JP3359150B2 - Optical component optical loss measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring light loss of an optical component used for optical communication and the like.

[0002]

2. Description of the Related Art The optical loss of an optical component such as an optical fiber or an optical waveguide chip is measured during optical communication or the like. FIG. An example of an apparatus for measuring the optical loss of the core 4 of the waveguide chip 8 is shown. In the figure, a light emitting diode (LE)
A single-mode optical fiber 6 functioning as an optical component for introducing incident light is connected to a light source 11 such as D), and a measurement object to be measured for optical loss is provided on the end face 20 of the single-mode optical fiber 6 on the emission side. The incident side end face 21 of the core 4 of the optical waveguide chip 8 functioning as an optical component is arranged to face the center of the core 4 with an interval L therebetween, and the output side end face 22 of the core 4 is provided with a multimode optical fiber 14 having a large core diameter. The optical power meter 13 is connected to the multi-mode optical fiber 14 in a state where the optical axes are approximately aligned with each other. The optical waveguide chip 8 is fixed, and the optical axis of the single mode optical fiber 6 and the optical axis of the core 4 of the optical waveguide chip 8 are aligned by finely moving the fine movement stage 10.

In such an apparatus, when measuring the optical loss of the core 4 of the optical waveguide chip 8, the incident light introduced into the single mode optical fiber 6 from the light source 11 is made incident on the core 4 of the optical waveguide chip 8. At this time, while finely moving the fine movement stage 10 so that the optical axis of the single mode optical fiber 6 and the core 4 are aligned, the received light intensity of the light emitted from the end face 22 on the emission side of the core 4 is changed via the multimode optical fiber 14. Then, the position where the received light intensity is maximum is determined as the centering position where the optical axes of the single mode optical fiber 6 and the core 4 of the optical waveguide chip 8 are aligned.
Then, based on the difference between the received light intensity at this position and the intensity of the incident light, the light transmission loss of the core 4 of the optical waveguide chip 8 is obtained by subtracting the value of the received light intensity from the value of the incident light intensity. ing.

In this measurement, the core diameter of the multimode optical fiber 14 is large, and the optical coupling loss between the end face 22 of the core 4 and the multimode optical fiber 14 can be almost neglected. Assuming that the light passing loss of the optical power meter 14 can be neglected, the value of the received light intensity measured by the optical power meter 13 is used as it is as the received light intensity of the light emitted from the end face 22 of the core 4. Since the optical coupling loss between the single mode optical fiber 6 and the core 4 is negligible when the and the core 4 are at the centering position, the value of the received light intensity (maximum received light intensity) at the centered position is determined by the value of the incident light. Core 4 subtracted from the strength value
Was measured for light transmission loss.

[0005]

However, in order to measure the light passing loss of the core 4 of the optical waveguide chip 8 by the above-described method, for example, the displacement of the optical axis between the single mode optical fiber 6 and the core 4 is measured. It is necessary to adjust the optical axis in units of 0.1 μm so that the deviation of the optical axis between the single mode optical fiber 6 and the core 4 becomes almost zero. 0.1 μ
Alignment between the single mode optical fiber 6 and the core 4 must be performed by repeating the fine movement in units of m many times, and there is a problem that it takes a very long time. In particular, when measuring the optical loss (light transmission loss) of an optical component such as an optical waveguide chip 8 having a plurality of cores 4 or an optical fiber array having multiple optical fibers, a single mode optical fiber 6 or the like is required. Optical component and optical waveguide chip 8 for introducing incident light
Since the cores and the optical fibers of the optical component to be measured for optical loss must be aligned respectively, such as when the respective cores 4 are aligned, it takes a very long time. It was a problem.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method for measuring the optical loss of an optical component, which can measure the optical transmission loss of the optical component in a short time. It is in.

[0007]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention provides an optical component for introducing incident light and an optical component to be measured which is an optical loss measurement object, facing each other, and makes incident light incident on the optical component to be measured from the optical component for introducing incident light, and An optical component light loss measuring method for measuring a light receiving intensity of light emitted from an emission side of an optical component and obtaining a light passing loss of an optical component to be measured based on a difference between the received light intensity and the intensity of the incident light. The distribution of the optical coupling intensity due to the axis deviation of the optical axis center between the optical component for introducing incident light and the optical component to be measured is represented by the distribution of the received light intensity H (dB), and a, b, and c are constants, X perpendicular to
-The amount of axial deviation の in the X direction on the Y plane and the amount of axial deviation η in the Y direction
Approximating, different incident light introduction optical component and the target light component from opposed positions of one or both directions of the X direction and the Y direction position by a quadratic function of the received light intensity ^{H = aξ 2 + bη 2 +} c by The light receiving intensities at five points when one or both of the optical component for introducing the incident light and the optical component to be measured are slightly moved are _denoted by H ₀ , H ₁ , H ₂ , H ₃ , and H ₄ , respectively, from H ₀ to H ₄ . An original simultaneous quadratic equation is created, and the simultaneous quadratic equation is solved to obtain the value of c when the values of ξ and η of the quadratic function become zero. Based on the difference between the received light intensity and the intensity of the incident light as the received light intensity after the optical axis adjustment when the optical axis is adjusted such that the axis deviation of the optical axis center between the optical component and the optical component to be measured becomes zero. It is characterized in that the light transmission loss of the optical component to be measured is obtained.

[0008]

[Action] In the present invention configured as described above, the received light intensity is axial misalignment of the shaft misalignment amount ξ and Y direction of the X-direction η H = aξ ²
+ Bη ² + c, which is approximated by a quadratic function of the incident light introducing optical component and the incident light introducing optical component at one or both different directions in the X direction and the Y direction from the position where the incident light introducing optical component and the measurement target optical component are arranged to face each other. One or both of the optical components to be measured are finely moved, and the received light intensities at five points at different positions are expressed by a quinary simultaneous quadratic equation of H _{0 to} H _4. By solving this simultaneous quadratic equation, the incident light is obtained. The received light intensity after the optical axis adjustment when the optical axis adjustment is performed so that the axis deviation of the optical axis center between the introduction optical component and the optical component to be measured becomes zero is obtained, and the received light intensity and the intensity of the incident light are obtained. Then, the light transmission loss of the optical component to be measured is obtained based on the difference from the optical component.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same symbols are assigned to the same parts as in the conventional example, and the detailed description thereof is omitted.
FIG. 1 shows an optical component light loss measuring method according to the present invention.
One example of an apparatus for performing optical loss measurement is shown.

Referring to FIG. 1, a light emitting diode (LED)
On the side of the light source light emitting side end face 23 of the light source 11 and the like, the incident side end face 25 of the optical fiber array 9 is connected, and the optical fiber array 9 is provided with a fine moving stage 10, and by the function of the fine moving stage 10. XY perpendicular to the optical axis Z of the optical fiber array device 9
It is configured to be finely movable in the X and Y directions on a plane. An optical waveguide chip 8 of an optical component is disposed on the emission side end face 20 side of the optical fiber arraying device 9 with an interval L therebetween, and the emission side end face 22 of the optical waveguide chip 8 has a core diameter of 50 μm.
The multimode optical fiber 14 is connected, and the optical power meter 13 is connected to the exit side end face 24 side of the multimode optical fiber 14.

[0011] The optical fiber arranging device 9 accurately adjusts the single mode optical fiber 6 so that the error range is 0.5 μm or less.
The two single-mode optical fibers 6a, 6b at both ends are configured such that the light of the light source 11 is incident from the incident-side end faces 25 of the two single-mode optical fibers 6a, 6b. The optical waveguide chip 8 has a width of 8 μm in which quartz glass is laminated on a silicon substrate and titanium glass is doped on quartz glass.
This is a parallel waveguide in which eight rectangular cores 4 are laminated and the periphery of the core 4 is covered with a cladding, and the refractive index difference between the core 4 and the cladding is 0.3%. In this embodiment, the single-mode optical fibers 6a and 6b at both ends of the optical fiber array tool 9 function as optical components for introducing incident light, and the cores 4a and 4b at both ends of the waveguide chip 8 are provided. Is an optical component to be measured as an optical loss measurement target, and incident light (light from the light source 11) is incident on the cores 4a and 4b from the single mode optical fibers 6a and 6b.

The distance L between the optical fiber arrangement 9 and the waveguide chip 8 is within 5 μm, and the optical coupling loss due to the distance L between the single mode optical fiber 6 and the core 4 is 0.01 μm.
The optical fiber arrangement 9 and the waveguide chip 8 are arranged such that the deviation of the optical axis between the optical fiber arrangement 9 and the waveguide chip 8 is within 0.1 deg. Are arranged so that the optical coupling loss due to the angular deviation of the optical axis between the single mode optical fiber 6 and the core 4 can be almost ignored. Therefore, the optical coupling loss between the single mode optical fiber 6 and the core 4 in this embodiment is almost
Is determined on the XY plane perpendicular to the optical axis Z in the X and Y directions.

A personal computer 12 is connected to the optical power meter 13, and the personal computer 12 is connected to the fine movement stage 10. The personal computer 12 receives light intensity detected by the optical power meter 13 and
The positions of the single mode fiber 6 incorporated in the optical fiber array 9 in the X and Y directions on the XY plane perpendicular to the optical axis Z are simultaneously recorded and analyzed by the arithmetic circuit.
It has a function of controlling the fine movement of the fine movement stage 10 and moving the optical fiber alignment tool 9 in the X direction and the Y direction as desired.

As described above, the optical loss measuring device is constructed. Next, the core 4a of the optical waveguide chip 8 is connected to the two single-mode optical fibers 6a and 6b at both ends incorporated in the optical fiber array device 9. , 4b will be described, and the operation of obtaining the optical loss (light transmission loss) of the cores 4a, 4b at the same time will be described. First, each light intensity emitted from the emission side end face 23 side of the light source 11, passes through the single mode optical fibers 6 a, 6 b on both ends of the optical fiber arrangement tool 9, and emerges from the emission side end face 20 of the single mode fibers 6 a, 6 b. To
The measurement is performed by the optical power meter 13 in advance, and the measured values are stored in the personal computer 12 as the incident light intensity.

Next, the single mode optical fibers 6a, 6
b emitted from the optical waveguide chip 8 into the cores 4a and 4b.
The core 4 of the optical waveguide chip 8 enters from the incident side end face 21.
a, 4b, through the multimode optical fiber 14,
The light is emitted from the emission side end face 24 of the multimode optical fiber 14. Then, the exit side end face 24 of the multimode optical fiber 14
The light emitted from is detected by the optical power meter 13 based on the received light intensity H (unit: dB), and the detected received light intensity H is input to the personal computer 12. At this time, the personal computer 12 simultaneously detects and records the positions of the single mode optical fiber 6 incorporated in the optical fiber array 9 in the X and Y directions on the XY plane perpendicular to the optical axis Z.

As shown in FIG. 2, the light receiving intensity H becomes maximum when the optical axis Z of the optical components such as the single mode optical fiber 6 and the core 4 is at the centering position, and It is already known that the optical axis Z becomes smaller when the optical axis Z deviates from the centering position, and the distribution of the received light intensity H is a curve distribution close to a quadratic function curve. Therefore, in the present embodiment, the distribution of the received light intensity H is expressed by the X-Y plane perpendicular to the optical axis.
軸 and η in the Y direction are approximated by a quadratic function of ξ and η shown in the following equation (1), and this quadratic equation is solved by an arithmetic circuit built in the personal computer 12. As a result, the light receiving intensity at the optical axis alignment position where the light receiving intensity becomes maximum is calculated as described below, and the optical loss of the core 4 is determined based on the value of the received light intensity (a, b, c). Is a constant).

H = aξ ² + bη ² + c (1)

First, the optical fiber array tool 9 and the optical waveguide chip 8 are arranged to face each other and the single mode optical fibers 6a,
At positions where the core 6a and the cores 4a and 4b face each other, the received light intensity H ₀ is measured, and the single mode optical fiber 6 from the optical axis alignment position at this time is measured.
Assuming that the amount of axial deviation in the X direction on the XY plane perpendicular to the optical axis Z between the a and 6b and the cores 4a and 4b is ξ and the amount of axial deviation in the Y direction is η, the received light intensity H at this position is assumed. ₀ is expressed as the following equation (2) by the quadratic function equation shown in the above equation (1), and is approximated by a quadratic function of ξ and η (a, b, and c are constants).

H ₀ = aξ ² + bη ² + c (2)

Next, the position at which the received light intensity H ₀ is measured is set as a reference position, and the fine movement stage 10 is finely moved under the control of the personal computer 12 to move the single mode fiber 6 in the X and Y directions on the XY plane. and fine movement in one or both directions of different locations, and detecting the received light intensity at this time by the optical power meter 13, the following equation received light intensity H _n fine movement amount .DELTA..xi _n in the X direction, the Y-direction fine movement amount .DELTA..eta _n Represented by (3) and approximated. Here, n is an integer, and Δξ _n , Δη _n
Is a real number including zero.

H _n = a (ξ− △ ξ _n ) ² + b (η−Δη _n ) ² + c (3)

Therefore, for example, X from the reference position
The received light intensity at the time of fine movement to four different positions in one direction or both directions in the direction and the Y direction is approximated by the following equations (4) to (7).

H ₁ = a (ξ−Δξ ₁ ) ² + b (η−Δη ₁ ) ² + c (4)

H ₂ = a (ξ−Δξ ₂ ) ² + b (η−Δη ₂ ) ² + c (5)

H ₃ = a (ξ−Δξ ₃ ) ² + b (η−Δη ₃ ) ² + c (6)

H ₄ = a (ξ−Δξ ₄ ) ² + b (η−Δη ₄ ) ² + c (7)

In this embodiment, Δξ ₁ = + 2 μm,
Δη ₁ = 0, Δξ ₂ = −2 μm, Δη ₂ = 0, Δξ ₃ =
0, Δη ₃ = + 2 μm, Δξ ₄ = 0, Δη ₄ = −2 μm
To slightly move the single mode optical fibers 6a and 6b,
The received light intensity _{H 1, H 2, H 3} , H 4 of each fine movement position was measured and approximated by the equation (4) to (7).

Next, the values of the received light intensity measured on the core 4a side and the core 4b side and the received light intensity formulas (2) and (4) 〜
By solving the quinary simultaneous quadratic equation of the equation (7), c values when the values of ξ and η are zero are obtained, and the respective values of c are determined by the single mode optical fiber 6 a and the core 4.
a, the value of the received light intensity after the optical axis adjustment when the optical axis adjustment is performed such that the axis deviation (positional deviation in the X direction and the Y direction) of the optical axis center between the single mode optical fiber 6b and the core 4b becomes zero. I do.

By subtracting these values of the received light intensity from the values of the incident light intensity stored in the personal computer 12, the respective cores 4a, 4b
Was calculated.

According to the present embodiment, by the above operation, the optical fiber alignment tool 9 is slightly moved to
Is slightly moved from the position where the core 4 is first arranged to face the core 4 to a different position in one of the X direction and the Y direction, the received light intensity at five points at that time is measured, and each received light intensity is set to H _0. ## EQU00001 ## by approximating with a _quaternary simultaneous quadratic equation of H.sub.4 and solving this simultaneous quadratic equation to obtain the value of c of the quadratic function, without aligning the single mode optical fiber 6 with the core 4. In both cases, the received light intensity at the centering position can be obtained. Therefore, unlike the conventional method of measuring the received light intensity at the time by performing fine adjustment in units of 0.1 μm and performing alignment, the received light intensity (alignment position) after the optical axis adjustment is shortened in a short time. At the same time, and based on the difference between the value of the received light intensity and the intensity of the incident light, the light transmission loss of each of the cores 4a and 4b of the optical waveguide chip 8 can be accurately and simultaneously determined in a short time. You can ask.

According to the present embodiment, as described above,
Since the optical axes of the single-mode optical fibers 6a and 6b and the cores 4a and 4b of the optical waveguide chip 8 do not need to be completely aligned, the pitch interval between the single-mode optical fibers 6 of the optical fiber array device 9 and the optical waveguide chip 8 Even if the pitch interval between the cores 4 is shifted by several μm, the light transmission loss of each core 4 of the optical waveguide chip 8 can be measured without any problem.

The present invention is not limited to the above-described embodiment, but can take various embodiments. For example, in the above embodiment, the cores 4a, 4a at both ends of the optical waveguide chip 8 are used.
b, only incident light was measured, but incident light was incident on all the cores 4 of the optical waveguide chip 8 from all the single-mode optical fibers arranged in the optical fiber aligner 9, for example, a multimode fiber. Using the array, the multi-mode optical fibers 14 arranged in the multi-mode fiber array are connected to the outgoing end faces 22 of all the cores 4 of the optical waveguide chip 8 to receive light emitted from the end face 22 of each core 4. If the intensity is detected by the optical power meter 13, the light transmission loss of all the cores of the optical waveguide chip 8 can be measured simultaneously. As described above, the number of optical components to be measured at the same time is appropriately set.

In the above embodiment, when the optical fiber alignment tool 9 is finely moved by the fine movement stage 10, the single mode optical fiber 6 and the core 4 are arranged in the X direction and the Y direction from the position where they are opposed to each other (reference position). Although the fine movement has been made to a different position in any one direction, the fine movement may be made to a different position in both the X direction and the Y direction from the reference position. Further, in the above embodiment, the received light intensity at the reference position is defined as H _0, and the received light intensity after the optical axis adjustment is obtained based on the received light intensity H ₀ to H ₄ at the five different positions including the reference position. , the H ₀ without including the received light intensity at the reference position, the received light intensity when the fine movement in five different positions from the reference position as H ₄ from H ₀
It may be calculated for the received light intensity of the adjusted optical axis based on the values of H ₄ from. Also, as mentioned above, the different 5
Although the received light intensity after optical axis adjustment can be obtained based on the received light intensity at the point position, the received light intensity at five or more different positions is obtained to form a five-element or more simultaneous quadratic equation. The following equation may be solved to determine the received light intensity after the optical axis adjustment.

Further, in the above embodiment, the single mode optical fiber 6 of the optical fiber arrangement tool 9 is finely moved by ± 2 μm from the reference position in one direction of the X direction or the Y direction, but the fine movement distance of the single mode optical fiber 6 is 1 μm. However, the fine movement distance of the single mode optical fiber 6 may be appropriately set.

Further, in the above-described embodiment, the single mode optical fiber 6 is finely moved by finely moving the optical fiber alignment tool 9 by the fine movement stage 10 while the optical waveguide chip 8 is fixed and the position of the core 4 is fixed. On the contrary, the position of the single mode optical fiber 6 is fixed, and the optical waveguide chip 8 is finely moved by the fine movement stage 10 so that the core 4 is moved.
May be finely moved, or both the optical fiber alignment tool 9 and the optical waveguide chip 8 may be finely moved to finely move the positions of the single mode optical fiber 6 and the core 4 together.

Further, in the above embodiment, the intensity of the incident light,
That is, each light intensity emitted from the emission side end face 20 of the single mode optical fibers 6a and 6b is previously measured by the optical power meter 13.
The measured values are stored in the personal computer 12 as the incident light intensity, and the incident light intensity, the single mode optical fibers 6a and 6b and the core 4 are measured.
Although the light passing loss of the cores 4a and 4b is determined based on the difference between the received light intensities of the cores 4a and 4b, the incident light intensity is not necessarily measured in advance, and the single mode optical fiber 6a , 6b and the cores 4a, 4b, after measuring the received light intensity after the optical axis adjustment, the incident light intensity is measured,
The light passing loss of the cores 4a and 4b may be determined based on the difference between the incident light intensity and the received light intensity after the optical axis adjustment.

Furthermore, in the above embodiment, the incident light introducing optical component is the single mode optical fiber 6 and the measuring object optical component is the core 4 of the optical waveguide chip 8, but the incident light introducing optical component is the single mode optical fiber. The optical component to be measured is not limited to the fiber 6, and the optical component to be measured is not limited to the core 4 of the optical waveguide chip 8, and the optical component for introducing incident light and the optical component to be measured may be other optical components used for optical communication. . Further, instead of connecting the multi-mode optical fiber 14 as in the above embodiment, a single-mode optical fiber may be connected to the emission side of the optical component to be measured such as the core 4 of the optical waveguide chip 8, The optical loss measuring device may be configured to measure the light receiving intensity of light emitted from the emission side of the optical component to be measured.

[0038]

According to the present invention, one or both of the incident light introducing optical component and the measuring object optical component are slightly moved from the position where the incident light introducing optical component and the measuring object optical component are opposed to each other to different positions. The received light intensity at the five points at the time is measured, and each received light intensity is approximated by a simultaneous quadratic equation to solve the simultaneous quadratic equation, thereby obtaining the center of the optical axis between the optical component for introducing incident light and the optical component to be measured. Since the received light intensity after the optical axis adjustment when the optical axis adjustment is performed so that the axis deviation becomes zero can be obtained,
One or both of the incident light introducing component and the optical component to be measured are finely moved, for example, in units of 0.1 μm to adjust the optical axis, and it does not take much time as in the conventional method for obtaining the received light intensity at this time. The received light intensity after the optical axis adjustment can be accurately obtained with time. Therefore, the light transmission loss of the optical component to be measured can be accurately obtained in a short time based on the difference between the obtained light receiving intensity after the optical axis adjustment and the intensity of the light incident on the optical component to be measured.

In particular, conventionally, when measuring the light transmission loss of each optical waveguide of an optical waveguide chip having a multi-core optical waveguide, the optical fiber of an optical fiber array having a multi-core optical fiber array is used. When measuring the passage loss, the optical axis is adjusted for each optical waveguide or each optical fiber, and the light receiving intensity after the optical axis adjustment is obtained. For example, simultaneously measuring the received light intensity emitted from the output side of a multi-core optical waveguide or a multi-core optical fiber, and approximating each received light intensity with a simultaneous quadratic equation to solve those simultaneous quadratic equations As a result, the received light intensity after adjusting the optical axis of each optical waveguide and each optical fiber with respect to the incident light introducing optical component can be obtained at the same time, so that the number of movements of the optical component and the number of measurements of the received light intensity per core are increased. No need, Was based on the value of the light reception intensity after optical axis adjustment, it is possible to obtain the light transmission loss of the optical waveguides and the optical fiber very short time precisely.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of an apparatus for measuring an optical loss of a core 4 of an optical waveguide chip 8 based on an optical component optical loss measuring method according to the present invention.

FIG. 2 is an explanatory diagram showing a received light intensity distribution according to a shift amount of an optical axis between optical components.

FIG. 3 is an explanatory diagram showing an example of an apparatus for performing optical loss measurement by a conventional optical component optical loss measurement method.

[Description of Signs] 4 Core 6 Single Mode Optical Fiber 8 Optical Waveguide Chip 9 Optical Fiber Array Tool 10 Fine Movement Stage 12 Personal Computer 13 Optical Power Meter

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-281850 (JP, A) JP-A-4-190307 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 11/00-11/02 G02B 6/00 G02B 6/24-6/26 G02B 6/36-6/42 G02B 7/00

Claims (1)

(57) [Claims] 1. An optical component for introducing incident light and an optical component to be measured as an optical loss measuring object are arranged to face each other, and incident light is made incident on the optical component to be measured from the optical component for introducing incident light. An optical loss measuring method for an optical component, comprising measuring a light receiving intensity of light emitted from an emission side of the component and obtaining a light passing loss of the optical component to be measured based on a difference between the received light intensity and the intensity of the incident light. Then, the distribution of the optical coupling strength due to the axis shift of the optical axis center between the optical component for introducing incident light and the optical component to be measured is determined by the received light intensity H (d
B), where a, b, and c are constants, and the received light intensity is expressed as H = a に よ っ て² by the amount of axis deviation の in the X direction on the XY plane perpendicular to the optical axis and the amount of axis deviation η in the Y direction. + Bη ² + c 2
Approximate by the following function, the incident light introducing optical component and the measuring object optical component are placed at different positions in one or both directions of the X direction and the Y direction from the position where the incident light introducing optical component and the measuring object optical component are arranged to face each other. On the other hand, or the received light intensity of 5 points when both were finely respectively _{H 0, H 1, H 2} , H 3, as _{H 4} from _{H 0} to make a 5-way simultaneous quadratic equations _{H 4,} the secondary simultaneous The value of c when the values of ξ and η of the quadratic function become zero is determined by solving the equation, and the value of c is calculated as the axis shift of the optical axis center between the optical component for introducing incident light and the optical component to be measured. The light transmission loss of the optical component to be measured is obtained based on the difference between the received light intensity and the intensity of the incident light as the received light intensity after the optical axis adjustment when the optical axis adjustment is performed so that is zero. Optical component loss measurement method.