram showing a cross section of the light beam B in a plane S1 whose normal is the traveling direction (Z direction) of the light beam B. The cross section of the light beam B at the plane S1 is circular. The straight line in the X direction passing through center 0 of the circle is called the X axis, the straight line in the Y direction passing through center 0 is called the Y axis, and the straight line in the Z direction passing through center 0 is called the Z axis. In the surface S1, the light beam B has a maximum beam power at the center 0, and the beam power decreases as it moves away from the center 0.

The power meter (power measuring section) 16 measures the power of the light beam B received by the light receiving section 12 .

FIG. 3 is a diagram showing a plurality of straight lines X1, X2, X3, X4, and X5 along which (the tip of) the light receiving section 12 moves.

The moving unit 14 moves the light receiving unit 12 along a plurality of straight lines X1, X2, X3, X4, and X5 that are parallel to each other on a plane (S1) whose normal is the traveling direction (Z direction) of the light beam B. let For example, when the light receiving section 12 is a bulbous fiber, the tip of the light receiving section 12 is moved along straight lines X1, X2, X3, X4, and X5. Note that the straight lines X1, X2, X3, X4, and X5 may be equally spaced. For example, assume that straight line X3 coincides with the X axis.

FIG. 4 is a graph showing the measurement results by the power meter 16 on the straight line X3.

The light beam diameter deriving unit 18 calculates the maximum value (straight line X3 coinciding with the 4, the measurement result is greater than the first predetermined ratio (in Figure 4, it is "1/e ² " (where e is the base of the natural logarithm)). Based on the first range, the diameter (mode field diameter) of the light beam B is derived. Note that the light beam diameter deriving unit 18 acquires from the moving unit 14 which straight line has received the measurement result.

The measurement results of the straight lines X1, X2, X3, X4, and X5 by the power meter 16 take maximum values at the points where each line intersects with the Y axis. The straight line in which these maximum values are maximum is the straight line X3 that coincides with the X-axis, and the maximum values thereof are maximum at the point where straight line X3 and the Y-axis intersect (ie, center 0).

In FIG. 4, the beam power is illustrated with the X coordinate on the straight line X3 taken as the horizontal axis and the beam power taken as the vertical axis. However, the beam power at the center 0 is set to "1". Here, let dx be the length of the first range, which is the range where the beam power is 1/e ² or more.

Here, it is assumed that the wavelength of the light beam B is λ, and the distance between the emission end surface 2E (see FIG. 1) of the light beam B and the surface S1 is Z (see FIG. 1). Note that Z is, for example, about 10 to 200 μm.

Generally, the diameter d(Z) of the light beam B at the surface S1 can be expressed as in the following equation (1).

ただし、MFDは、光ビームＢのモードフィールド径（直径）である。このモードフィールド径（直径）においては、光ビームＢの強度が、最大値の1/e²となる。

However, MFD is the mode field diameter (diameter) of the light beam B. At this mode field diameter (diameter), the intensity of the light beam B becomes 1/e ² of the maximum value.

However, Z needs to satisfy the following condition (formula (2)).

ここで、式（１）のd(Z)に第一範囲の長さdxを代入し、かつ、（4λZ/(πMFD²)）²が１よりも極めて大きいものとする。すると、MFDは4λZ/(πdx)となる。よって、光ビーム径導出部１８は、光ビームＢの直径（モードフィールド径）を4λZ/(πdx)として導出する。ただし、この直径（モードフィールド径）は、Ｘ方向についての直径であるものとする。

Here, it is assumed that the length dx of the first range is substituted for d(Z) in equation (1), and (4λZ/(πMFD ² )) ² is extremely larger than 1. Then, the MFD becomes 4λZ/(πdx). Therefore, the light beam diameter deriving unit 18 derives the diameter (mode field diameter) of the light beam B as 4λZ/(πdx). However, this diameter (mode field diameter) is assumed to be the diameter in the X direction.

FIG. 5 is a diagram showing a plurality of orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 along which (the tip of) the light receiving section 12 moves.

The moving unit 14 further moves the light receiving unit 12 along a plurality of orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 that are orthogonal to the straight lines X1, X2, X3, X4, and X5 and parallel to each other. For example, when the light receiving section 12 is a spherical fiber, the tip of the light receiving section 12 is moved along orthogonal straight lines Y1, Y2, Y3, Y4, and Y5. Note that the orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 may be equally spaced. For example, assume that the orthogonal straight line Y3 coincides with the Y axis.

FIG. 6 is a graph showing the measurement results by the power meter 16 on the orthogonal straight line Y3.

The light beam diameter deriving unit 18 further selects an orthogonal straight line (orthogonal straight line Y3 that coincides with the Y axis) for which the maximum value of the measurement result by the power measuring unit 16 is the maximum among the plurality of orthogonal straight lines Y1, Y2, Y3, Y4, and Y5. ) in the second range where the measurement result is greater than or equal to the second predetermined ratio (in FIG. 6, it is “1/e ² ”) with respect to the maximum value in (in FIG. 6, it is “1”) Based on this, the diameter (mode field diameter) of the light beam B is derived. Note that the light beam diameter deriving unit 18 acquires from the moving unit 14 which orthogonal straight line has received the measurement results.

The measurement results of the orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 by the power meter 16 take maximum values at the points where each intersects with the X axis. The straight line in which these maximum values are maximum is the orthogonal straight line Y3 that coincides with the Y-axis, and their maximum values are maximum at the point where the orthogonal straight line Y3 and the X-axis intersect (ie, center 0).

In FIG. 6, the beam power is illustrated with the horizontal axis representing the Y coordinate of the orthogonal straight line Y3 and the vertical axis representing the beam power. However, the beam power at the center 0 is set to "1". Here, let dy be the length of the second range where the beam power is 1/e ² or more.

Here, it is assumed that the length dy of the second range is substituted for d(Z) in equation (1), and (4λZ/(πMFD ² )) ² is extremely larger than 1. Then, the MFD becomes 4λZ/(πdy). Therefore, the light beam diameter deriving unit 18 derives the diameter (mode field diameter) of the light beam B as 4λZ/(πdy). However, this diameter (mode field diameter) is assumed to be the diameter in the Y direction.

Next, the operation of the first embodiment will be explained.

First, a light beam B is output from the optical device 2. However, it is assumed that the distance Z between the surface S1 and the output end surface 2E of the light beam B satisfies the condition of equation (2).

Here, in the plane S1, the light receiving section 12 (the tip of the spherical fiber) is moved by the moving section 14 along straight lines X1, X2, X3, X4, and X5 (see FIG. 3). At this time, the power of the light beam B received by the light receiving section 12 is measured by the power meter 16. The measurement result is at a first predetermined ratio (Fig. Based on the length dx of the first range, which is greater than or equal to "1/e ² ", the diameter of the light beam B (mode field diameter) is derived as 4λZ/(πdx) in the X direction. .

Furthermore, in the plane S1, the light receiving section 12 (the tip of the spherical fiber) is moved by the moving section 14 along orthogonal straight lines Y1, Y2, Y3, Y4, and Y5 (see FIG. 5). At this time, the power of the light beam B received by the light receiving section 12 is measured by the power meter 16. The measurement result is a second predetermined ratio (indicated as "1" in FIG. 6) to the maximum value (in FIG. 6, "1") on the orthogonal straight line (orthogonal straight line Y3 that coincides with the Y-axis) where the maximum value of the measurement result is the maximum. In Fig. 6, the diameter of the light beam B (mode field diameter) is set as 4λZ/(πdy) in the Y direction based on the length dy of the second range, which is greater than or equal to "1/e ² " in Fig. 6. Derive.

According to the first embodiment, the diameter (mode field diameter) of the light beam B output from the optical device 2 can be measured without rotating the optical device 2.

Furthermore, according to the first embodiment, the distance Z between the surface S1 and the output end surface 2E of the light beam B is as short as, for example, about 10 to 200 μm, and even if the beam power of the light beam B is weak, accurate measurement is possible. becomes possible.

Furthermore, according to the first embodiment, since the optical device 2 can remain fixed, there is no need to connect an optical fiber to the input side of the optical device 2, which reduces the time and monetary costs associated with measurement. Cost can be reduced.

Modification Example In the first embodiment, the light receiving unit 12 measures one surface (surface S1), but a modification example in which a plurality of surfaces (for example, surface S1 and surface S2) is measured is also possible. Conceivable.

FIG. 7 is a functional block diagram showing the configuration of a light beam diameter measuring device 1 according to a modification of the first embodiment. The second embodiment is the same as the first embodiment except that the surface S2 is added. Surface S1 and surface S2 are parallel to each other. For example, the surface S2 is closer to the output end surface 2E than the surface S1. Of course, the surface S2 may be further away from the output end surface 2E than the surface S1. Further, the number of surfaces is not limited to two (S1, S2), and there may be three or more surfaces as long as they are parallel to each other.

The measurement of the beam power performed on the surface S1 and the derivation of the diameter (mode field diameter) of the light beam B in the X direction and the Y direction are similarly performed on the surface S2. Based on the diameter (mode field diameter) of the light beam B derived based on the measurement results on the surface S1 and the diameter (mode field diameter) of the light beam B derived based on the measurement results on the surface S2 (for example, (by taking an average, etc.), the diameter of the light beam B (mode field diameter) can be derived more accurately.

Second Embodiment The light beam diameter measuring device 1 according to the second embodiment is different from the light beam diameter according to the first embodiment in that a reflectance deriving section 27 for deriving the reflectance of the optical waveguide 8 is added. Different from measuring device 1.

FIG. 8 is a functional block diagram showing the configuration of the optical beam diameter measuring device 1 according to the second embodiment of the present invention. The light beam diameter measuring device 1 according to the second embodiment includes a light receiving section 12, a moving section 14, a power meter 16, a light beam diameter deriving section 18, a coupler 23, a light receiving section 22, a moving section 24, a power meter 26, and a reflection section. A rate deriving section 27 is provided. Hereinafter, parts similar to those in the first embodiment will be given the same reference numerals and explanations will be omitted.

In place of the optical device 2 in the first embodiment, an optical waveguide 8 is used in the second embodiment. The optical waveguide 8 has end faces 8E1 and 8E2. The end surface 8E1 is arranged on the light receiving section 12 side, and the end surface 8E2 is arranged on the light receiving section 22 side. The light source 4 provides light to the end surface 8E1 via the coupler 23 and the light receiving section 22. This light passes through the optical waveguide 8 and is emitted from the end surface 8E2.

The light receiving section 12, the moving section 14, the power meter 16, and the beam diameter deriving section 18 are the same as those in the first embodiment, and a description thereof will be omitted. However, the loss caused by inserting the optical waveguide 8 is also measured by bringing the light receiving section 12 into contact with the end surface 8E2 and measuring the power with the power meter 16. That is, by comparing the power (known) of the light emitted by the light source 4 and the power measured by the power meter 16, the loss due to insertion of the optical waveguide 8 can be determined. However, it is assumed that the branching ratio of the coupler 23 is known (for example, 1:1), and that the losses at the end face 8E1 and the end face 8E2 are also known.

The light receiving section 22 (for example, a spherical fiber) is brought into contact with the end surface 8E1 and receives reflected light from the end surface 8E1. The coupler 23 is connected to the light source 4, the light receiving section 22, and the power meter 26. The power meter 26 measures the power of the light beam received by the light receiving section 22 (that is, the light reflected from the end surface 8E1 of the optical waveguide 8). The moving section 24 moves the light receiving section 22 in the X direction and the Y direction. The reflectance deriving section 27 derives the reflectance of the optical waveguide 8 based on the measurement result by the power meter (power measuring section) 26. That is, the reflectance deriving unit 27 can derive the reflectance of the optical waveguide 8 by comparing the power (known) of the light emitted by the light source 4 and the power measured by the power meter 26. It is assumed that the coupling loss between the light reflected by the end surface 8E1 of the optical waveguide 8 and the light receiving section 22 is known (for example, 1 dB). Note that the reflectance deriving unit 27 acquires from the moving unit 24 which part has received the measurement results. This makes it possible to know which part of the end face 8E1 has the reflectance derived, that is, the reflectance distribution.

Note that it is also possible to obtain the refractive index n using the derived reflectance R [dB]. That is, by transforming Fresnel's formula, n=(1+10 ^R/20 )/(1-10 ^R/20 ) can be obtained.

Next, the operation of the second embodiment will be explained.

First, the loss caused by inserting the optical waveguide 8 is measured. That is, light is emitted from the light source 4 and applied to the end surface 8E1 via the coupler 23 and the light receiving section 22. This light passes through the optical waveguide 8 and is emitted from the end surface 8E2. The light receiving section 12 is brought into contact with the end surface 8E2, and the power is measured by the power meter 16, and the loss caused by inserting the optical waveguide 8 is measured.

Next, the reflectance distribution of the end surface 8E1 is measured. That is, the light receiving section 22 (for example, a spherical fiber) is brought into contact with the end surface 8E1 to receive the reflected light from the end surface 8E1. The reflected light is measured by a power meter 26 via a coupler 23. By comparing the power (known) of the light emitted by the light source 4 and the power measured by the power meter 26, the reflectance deriving unit 27 can derive the reflectance distribution of the end surface 8E1 of the optical waveguide 8. Note that it is possible to obtain from the moving unit 24 which part's reflectance is being measured.

Finally, the mode field diameter of the light beam B emitted from the end surface 8E2 is measured. This is the same as the first embodiment, and the explanation will be omitted.

According to the second embodiment, the reflectance distribution of the end surface 8E1 of the optical waveguide 8 can be derived in addition to the same effect as the first embodiment.

Moreover, the above embodiment can be realized as follows. A computer equipped with a CPU, a hard disk, and a media (USB memory, CD-ROM, etc.) reading device reads the media in which programs for realizing each of the above sections, for example, the light beam diameter deriving section 18 and the reflectance deriving section 27, are recorded. and install it on your hard disk. The above function can also be achieved by such a method.

1 Light beam diameter measuring device 2E Output end face 12 Light receiving section (tipped fiber)
14 Moving part 16 Power meter (power measuring part)
18 Light beam diameter deriving section 27 Reflectance deriving section B Light beams X1, X2, X3, X4 and X5 Straight lines Y1, Y2, Y3, Y4 and Y5 Orthogonal straight lines S1, S2 Surface
dx length of first range
dy length of second range

Claims (13)

a light receiving section that receives the light beam;
a moving unit that moves the light receiving unit along a plurality of mutually parallel straight lines on a plane whose normal is the traveling direction of the light beam;
a power measuring unit that measures the power of the light received by the light receiving unit;
The light beam is adjusted based on a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the power measurement unit is the maximum among the plurality of straight lines. a light beam diameter derivation unit for deriving the diameter of the beam;
Optical beam diameter measuring device equipped with The light beam diameter measuring device according to claim 1,
A light beam diameter measuring device, wherein the first predetermined ratio is 1/e ² (where e is the base of a natural logarithm). The light beam diameter measuring device according to claim 2,
When the length of the first range is dx, the wavelength of the light beam is λ, and the distance between the emission end surface of the light beam and the surface is Z,
A light beam diameter measuring device in which the light beam diameter deriving section derives the diameter as 4λZ/(πdx). The light beam diameter measuring device according to claim 1,
The moving unit further moves the light receiving unit along a plurality of orthogonal straight lines that are orthogonal to the straight line and parallel to each other,
The light beam diameter deriving section further calculates a second predetermined ratio of the measurement result to the maximum value on the orthogonal straight line in which the maximum value of the measurement result by the power measuring section is the maximum among the plurality of orthogonal straight lines. A light beam diameter measuring device that derives the diameter of the light beam based on the above second range. The light beam diameter measuring device according to claim 4,
A light beam diameter measuring device, wherein the second predetermined ratio is 1/e ² (where e is the base of a natural logarithm). The light beam diameter measuring device according to claim 5,
The length of the first range is dx,
The length of the second range is dy,
The wavelength of the light beam is λ,
When the distance between the emission end face of the light beam and the surface is Z,
The light beam diameter deriving section is
The diameter in the direction of the straight line is 4λZ/(πdx),
The diameter in the direction of the orthogonal straight line is 4λZ/(πdy),
A light beam diameter measuring device that derives the information as follows. The light beam diameter measuring device according to any one of claims 1 to 6,
A light beam diameter measuring device having a plurality of planes parallel to each other. The light beam diameter measuring device according to any one of claims 1 to 6,
A light beam diameter measuring device, wherein the light receiving section is a spherical fiber. The light beam diameter measuring device according to any one of claims 1 to 6,
An optical beam diameter measuring device, wherein the optical beam is emitted from an optical waveguide. The light beam diameter measuring device according to any one of claims 1 to 6,
The light beam further includes reflected from an optical waveguide;
A light beam diameter measuring device comprising a reflectance deriving section that derives a reflectance of the optical waveguide based on a measurement result by the power measuring section. a light receiving section that receives the light beam; a moving section that moves the light receiving section along a plurality of parallel lines on a plane normal to the traveling direction of the light beam; A method for performing a light beam diameter measurement process in a light beam diameter measuring device having a power measuring section for measuring the power of an object, the method comprising:
The light beam diameter measurement process includes:
The light beam is adjusted based on a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the power measurement unit is the maximum among the plurality of straight lines. A light beam diameter measuring method comprising a light beam diameter deriving step of deriving the diameter of the light beam. a light receiving section that receives the light beam; a moving section that moves the light receiving section along a plurality of parallel lines on a plane normal to the traveling direction of the light beam; A program for causing a computer to execute a light beam diameter measurement process in a light beam diameter measuring device having a power measurement unit that measures the power of an object,
The light beam diameter measurement process includes:
The light beam is adjusted based on a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the power measurement unit is the maximum among the plurality of straight lines. A program that includes a process for deriving the diameter of a light beam. a light receiving section that receives the light beam; a moving section that moves the light receiving section along a plurality of parallel lines on a plane normal to the traveling direction of the light beam; A computer-readable recording medium recording a program for causing a computer to execute a light beam diameter measurement process in a light beam diameter measuring device having a power measurement unit that measures the power of an object,
The light beam diameter measurement process includes:
The light beam is adjusted based on a first range in which the measurement result is at least a first predetermined ratio with respect to the maximum value on the straight line in which the maximum value of the measurement result by the power measurement unit is the maximum among the plurality of straight lines. A recording medium comprising a light beam diameter deriving step for deriving the diameter of the light beam.

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