JPH09184944A - Method and device for adjusting optical axis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for optical axis adjustment which can efficiently adjust the optical axis of an optical module in a short time with high precision irrelevantly to variance in the optical axis of the optical component and differences in specifications. SOLUTION: As for the optical adjusting method of optical module assembly for joining a light emission unit and an optical fiber unit, the light intensity distribution of a projection beam is measured at least at two points on a perpendicular facing the light emission unit, the focus position of the projection beam is found on the basis of information on the respective obtained beam center positions and beam spot diameters, and the core tip part of the optical fiber is set at the focus position. As for the optical axis adjusting method of optical module assembly for joining a light reception unit and the optical fiber unit, the light intensity distribution of the projection beam is measured at least two points on the perpendicular line facing the optical fiber unit, the focus position of the projection beam is found on the basis of information on the respective obtained beam center positions and beam spot diameters, and the light reception surface of the light reception unit is set at the focus position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis adjusting method and an apparatus therefor, and more particularly to an optical axis adjusting method and an apparatus therefor in an optical module assembly for joining a light emitting / receiving unit and an optical fiber unit. In this type of optical module assembly, since the diameter φ of the optical fiber core portion is 10 μm or less, accuracy on the order of submicrons is required. Therefore, it is desired to provide an optical axis adjusting method and an apparatus for efficiently performing such highly accurate optical axis adjustment (optical axis adjustment) and module assembly.

[0002]

2. Description of the Related Art FIG. 8 is a diagram for explaining a conventional technique. FIG. 8A is a sectional view of an example of a light emitting (LD) module,
In the figure, 1 is an optical fiber, 2 is a core part, 3 is a fiber holder, 4 is a package, 5 is a lens, and 6 is a laser diode (LD).

In the LD module in which the optical axis is properly adjusted, the beam emitted from the LD 6 is condensed by the lens 5 and is incident on the tip portion (focus point) of the core portion 2. But in general L
There are variations in the incorporation into D6 and package 4,
This appears as a change in the beam emission position offset, the beam emission angle, and the focal length. Therefore, a proper LD module cannot be obtained only by simply joining the optical fiber unit 3 and the LD unit 4.

Therefore, when assembling such an LD module, it is necessary to align the optical axis of each LD module so that the emitted beam of the LD is focused on the tip of the core portion.
Hereinafter, this is called optical axis adjustment. FIG. 8B is a diagram showing a configuration of a conventional optical axis adjusting / assembling apparatus. In the figure, 11 is a vibration isolation table, 12 is an XY axis moving stage, 13 is a package holding jig, 14 is a Z axis moving stage, Reference numeral 15 is a fiber grip, 16 is a holder holding jig, 21 is an optical power meter,
Reference numeral 22 denotes an information processing unit (personal computer or the like), 23
Is a control unit that controls the drive of each unit.

An XY axis moving stage 12 is mounted on a vibration isolation table 11.
And a Z-axis moving stage 14 are provided, and position control of these is performed with common spatial coordinates (X, Y, Z). The package holding jig 13 is provided on the XY axis moving stage 12 and can move in the directions of the XY plane. The fiber gripper 15 is provided on the Z-axis moving stage 14 and can move in the Z-axis direction.

Further, the package 4 incorporating the LD 6 is held by the package holding jig 13. On the other hand, the fiber holder 3 into which the optical fiber 1 is inserted is held by the holder holding jig 3. In this case, the optical fiber 1 is gripped by the fiber gripper 15 and can be finely moved in the Z direction in the fiber holder 3. The conventional optical axis adjusting method will be described below.

First, the LD 6 in the package 4 is made to emit light,
The light intensity is monitored by an optical power meter 21 connected to the end of the optical fiber 1. Further, the control unit 23 initializes each of the X, Y, and Z stages with initial setting values according to the specifications of the LD module, and the positional relationship between the optical fiber 1 and the package 4 is set to a predetermined value near the maximum light receiving intensity. Set to the initial position of.

Next, each stage of the X, Y, and Z axes is finely moved according to a predetermined sequence, and the optical fiber 1 (Z axis) and the package 4 (XY are set so that the received light intensity becomes maximum.
Make fine adjustments to the (axis) position. When the maximum received light intensity is obtained in this manner, the optical fiber 1 and the fiber holder 3, and the fiber holder 3 and the package 4 are sequentially fixed by YAG laser welding or the like to complete the LD module.

[0009]

By the way, in this kind of optical axis adjustment, since the diameter φ of the optical fiber core portion 2 is generally 10 μm or less, fine adjustment on the order of submicron is required. On the other hand, with respect to the assembly of this type of LD unit, it is necessary to allow for some wide variation.

Therefore, in the method of performing the initial setting of each X, Y, Z stage with the initial setting value according to the specifications of the LD module as in the above-mentioned conventional case, the initial setting position happens to be near the maximum light intensity position. In some cases, it is good, but in other cases, a wide range is searched at a fine pitch until the maximum light intensity is detected, and it takes a lot of time to adjust the optical axis.

Further, when adjusting and assembling LD modules having different specifications, it is necessary to change the initial setting (adjustment start) position and the moving pitch of each stage for each specification, and the parameter management of the optical axis adjusting program is performed. Becomes complicated. The above problems are caused by the adjustment of the PD module in which the optical fiber unit is joined to the photodiode (light receiving) unit.
The same goes for assembly.

An object of the present invention is to provide an optical axis adjusting method and apparatus capable of efficiently performing highly accurate optical axis adjustment of an optical module in a short time regardless of variations in optical axes of optical components and differences in specifications. To do.

[0013]

The above-mentioned problem is solved, for example, by referring to FIG.
The problem is solved by the configuration of (A). That is, the optical axis adjusting method of the present invention (1) is an optical axis adjusting method in an optical module assembly in which a light emitting unit and an optical fiber unit are joined to each other, and at least two points Z1 and Z2 on a vertical line facing the light emitting unit emit an emission beam. The light intensity distribution of
The step of obtaining the focal position of the emitted beam based on the obtained information on the center position of each beam and the beam spot diameter and aligning the core tip of the optical fiber to the focal position is provided.

According to the present invention (1), since the light intensity distribution of the light emitting unit is measured in advance and the tip end portion of the core of the optical fiber is aligned with the focal position of the obtained emission beam, the variation of the optical axis of the light emitting unit. Despite the differences in specifications, the common algorithm enables highly accurate optical axis adjustment in a short time and with high efficiency. Further, since the light intensity distribution of the emitted beam is measured at at least two points Z1 and Z2 on the vertical line facing the light emitting unit, the focal position of the emitted beam can be obtained by calculation,
It takes less time to measure the light intensity distribution.

The focus position of the emitted beam may be the beam center position at the time when the beam spot diameter not more than a predetermined value or the minimum beam spot diameter is detected by measuring the light intensity distribution a plurality of times. In this case, since each light intensity distribution can be measured on a two-dimensional plane, the focus position can be detected more efficiently than in the conventional case where the maximum light intensity is searched by trial and error with an optical power meter. . That is, the measurement plane may be moved only on the Z axis while monitoring the light intensity distribution measurement result.

Further, the optical axis adjusting method of the present invention (2) is an optical axis adjusting method in an optical module assembly in which a light emitting unit and an optical fiber unit are joined to each other, and at least two points on the vertical line facing the light emitting unit A step of measuring the light intensity distribution, obtaining the optical axis or emission angle of the emitted beam based on the obtained information on the center position of each beam, and aligning the core tip of the optical fiber in the optical axis or in the direction of the emission angle. Be prepared.

By the way, in applications where the light emitting module of this type does not require extra high precision, it is sufficient to align the core tip of the optical fiber with the optical axis of the emission beam or in the direction of the emission angle. Axial adjustment effect can be obtained. Moreover, according to the present invention (2), the adjusting equipment and control in the focal direction (Z-axis direction) can be omitted, and therefore the adjusting equipment and control can be greatly simplified.

Preferably, in the present invention (3), after aligning the core tip of the optical fiber, the light receiving intensity of the optical fiber is monitored while the light receiving intensity is maximized so that the light receiving intensity becomes maximum. Fine-tune the direction. The present invention (3)
According to this, even if a fine adjustment process of the submicron order is required, this can always be started in the vicinity of the optimum position, and therefore the fine adjustment of the submicron order can be efficiently performed in a short time without waste.

The above problem can be solved by, for example, the configuration of FIG. That is, the optical axis adjusting method of the present invention (4) is an optical axis adjusting method in an optical module assembly in which a light receiving unit and an optical fiber unit are joined, and at least two points Z1 on the vertical line facing the optical fiber unit.
A step of measuring the light intensity distribution of the emission beam at Z2, obtaining the focal position of the emission beam based on the obtained information of the beam center position and the beam spot diameter, and aligning the light receiving surface of the light receiving unit with the focal position It is a thing.

Therefore, also in assembling the light-receiving module, high-precision optical-axis adjustment can be efficiently performed in a short time by a common algorithm regardless of variations in the optical axes of the light-receiving units and differences in specifications. It should be noted that the beam center position at the time point when a beam spot diameter not more than a predetermined value or the minimum is detected by measuring the light intensity distribution a plurality of times may be the focal position of the emission beam.

The optical axis adjusting method of the present invention (5) is an optical axis adjusting method in an optical module assembly for joining a light receiving unit and an optical fiber unit, wherein at least two points Z1 and Z2 on a vertical line facing the optical fiber unit. At, the light intensity distribution of the exit beam is measured, the optical axis or exit angle of the exit beam is obtained based on the obtained information of the center position of each beam, and the light receiving surface of the light receiving unit is aligned on the optical axis or in the direction of the exit angle. It includes a step of inserting.

In a light receiving unit such as a photodiode, the light receiving area is often larger than the core area of the optical fiber. In such a case, a sufficient optical axis adjusting effect can be obtained only by aligning the light receiving surface of the light receiving unit on the optical axis of the beam emitted from the optical fiber unit or in the direction of the emission angle. Moreover, according to the present invention (5), the adjusting equipment and the control in the focal direction (Z-axis direction) can be omitted, so that the adjusting equipment and the control can be greatly simplified.

Preferably, in the present invention (6), after aligning the light receiving surfaces of the light receiving units, the XY is maximized while monitoring the light receiving intensity of the light receiving element.
Finely adjust the plane and Z-axis. According to the present invention (6), even when a fine adjustment process of the submicron order is required, this can always be started in the vicinity of the optimum position, and therefore the fine adjustment of the submicron order can be efficiently performed in a short time without waste.

The above problem can be solved by, for example, the configuration of FIG. That is, in the optical axis adjusting device of the present invention (7), the light intensity distribution measuring unit and the optical fiber unit are arranged in parallel, and both of them and the light emitting unit are configured to face each other. It is configured to perform the optical axis adjustment of 2) or (3). Therefore, the present invention (1),
The optical axis adjustment according to (2) or (3) can be realized with high efficiency and high reliability.

The above problem can be solved by, for example, the configuration of FIG. That is, in the optical axis adjusting device of the present invention (8), the light intensity distribution measuring unit and the light receiving unit are arranged in parallel, and both of them and the optical fiber unit can be faced to each other. The optical axis is adjusted. Therefore, the optical axis adjustment according to the present invention (4), (5) or (6) can be realized with high efficiency and high reliability.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the same reference numerals indicate the same or corresponding parts throughout the drawings. FIG. 2 is a diagram showing the configuration of the optical axis adjusting / assembling apparatus according to the first embodiment, and shows a case where the optical axis adjusting / assembling is performed between the laser diode (LD) unit and the optical fiber unit. .

In the figure, 1 is an optical fiber, 3 is a fiber holder, 4 is an LD package (LD unit), and the internal structure thereof may be the same as in FIG. 8A. Further, an X-axis moving stage 17, an XY-axis moving stage 12 and a Z-axis moving stage 14 are provided on the anti-vibration table 11, and their positions are controlled by common spatial coordinates (X, Y, Z).
In this case, the X-axis moving stage 17 holds the XY-axis moving stage 12 and can move the specified distance between the light intensity distribution measuring instrument 30 and the holder holding jig 16 at a relatively high speed.

Further, a light intensity distribution measuring device 30, a collimator lens 31, and a YAG laser welding machine 40 are provided on the vibration isolation table 11. The collimator lens 31 is movable in the Z-axis direction with common spatial coordinates (X, Y, Z).
Other package holding jig 13, fiber grip 15,
The holder holding jig 16 may be equivalent to that shown in FIG. Further, 21 is an optical power meter, 22 is an information processing unit (personal computer or the like) that controls and processes the entire apparatus, and 23 is a control unit that drives and controls each unit.

FIG. 2A shows a beam profile process, in which the beam profile of the LD unit 4 is preliminarily obtained to obtain the position coordinates (X0, Y0, Z0) of the position (focus point) at which the emitted beam converges. Preferably, as described below, the laser beam on the Z-axis perpendicular to the beam emission surface of the LD unit 4 is 2
The beam profile is performed for each point, and the focal position (X0, Y0, Z0) of the emission beam is calculated by the calculation based on the obtained information of the beam center position and the beam spot diameter.

Alternatively, the beam profile may be continuously performed, and the focal point position (X0, Y0, Z0) of the emission beam may be set to the beam center position at the time when the beam spot diameter not more than a predetermined value or the minimum is detected. FIG. 2B shows the steps of fine adjustment and welding in the submicron order.
That is, the X-axis moving stage 17 moves the LD unit 4 after the beam profile just below the fiber holder 3. On the other hand, the XY axis moving stage 12 initializes the LD unit 4 so that the beam focal plane position (X0, Y0) of the LD unit 4 is directly below the center of the core portion 2 of the optical fiber 1. Further, the Z-axis moving stage 14 initializes the optical fiber 1 so that the tip of the core portion 2 comes to the height Z0 of the beam focus position.

Thus, no matter how the optical axis (emission position, emission angle, and focal position) of the LD unit 4 varies, the LD unit 4 is always optimal for starting fine adjustment on the order of submicrons. Initialized to position. After that, while monitoring the received light output of the optical fiber 1 with the optical power meter 21, while performing fine adjustment on the order of submicron,
The laser welding machine 40 welds and fixes between the optical fiber 1 and the fiber holder 3, and between the fiber holder 3 and the package 4 at the position where the maximum received light intensity is obtained.

FIG. 3 is a view for explaining the light intensity distribution measuring process of the LD unit, and FIG. 3 (A) shows the principle configuration thereof. In the figure, 30 is a light intensity distribution measuring device, 32 is an ND filter, 33 is a light receiving unit (for example, a photodiode array) in a two-dimensional array, 34 is a drive circuit section, and 35 is
Is an image processing unit.

The beam emitted from the LD unit 4 is converted into a parallel beam by the collimator lens 31 and is incident on the distant light intensity distribution measuring device 30. In this case, since the exit beam of the LD 6 is condensed by the lens 5, the package 4
The emitted beam from is in the shape of a cone directed toward the optical axis O, and a beam having a beam spot diameter φ corresponding to the height Z of the collimator lens 31 enters the light intensity distribution measuring instrument 30.

The incident beam is attenuated in light intensity by the ND filter 32 if necessary, and is input to the photodiode array 33. The drive circuit unit 34 scans the received light output of each photodiode element, amplifies these, and A / D converts them to generate light intensity data for each pixel. The image processing unit 35 uses the two-dimensional XY for each light intensity data.
And the following beam profile processing is performed.

In FIG. 3B, an example of beam profile processing is performed on an optical area of 0.5 mm × 0.5 mm square. The image processing unit 35 scans the memory space corresponding to the optical area in the X-axis and Y-axis directions and obtains the plane coordinates (X1, Y1) of the point where the received light intensities IX, IY are maximum. Since the height Z1 of the collimator lens 31 at that time is known, the point coordinates (X1, Y1, Z1) in space can be obtained. This is nothing but one point on the optical axis O. Furthermore, each light intensity data is set to a predetermined threshold value TH1.
By slicing with, the diameter φ1 of the beam spot at which the beam intensity becomes constant (for example, detection output 1 mW) or more is obtained.

Next, the height of the collimator lens 31 is set to Z2.
(For example, Z2> Z1), the same beam profile processing as above is performed, and the spatial coordinates (X2, Y2, Z2) of another point on the optical axis O and the beam spot diameter φ at that time.
Ask for 2. When the height Z of the collimator lens 31 is changed, the beam bundle density incident on the PD array 33 is different, and therefore the threshold value TH2 may be selected in accordance with the beam diameter φ2. In this way, the second beam spot diameter φ2 is obtained on the extension of the line passing through the conical first beam spot diameter φ1. On the other hand, since the maximum value of the received light intensity can be detected relatively, the same algorithm is used.

FIG. 4 shows the optical axis adjustment / adjustment according to the first embodiment.
In the flow chart of the assembling process, this figure shows the process for adjusting and assembling the optical axis between the LD unit and the optical fiber. This processing is performed by the information processing unit 22.
In step S1, the device is set to the state shown in FIG.
Attach each unit 3, 4 etc.

In step S2, the LD 6 is made to emit light. In step S3, the collimator lens 31 is moved to the position of height Z1. In step S4, the light intensity distribution of the LD unit 4 is measured to determine the first beam center position (X1, Y1) and the beam spot diameter φ1. In step S5, the collimator lens 31 is moved to the position of height Z2 (Z2> Z1).

In step S6, the light intensity distribution of the LD unit 4 is measured again, and the second beam center position (X2, Y) is measured.
2) and the beam spot diameter φ2. Step S7
Then, the exit angle θ of the beam is obtained based on the difference between the beam center positions (X2-X1, Y2-Y1) and the difference between the measurement heights (Z2-Z1). In step S8, the difference in beam diameter (φ2-φ
The height Z0 of the beam focus is obtained based on 1) and the difference between the measured heights (Z2-Z1).

In step S9, the beam focus height Z0,
Beam exit angle θ and one beam center position (X1, Y1
or X2, Y2), the plane coordinates (X0, Y0) of the beam focus are obtained. In step S10, FIG.
As shown in (B), the package holding jig 13 is moved from the light intensity distribution measuring device 30 side to the fiber holding jig 15 side, and at the same time, the position of each component is adjusted in accordance with the obtained spatial coordinates (X0, Y0, Z0). Perform initial settings.

In step S11, fine adjustment is performed for each of the components 1 and 4 on the submicron order on the X, Y, and Z axes. In step S12, the parts are welded and fixed after the fine adjustment is completed. In step S13, the completed part is removed, and the state shown in FIG. 2A is returned to if necessary to assemble the next part.

FIG. 5 is a diagram for explaining an example of optical data calculation processing according to the first embodiment. FIG. 5A is a perspective view of the optical system, and FIGS. 5B and 5C are beam profiles respectively. FIG. 5D is a plan view of a surface including the optical axis O of the emitted beam, and FIGS. It is needless to say that this optical data calculation process is an example, and various other calculation methods can be applied.

In FIG. 5 (A), a laser beam is emitted from the surface of the LD unit 4 in a conical shape, and the posture of its optical axis O is offset from the Z axis, which is a reference assumed in space, as shown in the figure. ing. That is, the position of the beam emission point (center point) is laterally displaced from the origin, and the beam emission direction is also inclined. This shows the general state of this type of LD unit 4.

The collimator lens 31 is moved to the position of height Z1 (for example, 1 mm), and the first beam profile (1) is performed. The result is shown in FIG. According to the beam profile (1), the plane coordinates of the first point P1 on the optical axis O are (X1, Y1), and the height of the point P1 is Z.
It is one. Further, the first spot beam diameter is φ1.

Next, the collimator lens 31 is moved to the height Z2.
After moving to a position (for example, 2 mm), a second beam profile (2) is performed. The result is shown in FIG.
According to the beam profile (2), the plane coordinates of the second point P2 on the optical axis O are (X2, Y2), and the height of the point P2 is Z2. The second spot beam diameter is φ
2 (φ2 <φ1).

Furthermore, the beam profile (1),
Two points P1 projected on the same plane based on both results of (2)
Line segment F passing through (X1, Y1) and P2 (X2, Y2)
(See FIG. 5C). In this case, the plane coordinates of the point p1 where the line segment F and the outermost periphery of the beam spot φ1 intersect can be represented by F (x1, y1), and the plane of the point p2 where the line segment F and the outermost periphery of the beam spot φ2 intersect. The coordinates are F (x
2, y2). These are none other than two points on the line segment L included in the outer circumference of the conical emission beam.

Further, when the above-obtained line segment F is translated in the Z-axis direction, the surface F of FIG. 5A is obtained. A plan view of FIG. 5D is obtained by viewing the surface F at a right angle. FIG.
In (D), the coordinates of the Z axis are 1: 1 with the coordinates of the reference space.
It corresponds to. On the other hand, the coordinates of the F axis are X and Y in the reference space.
It can be represented by the composite coordinates F (X, Y) and F (x, y) of the axis component.

Thus, the coordinates of the two points P1 and P2 on the optical axis O on the ZF plane {Z1, F (X1, Y1)}, {Z.
2, F (X2, Y2)} and the coordinates {Z1, F (x1, y) of two points p1 and p2 on the line segment L corresponding to the beam periphery.
1)}, {Z2, F (x2, y2)} were obtained. After that, various optical data can be easily obtained by a mathematical method as a problem of two straight lines O and L passing through two points (P1, P2) and (p1, p2) on the plane.

For example, the beam exit angle θ is tan ⁻¹ {F
(X2, Y2) -F (X1, Y1)} / (Z2-Z1)
Is determined by Also, the coordinates of the beam focus point {F (X0, Y
0), Z0} is obtained as the coordinates of the point where the optical axis O and the line segment L intersect. Thus, the spatial coordinates (X0, Y0, Z0) of the beam focus position are finally obtained. Further, the spatial coordinates of the beam emission point are also obtained as the coordinates of the point where the optical axis O and the line segment F of Z = 0 intersect.

It is needless to say that the optical data may be calculated from the beginning using the reference spatial coordinate system (X, Y, Z). Based on the above calculation results, the core tip of the optical fiber 1 is initialized to the height of ZO. As a result, the tip of the core of the optical fiber 1 becomes Z in FIG.
Located at the height of Z0 on the axis. On the other hand, the LD unit 4 is offset from the Z-axis origin position to the left side in FIG. 5D by an amount corresponding to the difference between the plane position F (X0, Y0) of the beam focus and the plane position of the emission point. To the initial position. As a result, the tip of the core of the optical fiber 1 is initially set (aligned) at the focal position (X0, Y0, Z0) of the emitted beam.

FIG. 6 shows the optical axis adjustment / adjustment according to the second embodiment.
FIG. 1 is a diagram showing a configuration of an assembling apparatus, which shows a case where an optical axis adjustment / assembly is performed between a photodiode (PD) unit and an optical fiber unit. In this example, an X-axis moving stage 17, an XY-axis moving stage 12, a light intensity distribution measuring device 30, and a collimator lens 31 are arranged on the vibration isolation table 11, respectively, and these have common spatial coordinates (X, Y, Z). ) Position control. In this case, the X-axis moving stage 17 holds the XY-axis moving stage 12, the light intensity distribution measuring device 30, and the collimator lens 31, and can move them relatively at a predetermined distance.

The other package holding jig 13, holder holding jig 16, and YAG laser welding machine 40 may be the same as those in FIG. Further, 22 is an information processing unit that controls and processes the entire apparatus, 23 is a control unit that drives and controls each unit, and 24
Is a light emitting part. In this example, a fine adjustment function in the Z-axis (focus) direction (Z-axis moving stage 14, fiber holder 3
Etc.) is omitted, and the structure is simplified accordingly.
In practical use, even if the fine adjustment function in the Z-axis direction is omitted, there are many cases in which a sufficient adjustment effect can be obtained by performing fine adjustment in the optical axis (horizontal) direction.

FIG. 7 is a diagram for explaining the light intensity distribution measuring process of the optical fiber unit, and FIG. 7A is a sectional view of the PD module. The PD module is a module that converges the light beam sent from the optical fiber 1 onto the light receiving surface of the PD 7 via the lens 5 and converts it into an electric signal. In this example, the optical fiber 1 and the fiber holder 3 are fixed in advance, and the optical axis is adjusted in the horizontal direction.

FIG. 7B shows the principle configuration of the light intensity distribution measuring process of the optical fiber unit. In this example, since the optical fiber unit 3 faces downward, the light intensity distribution measuring instrument 30 is faced from the lower side. The beam emitted from the optical fiber unit 3 is converted into a parallel beam by the collimator lens 31, and enters the light intensity distribution measuring device 30. In this case, since the emitted beam of the optical fiber 1 is condensed by the lens 5, the emitted beam from the holder 4 has a conical shape directed toward the optical axis O and corresponds to the height Z of the collimator lens 31. A beam having a spot diameter φ enters the light intensity distribution measuring device 30. The incident beam has its light intensity attenuated by the ND filter 32 and enters the photodiode array 33. The drive circuit unit 34 scans the received light output of each photodiode element, amplifies and A / D converts them, and outputs light intensity data for each pixel. The image processing unit 35 stores each light intensity data in a two-dimensional XY memory space and performs beam profile processing in the same manner as above.

Returning to FIG. 6, FIG. 6A shows the beam profile process of the optical fiber unit. First, the optical fiber unit 3 and the PD unit 4 are held, and then laser light (for example, He—Ne laser) is incident from the other end of the optical fiber 1. In this state, move the collimator lens 31 from the exit surface to a height of 1.0 mm,
The beam profile (1) is performed for the m-square optical region.

Next, the collimator lens 31 is moved to a height of 2.0 mm from the exit surface, and the beam profile (2) is similarly obtained. Based on these two beam profile results, as in the first embodiment, the spatial coordinates (X0, Y0, Z) of the position (focus point) at which the emitted beam converges.
0), or the optical axis O of the exit beam or the exit angle θ.

FIG. 6B shows a process of assembling the PD module. The PD unit 4 is carried by the X-axis moving stage 17 directly below the fiber holder 3 after the beam profile. Furthermore, by the XY axis moving stage 12,
The PD package 4 is positioned such that the light receiving surface of the PD package 4 is located on the optical axis O of the emitted beam, and the laser welding machine 40 is used to position the optical fiber unit 3 and the PD unit 4.
Weld and fix.

In the second embodiment, the case where the sub-micron order fine adjustment is not performed has been described, but the present invention is not limited to this. Also in the second embodiment, the Z-axis moving stage 14 and the fiber gripper 15 are provided, and the PD
By connecting the optical power meter 21 to the unit 4, it is apparent that adjustment in the Z-axis direction (initial setting) and subsequent fine adjustment on the submicron order can be performed, as in the first embodiment.

In each of the above embodiments, the case where the fiber holder 3 side is fixed has been described, but the fiber holder 3 side may be configured to move on the XY plane. Further, in each of the above-described embodiments, the focal position and the like of the emission beam are obtained from the beam profile of two points on the vertical line. However, when the beam spot diameter below a predetermined value or the minimum beam spot diameter is detected by a plurality of consecutive beam profiles, It may be configured such that the focal position of the emitted beam is defined by the spatial coordinates (X0, Y0, Z0). Although not described in detail, it is clear from the description of each of the above embodiments.

Although the optical data calculation processing of the above example has been described, it goes without saying that the information of the exit angle and the focal position can be obtained by various methods. Although a plurality of preferred embodiments of the present invention have been described above, it goes without saying that various changes can be made to the configuration, control, processing and combinations thereof without departing from the spirit of the present invention.

[0061]

As described above, according to the present invention, highly accurate optical axis adjustment can be performed efficiently in a short time regardless of variations in the optical axes of components constituting the optical module and differences in specifications.
It is possible to provide an optical module of high quality and high reliability.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a configuration of an optical axis adjusting / assembling device according to a first embodiment.

FIG. 3 is a diagram illustrating a light intensity distribution measurement process of an LD unit.

FIG. 4 is a flowchart of an optical axis adjusting / assembling process according to the first embodiment.

FIG. 5 is a diagram illustrating an example of optical data calculation processing according to the first embodiment.

FIG. 6 is a diagram showing a configuration of an optical axis adjusting / assembling device according to a second embodiment.

FIG. 7 is a diagram illustrating a light intensity distribution measuring process of the optical fiber unit.

FIG. 8 is a diagram illustrating a conventional technique.

[Explanation of symbols]

 1 Optical Fiber 2 Core Part 3 Fiber Holder 4 Package 5 Lens 6 Laser Diode 7 Photodiode 11 Anti-Vibration Table 12 XY Axis Moving Stage 13 Package Holding Jig 14 Z Axis Moving Stage 15 Fiber Grip 16 Holder Holding Jig 17 X Axis Moving stage 21 Optical power meter 22 Information processing unit 23 Control unit 24 Light emitting unit 30 Light intensity distribution measuring instrument 31 Collimator lens 32 ND filter 40 Laser welding machine

Claims (8)

[Claims] 1. A method of adjusting an optical axis in an optical module assembly for joining a light emitting unit and an optical fiber unit, wherein a light intensity distribution of an emitted beam is measured at at least two points on a vertical line facing the light emitting unit, and each obtained value is obtained. An optical axis adjusting method comprising a step of obtaining a focal position of an outgoing beam on the basis of information on a beam center position and a beam spot diameter and aligning a core tip of an optical fiber with the focal position. 2. An optical axis adjusting method in an optical module assembly for joining a light emitting unit and an optical fiber unit, wherein the light intensity distribution of an emission beam is measured at at least two points on a vertical line facing the light emitting unit, and each obtained An optical axis adjusting method comprising a step of obtaining an optical axis or an emission angle of an emission beam based on information on a beam center position and aligning a core tip of an optical fiber in the optical axis or in the direction of the emission angle. 3. A fine adjustment in the XY plane and the Z-axis direction is performed so that the light receiving intensity of the optical fiber is monitored and the light receiving intensity of the optical fiber is maximized after the core tips of the optical fibers are aligned. The optical axis adjusting method according to claim 1 or 2. 4. An optical axis adjusting method in an optical module assembly for joining a light receiving unit and an optical fiber unit, wherein at least 2 on a vertical line facing the optical fiber unit.
Measuring the light intensity distribution of the emission beam at each point, obtaining the focal position of the emission beam based on the obtained information of the beam center position and beam spot diameter, and aligning the light receiving surface of the light receiving unit with the focal position An optical axis adjusting method characterized by the above. 5. An optical axis adjusting method in an optical module assembly for joining a light receiving unit and an optical fiber unit, wherein at least 2 on a vertical line facing the optical fiber unit.
Measure the light intensity distribution of the exit beam at the point, find the optical axis or exit angle of the exit beam based on the obtained information on the center position of each beam, and position the light-receiving surface of the light-receiving unit on the optical axis or in the direction of the exit angle. An optical axis adjusting method comprising a step of adjusting. 6. The light receiving surface of the light receiving unit is aligned, and then the light receiving intensity of the light receiving element is monitored and fine adjustment is performed in the XY plane and the Z axis direction so as to maximize the light receiving intensity. The optical axis adjusting method according to claim 4 or 5. 7. The optical intensity distribution measuring section and the optical fiber unit are arranged in parallel, and both are arranged so that they can face each other, and the optical axis adjustment according to claim 1, 2 or 3 is performed. An optical axis adjusting device characterized in that 8. The light intensity distribution measuring section and the light receiving unit are arranged in parallel, and both of them and the optical fiber unit are configured to face each other, and the optical axis adjustment according to claim 4, 5 or 6 is performed. An optical axis adjusting device characterized in that