JPH07109450B2 - Optical axis adjustment method for semiconductor lasers and optical fibers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a semiconductor laser / optical fiber optical axis adjusting method for aligning an optical axis of a semiconductor laser with an optical axis of an optical fiber.

[Conventional technology]

FIG. 3 is a flowchart showing an example of a conventional semiconductor laser / optical fiber optical axis adjusting method, and FIGS. 4 (a), (b),
(C) is a perspective view, a front view of a main part and a plan view of the main part of the optical axis adjusting device used in the method of FIG. 3, respectively.

In step S11 shown in FIG. 3, the semiconductor laser is held and the first holder 12 fixed to the holder fixing tool 11 and the optical fiber.
The second, which holds the end of 15 and is fixed on the XY stages 13 and 14
The holder 16 and the holder 16 are brought into contact with each other at the holder end surfaces which are perpendicular to each other, and the three pin holes 18 of the holder fixing jig 11 are pressed by the taper pins 19 provided on the three pressing arms 17, so that the holder end surface is Are brought into close contact and pressed.

In step S12, the XY stages 13 and 14 are moved to move the optical fiber 15
The second holder 16 is aligned in a plane perpendicular to the optical axis so that the laser light output of the semiconductor laser that has passed through is maximized.

In step S13, the optical coupling efficiency between the semiconductor laser of the first holder 12 and the optical fiber 15 of the second holder 16 is measured,
When compared with the judgment value and the judgment value is not reached, the process returns to step S12.

Actually, after the optical axis adjustment is completed, the first
The holder and the second holder are fixed. However, if the contact surface floats, it will be a major cause of positional deviation during welding.
Positioning is performed so that the first and second holders 12 and 16 are in a pressed state of about 1 kg.

[Problems to be Solved by the Invention]

In the above-described conventional method for adjusting the optical axis of the semiconductor laser / optical fiber, the first holder 12 holding the semiconductor laser and the second holder 16 holding the optical fiber 15 are closely pressed by the end faces perpendicular to the optical axis. As the position is aligned between the surfaces perpendicular to the optical axis, the frictional resistance of the contact surface causes
Of the first holder 12 and the second holder 16 with respect to the movement amount of the XY stages 13 and 14 is caused by the second holder 16 on the moving side being dragged and moved, and at the moment the strain is released. The relative deviation amounts do not match, the step S12 is repeated, it takes time, reproducibility of alignment cannot be obtained, and there is a drawback that only a rough peak position search is performed.

[Means for Solving the Problems]

A method for adjusting an optical axis of a semiconductor laser / optical fiber according to the present invention,
A first holder that holds a semiconductor laser and has an end face perpendicular to the optical axis, and a second holder that holds an optical fiber and has an end face perpendicular to the optical axis.
Of the semiconductor laser which has passed through the optical fiber while slightly pressing at least one of the first holder and the second holder in the optical axis direction by bringing the holder and the holder into close contact with each other by their end faces perpendicular to each other's optical axis. Of the first and second end faces perpendicular to each other's optical axis so that the laser light output of
The feature is that the holder is aligned.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a flow chart showing an embodiment of the present invention,
(A) and (b) are respectively a perspective view of an optical axis adjusting device and a perspective view of an arm 8 used in this embodiment.

In step S1 shown in FIG. 1, the second optical fiber 4 is held.
The holder 3 is fixed on the XY stations 5 and 6, and the first holder 2 holding the semiconductor laser is fixed to the holder fixing jig 1 supported by the Z stage 7 via the arm 8, and then the Z stage 7 Is vertically lowered to bring the end surfaces of the holders 2 and 3 perpendicular to the optical axis into contact with each other, and after the contact, the fine stroke Z stage 7 is further processed to bring the end surfaces of the holders 2 and 3 into close contact with each other.

In step S2, the XY stages 5 and 6 are moved while slightly vibrating the Z stage 7 with an amplitude larger than the minute stroke so that the laser light output of the semiconductor laser held by the holder 2 that has passed through the optical fiber 4 is maximized. Positioning is performed in a plane perpendicular to the optical axis.

In step S3, the optical coupling efficiency between the semiconductor laser of the first holder 2 and the optical fiber 4 of the second holder 3 is measured and compared with the judgment value. If the judgment value is not reached, the process returns to step S2.

In step S2, the holder is usually used during laser welding in the subsequent process.
If the contact surfaces of 2 and 3 are floating, it can be a major factor of the optical axis shift, so align the surfaces perpendicular to the optical axis with a pressure of about 1 kg. For example, in the Z stage 7 and the arm 8 having a resolution of 1 μm, the width b = 20 mm, the height h = 10 mm, the length l =
Using a steel beam with a rectangular section of 80 mm, Z stage 7
If the minute stroke of is set to 5 μm, the pressed state will be about 1 kg.

On the other hand, for the small vibration of the Z stage 7, the vibration amplitude is
When set to 10 μm (10 pulses) and driving the pulse motor of the drive source with a pulse of 1 kpps, a minute vibration of about 50 Hz is given, and a certain stress amplitude can be given even when the contact surfaces of holders 2 and 3 separate. it can. In normal semiconductor laser / optical fiber assembly, the allowable range of misalignment in the optical axis direction is larger than the allowable range of misalignment in the direction perpendicular to the optical axis, and a deviation of about 10 μm has almost no effect on coupling efficiency.
The small vibration of does not affect the alignment of the optical axis, and the frictional resistance of the contact surfaces of the holders 2 and 3 can be reduced and released.

By the way, for the microvibration in the optical axis direction, an ultrasonic vibrator may be used instead of the pulse stage, and in this case, microvibration of high frequency can be applied.

〔The invention's effect〕

A method for adjusting an optical axis of a semiconductor laser / optical fiber according to the present invention,
In the step of bringing the first holder holding the semiconductor laser and the second holder holding the optical fiber into close contact with each other at their end faces perpendicular to the optical axis, and performing alignment in a plane perpendicular to the optical axis, By microvibrating at least one of the first holder and the second holder in the optical axis direction, there is an effect that the frictional resistance of the contact surfaces of the holders can be reduced and released.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the present invention,
1A and 1B are a perspective view of an optical axis adjusting device and a perspective view of an arm 8 used in this embodiment, respectively. FIG. 3 is a flow chart showing a conventional semiconductor laser / optical fiber optical axis adjusting method, 4 (a), (b) and (c) are respectively a perspective view, a front view of the main part and a plan view of the main part of the optical axis adjusting device used in the method shown in FIG. 1,11 …… Holder fixing jig, 2,12 …… First holder, 3,16
…… Second holder, 4,15 …… Optical fiber, 5,13 …… Stage, 6,14 …… Y stage, 7 …… Z stage, 8 ……
Arm, 17 ... Pressurizing arm, 18 ... Pin hole, 19 ... Taper pin.

Claims (1)

[Claims] 1. A first holder, which holds a semiconductor laser and has an end face perpendicular to the optical axis, and a second holder, which holds an optical fiber and has an end face perpendicular to the optical axis, are perpendicular to each other's optical axis. The end face is closely contacted and pressed so that the laser light output of the semiconductor laser transmitted through the optical fiber is maximized while slightly vibrating at least one of the first holder and the second holder in the optical axis direction. A method for adjusting an optical axis of a semiconductor laser / optical fiber, characterized in that the first and second holders are aligned between end faces perpendicular to each other's optical axis.