JP2973206B2 - Semiconductor laser module with optical isolator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor laser module with an optical isolator used in optical communication, optical measurement, and the like.

[Conventional technology]

2. Description of the Related Art Conventionally, an optical isolator is attached to a semiconductor laser module used for optical communication or the like in order to prevent light returning to the semiconductor laser.

FIG. 5 shows an example of this type of semiconductor laser module with an optical isolator, which is described in Japanese Patent Application Laid-Open No. Sho 61-70516.

As shown in the figure, the semiconductor laser module 8 with an optical isolator has a support 85 on which a semiconductor laser 81 and a spherical lens 83 are mounted, a support 91 on which a Faraday rotator 87 is mounted, and a support on which an analyzer 93 is mounted. Fixture 95 and ball lens 97
, A support tool 84 to which the optical fiber 82 is mounted, and a cap 86 surrounding these.

In order to assemble the semiconductor laser module 8 with an optical isolator, a support 91 and a support 95
Then, the support tool 99 and the support tool 84 are sequentially attached, and then these are fixed, and then the cap 86 is put on.

Here, when mounting the support 91 on the support 85, the support 91 is finely adjusted on the end face of the support 85 so that the output of light passing through the Faraday rotator 87 is maximized. I do.

Next, when mounting the support 95 on the support 91, the support 93 is finely adjusted on the end face of the support 91, and the analyzer 93 is adjusted so as to match the inclination of the light rotated by the Faraday rotator 87.
To rotate.

Next, when the support 99 is mounted on the support 95, the support 99 is finely adjusted on the end face of the support 95 to perform optical axis alignment.

Further, when mounting the support 84 on the support 99, the support 84 is finely adjusted on the end face of the support 99, and the ball lens 97 is adjusted.
In this case, the light condensed by the light is accurately incident on the thin optical fiber 82.

[Problems to be solved by the invention]

However, in the conventional semiconductor laser module with an optical isolator as described above, since each optical component requires a support, not only the number of components is large, but also the positioning of each optical component requires time and effort. There has been a problem that many jigs are required for alignment.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a semiconductor laser module with an optical isolator that not only has a small number of components but also facilitates alignment between optical components, and a method of manufacturing the same.

[Means for solving the problem]

In order to solve the above problems, the present invention provides at least a semiconductor laser, a first light condensing means for collimating light emitted from the semiconductor laser, and a magneto-optical crystal that rotates a direction of linearly polarized light by 45 ° around an optical axis. An analyzer set at an angle that allows the linearly polarized light rotated by 45 ° to pass through the magneto-optical crystal, and a second condensing unit that condenses the collimated light passing through the analyzer to an optical fiber. In a semiconductor laser module with an optical isolator, which is disposed on an axis and has a magnet for applying a saturation magnetic field to the magneto-optical crystal, a first cylindrical tube in which a semiconductor laser is fixed to one end side inside.
A case, and a second case provided with an insertion hole for holding a ferrule holding the optical fiber on its central axis while holding the second condensing means, wherein the magnet is formed in a cylindrical shape, The first condensing means, the magneto-optical crystal, and the analyzer are fixed inside, and the magnet is fixed inside the first case, and the second case is fixed to the first case.
A semiconductor laser module with an optical isolator was configured by fixing the case.

[Action]

By configuring the semiconductor laser module with an optical isolator as described above, a portion between the semiconductor laser that needs to be strictly aligned and the first focusing means (light emitted by the semiconductor laser is collimated by the first focusing means). The fine adjustment) is in the first case, and the portion between the second light collecting means and the optical fiber (fine adjustment for collecting the collimated light into the optical fiber by the second light collecting means) is in the second case. Since the two cases can be separated from each other, the parts that require fine adjustment can be finely adjusted separately. If the two cases are connected after the fine adjustment is completed, the semiconductor laser module with the optical isolator is completed. However, the connection between the two cases is easy because the adjustment is only required to align the optical axes of the two. Therefore, it is easy to adjust not only the portion requiring fine adjustment but also the connection between the two cases.

In the present invention, since the first condensing means, the polarizer (sometimes unnecessary), the magneto-optical crystal, and the analyzer are fixed in the magnet, the support for these optical components becomes unnecessary.
It is not necessary to use a support that has been attached to each optical component as in the related art, so that the number of components can be reduced, and the size and cost can be reduced.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view showing a semiconductor laser module 1 with an optical isolator according to one embodiment of the present invention.

As shown in FIG. 1, the semiconductor laser module 1 with an optical isolator includes a semiconductor laser 11, a first focusing means 13, a polarizer 15, a magneto-optical crystal 17, an analyzer 19, and a second focusing means 23.
Are arranged in this order on a straight line, a magnet 21 is attached to the outer periphery of the magneto-optical crystal 17, and these optical components are housed in a first case 29 and a second case 27.

Hereinafter, each component and an assembling method thereof will be described in detail.

The semiconductor laser 11 is attached to the center of the substrate 111,
A terminal 113 is attached to the opposite surface.

Although the first light condensing means 13 and the second light converging means 23 use spherical lenses in this embodiment, rod lenses, convex lenses or the like may be used instead.

The polarizer 15 is composed of a polarizing beam splitter or the like.

The magneto-optical crystal 17 has a plane of polarization of linearly polarized light of 45 under a saturation magnetic field.
゜ It is formed to the thickness to be rotated.

The analyzer 19 is constituted by a polarizing beam splitter or the like, and is fixed at an angle rotated by 45 ° around the optical axis as compared with the polarizer 15.

And these polarizer 15, magneto-optic crystal 17, analyzer 19,
As shown in FIG. 3, they are all formed in a columnar shape having the same diameter,
And these are bonded together. Note that these need not necessarily be adhered, and may be integrally fixed using a jig.

The magnet 21 is a permanent magnet for applying a saturation magnetic field to the magneto-optical crystal 17 and is formed in a cylindrical shape, and has an inner diameter that allows the polarizer 15, the magneto-optical crystal 17, and the analyzer 19 to be inserted.

The first case 29 is formed in a cylindrical shape, and has an inner diameter that allows the outer periphery of the magnet 21 to be slidably inserted.

The second case 27 is formed at one end thereof with a flange portion 271 which is in contact with one end surface of the first case 29, and has a holding hole 273 for holding the second condensing means 23 and an optical fiber at the center thereof. An insertion hole 275 for inserting the ferrule held on the central axis is provided. The second case 2
Reference numeral 277 denotes an attachment portion for attaching an optical fiber connector plug.

Next, this semiconductor laser module with optical isolator 1
Will be described.

FIG. 2 is a view showing a method of assembling the semiconductor laser module 1 with an optical isolator.

As shown in the figure, first, a substrate 111 on which the semiconductor laser 11 is mounted is fixed to the left end surface of the first case 29. At this time, the semiconductor laser 11 is positioned on the center line of the first case 29.

Next, as shown in FIG. 3, the integrated polarizer 15, magneto-optical crystal 17, and analyzer 19 are inserted and fixed inside the magnet 21, and the inside of the magnet 21 on the side of the semiconductor laser 11 is fixed. The first light collecting means 13 is fixed to the part by a ring-shaped component fixing jig 31.

Here, as shown in FIG. 2, the first case 29 and the magnet
The portion 21 is designated as portion A, and the portion of the second case 27 is designated as portion B. Since the optical components are finely adjusted for each of the portion A and the portion B, the method will be described below.

First, for part A, the magnet 21 having the magneto-optic crystal 17 and the like fixed thereto is inserted into the first case 29. At this time, the light emitted from the semiconductor laser 11 is collimated by the first focusing means 13 into collimated light. The position in the direction of the optical axis is finely adjusted so as to achieve. At the same time, the magnet 21 is rotated in the circumferential direction and finely adjusted so that the intensity of the light passing through the polarizer 15, the magneto-optical crystal 17, and the analyzer 19 is maximized.

Here, in the semiconductor laser module 1 with an optical isolator, the light emitted from the semiconductor laser 11
Semiconductor laser 11 for converting the light into collimated light by focusing means 13
Between the first focusing means 13 and the collimated light
Fine adjustment is required for the adjustment between the second condensing means 23 and the optical fiber for condensing the light in the optical fiber by the condensing means 23, but the fine adjustment between the semiconductor laser 11 and the first condensing means 13 is required. Is performed as described above.

The polarizer 15, the magneto-optical crystal 17, and the analyzer 19 are fixed in the magnet 21, but they only need to pass the collimated light within their effective diameters. Strict alignment such as adjustment between the light means 13 is not required.

Next, regarding the portion B, in the holding hole 273 of the second case 27,
The second light condensing means 23 is inserted and fixed by the component fixing jig 25. At this time, a ferrule holding the optical fiber on its central axis is inserted into the insertion hole 275 of the second case 27 until the end surface of the ferrule contacts the stopper 26, and light is incident from the other end side of the optical fiber. The position of the second light condensing means 23 in the optical axis direction is adjusted so that the light emitted from the second light condensing means 23 (to the left in the figure) becomes collimated light.

In the case where collimated light enters the second condensing means 23 from the left side of the drawing, the light is always condensed in the optical fiber.

As described above, the part A and the part B are separately adjusted. However, the light emitted from the semiconductor laser 11 by the part A is always a collimated light, and the collimated light incident on the second focusing means 23 by the part B. Light will always be focused in the optical fiber.

To assemble the A portion and the B portion, first, the flange portion 271 of the second case 27 is brought into contact with the right end surface of the first case 29.

Next, optical adjustment between the two is performed, but this adjustment need only be performed by movement only in a plane perpendicular to the optical axis. This is because the light emitted from the analyzer 19 in the part A is a collimated light, while the light emitted from the
If the light incident on the optical fiber is a collimated light, this light is always condensed in the optical fiber, so it is only necessary to adjust the two optical axes so that they are aligned.

After the fine adjustment is completed, if the contact surfaces of the first case 29 and the second case 27 are fixed by means such as soldering or laser welding, the fixing of both is completed.

Here, in comparison with the conventional method of assembling the semiconductor laser module 8 with an optical isolator shown in FIG. 5, in the related art, when the spherical lens 83 is mounted on the semiconductor laser 81, the position is finely adjusted, and then the Faraday rotation is performed. Set the analyzer 87 and adjust its position, then install and adjust the analyzer 93 on the Faraday rotator 87, and then adjust the spherical lens on the analyzer 93.
The position of the optical fiber 97 was adjusted by adjusting the position of the optical fiber 97, and the optical fiber 82 was further adjusted on the optical fiber 82 so that the light was focused on the optical fiber 82.

On the other hand, in the case of the present invention, portions that require strict alignment (between the semiconductor laser 11 and the first focusing means 13 and between the second focusing means 23 and the optical fiber) are divided, and Since the fine adjustment is performed, unnecessary strict alignment is unnecessary, the assembly is very simple, and the coupling efficiency is high.

FIG. 4 is a view showing another embodiment of the semiconductor laser module with an optical isolator according to the present invention.

The semiconductor laser module with optical isolator 1 'in this embodiment has a structure in which the polarizer 15 is omitted from the semiconductor laser module with optical isolator 1 shown in FIG. That is, of the light emitted from the semiconductor laser 11, the reflected return light reflected on the end face of the optical fiber or the like is the analyzer 19.
When the polarization plane is rotated by the magneto-optical crystal 17 and returns to the semiconductor laser 11, the analyzer makes an angle of 90 ° between the oscillation polarization direction of the semiconductor laser 11 and the return light polarization direction.
By setting 19, the polarizer 15 is omitted. Therefore, a smaller semiconductor laser module 1 'with an optical isolator can be provided.

In the method of assembling the semiconductor laser module with an optical isolator 1 shown in FIG. 2, the substrate 11 is mounted on the left end surface of the first case 29 so that the semiconductor laser 11 is on the optical axis.
1 is fixed, and then the magneto-optical crystal 17 is
The position is finely adjusted by inserting the magnet 21 to which the components are fixed, but the assembling method is not limited to this, and the assembling method may be as follows.

That is, first, the semiconductor laser 11 is placed on the left end face of the first case 29.
Press the substrate 111 to which is attached. At this time, play is provided at the joint between the substrate 111 and the first case 29 so that the substrate 111 can be finely moved in a direction perpendicular to the optical axis. Next, the magnet 21 having the magneto-optic crystal 17 and the like fixed inside the first case 29
And fine-tune its position. And then substrate 11
1 is slightly moved in a plane perpendicular to the optical axis to adjust the semiconductor laser 11 so as to coincide with the optical axis. Thereafter, the board 111 is fixed to the first case 29, thereby completing the assembly of the portion A.

〔The invention's effect〕

As described above in detail, according to the semiconductor laser module with an optical isolator according to the present invention, a portion requiring strict alignment (between the semiconductor laser and the first focusing means,
And between the second focusing means and the optical fiber) respectively.
Since the case and the second case are divided, both parts can be finely adjusted separately. In addition, the light emitted from the first case is a collimated light, while the light incident on the second case is always condensed in an optical fiber if it is collimated light. It can be performed only by moving in the plane direction perpendicular to the optical axis so that the optical axis of the case is aligned, and fine adjustment and assembly thereof can be easily performed. Therefore, the semiconductor laser module with the optical isolator can be assembled very simply and has an excellent effect that the coupling efficiency is high.

Further, in the present invention, the first condensing means, the polarizer (sometimes unnecessary), the magneto-optical crystal and the analyzer are fixed in a magnet, and the magnet is housed in the first case to which the semiconductor laser is fixed. Since the second condensing means only needs to be housed in the second case, there is no need for a support attached to each optical component as in the prior art, and a compact, inexpensive, and simple semiconductor laser module with an optical isolator is provided. it can.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a semiconductor laser module 1 with an optical isolator according to one embodiment of the present invention, FIG. 2 is a view showing a method of assembling the semiconductor laser module 1 with an optical isolator, and FIG. And magneto-optic crystal 17 and analyzer
FIG. 4 is a perspective view showing an integrated state of the semiconductor laser module with the optical isolator 19, FIG. 4 is a view showing another embodiment of the semiconductor laser module with an optical isolator according to the present invention, and FIG. 5 is an example of a conventional semiconductor laser module with an optical isolator. FIG. In the figure, 1,1 '... semiconductor laser module with optical isolator, 11 ... semiconductor laser, 13 ... first condensing means, 15 ...
... Polarizer, 17 ... Magneto-optical crystal, 19 ... Analyzer, 21 ...
Magnet, 23 second light collecting means, 27 second case, 275
... insertion holes, 29 ... first case.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-52511 (JP, A) JP-A-1-142512 (JP, A) JP-A-63-88885 (JP, A) JP-A-1 232785 (JP, A) Japanese Utility Model 60-600057 (JP, U) Japanese Utility Model 60-187019 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/18 G02B 6 / 42

Claims (2)

(57) [Claims] 1. A semiconductor laser, at least a first condensing means for collimating light emitted from the semiconductor laser, a magneto-optical crystal for rotating the direction of linearly polarized light by 45 ° around an optical axis, and a magneto-optical crystal. An analyzer set at an angle for passing the linearly polarized light rotated by 45 ° and a second condensing means for condensing the collimated light passing through the analyzer to an optical fiber are arranged on the optical axis in this order. An optical isolator-equipped semiconductor laser module having a magnet for applying a saturation magnetic field to the magneto-optical crystal, wherein a cylindrical first case having a semiconductor laser fixed to one end inside thereof and the second condensing means are held. A second case provided with an insertion hole for inserting a ferrule holding the optical fiber on a central axis thereof, wherein the magnet is formed in a cylindrical shape, and the first condensing means is provided inside the tube. It is fixed to an analyzer-optical crystal, the semiconductor laser module with optical isolator, characterized in that to secure the magnet to the inside of the first case, and further fixing the second casing to the first casing. 2. The magnet according to claim 1, wherein said magnet is formed in a cylindrical shape, said magneto-optical crystal and said analyzer are formed in a cylindrical shape so as to be inscribed inside said magnet, and said magneto-optical crystal and said analyzer are bonded to each other. 2. The semiconductor laser module with an optical isolator according to claim 1, wherein: