JP2004303876A - Alignment device of lens and laser chip in laser diode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alignment device capable of automatically adjusting the mutual positions of a lens and a laser chip in the alignment device relatively aligning the position of the lens installed to a cap and the position of the laser chip being mounted on a stem and radiating light beams. <P>SOLUTION: The alignment device has a prism for reflecting a light from the laser chip; a photo detector for receiving the light from the laser chip reflected by the prism; a half mirror which is installed on a first optical axis between the prism and the photo detector, through which a light on the optical axis is transmitted, and which reflects the light to a second optical axis orthogonal to the first optical axis; a light source secured on the second optical axis; and a lens-center position detecting means by which the light reflected in order of the prism, the lens and the prism and transmitted through the half mirror is imaged by the photo detector, and the central position of the lens is obtained on the basis of a signal output from the photo detector. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an alignment device that relatively aligns a position of a lens provided on a cap with a position of a laser chip provided on a stem and generating a light beam.
[0002]
[Prior art]
FIG. 5 is a block diagram showing a conventional positioning device PS11.
[0003]
The conventional positioning device PS11 is a positioning device that relatively aligns the position of the lens L1 provided on the cap CA with the position of the laser chip 10 that is provided on the stem S and generates a light beam. 20, a light receiving element 30, a moving unit 70a, an image processing device 92, and a CRT monitor 93.
[0004]
Then, when matching the position of the lens L1 with the position of the laser chip 10, the laser chip 10 emits light, and the emitted light passes through the lens L1, is reflected by the prism 20, and forms an image on the light receiving element 30. Based on the image formed by the light receiving element 30, the center position of the laser chip 10 can be visually checked on the CRT monitor 93, and the center position of the laser chip 10 is moved while moving the XY drive motor 72. The laser chip 10 is moved and the center position of the laser chip 10 is adjusted to the center position of the lens L1.
[0005]
In this case, the center position of the laser chip 10 is adjusted to the center position of the lens L1 by manually moving the XY stage 71.
[0006]
A laser diode for optical communication (basically constituted by the laser chip 10 and the spherical lens L1) used for optical fiber communication capable of high-speed and large-capacity data transmission converts laser light with high efficiency. It is necessary to introduce the laser beam into the optical fiber, so that the optical axis accuracy of the laser beam is required.
[0007]
The operation of aligning the center position of the laser chip 10 with the center position of the lens L1 is performed manually and cannot be automated.
[0008]
[Problems to be solved by the invention]
Therefore, in the above-described conventional example, in the positioning device that relatively aligns the position of the lens provided on the cap with the position of the laser chip 10 that is provided on the stem and generates a light beam, the lens L1 and the laser chip 10 There is a problem that the mutual position cannot be automatically adjusted.
[0009]
The present invention provides an alignment apparatus that relatively aligns the position of a lens provided on a cap with the position of a laser chip that is provided on a stem and generates a light beam. It is an object of the present invention to provide an alignment device that can be adjusted.
[0010]
[Means for Solving the Problems]
The present invention provides a positioning device that relatively aligns a position of a lens provided on a cap with a position of a laser chip that is provided on a stem and generates a light beam, and a prism that reflects light from the laser chip. A light receiving element that receives light from the laser chip reflected by the prism; and a light receiving element that is provided on a first optical axis between the prism and the light receiving element, and transmits light on the first optical axis. A half mirror that transmits and reflects to a second optical axis orthogonal to the first optical axis; a light source provided on the second optical axis; The light reflected by the prism, the lens, and the prism in this order, transmitted through the half mirror, forms an image on the light receiving element, and determines a center position of the lens based on a signal output by the light receiving element. A positioning device between the lens and the laser chip in the laser diode; and a position detecting means.
[0011]
Embodiments and Examples of the Invention
FIG. 1 is a diagram showing an alignment apparatus PS1 for a lens and a laser chip in a laser diode according to an embodiment of the present invention.
[0012]
The positioning device PS1 is a positioning device that relatively aligns the position of the lens L1 provided on the cap CA with the position of the laser chip 10 that is provided on the stem S and generates a light beam. , Light receiving element 30, half mirror 40, light source 50, lens center position detecting means 60, moving means 70, lens center position storing means M1, laser chip center position detecting means 80, laser chip center position storing It has means M2, alignment control means 90, and CRT monitor 91.
[0013]
FIG. 2 is a diagram showing a cross section of the laser diode LD manufactured according to the above embodiment.
[0014]
The laser diode LD has a laser chip 10, a stem S fixing the laser chip 10, a cap CA, a ball lens L1 held by the cap CA, and a lead LD.
[0015]
Here, since the laser chip 10 is fixed to the stem S and the ball lens L1 is fixed to the cap CA, when the laser chip 10 and the ball lens L1 are aligned, the stem S and the cap CA are relatively positioned. Go to and align.
[0016]
The prism 20 is a prism that reflects light from the laser chip 10.
[0017]
The light receiving element 30 is a light receiving element that receives light from the laser chip 10 reflected by the prism 20, and is a CCD or the like.
[0018]
The half mirror 40 is a half mirror that reflects light on a second optical axis A2 orthogonal to the first axis A1 between the prism 20 and the light receiving element 30.
[0019]
The light source 50 is a light source provided on the second optical axis A2.
[0020]
The lens center position detecting means 60 reflects the light from the first light source 50 on the half mirror 40, the prism 20, the lens L1, and the prism 20, and forms the light transmitted through the half mirror 40 on the light receiving element 30 to form an image. This is a means for determining the center position of the lens L1 based on the signal output from the element 30.
[0021]
The moving means 70 is means for relatively moving the position of the cap CA and the position of the stem S, and includes an XY stage 71, an XY drive motor 72 for driving the XY stage 71, and a motor. And a controller 73.
[0022]
The lens center position storage unit M1 is a memory that stores the position of the lens center detected by the lens center position detection unit 60.
[0023]
The laser chip center position detecting means 80 detects that the light emitted by the laser chip 10 passes through the lens L1, is reflected by the prism 20, and the light that has passed through the half mirror 40 forms an image on the light receiving element 30. This is a means for determining the center position of the laser chip 10 based on the output signal.
[0024]
The laser chip center position storage unit M2 is a memory that stores the position of the laser chip center detected by the laser chip center position detection unit 80.
[0025]
The positioning control unit 90 is a unit that controls the lens center position and the laser chip center position to be aligned with each other while the moving unit 70 relatively moves the position of the cap CA and the position of the stem S.
[0026]
FIG. 3 is a diagram showing an example in which the reflected light of the lens L1 and the light received from the laser chip 10 are displayed on the CRT monitor 91 during the alignment process in the above embodiment.
[0027]
Next, the operation of the above embodiment will be described.
[0028]
FIG. 4 is a flowchart showing the operation of the above embodiment.
[0029]
In the above embodiment, after the coarse adjustment shown in FIG. 4A is performed, the fine adjustment shown in FIG. 4B is performed.
[0030]
In the coarse adjustment, first, the light source 50 is turned on, and the center position of the lens L1 is obtained (S1). As shown in FIG. 1, light from a light source 50 is irradiated from below in the figure via an optical fiber 51, reflected by a half mirror 40, reflected by a prism 20, reflected by a surface of a lens L1, Light reflected by the prism 20 and passed through the half mirror 40 forms an image on the light receiving element 30.
[0031]
The output signal of the light receiving element 30 is sent to the lens center position detecting means 60, and is subjected to image processing to determine the center position of the lens L1. In other words, image processing is performed on the reflected light of the light illuminated on the lens L1 provided on the cap CA, a lens pattern is obtained, and the center point of the lens pattern is obtained based on the obtained lens pattern, and is set as the lens center position. . For example, in the image of the lens pattern, the position with the highest luminance is obtained as the position of the center point of the lens pattern.
[0032]
As shown in FIG. 3, the position of the center of the light reflected by the lens L1 is obtained as coordinates (x1, y1) and displayed. The lens center position obtained in this way is stored in the lens center position storage means M1.
[0033]
The coordinates (x, y) of the upper left corner of the CRT monitor 91 shown in FIG. 3 are (0, 0).
[0034]
Next, the light source 50 is turned off (S2), the laser chip 10 emits light, and the center position of the laser chip 10 is obtained (S3). As shown in FIG. 1, light generated by the laser chip 10 is reflected by the prism 20, passes through the half mirror 40, and forms an image on the light receiving element 30. The output signal of the light receiving element 30 is sent to the laser chip center position detecting means 80 and subjected to image processing to determine the center position of the laser chip 10.
[0035]
That is, the image of the light from the laser chip 10 is subjected to image processing, a laser beam pattern is obtained, and a center point of the laser beam pattern is obtained based on the obtained laser beam pattern, and is set as the center position of the laser chip 10. For example, in the image of the laser beam pattern, the position with the highest luminance is obtained as the position of the center point of the laser beam pattern.
[0036]
As shown in FIG. 3, the center position of the light received from the laser chip 10 is obtained and displayed as coordinates (x2, y2). The laser chip center position obtained in this way is stored in the laser chip center position storage means M2.
[0037]
Next, the distance L between the center position (x1, y1) of the lens L1 and the center position (x2, y2) of the laser chip 10 is calculated by the positioning control means 90 (S4), and the calculated distance L And the reference for coarse adjustment, for example, 30 μm, is compared by the positioning control means 90 (S 5). If the distance L is longer than 30 μm, the positioning control means 90 moves the motor 72 (S 6). Returning to S4, the distance L is obtained again, and the obtained distance L is compared with a reference length of 30 μm. When the distance L becomes equal to or less than 30 μm (S5), the coarse adjustment operation is terminated after driving the motor 72 (S8).
[0038]
When the coarse adjustment is completed, the process proceeds to a fine adjustment operation. As shown in FIG. 4B, the center position of the laser chip 10 is determined with respect to the center position of the stored lens L1 (S13).
[0039]
Next, a distance La between the center position of the lens L1 and the center position of the laser chip 10 is calculated (S14), and the calculated distance La is compared with, for example, 1 μm which is a reference for fine adjustment (S15). If the distance La is longer than 1 .mu.m, the motor 72 is moved (S16), the process returns to step S41, the distance La is calculated again, and the calculated distance La is compared with 1 .mu.m. If the distance La is equal to or less than 1 μm (S15), the laser chip 10 is turned off (S17), and the fine adjustment operation is completed (S18).
[0040]
According to the above-described embodiment, in a positioning apparatus that relatively aligns the position of the lens L1 provided on the cap CA with the position of the laser chip 10 provided on the stem S and generating a light beam, The mutual position with the laser chip 10 can be automatically adjusted.
[0041]
In the above embodiment, if the distance between the center position of the lens and the center position of the laser chip is equal to or less than a predetermined reference distance, a fixing means for fixing the cap CA and the stem S is provided. In this case, the fixing means may be resistance welding means. In the case of resistance welding, the center of the lens and the center of the beam are made to coincide with each other, and in this state, the welding electrode is relatively approached to press the cap CA and the stem S, and welding is performed by supplying a welding current.
[0042]
Further, in the above embodiment, when the distance between the lens center position and the laser chip center position is equal to or less than a predetermined reference distance, a means for shifting the lens center position and the laser chip center position by a predetermined amount is provided. Is also good.
[0043]
As described above, when the center position of the lens and the center position of the laser chip are shifted by a predetermined amount, a fiber (not shown) provided close to the laser diode LD constituted by the lens L1 and the laser chip 10 is used. After centering the center position of the lens and the center position of the laser chip in the direction of the cut surface, the center position is shifted by a predetermined amount. By doing so, light passing loss when light enters the fiber is reduced, and light receiving efficiency is improved, that is, fiber coupling efficiency is improved.
[0044]
The predetermined amount to be shifted has a significant meaning as an offset amount, and by adjusting the fiber cutting angle and the incident angle of the laser beam, the characteristics of the laser diode can be changed to produce a wide variety of lasers. .
[0045]
【The invention's effect】
According to the present invention, in a positioning apparatus that relatively aligns a position of a lens provided on a cap with a position of a laser chip that is provided on a stem and generates a light beam, a mutual position of the lens and the laser chip is provided. Can be automatically adjusted.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positioning device PS1 according to an embodiment of the present invention.
FIG. 2 is a diagram showing a cross section of a laser diode LD manufactured according to the embodiment.
FIG. 3 is a diagram showing an example in which light reflected by a lens L1 and light received from a laser chip 10 are displayed on a CRT monitor 91 in the alignment process in the embodiment.
FIG. 4 is a flowchart showing the operation of the embodiment.
FIG. 5 is a block diagram showing a conventional positioning device PS11.
[Explanation of symbols]
PS1: Positioning device,
L1 ... Lens,
CA… Cap,
S ... stem,
10 laser chip,
20 ... Prism,
30 ... light receiving element,
40 ... half mirror,
50 ... light source,
51 ... optical fiber,
60 ... lens center position detecting means,
M1: lens center position storage means,
70 ... Transportation means,
71 ... XY stage,
72 ... XY drive motor,
73 ... motor controller,
74 ... movable contactor,
80 ... Laser chip center position detecting means,
M1: laser chip center position storage means,
90 ... alignment control means,
91 ... CRT monitor,
L, La: distance between the center position of the lens L1 and the center position of the laser chip 10.

Claims (8)

In a positioning device that relatively aligns the position of the lens provided on the cap with the position of the laser chip that is provided on the stem and generates a light beam,
A prism for reflecting light from the laser chip;
A light receiving element for receiving light from the laser chip reflected by the prism;
It is provided on a first optical axis between the prism and the light receiving element, transmits light on the first optical axis, and reflects light on a second optical axis orthogonal to the first optical axis. A half mirror;
A light source provided on the second optical axis;
The light from the light source is reflected in the order of the half mirror, the prism, the lens, and the prism, and the light transmitted through the half mirror forms an image on the light receiving element, based on a signal output from the light receiving element. Lens center position detecting means for obtaining the center position of the lens;
A positioning device for a lens and a laser chip in a laser diode, comprising: In claim 1,
A positioning device for a lens and a laser chip in a laser diode, comprising a moving means for relatively moving the position of the cap and the position of the stem. In claim 1,
An apparatus for aligning a lens and a laser chip in a laser diode, comprising a lens center position storing means for storing the position of the lens center detected by the lens center position detecting means. In claim 2,
Lens center position storage means for storing the position of the lens center detected by the lens center position detection means;
The light emitted by the laser chip is transmitted through the lens, reflected by the prism, transmitted through the half mirror, imaged by the light receiving element, and based on a signal output by the light receiving element, the laser chip Laser chip center position detecting means for obtaining the center position of the laser chip;
Laser chip center position storage means for storing the position of the laser chip center detected by the laser chip center position detection means;
Positioning control means for controlling the lens center position and the laser chip center position to be aligned with each other while relatively moving the position of the cap and the position of the stem by the moving means;
A positioning device for a lens and a laser chip in a laser diode, comprising: In claim 4,
The lens in a laser diode, wherein the control means has fixing means for fixing the cap and the stem if a distance between the lens center position and the laser chip center position is equal to or less than a predetermined reference distance. Alignment device with laser chip. In claim 5,
The positioning device for a lens and a laser chip in a laser diode, wherein the fixing means is a resistance welding means. In claim 1,
When the distance between the lens center position and the laser chip center position is equal to or less than a predetermined reference distance, the lens in the laser diode having means for shifting the lens center position and the laser chip center position by a predetermined amount, Alignment device with laser chip. In claim 7,
When the center position of the lens and the center position of the laser chip are shifted by a predetermined amount after centering, in the direction of a cut surface of a fiber provided in close proximity to a laser diode formed by the lens and the laser chip, An apparatus for aligning a lens and a laser chip in a laser diode, wherein the center position of the lens and the center position of the laser chip are shifted by a predetermined amount.

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