JPH1172382A - Apparatus for measuring light intensity and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus for measuring light intensity by which an actual light intensity distribution can be displayed with high accuracy by a method wherein a plurality of Gaussian approximate curves are found on the basis of data and a curve which is expressed by a composite function composed of part of the respective Gaussian approximate curves is created. SOLUTION: Data is divided by a data division part 12 which is subject to a light intensity range which is set in advance by a condition setting part 11 or to the dividing condition of position data. A Gaussian approximation operation is executed to respective pieces of divided data, and a plurality of Gaussian approximate curves are obtained. A composite function G(x) is created by a composite function computing part 14. The composite function G(x) which is created here is output, as a characteristic curve 17 expressing a light intensity distribution to a monitor, a plotter, a printer or the like by an output part 15. Whether a next sample to be measured exists or not is judged by a next- sample-to-be-measured existence judgment part 18 so as to be transmitted to a control part 19. In this manner, the control part 19 controls a light detection mechanism part 10 as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to measurement of the light intensity distribution of a laser beam such as a semiconductor laser, a gas laser, a solid-state laser, and a dye laser.

[0002]

2. Description of the Related Art First, an outline of a mechanism portion and an optical system portion of a general light intensity distribution measuring device will be described by taking a semiconductor laser as an example.
This will be described with reference to FIG.

In FIG. 7A, a semiconductor laser 71 pre-positioned in the apparatus emits light with a predetermined light output.
The photodetectors 74a, 74b installed on the rotation mechanisms 72a, 72b via the arms 73a, 73b rotate around the light emitting point (not shown) of the semiconductor laser 71 around the semiconductor laser 71 ( In the figure, the light output spread over a space at a certain distance from the light emitting point is detected while arrows 75a and 75b are shown. Reference numeral 76 denotes a light emission state of the semiconductor laser 71, and slits (not shown) having a width of several tens to several hundreds of micrometers are provided on the light receiving surfaces of the photodetectors 74a and 74b.

The relative position data (hereinafter referred to as position data) between the light detectors 74a and 74b and the light emitting point and the data of the light output detected by the light detectors 74a and 74b are discrete values. . This is because in order to obtain data that is almost continuous, the number of times of data detection increases, a large amount of time is required for measurement, and the mechanism of the measurement device becomes complicated and expensive. For this reason, the number of data detections is appropriately suppressed to obtain discrete data, and the approximate calculation is performed using the position data of the photodetectors 74a and 74b and the data of the detected light output. A technique for obtaining a characteristic curve representing the intensity distribution is effective. The above contents are often used when measuring a far-field image (FFP) of light intensity.

In FIG. 7 (b), a semiconductor laser 71 pre-positioned in the apparatus is radiated at a predetermined light output.
Near-field images (NFP) of light intensity in a space very close to the light emitting point 70 of the semiconductor laser 71 are converted into optical lenses 78a and 78.
The magnification is increased several hundred times through the magnifying optical system 78 by b, and the NFP of the light source to be measured is detected by the minute movement of the photodetector 81. The light receiving surface of the photodetector 81 is provided with a slit (not shown) having a width of several tens of μm. Further, the photodetector 81 may be a silicon vidicon or the like. Filters 79 and 80 are provided in front of the photodetector 81 in accordance with the light output of the semiconductor laser 71.

The relative position data between the light detector 81 and the light emitting point 77, ie, the relative position data between the temporary light emitting point 82 and the light detector 81 obtained by being enlarged by the magnifying optical system 78, and A method of obtaining a characteristic curve representing the light intensity distribution of the light source by performing an approximate calculation using the data of the light output is effective.

By the way, since there is a case where a ripple exists in a laser beam, the detected data is often rattled. Therefore, the approximation operation needs to be converted into smooth curve data by approximation.

In the case of FFP, the angle of movement of the photodetectors 74a and 74b is often used as position data.
In the case of the NFP, the movement amount in the directions 83a and 83b perpendicular to the optical axis 70 of the semiconductor laser 71 is often used. The light intensity distribution of the semiconductor laser has a characteristic that, when the position data is taken on the horizontal axis and the radiation output is taken on the vertical axis, the shape becomes almost a Gaussian curve, so that the position data and the detected radiation output data are used, and the accuracy is high. It is desirable to perform a Gaussian curve approximation.

In many cases, the photodetectors are arranged in two axial directions for detecting the light intensity distribution in the direction parallel to the bonding surface of the semiconductor laser crystal and in the direction perpendicular to the bonding surface. In order to know the overall light intensity distribution, in addition to the two axes, there is also a mechanism in which the photodetector rotates 360 °, or an optical measuring instrument having a mechanism that scans in a plane perpendicular to the optical axis of the semiconductor laser. doing.

The light intensity distribution is measured, and the full width at half maximum (radiation angle at which the light intensity is に 対 し of the peak light intensity), 1 / e,
Obtaining accurate values such as 1 / e ² , light beam diameter, and light deflection angle is extremely important not only for laser research, but also for selecting good products in the inspection process during mass production. Element.

Next, a light intensity distribution curve based on Gaussian approximation will be described with reference to FIGS.

When the mass production of semiconductor lasers started, the processing speed of the arithmetic processing function of the automatic measuring device was extremely slow as compared with the present. Therefore, it took a very long time to acquire data from the measuring head of the measuring instrument and to perform an approximate calculation using the data.

For example, the following equation y = (aａexp ｛−a ² · (x-μ) ² ｝) / √ (π) (1) (where x is position data of the photodetector, and y is detection When the approximation with a Gaussian curve expressed by the following equation is performed, μ and a indicate constants.
Processing time of several tens of seconds to several minutes was required for the number of detected data of 20. Therefore, at that time, it was impossible to employ Gaussian approximation for the approximate calculation processing in the inspection process in mass production from the viewpoint of maintaining the processing capability of the process. For this reason, another simple approximation method described below has been adopted without using the approximation by the Gaussian curve.

As shown in FIG. 8A, a quadratic curve is approximated in the upper part 90 of the light intensity distribution shape, and 1
The following linear approximation was performed to reduce the processing speed. Here, the vertical axis indicates the light intensity (relative value), and the horizontal axis indicates the position data, and the same illustration will be used hereinafter for the figures showing the light intensity distribution curves. A black point group 92 indicates a plot of the detected position data and the light output data, 93 indicates a secondary approximate curve, and 94a and 94b indicate primary approximate curves. In such a method, the degree of correlation becomes worse with respect to the light intensity distribution having characteristics close to the Gaussian distribution, and the divergence between the data and the approximate curve / straight line increases. In particular, the divergence becomes extremely large in the lower part 95. This method was widely used when mass production of semiconductor lasers was started, but it was only about half-width full width 96 that can be obtained with relatively high accuracy.

In recent years, however, the processing speed has been greatly improved due to the remarkable development of technology. Even when approximation is attempted with the Gaussian curve represented by the above equation (1) using the number of detected data of several tens to several hundreds, The arithmetic processing can be performed in several seconds to several tens of seconds.

For this reason, a method for obtaining a light intensity distribution by approximating Gaussian data to measurement data has also been introduced in the inspection process of mass production of semiconductor lasers.

For example, Japanese Patent Application Laid-Open No. 7-43210 discloses an example in which Gaussian approximation is performed from the light intensity of a light beam to be measured and the amount of movement of a photoconductor to obtain a beam shape.

In JP-A-8-110263, only the outer periphery of a laser beam or an electron beam is measured, and from the measurement results, the entire shape and intensity distribution of the laser beam or the electron beam are calculated using Gaussian approximation. Is disclosed.

Generally, when the optical waveguide inside the semiconductor laser chip is an ideal rectangular waveguide, the tendency is strong. However, considering the actual optical waveguide, the structure that the light absorption is small in the lateral direction, that is, near the center in the active layer, but increases as the distance from the center increases, and the refraction between the upper and lower cladding layers and the active layer Most semiconductor laser chips that are actually manufactured do not have an ideal rectangular optical waveguide state because of the unevenness of the rate difference and non-uniformity. Has a tendency to deviate from the Gaussian curve. In most cases, as shown in FIG. 8B, it is general that the shape has a broader skirt with respect to the Gaussian curve. Here, a black point group 100 indicates a plot of the detected position data and radiation output data, and a curve 101 indicates a Gaussian approximate curve based on all data. Near the apex 102 of the light intensity distribution, that is, the center of the light beam is approximated with high accuracy, but the actual data and the Gaussian approximation curve depart from each other as they are located outside from the center of the light beam,
In the vicinity 103 of the bottom of the light intensity distribution, that is, in the outer peripheral portion of the light beam, the divergence becomes large and the approximation is not accurately performed. The divergence between the Gaussian curve and the actual light intensity distribution tends to increase as the position is closer to the foot.

It is extremely difficult to obtain various parameters from the approximation results. It has a value of about 0.135 with respect to the peak intensity 1 and is located at the foot of the light intensity distribution.
In the case of e ² , the Gaussian curve approximating the actual light intensity distribution largely deviates in the vicinity of the base, so that 1 / e
^{The two} values deviate greatly, and the actual 1 / e ² cannot be obtained correctly. Therefore, a large error occurs in the beam diameter defined by the light intensity of 1 / e ² (spread of the beam in the radial direction with the beam traveling direction as the center). In FIG. 8B, 104a is a beam diameter assumed from actual data, and 104b is the Gaussian approximate curve 1
Although the beam diameter is shown by 01, there is a great difference between the two.

In addition, a divergence of the Gaussian curve approximating the actual light intensity distribution occurs near the half-value, so that the half-value full-angle is smaller than the actual value. In FIG. 8B, 105a indicates a full width at half maximum assumed from actual data, and 105b indicates a full width at half maximum according to the Gaussian approximate curve 101. Both have large errors.

In particular, with respect to the horizontal axis, generally, the amount of movement in the direction perpendicular to the optical axis is often used as the position data when measuring the beam diameter, and the angle of the photodetector is often used when measuring full-width at half maximum.

When trying to give 1 / e ² with high accuracy, all the detected data are not used for Gaussian approximation, and only the data near the foot of the light intensity distribution, that is, the data on the outer periphery of the light beam are used for approximation. FIG. 8C shows the result.
Here, the black point group 110 indicates a plot of the detected position data and the radiation output data, and the curve 111 indicates a Gaussian approximation curve based only on the data near the foot of the light intensity distribution, that is, the outer peripheral portion of the detected data. . The Gaussian approximation near the tail 112 of the light intensity distribution is accurately approximated, but the Gaussian approximation curve is not accurately approximated near the apex 113 of the light intensity distribution, ie, the center of the light beam because actual data and the Gaussian approximation curve are separated. Since the peak intensity of the Gaussian curve 111 obtained by this approximation is smaller than the actual peak intensity, an accurate peak intensity is obtained again by using some means, and 1 / e ^{2 of the} obtained accurate peak intensity is obtained. Alternatively, it is necessary to obtain 1 / e, full width at half maximum, and the like. In this case, the largest value data 110a among the discrete data detected as the peak intensity
It is not desirable to use. 110a is often
Ripple caused by turbulence of the beam due to the deposit on the end face of the semiconductor laser crystal, reflection of the light emitted from the rear end face by the monitor diode, etc., the deposit on the exit window, flaws, etc., and the maximum light intensity in the light intensity distribution of the light source to be measured. This is because they are not directly reflected.

The deflection angle 115 of the beam of the light source to be measured is
In order to accurately determine (defined in FIG. 9), it is necessary to find an average light intensity distribution in a certain area near the peak intensity, and it is extremely important to accurately approximate the vicinity of the peak intensity. It is. As described above, the method of FIG. 8C has a problem that the vicinity of the peak intensity cannot be accurately approximated.

FIG. 8D shows a case where an attempt was made to give the full width at half maximum with high accuracy, and data which existed in a certain range near the half value of the peak intensity among the detected data was used for approximation. . In this case, near the half value of the light intensity distribution 12
Although the Gaussian approximation 2 is accurately performed, the vicinity 123 of the top of the light intensity distribution and the vicinity 124 of the base of the light intensity distribution are not accurately approximated and are separated. Here, the black point group 120 indicates a plot of the detected position data and the light output data, and the curve 121 indicates a case where approximation is performed by using data existing in a certain range near the half value of the detected data. 2 shows a Gaussian approximation curve.

For the above reasons, Japanese Patent Application Laid-Open No. 7-43210
Then, any of the problems described above is included.

In Japanese Patent Application Laid-Open No. HEI 8-110263, only the outer peripheral portion of a laser beam or an electron beam is measured, and Gaussian approximation is performed based on the measurement result. There is a problem that the Gaussian curve and the actual light intensity distribution are separated.

[0028]

In the above prior art, when the data of the light intensity distribution obtained discretely is subjected to the Garcian approximation based on the data corresponding to the center of the light beam, the light beam In the vicinity of the data corresponding to the outer peripheral portion, a deviation occurs between the approximate curve and the actual data. On the other hand, when Garcian approximation is performed on the basis of data corresponding to the outer periphery of the light beam, there is a problem that a difference occurs between the approximate curve and actual data near the data corresponding to the center of the light beam. .

In the present invention, the light output spread over a space at a fixed distance from the light emitting point of the light source to be measured is detected, the relative position data between the light detector and the light detector for detecting the light output, and the detected light output. In the optical measurement device that performs Gaussian approximation based on data and measures the light intensity distribution of the light source, the light output present in each of the light intensity ranges 1, 2,. Using the position data to perform Gaussian approximation, the obtained plurality of Gaussian approximate curves are represented by g ₁ (x), g ₂ (x),.
_{Let n} (x). A synthesis function G (x) composed using a part of the obtained Gaussian approximation curve is created and used as a characteristic curve representing a light intensity distribution to be obtained. This can represent the actual light intensity distribution based on the detected light output and the position data with extremely high accuracy. Further, by using this composite function, high-precision full width at half maximum, 1 / e, 1 / e ² , beam diameter, light It is an object of the present invention to provide an optical measurement device capable of measuring a deflection angle of the light.

[0030]

According to a first aspect of the present invention, there is provided an optical measuring device for detecting an optical output spread over a predetermined distance from a light emitting point of a light source to be measured, and the optical detector. Means for performing Gaussian approximation based on relative position data between the light source and the light output detected by the photodetector, and means for outputting data processed by the means, and a light intensity distribution of the light source. In an optical measurement device that measures and outputs the data, among the detected data, a plurality of Gaussian approximate curves are obtained based on the data existing in the light intensity range divided into a plurality by an arbitrary number of divisions and division widths. It is characterized in that a curve represented by a composite function consisting of a part of a Gaussian approximate curve is created and output as a light intensity distribution.

According to a second aspect of the present invention, there is provided an optical measurement device, comprising: a photodetector for detecting a light output spread in a space at a fixed distance from a light emitting point of a light source to be measured; Means for performing Gaussian approximation based on dynamic position data and light output data detected by the light detector, and means for outputting data processed by the means, and light for measuring and outputting the light intensity distribution of the light source In the measuring device,
Among the detected data, a plurality of Gaussian approximate curves are obtained based on the data present at relative positions divided into a plurality by an arbitrary number of divisions and a division width, and a composite function including a part of each Gaussian approximate curve is obtained. A characteristic curve is created and output as a light intensity distribution.

A recording medium according to a third aspect of the present invention detects a light output spread over a certain distance from a light emitting point of a light source to be measured, and detects relative position data between a light detector and a light emitting point and the light output. When performing Gaussian approximation using the data of the light output detected by the detector, the light intensity range of the detected data is divided into a plurality, and a plurality of Gaussian approximation curves are obtained based on the data within each divided range. The program stores a program for creating a characteristic curve of the light intensity distribution of the entire light beam by synthesizing a part of each Gaussian approximate curve and outputting the light intensity distribution.

The recording medium according to claim 4 of the present invention detects the light output spread over a space at a fixed distance from the light emitting point of the light source to be measured, and detects relative position data between a light detector and the light emitting point and the light output. When performing Gaussian approximation based on the light output data detected by the detector, the relative position data range of the detected data is divided into a plurality, and a plurality of Gaussian approximate curves are obtained based on data within each divided range. A characteristic curve of the light intensity distribution of the entire light beam by synthesizing a part of each Gaussian approximate curve, and storing a program for executing an operation of outputting the light intensity distribution.

[0034]

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

A method for obtaining a light intensity distribution curve according to the present invention will be described with reference to FIGS.

As shown in FIG. 1A, the Gaussian approximation is performed using the light output present in each of the plurality of light intensity ranges 1, 2,..., N and the corresponding position data. Then, a plurality of Gaussian approximate curves obtained as above are designated as g ₁ (x), g ₂ (x),..., G _n (x). FIG.
In (a), g ₁ (x), g ₂ (x), and g _n (x) are indicated by a solid line, a dotted line, and an alternate long and short dash line, respectively. A composite function G constructed using a part of the obtained Gaussian approximate curve
(X) is created and used as a characteristic curve representing the light intensity distribution to be obtained. Black point group 4 shows actual data.

FIG. 1B shows a method of creating a composite function.

Gaussian approximate curves g _n-1 (x) and g
_n (x) is _defined by their intersection C _n1 (x _n1 , y _n1 ), C _n2 (x
_n2 , _yn2 ). In each section determined by the demarcated intersection points, a Gaussian approximation curve that better correlates with the actual data represented by the black point group 4a is adopted as an element constituting the synthesis function. In FIG. 1B, x _n2 ≦ x ≦
x _n1 in _{g n1 (x), x>} x n1 and x <In x _n2 g _n
(X), g _n (x) _where x _n2 ≦ x ≦ x _n1 , x>
g _n-1 (x) at x _n1 and x <x _n2 are deleted. The above scanning is performed for one photodetector or one direction of light output detection. FIG. 1C shows the composite function G (x) 8 obtained by the above-described means.

As shown in FIG. 2A, the Gaussian approximation is performed using the light outputs existing in the position data ranges 1, 2,..., N divided into a plurality of ranges and the corresponding position data. The plurality of Gaussian approximation curves obtained by performing the above operations are defined as f ₁ (x), f ₂ (x),..., F _n (x). In FIG. 2A, f ₁ (x), f ₂ (x), and f _n (x) are indicated by a solid line, a dotted line, and an alternate long and short dash line, respectively. Black point group 4 shows actual data.

In the same manner as in the method of creating the composite function shown in FIG. 1B, a composite function F (x) constituted by using a part of the Gaussian approximate curve is created to represent the light intensity distribution to be obtained. Characteristic curve. FIG. 2B shows the obtained composite function F (x) 9.

The composite function G (x) 8 obtained as described above
Alternatively, F (x) 9 represents the actual light intensity distribution based on the detected radiation output and position data with extremely high accuracy. Therefore, by using these combined functions, the full width at half maximum 5, 1 / e, 1 / e ² , the beam diameter 6, the light deflection angle 7, and the like can be measured with high accuracy.

FIG. 3 shows a block diagram of the optical measuring device according to the present invention.

The light detection mechanism 10 includes a mechanism portion, an optical system portion, and the like, which are schematically shown in FIG. 7A or 7B. The light output detection portion 10a outputs detected light output data 10aa ( Although not shown in the figure, there are cases where several stages of amplification calculation processing are performed.), And position data 10bb corresponding to the number of pulses are given from the stepping motor 10b. Both data are stored in the condition setting unit 1 before measurement.
Receiving the light intensity range set in 1 or the condition for dividing the position data, the data is divided by the data dividing unit 12. Gaussian approximation is performed on each of the divided data,
A plurality of Gaussian approximate curves are obtained. In this configuration example,
In the Gaussian approximation units 13a, 13b, and 13c, g
₁ (x), g ₂ (x) and g ₃ (x) are obtained. G
_{Using a part of 1} (x), g ₂ (x), and g ₃ (x), a synthesis function G (x) that faithfully represents the light intensity distribution based on the actually detected data is created by the synthesis function calculator 14. Is done.
The synthesized function G (x) created here is monitored by the output unit 15 as a characteristic curve 17 representing the light intensity distribution, or
Output to a plotter, printer, etc. Further, the parameter calculation unit 16 calculates the half-width full-width, 1 /
Various parameters such as e, 1 / e ² , light beam diameter, and light deflection angle are obtained, and the monitor or the plotter,
Output to a printer or the like. The presence / absence of the next measurement sample is determined by the next measurement sample presence / absence determination unit 18 and transmitted to the control unit 19. As described above, the control unit 19 controls the light detection mechanism unit 10.
Performs general control of. Although not shown, all or part of the data output by the output unit 15 can be recorded in a magneto-optical recording medium or a memory of a magnetic recording medium.

A first embodiment according to the present invention will be described with reference to FIG.

The horizontal axis shows the position data, and the vertical axis shows the light intensity (relative value) of the detected radiation output.

The detected radiation output data 20 (shown by a group of black dots in the figure. This is an example of a setting for detecting 100 data, but the number of black dot groups is partially omitted for easy understanding. The light intensity range is 100% or less to 70% or more of the light intensity ranges 21 and 7 with respect to the average value 20b of several data groups 20a near the maximum value of the light intensity included in the above.
Light intensity range of less than 0% to 40% or more 22, less than 40% to
It is divided into three light intensity ranges 23 of 0% or more. The Gaussian approximation is performed using the radiation output data present in each of the light intensity ranges 21 to 23 and the corresponding position data, and the obtained three Gaussian approximation curves are represented by g.
₁ (x), g ₂ (x), and g ₃ (x). The intersections of g ₁ (x) and g ₂ (x) are represented by C ₁ (x ₁ , y ₁ ), C ₂ (x ₂ ,
y ₂ ), g ₂ (x) and g ₃ (x) intersect at C ₃ (x ₃ ,
_{y 3), C 4 (x} 4, y 4) and to the time, x ₂ ≦ x ≦ x ₁ in g ₁ a _{(x), x 1 <x} ≦ x 3 and x ₄ ≦ x <x ₂ in g ₂
(X) and g ₃ (x) for x> x ₃ and x <x ₄ are adopted as elements constituting the composite function.

As described above, the combined function G (x) 24 of the Gaussian approximate curve in the entire light intensity range is given, and the characteristic curve represents the light intensity distribution to be obtained.

The determination of various characteristic parameters is performed as follows.

The maximum value 24a of the composite function G (x) 24 is defined as the peak intensity of the light intensity distribution of the light source to be measured, and the relative value 1.
Set to 0. Half value of the peak intensity, 1 / e, 1 /
to determine the e ² and the like. Also, the full width at half maximum 2
6. Determine beam diameter 27, deflection angle 28, and the like. As the position data, the amount of movement of the photodetector in the direction perpendicular to the angle or the optical axis is used. The former is used when measuring the full width at half maximum and the deflection angle, and the latter is used when measuring the beam diameter. Both can be easily converted by calculation.

As described above, the synthesis function G (x) 24 that faithfully reproduces the actual light intensity distribution can be obtained, and various parameters relating to the light beam can be obtained with high accuracy. When a light intensity distribution measuring instrument having the configuration shown in FIGS. 7A and 7B is used for a semiconductor laser or the like, two directions, a horizontal direction to a bonding surface of the semiconductor laser chip and a direction perpendicular to the bonding surface, are used. The method of measuring the light intensity distribution according to the above embodiment is effective. The number of divisions of the light intensity range and the setting of the division width are not performed for each measurement or for each sample to be measured.
It is desirable to set before starting the measurement and store it in a control computer or the like from the viewpoint of efficiency.

A first alternative embodiment will be described with reference to FIG.

This embodiment is different from the first embodiment in that the number of radiation output data 40 to be detected is increased and the division of the light intensity range is reduced as compared with the first embodiment. The number of radiation output data 40 to be detected is 300, and the light intensity range is divided into light intensity ranges 41 and 4 of 100% or less to 40% or more.
The light intensity range 42 of less than 0% to 0% or more is set to be divided into two.

The feature of this embodiment is that when the mechanism of the light intensity distribution measuring instrument is designed to be relatively high-grade, for example, the arm including the photodetector is operated at high speed, with high resolution and with high accuracy. This is effective when the user has such a device.

That is, the improvement of the measurement accuracy can be compensated for by increasing the number of optical output data 40 to be detected, and the processing speed can be reduced by reducing the number of Gaussian approximations. In particular, although the performance of computers has been rapidly improving, it is surprisingly often that computers with slow processing speeds are used for a long period of time in the inspection process for mass production once capital investment was made. Therefore, in such a case where the processing speed of the computer for arithmetic processing is slightly slow, reducing the number of Gaussian approximations to the extent that measurement accuracy is not impaired,
This is an effective means for reducing the processing speed.

Here, the respective light intensity ranges 41, 4
The Gaussian approximation is performed using the radiation output data and the position data corresponding thereto, and the obtained Gaussian approximation curves are defined as g ₁ (x) and g ₂ (x). Hereinafter, in the same manner as in the previous embodiments, the synthesis function G
(X) 43, which is a characteristic curve representing the light intensity distribution to be obtained. Thus, the obtained synthesis function faithfully reproduces the actual light intensity distribution, and the various parameters can be obtained with high accuracy.

A second embodiment according to the present invention will be described with reference to FIG.

In the case of a semiconductor laser, the divergence angle of the light beam is different between a direction horizontal to the bonding surface and a direction perpendicular to the bonding surface. In this embodiment, the position data of the photodetector is divided into regions 31, 32, and 33 in the direction horizontal to the bonding surface, and is divided into regions 34, 35, and 36 in the direction perpendicular to the bonding surface. The example which performed Gaussian approximation according to the range is shown.

In the direction horizontal to the bonding surface, the position data of the photodetector is stored in an area 31 of 0 ° ± 5 °, an area 32 consisting of 10 ° ± 5 ° and −10 ° ± 5 °, 20 ° ± 5 ° and The area 33 is divided into three areas of −20 ° ± 5 °. In the direction perpendicular to the joining surface, the position data of the photodetector is stored in the 0 ° ± 10 ° region 34, 25 ° ± 15 ° and -2.
It is divided into three regions: a region 35 composed of 5 ° ± 15 °, a region 36 composed of 50 ° ± 10 ° and a region 36 composed of −50 ° ± 10 °. Gaussian approximation is performed using the position data present in the respective regions 31 to 33 and 34 to 36 and the corresponding radiation output data in the direction parallel to the bonding surface and the direction perpendicular to the bonding surface. The obtained Gaussian approximate curves in the horizontal direction to f
Let _P1 (x), _fP2 (x), _fP3 (x). f _P1 (x)
And f _P2 (x) are defined as C ₅ (x ₅ , y ₅ ), C ₆ (x ₆ ,
y ₆ ), the intersection C ₇ (x ₇ , f _P2 (x) and f _P3 (x)
y ₇ ) and C ₈ (x ₈ , y ₈ ), f _P1 (x) when x ₆ ≦ x ≦ x ₅ and f _p1 when x ₅ <x ≦ x ₇ and x ₈ ≦ x <x _6.
P2 a (x), the x> x ₇ and x <x ₈ f _P3 a (x),
Adopted as an element that composes the composite function.

As described above, the composite function F of the Gaussian approximate curve in the entire light intensity range in the direction horizontal to the bonding surface is obtained.
_P (x) 25a can be given, and becomes a characteristic curve representing the light intensity distribution to be obtained.

Next, the respective Gaussian approximate curves obtained in the direction perpendicular to the joining surface are represented by f _V1 (x), f _V1 (x)
_V2 (x) and _fV3 (x). In the same manner as in the case of the direction horizontal to the joint surface, the composite function F of the Gaussian approximate curve is obtained.
_V (x) 25b can be given, and is a characteristic curve representing the light intensity distribution to be obtained.

Hereinafter, the synthesis function F _P (x) 25a, F
_The method for obtaining various parameters related to the light beam from _V (x) 25b is the same as that in the first embodiment. The obtained synthesis function faithfully reproduces the actual light intensity distribution, and the various parameters are highly accurate. It goes without saying that you can get It is desirable that the number of divisions and the division width of the position data be set before the start of measurement and stored in a control computer or the like, instead of being performed for each measurement or for each sample to be measured. Black point groups 30, 39 show actual radiation output data.

As described above, a program for realizing a series of processing by the optical measuring apparatus of the present invention includes a floppy disk, a hard disk, a magnetic tape, a medium such as a CD-ROM / optical disk / magneto-optical disk, an MD, and a ROM / RAM memory. The following are stored in the recording medium.

The stored program contents are obtained by detecting a light output spread over a space at a fixed distance from the light emitting point of the light source to be measured, and by detecting relative position data between the light detector and the light emitting point and the light detector. When performing Gaussian approximation using the data of the light output, the light intensity range of the detected data is divided into a plurality, and a plurality of Gaussian approximation curves are obtained based on the data within each divided range. A characteristic curve of the light intensity distribution of the entire light beam is created by combining a part of the light beam, and the light intensity distribution is output. At this time, full width at half maximum, 1 / e, 1 / e ² , light beam diameter, light deflection angle And output of various parameters such as output, and the operation of storing and recording, and the light output spread over a certain distance from the light emitting point of the light source to be measured are detected, and the relative position data between the light detector and the light emitting point are detected. When performing Gaussian approximation based on the data of the light output detected by the photodetector and the photodetector, the relative position data range of the detected data is divided into a plurality of pieces, and a plurality of Gaussians are defined based on the data within each divided range. An approximate curve is obtained, and a part of each Gaussian approximate curve is combined to create a characteristic curve of the light intensity distribution of the entire light beam, and the light intensity distribution is output. At this time, the full width at half maximum, 1 / e, 1 / e ^{2. It} outputs the various parameters such as the light beam diameter and the light deflection angle, and executes the operation of storing and recording.

[0064]

According to the optical measuring apparatus of the present invention, the following effects can be obtained in each claim.

In the first and third aspects of the present invention, the light intensity distribution is measured, and the half value of the peak intensity, 1 / e, 1
At / e ² , parameters such as the full width at half maximum, the beam diameter, and the light deflection angle can be accurately obtained.

The second and fourth aspects of the present invention are effective when the ripple is large and the maximum value exceeds the allowable value when divided in the light intensity range. Particularly in the case of a semiconductor laser, the divergence angle of the light beam in a direction horizontal to the bonding surface and in a direction perpendicular to the bonding surface are different, which is effective.

As described above, according to the present invention, there is provided a photodetector for detecting the radiation output of the light source to be measured spread over a space at a fixed distance from the light emitting point, and relative position data between the light detector and the light emitting point and the detected light According to the output data, in an optical measurement device that measures the light intensity distribution of the light source, the light intensity range or the position data range is divided into a plurality, and the light output present in each and the position data corresponding thereto are used. By performing Gaussian approximation and obtaining a composite function composed of a part of the plurality of obtained Gaussian approximate curves, the light intensity distribution of the light source to be measured can be represented very faithfully. This makes it possible to provide an optical measurement device that measures various parameters related to the light beam with high accuracy. Moreover, the economic effect is great.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for obtaining a light intensity distribution based on data existing in a light intensity range in the present invention.

FIG. 2 is a diagram illustrating a method for obtaining a light intensity distribution based on relative position data in the present invention.

FIG. 3 is a diagram illustrating a configuration of an optical measurement device according to the present invention.

FIG. 4 is a diagram showing a first embodiment of the present invention.

FIG. 5 is a diagram showing a second embodiment of the present invention.

FIG. 6 is a diagram showing a first different embodiment of the present invention.

FIG. 7 is a configuration diagram of a general light intensity distribution measuring device in a semiconductor laser.

FIG. 8 is a diagram showing Gaussian approximation according to the prior art.

FIG. 9 is a diagram showing a definition of a beam deflection angle.

[Explanation of symbols]

 4 Black point group indicating detected light output data 5 Full width at half maximum 6 Beam diameter 7 Light deflection angle 8 Synthesis function G (x)

Claims (4)

[Claims] 1. A photodetector for detecting a light output spread over a space at a fixed distance from a light emitting point of a light source to be measured, relative position data between the photodetector and the light emitting point, and detected by the photodetector. A light measuring device for measuring and outputting the light intensity distribution of the light source, comprising: means for performing Gaussian approximation using light output data; and means for outputting data processed by the means. By obtaining a plurality of Gaussian approximate curves based on the data present in the light intensity range divided into a plurality by the number of divisions and the division width, and creating a curve represented by a composite function composed of a part of each Gaussian approximate curve An optical measurement device for outputting as a light intensity distribution. 2. A light detector for detecting a light output spread over a space at a fixed distance from a light emitting point of a light source to be measured, relative position data between the light detector and the light emitting point, and light detected by the light detector. A light measuring device for measuring and outputting the light intensity distribution of the light source, comprising: means for performing Gaussian approximation using light output data; and means for outputting data processed by the means. By obtaining a plurality of Gaussian approximate curves based on the data present at the relative positions divided into a plurality by the number of divisions and the division width, and creating a curve represented by a composite function composed of a part of each Gaussian approximate curve An optical measurement device for outputting as a light intensity distribution. 3. A light output spread over a space at a fixed distance from a light emitting point of a light source to be measured, and data on a relative position between the light detector and the light emitting point and data on a light output detected by the light detector. When performing Gaussian approximation, the light intensity range of the detected data is divided into a plurality, the multiple Gaussian approximation curves are obtained based on the data within each divided range, and a part of each Gaussian approximation curve is synthesized. A recording medium storing a program for executing an operation of creating a characteristic curve of the light intensity distribution of the entire light beam and outputting the light intensity distribution. 4. A light output spread over a space at a fixed distance from a light emitting point of a light source to be measured, and data on a relative position between the light detector and the light emitting point and data on a light output detected by the light detector. When Gaussian approximation is performed, the relative position data range of the detected data is divided into a plurality, the plurality of Gaussian approximation curves are obtained based on the data within each divided range, and a part of each Gaussian approximation curve is synthesized. A recording medium storing a program for executing an operation of creating a characteristic curve of the light intensity distribution of the entire light beam and outputting the light intensity distribution.