JPH03106092A - Semiconductor laser module with optical isolator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser module with an optical isolator used in optical communication, optical measurement, etc.

[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 from returning to the semiconductor laser.

FIG. 5 is a diagram showing an example of this type of semiconductor laser module with an optical isolator, which is described in Japanese Patent Application Laid-open No. 70516/1983.

As shown in the figure, this semiconductor laser module 8 with an optical isolator includes a support 85 to which a semiconductor laser 81 and a ball lens 83 are attached, a support 91 to which a Faraday rotator 87 is attached, and an analyzer 93. It is composed of a support 95, a support 99 to which a ball lens 97 is attached, a support 84 to which an optical fiber 82 is attached, and a cap 86 surrounding these.

And this semiconductor laser module 8 with optical isolator
To assemble the holder, the support 91, the support 95, the support 99, and the support 84 are sequentially attached to the support 85, and then these are fixed, and then the cap 86 is placed on the support.

Note that when attaching the support 91 on the support 85, the support 91 is slightly adjusted on the end face of the support 85 so that the output of the light that has passed through the Faraday rotation 87 is maximized. do.

Next, when attaching the support 95 to the support 91, finely adjust the support 95 on the end face of the support 91 so that the analyzer 93 matches the inclination of the light rotated by the Faraday rotation 87. Rotate.

Next, when attaching the support 99 onto the support 95, the optical axis alignment is performed by finely adjusting the support 99 on the end surface of the support 95.

Furthermore, when attaching the support 84 on the support 99,
By finely adjusting the support 84 on the end face of the support 99, the light focused by the ball lens 97 can be accurately adjusted to the thin optical fiber 82.
Make it incident inside.

[Problem to be solved by the invention]

However, in the conventional semiconductor laser module with an optical isolator as described above, each optical component requires its own support, which not only requires a large number of parts, but also requires time and effort to align each optical component. There was a problem in that a large number of jigs were required for positioning.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a semiconductor laser module with an optical isolator, which not only has a small number of parts but also allows easy alignment between optical parts, and a method for manufacturing the same.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a semiconductor laser,
A first focusing means for collimating the emitted light of the semiconductor laser, a polarizer (unnecessary in some cases), a magneto-optic crystal that rotates the direction of linearly polarized light by 451 around the optical axis, and a magneto-optic crystal that rotates the direction of linearly polarized light by 451 An analyzer set at an angle that allows the rotated linearly polarized light to pass through, and a second focusing means that focuses the collimated light that has passed through the analyzer onto an optical fiber are arranged in this order on the optical axis, A semiconductor laser module with an optical isolator including a magnet that applies a saturation magnetic field to the magneto-optic crystal, comprising a first case having a cylindrical hole therein, the semiconductor laser being fixed to one end of the hole, and A second case is provided with an insertion hole into which a ferrule holding an optical fiber on its central axis is inserted, and the second light condensing means is held inside the second case, and the magnet is configured in a cylindrical shape and inside the second case. The first light condensing means, the polarizer (unnecessary in some cases), the magneto-optical crystal, and the analyzer are fixed, and this magnet is further inserted into the hole of the first case and fixed, and then the first case is fixed. A semiconductor laser module with an optical isolator was constructed by fixing the second case.

The present invention also provides a method for manufacturing a semiconductor laser module with an optical isolator, including means for fixing the first light condensing means, a polarizer (in some cases unnecessary), a magneto-optic crystal, and an analyzer inside the magnet; a first case in which a cylindrical hole is provided and a semiconductor laser is fixed to one end of the hole, and the magnet is inserted into the hole of the first case so that the emitted light of the semiconductor laser is focused on the first case. The second condensing means is inserted into a second case provided with a means for adjusting and fixing the position of a magnet so that the light is collimated by an optical means, and an insertion hole into which a ferrule to which the optical fiber is attached is inserted. means for adjusting and fixing the position of the second condensing means so that the light from the optical fiber side is collimated by the second condensing means; and aligning the optical axes of the first case and the second case. and a means for fixing after adjustment.

[Effect]

By configuring the semiconductor laser module with an optical isolator as described above, the part between the semiconductor laser and the first focusing means that requires strict alignment (the light emitted by the semiconductor laser is collimated by the first focusing means) The part between the second focusing means and the optical fiber (fine adjustment for focusing the collimated light into the optical fiber by the second focusing means) is located inside the second case. Since both cases can be separated, parts that require fine adjustment can be fine-tuned separately. After the fine adjustment is completed, the semiconductor laser module with an optical isolator is completed by connecting both cases, but the connection between the two is easy because the only adjustment required is to align the optical axes of the two.

Therefore, it is not only easy to adjust the parts that require fine adjustment, but also to connect both cases.

Furthermore, in the present invention, since the first light condensing means, the polarizer (unnecessary in some cases), the magneto-optical crystal, and the analyzer are fixed within the magnet, there is no need for a support for these optical components, which is different from the conventional method. Supports attached to each optical component are no longer necessary, and the number of parts can be reduced, and the size and cost can be reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

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

As shown in the figure, this semiconductor laser module 1 with an optical isolator includes a semiconductor laser 11 and a first focusing means 13.
The polarizer 15, the magneto-optic crystal 17, the analyzer 19, and the second condensing stage 23 are arranged in this order on a straight line, and
A magnet 21 is attached to the outer periphery of the magneto-optic crystal 17, and these optical components are attached to the first case 29 and the second case 2.
7.

Each component and its assembly method will be explained in detail below.

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

In this embodiment, spherical lenses are used for the first condensing means 13 and the second condensing means 23, but other lenses such as a rond lens or a convex lens may also be used.

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

The magneto-optic crystal 17 changes the plane of polarization of linearly polarized light to 4 under a saturated magnetic field.
It is molded to a thickness that allows it to be rotated 5 degrees.

The analyzer 19 is composed of a polarizing beam splitter or the like, and is fixed at an angle rotated by 45'' around the optical axis compared to the polarizer 15.

These polarizer 15, magneto-optic crystal 17, analyzer 1
As shown in FIG. 3, the cylindrical parts 9 are all cylindrical in shape and have the same diameter, and are bonded together. Note that these do not necessarily need to be bonded, and may be fixed together using a jig.

The magnet 21 is a permanent magnet for applying a saturation magnetic field to the magneto-optic crystal 17, and has a cylindrical shape, and its inner diameter is large enough to allow insertion of the polarizer 15, the magneto-optic crystal 17, and the analyzer 19. .

The first case 29 is formed into a cylindrical shape, and its inner diameter is large enough to allow the outer periphery of the magnet 21 to be slidably inserted therein.

The second case 27 has a pot portion 271 formed at one end thereof that contacts one end surface of the first case 29, and a holding hole 271 for holding the second light condensing means 23 in the center thereof.
3 and an insertion hole 275 for inserting a ferrule holding the optical fiber on its central axis. Note that 277 of the second case 27 is a mounting portion for mounting an optical fiber connector plug.

Next, a method of assembling this semiconductor laser module 1 with optical inlay will be explained.

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

As shown in the figure, first, the substrate 111 to which the semiconductor laser 11 is attached 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 end of the magnet 21 on the semiconductor laser 11 side is The first light condensing means 13 is fixed to the part using a ring-shaped fixing jig 31.

As shown in FIG. 2, the first case 29 and the magnet 21 are referred to as part A, and the second case 27 is referred to as part B. Note that the optical components for each of the A section and B section will be finely adjusted, and the method will be explained below.

First, regarding part A, the magnet 21 with the magneto-optic crystal 17 fixed thereon 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. Finely adjust the position in the optical axis direction so that

At the same time, a polarizer 15, a magneto-optic crystal 17 and an analyzer 19
This magnet 2 is set so that the intensity of the light that has passed through
Rotate 1 in the circumferential direction to make fine adjustments.

Here, semiconductor laser module 1 with optical isolator
In this case, the light emitted from the semiconductor laser 11 is
Adjustment between the semiconductor laser 11 and the first focusing means 13 for collimating light by the focusing means 13, and second focusing means for focusing the collimated light into the optical fiber by the second focusing means 23. Precise fine adjustment is required between the semiconductor laser 11 and the first optical fiber.
Fine adjustment between the focusing means 13 is performed as described above.

The polarizer 15, the magneto-optical crystal 17, and the analyzer 19 are fixed within the magnet 21, but it is only necessary that the collimated light passes through the effective diameter of these, and the above-mentioned semiconductor laser 11 and the first collection No strict alignment such as adjustment between the optical means 13 is required.

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

As a result, when collimated light enters the second condensing means 23 from the left side of the figure, it is always condensed into the optical fiber.

As described above, the A part and the B part are each adjusted separately, but the light emitted from the semiconductor laser 11 by the A part always becomes collimated light, and the B part collimates the light that enters the second condensing means 23. Light is always focused within the optical fiber.

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

Next, optical adjustment is made between the two, but this adjustment is
Adjustment only needs to be made by movement within a plane perpendicular to the optical axis.

This is because the light emitted from the analyzer 19 in section A is collimated light, while in section B, the light emitted from the second light condensing means 23
This is because if the incident light is frimate light, this light will always be condensed into the optical fiber, so it is only necessary to adjust the optical axes of both so that they match.

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

Here, when compared with the conventional method of assembling the semiconductor laser module 8 with optical isolator shown in FIG.
When installing the ball lens 83 on the semiconductor laser 81, finely adjust its position, then install the Faraday rotator 87 and adjust its position, and then install the analyzer 93 on the Faraday rotator 87. Next, install the ball lens 97 on the analyzer 93 and adjust its position, and then install the optical fiber 82 on top of the ball lens 97 and adjust the position of the ball lens 97.
Fine adjustments were made so that the light was focused on the area.

On the other hand, in the case of the present invention, the parts that require precise alignment (between the semiconductor laser 11 and the first condensing means 13, and between the second condensing stage 23 and the optical fiber) are divided, and each Since fine adjustments are made separately, there is no need for unnecessarily strict alignment, and assembly is extremely simple, with high coupling efficiency.

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

A semiconductor laser module 1' with an optical isolator in this embodiment has a structure in which the polarizer 15 is omitted from the semiconductor laser module 1 with an optical isolator shown in FIG. That is, out of the light emitted from the semiconductor laser 11,
When the reflected return light reflected by the end face of the optical fiber passes through the analyzer 19 and returns toward the semiconductor laser 11 with its plane of polarization rotated by the magneto-optic crystal 17, the semiconductor laser 11
By setting the analyzer 19 so that the oscillation polarization direction of the oscillation polarization direction and the polarization direction of the returned light form a 90° angle, the polarizer 15
is omitted. Therefore, an even smaller semiconductor laser module 1' with an optical isolator can be provided.

In the method for assembling the semiconductor laser module 1 with optical isolator shown in FIG. Although the magnet 21 to which the magneto-optic crystal 17 and the like are fixed is inserted into the magnet 29 and its position is finely adjusted, the assembly method is not limited to this and may be assembled as follows.

That is, first, the semiconductor laser 1 is placed on the left end surface of the first case 29.
1 is attached to the substrate 111. At this time, play is provided at the joint between the substrate 111 and the first case 29 so that the substrate 111 can move slightly in a direction perpendicular to the optical axis. Next, the magnet 21 to which the magneto-optic crystal 17 and the like are fixed is inserted into the first case 29, and its position is finely adjusted.

Next, the substrate 111 is slightly moved in a plane perpendicular to the optical axis to adjust the semiconductor laser 11 to align with the optical axis. After that, this board 111 is placed in the first case 2.
9, the assembly of part A is completed.

〔Effect of the invention〕

As described above in detail, according to the semiconductor laser module with optical isolator and the manufacturing method thereof according to the present invention, the parts that require strict alignment (the semiconductor laser and the first
between the light collecting means and between the second light collecting means and the optical fiber)
Since each is divided into the first case and the second case, both parts can be fine-tuned separately. Therefore, not only is it easy to make fine adjustments, but the connection between both cases can be made by simply aligning their optical axes. Therefore, a semiconductor laser module with an optical isolator can be assembled very easily, and its coupling efficiency is also high, which is an excellent effect.

Further, in the present invention, the first focusing means, the polarizer (unnecessary in some cases), the magneto-optical crystal, and the analyzer are fixed in a magnet, and this magnet is housed in the first case in which the semiconductor laser is fixed. Since the second light focusing means only needs to be housed in the second case, there is no need for supports attached to each optical component as in the past, providing a compact, inexpensive, and simple semiconductor laser module with an optical isolator. can.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a semiconductor laser module 1 with an optical inlay according to an embodiment of the present invention, FIG. 2 is a diagram showing a method of assembling the semiconductor laser module 1 with an optical isolator, and FIG. 3 is a polarizer. 15, a magneto-optical crystal 17, and an analyzer 19 are integrated. FIG. 4 is a diagram showing another embodiment of the semiconductor laser module with an optical isolator according to the present invention. FIG. 5 is a diagram showing a conventional optical 1 is a diagram showing an example of a semiconductor laser module with an isolator. In the figure, 1, 1'... Semiconductor laser module with optical isolator, 11... Semiconductor laser, 13... First condensing means, 15... Polarizer, l7... Magneto-optic crystal,
l9...Analyzer, 21...Magnet, 23...Second condensing means, 27...Second case, 275...Insertion hole,
29...first case.

Claims (6)

[Claims] (1) At least a semiconductor laser, a first focusing means for collimating the emitted light of the semiconductor laser, a magneto-optic crystal that rotates the direction of linearly polarized light by 45 degrees around the optical axis, and a magneto-optic crystal that rotates the direction of linearly polarized light by 45 degrees around the optical axis. An analyzer set at an angle that allows the rotated linearly polarized light to pass through, and a second focusing means that focuses the collimated light that has passed through the analyzer onto an optical fiber are arranged in this order on the optical axis, and the A semiconductor laser module with an optical isolator that is equipped with a magnet that applies a saturation magnetic field to a magneto-optic crystal, the first case having a hole therein and a semiconductor laser fixed to one end of the hole, and holding the second light condensing means. and a second case provided with an insertion hole into which a ferrule holding the optical fiber on its central axis is inserted, the magnet having a cylindrical shape, and the first light condensing means and the magneto-optical device arranged inside the magnet. A semiconductor laser module with an optical isolator, characterized in that a crystal and an analyzer are fixed, the magnet is inserted and fixed into a hole in the first case, and the second case is further fixed to the first case. (2) The magnet is formed into a cylindrical shape, and the magneto-optic crystal and the analyzer fixed inside the magnet are each formed into a cylindrical shape so as to be inscribed inside the magnet. 2. The semiconductor laser module with an optical isolator according to claim 1, wherein the photons are bonded together. (3) The method for manufacturing a semiconductor laser module with an optical isolator according to claim (1), further comprising: means for fixing the first focusing means, magneto-optic crystal, and analyzer inside a magnet; and within a hole of the first case. means for inserting the magnet into the second case and adjusting and fixing the position of the magnet so that the emitted light from the semiconductor laser becomes collimated light by the first condensing means; Inserting the ferrule to which the optical fiber is attached, and inserting the second condensing means into the second case so that the light from the optical fiber side becomes collimated light by the second condensing means. A semiconductor laser module with an optical isolator, comprising: means for adjusting and fixing the position of the means; and means for fixing the first case and the second case after adjusting their optical axes so that their optical axes are aligned. manufacturing method. (4) The semiconductor laser module with an optical isolator according to claim (1), characterized in that a polarizer is disposed on the optical axis between the magneto-optic crystal and the first focusing means. . (5) The magnet is configured in a cylindrical shape, and a polarizer, a magneto-optical crystal, and an analyzer fixed inside the magnet are each formed in a cylindrical shape so as to be inscribed inside the magnet, and these polarized light 5. The semiconductor laser module with an optical isolator according to claim 4, wherein the magneto-optic crystal and the analyzer are bonded together in this order. (6) The method for manufacturing a semiconductor laser module with an optical isolator according to claim (4), further comprising: means for fixing the first light condensing means, the polarizer, the magneto-optic crystal, and the analyzer inside a magnet; means for inserting the magnet into a hole in the case and adjusting and fixing the position of the magnet so that the emitted light from the semiconductor laser becomes collimated light by the first focusing means; Insert the ferrule to which the optical fiber is attached, and insert the second condensing means into the second case so that the light from the optical fiber side becomes collimated light by the second condensing means. 2. An optical isolator comprising: means for adjusting and fixing the position of the second light condensing means; and means for fixing the first case and the second case after adjusting their optical axes so that their optical axes are aligned. A method for manufacturing a semiconductor laser module.