JPH03167511A - Optical axis aligning method for semiconductor laser module - Google Patents

Abstract

PURPOSE:To obtain the reproducibility of position alignment and to allow the searching of a peak position having high reliability by supporting either of a laser unit or fiber unit in parallel in one optical axis alignment direction by means of a leaf spring having a spring property in the optical axis direction. CONSTITUTION:A fixing side holding part 7 is pressurized in the optical axis direction by means of 3 pieces of pressurizing pawls 8 and the contact surfaces of the units 1, 5 are brought into a tight contact and pressed state. A moving side holding part is then moved in an X direction 9 and the position of the max. output light quantity is determined. The holding part is moved in a Y direction 10 in this X position and the position of the max. output light quantity is determined. The approximate peak position 11 is sought by repeating a series of such operations as far as the output light quantity increases. A searching region 12 is set with the approximate peak position 11 as a center and step feeding is executed in the supporting direction (Y direction 10) of the leaf spring. The max. value of the output light quantity in the X direction 9 is determined in the respective Y positions and these operations are successively repeated to determine the max. output light quantity Pmax in the searching region 12 and the Y position y2 where the quantity is maximized. The optical axis alignment having the high reliability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for aligning the optical axis of a semiconductor laser module.

[Conventional technology]

Conventional optical axis alignment methods for semiconductor laser modules include a laser unit that has a contact surface for assembly that holds the light emitting element and is perpendicular to the optical axis, and a contact surface that holds the optical fiber and has a contact surface for assembly that is perpendicular to the optical axis. One of the fiber units having the There is a method in which the abutting surfaces of the unit are brought into a tightly pressed state and the units are aligned in a plane perpendicular to the optical axis so that the transmitted light output of the optical fiber is maximized.

Next, a conventional method for aligning the optical axis of a semiconductor laser module will be described in detail with reference to the drawings.

FIG. 4 is a flowchart showing an example of a conventional method for aligning the optical axis of a semiconductor laser module, and FIGS. 5 and 6 (
a) and (b) are a perspective view, a plan view, and a side view for explaining the method of FIG. 4;

Procedure Sll: The laser unit 18 that holds the light emitting element and has a contact surface for assembly is placed on the fixed side holding part 19, and the fiber unit 14 that holds the optical fiber and has a contact surface for assembly is provided on the XY stage 15.16. Attach the movable side holding part 17 with their abutting surfaces facing each other, pressurize the bottle hole 21 of the fixed side holding part 19 with three pressurizing claws 20 having taper pins 22, and press the abutting surfaces of both units}-14.18. is in a tightly pressed state.

Step S12: Move the movable side holder 17 in the X direction to find the maximum output light amount position, and then move it in the Y direction from this position to find the maximum output light amount position. These series of operations are repeated as long as the amount of output light increases.

Step 3.13 Measure the coupling efficiency of both units 14.15 and compare it with the judgment value. If the judgment value is not reached, repeat step S12,
If the determination value is reached, it is determined that the optical axes match, and the optical axis alignment is completed.

In reality, after the optical axis alignment is completed, the contact surfaces of the laser unit 18 and the fiber unit 14 are fixed by laser welding, but if the contact surfaces are floating, it will be a major cause of optical axis deviation of the welding surfaces, so It is necessary to align the optical axis in the pressed state, and step S12 is often repeated.

[Problem to be solved by the invention]

The conventional method for aligning the optical axis of a semiconductor laser module described above involves abutting both a laser unit that holds a light emitting element and has an abutment surface for assembly, and a fiber unit that holds an optical fiber and has an abutment surface for assembly. Because the contact surface is tightly pressed and alignment is performed in a plane perpendicular to the optical axis, the fixed laser unit is dragged by the moving fiber unit due to the frictional resistance of the contact surface, and the moment the strain is released. The relative deviation amount between the laser unit and the fiber unit with respect to the amount of movement of the XY stage does not match, and the step S12 is repeated, which takes time. In addition, the repeatability of positioning cannot be obtained, so the reliability of the peak is reduced. However, this method has the disadvantage that the peak position search is limited to a rough peak position search.

[Means to solve the problem]

The optical axis alignment method of a semiconductor laser module of the present invention is as follows: (A> A laser unit that holds a light emitting element and has a contact surface for assembly perpendicular to the optical axis; In a method for aligning optical axes with a fiber unit having an abutted surface, one of the laser unit and the fiber unit is mounted on a movable-side holder having an XY stage, and the other is mounted on a leaf spring having spring properties in the optical axis direction. The fixed side holder is supported parallel to one direction of the optical axis alignment direction and has a unit fixing part at the tip, with the abutting surfaces facing each other. (B) move the adjustment stage in the first direction (hereinafter referred to as the X direction) to find the maximum output light amount position; a second direction perpendicular to the first direction at the position (hereinafter referred to as the Y direction)
(C) Set a search area around the approximate peak position and support the leaf spring by repeating this series of operations as long as the output light intensity increases. (hereinafter referred to as the Y direction), and at each Y position, find the maximum value of the output light amount in the X direction, and repeat these sequentially to find the maximum output light amount and the maximum Y position in the search area, (D> Step-feeding in the X direction at the Y position where the maximum output light amount is obtained, and determining that the optical axes coincide when the output difference between the output light amount and the maximum output light amount becomes equal to or less than a determination value, and terminating the optical axis alignment. It consists of:

〔Example〕

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

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
Figures (a>, (b) and Figures 3 (a) to (c) are a plan view, a side view, and a graph for explaining the method of Figure 1.

Step S1 The fiber unit 1 that holds the optical fiber and has a contact surface perpendicular to the optical axis is brought into contact with the moving-side holder 4 having the XY stage 2.3 for assembly, which holds the light emitting element and is perpendicular to the optical axis. A laser unit 5 having a surface is supported parallel to one direction 10 of the optical axis alignment direction by a leaf spring 6 having spring properties in the optical axis direction, and a contact surface is provided to a fixed side holding part 7 having a unit fixing part at the tip. Both units 1 and 5 are mounted facing each other, and press the fixed side holding part 7 in the optical axis direction with the three pressure claws 8.
The contact surfaces of the parts are brought into a close pressed state.

Step S2: Move the movable side holder 4 in the X direction 9 to find the maximum output light amount position, and then move it from this X position in the Y direction 10 to find the maximum output light amount position. These series of operations are repeated as long as the amount of output light increases to search for the approximate peak 11.

? Step S3: Set the search area 12 around the approximate peak position 11 obtained in step S2, step-feed in the support direction of the leaf spring 6 (Y direction 10), and calculate the maximum value of the output light amount in the X direction 9 at each Y position. Find the maximum output light amount P max and the maximum Y position y2 in the search area 12 by repeating these steps one after another.
Find. Step S4: At the Y position y2 where the maximum output light amount P8 is obtained, step feed is performed in the X direction 9 from one end Xi of the search area 12, and a peak search in the X direction 9 is performed.

Step S5 Output light amount and maximum output light j for each step of step S4
lP. ．． ．． What difference is determined? When the output difference becomes less than or equal to the determination value, it is determined that the optical axes have coincided, and the optical axis alignment is completed.

In general, when aligning the optical axes of the laser unit 5 and the fiber unit 1 by pressing their abutting surfaces closely together, the fixed laser unit 5 moves to the movable fiber unit 1 due to the frictional resistance of the abutting surfaces. The movement is dragged by the XY stage 2.3, and slippage occurs the moment the strain is released.The relative displacement of both units 1.5 and the amount of movement of the XY stage 2.3 does not match, so the position is not reproducible and the Even if you return it to the position where it was determined that the maximum output light amount was obtained,
In many cases, the original output light amount cannot be obtained.

Therefore, the true peak position 13 cannot be found in the general conventional procedure S2, in which peak searches are repeated alternately in one direction at a time, and in the end, the optical axis is reached at the point where the operator determines that the peak is the peak through manual adjustment. I had finished matching.

In the present invention, after the completion of step S2, the approximate peak position 11
By setting the search area 12 around the peak and re-searching the vicinity of the peak, highly reliable optical axis alignment can be achieved.

In particular, when searching near the peak, step feed is performed in the support direction where the leaf spring 6 is easily deformed (X direction 10), and continuous feed is performed in the lateral direction (X direction 9) where leaf spring 6 is less likely to deform. Is the strain in the Y direction 10 immediately after step feeding to 10 equal to 9 in the X direction? By moving and canceling it, the maximum output light amount P8 in the search area 12 and the Y position y2 at that time can be searched with good reproducibility without being affected by the frictional resistance of the contact surfaces of both units 1.5.

〔Effect of the invention〕

The method for aligning the optical axis of a semiconductor laser module of the present invention is as follows:
By supporting the fixed side holding part with a leaf spring, it is possible to improve the fixity while maintaining the adhesion between the contact surfaces of both units.
Furthermore, by setting the search area at the approximate peak position and performing step feed in the support direction of the leaf spring and continuous feed in the lateral direction, the maximum output light amount in the search area is achieved without being affected by the frictional resistance of the contact surface. Since the position in the support direction of the leaf spring can be searched with good reproducibility, the position in the support direction of the leaf spring where the maximum output can be obtained is searched laterally, and the output difference between the output light amount and the maximum output light amount is below the judgment value. By determining that the optical axes have coincided, this has the effect of allowing highly reliable optical axis alignment.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
Figures (a>, (b) and Figure 3 (a), (b), (c)
1 is a plan view, a side view, and a graph for explaining the method shown in FIG. 1, FIG. 4 is a flowchart showing a conventional example, and FIGS. 5 and 6 (a>. 1, 14...Fiber unit, 2,15...X stage, 3,16...Y stage, 4,17...Movement. Side holding part, 5.18... Laser unit, 6...
Leaf spring, 7, 19...Fixed side holding part, 8, 20...
Pressure claw, 9...X direction, 10...Y direction, 11.
...Approximate peak position, 12... Search area, 13...
True peak position, 21... Bottle hole, 22... Taper pin.

Claims (1)

[Claims] (A) A laser unit that holds a light emitting element and has an abutment surface for assembly that is perpendicular to the optical axis, and a fiber that holds an optical fiber and has an abutment surface for assembly that is perpendicular to the optical axis. In the method for aligning the optical axis with the optical axis unit, either the laser unit or the fiber unit is attached to a moving-side holder having an The fixed side holding parts are supported parallel to the direction and have a unit fixing part at the tip, and are attached with their abutting surfaces facing each other. Steps for bringing the contact surface into a tightly pressed state: (B) moving the adjustment stage in the first direction (hereinafter referred to as the X direction) to find the maximum output light amount position; then moving the adjustment stage in the first direction at this X position; Perpendicular second direction (hereinafter referred to as the Y direction)
(C) Set a search area around the approximate peak position and support the leaf spring by repeating this series of operations as long as the output light intensity increases. step in the direction (hereinafter referred to as the Y direction), finding the maximum value of the output light amount in the X direction at each Y position, and sequentially repeating these steps to find the maximum output light amount and the maximum Y position in the search area, (D) Step-feeding in the X direction at the Y position where the maximum output light amount is obtained, and determining that the optical axes have coincided when the output difference between the output light amount and the maximum output light amount becomes equal to or less than a determination value, and terminating the optical axis alignment; A method for aligning an optical axis of a semiconductor laser module, the method comprising: