JPH0193710A - Lens fixing structure for semiconductor laser module - Google Patents

Abstract

PURPOSE:To improve the optical coupling efficiency and the reliability of an LD module by arranging an LD mount, a lens holder and a spacer in prescribed positional relations and adjusting positions in the contacting state to fix them. CONSTITUTION:Since a spacer 7 is closely brought into contact with an LD mount 2 freely slidably in the direction of an arrow A and the direction perpendicular to the surface of paper, the spacer 7 is moved in these directions to adjust positions of a lens 3 and an LD. Since a projection 6 of the spacer 7 is fitted to a hole 5 of a lens holder 4, the lens holder 4 is moved in the direction of an arrow B to adjust the position of the lens 3 in the same direction. Since the LD mount 2, the spacer 7 and the lens holder 4 are closely brought into contact with one another and the position of the lens 3 is adjusted in this state and they are fixed by laser welding as they are, the optical coupling efficiency and the reliability are improved.

Description

[Detailed Description of the Invention] Overview Regarding the lens fixing structure of a semiconductor laser module used on the transmitting side in an optical communication system, the present invention aims to increase optical coupling efficiency and improve reliability. In a semiconductor laser module in which a mount and a lens holder to which a lens is fixed are arranged in a predetermined positional relationship, a hole is provided in the lens holder, and a spacer having a protrusion corresponding to the shape of the hole is attached to the LD mount. The LD mount, spacer, and lens holder are constructed by laser welding the LD mount, spacer, and lens holder in a state in which they are slidably brought into close contact and the protrusion of the spacer is fitted into the hole of the lens holder.

INDUSTRIAL APPLICATION FIELD The present invention relates to a lens fixing structure for a half-bow body laser module used on the transmitting side in an optical communication system.

In optical communication systems, semiconductor lasers (hereinafter referred to as L
D) is modulated with a time-series electric signal, and this modulated light is introduced into an optical fiber via a lens system. The LD Luns system and the optical fiber for connection are as follows:
Usually, it is used as an integrated LD module. In terms of transmission loss, the higher the intensity of the signal light introduced into the optical fiber, the greater the transmission distance, which is convenient, so the optical coupling efficiency (the intensity of the light introduced into the optical fiber and There is a demand for an LD module with a high ratio (to the intensity of emitted light from an LD).

Conventional technology A conventional general LD module has two lenses.
In order to obtain high optical coupling efficiency, the LD and the lens on the LD side are integrated, the optical fiber and the lens on the optical fiber side are integrated, and the relative positional relationship of these integrated components is adjusted. I was doing it.

FIG. 5(a) is a sectional view of the integrated structure on the LD side.

Lens holder 34 and LD to which ball lens 32 is press-fitted
36 are fixed via an intervening material 38 such as adhesive or solder. When creating such an integrated object, for example, the output light of the LD 36 is made into a parallel beam by the ball lens 32, and the beam is parallel to the output optical axis of the LD 36. 34 was held, and in this state, the inclusion 38 was injected into the gap.

Problems to be Solved by the Invention However, with the structure of the integrated product on the LD side described above, the L
The reality is that complicated work is required to accurately hold D and the lens holder in a predetermined n relationship. If the predetermined positional relationship is not obtained, for example, Fig. 5(b)
As shown in FIG. 2, the optical axis of the light beam emitted from the ball lens 32 and the optical axis of the emitted light from the LD 36 are not parallel to each other, causing a problem in that high coupling efficiency may not be obtained.

Furthermore, even if a predetermined positional relationship is obtained, inclusions 3 may occur depending on the environmental conditions in which the module is used.
8 is deformed and the coupling efficiency is lowered, so there is also a problem that the reliability of the device is low.

The present invention was created in view of these problems.
The purpose is to increase optical coupling efficiency and improve reliability in an LD module.

Means to solve problems FIG. 1 is a diagram showing the principle configuration of the present invention.

This LD module is constructed by arranging an LD mount 2 to which an LDl is fixed and a lens holder 4 to which a lens 3 is fixed in a predetermined positional relationship.

The lens 3 is fixed by a structure as shown below.

5 is a hole provided in the lens holder 4.

A spacer 7 is slidably attached to the LD mount 2 and has a protrusion 6 having a shape corresponding to the shape of the hole 5.

The LD mount 2, spacer 7, and lens holder 4 are laser welded to each other with the protrusion 6 of the spacer fitted into the hole 5 of the lens holder.

In FIG. 1, the spacer 7 is slidably brought into close contact with the lo-o mount 2 by moving the spacer 7 into the figure and in a direction perpendicular to the plane of the paper. This is to perform position adjustment in the direction of.

The reason why the projection 6 of the spacer is fitted into the hole 5 of the lens holder is to move the lens holder 4 in the direction B in the figure and adjust the position of the lens 3 in the same direction.

In this way, the position of the lens 3 can be adjusted while the LD mount 2, spacer 7, and lens holder 4 are in close contact with each other, so they can be fixed by laser welding (No. 5). In the conventional example shown in the figure, laser welding could not be performed because the parts to be fixed were not necessarily in close contact with each other.)
.

*m-week Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is an exploded perspective view of an LD side integrated product of an LD module constructed by applying the present invention, FIG. 3 is a front view of the integrated product, and FIG. 4 is a side view thereof.

The LD chip 12 is fixed, for example, by soldering, to the edge of an LD chip carrier 14 made of a conductor that functions for heat radiation and for supplying electricity to one electrode. 16
is a mount to which the LD chip carrier 14 is fixed, and the LD chip 12 . A smooth surface 16a is formed on the side. 18 is a spacer having a smooth surface 18a on one side, and a generally cylindrical projection 20 on the other side. Since smooth surfaces are formed on the mount 16 and the spacer 18 in this manner, the spacer 18 can be slid with respect to the mount 16 in the x and y directions perpendicular to the output optical axis of the LD chip 12.

22 is a lens holder, through which a hole 22a for holding the lens and a hole 22b into which the protrusion 20 of the spacer is to fit are passed through. The ball lens 24 is fixed in the hole 22a by, for example, press fitting. The shape of the hole 22b is the same as the shape of the protrusion 20 of the spacer so that its inner peripheral surface is in close contact with the protrusion 20 of the spacer. In this way, the protrusion 20 of the spacer
Since the lens holder 22 is configured to fit into the hole 22b of the lens holder, the lens holder 22 can be moved relative to the spacer 18 in the optical axis direction (two directions) of the light emitted from the LD chip 12. At this time, since the shapes of the protrusion 20 and the hole 22b are the same, even if the lens holder 22 is moved in the Z direction, the lens holder 22 will not fit into the spacer 1.
8, there is no displacement in the X and y directions.

In the above configuration, by moving the spacer 18 in the x and y directions relative to the mount 16 and moving the lens holder 22 in the ZXJ direction relative to the spacer 18 f Relative positional relationships can be adjusted. For this reason, for example, the LD chip 12 is driven to emit light, and the ball lens 24
The light beam pattern emitted through the IR (infrared rays)
By performing the above position adjustment while monitoring with a camera, the ball lens 24 can be positioned at an optimal position.

Once the optimum position of the ball lens 24 has been determined, as shown in FIG. Each member is fixed to each other by laser welding.

In this case, since each member is in close contact with each other, there is no risk of welding defects occurring. In general, laser welding is performed by partially melting each member, so extremely strong fixing is possible, and the relatively large leap phenomenon seen in conventional soldering and other processes does not occur.

In this embodiment, the shape of the projection 20 of the spacer and the hole 22b of the lens holder is approximately cylindrical, but if the lens holder can move in the Z direction without play in the X and Y directions, Any shape can be adopted.

In FIG. 3, the shape of the portion to be laser welded is circular in order to equalize the residual stress caused by welding.

Effects of the Invention As detailed above, according to the present invention, the positions of the lens holder to which the lens is fixed and the LD mount to which the LD is fixed can be adjusted via the spacer, so that optical This has the effect that the lens can be fixed at an optimal position in terms of coupling efficiency.

In addition, since the lens position can be adjusted with the LD mount, spacer, and lens holder in close contact with each other, these can be fixed by laser welding, which has the effect of improving the reliability of the device. be.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is an exploded perspective view of an integrated LD module on the LD side showing an embodiment of the present invention, Fig. 3 is a front view of the integrated product, and Fig. 4 is the same. Side view of integrated product. FIG. 5 is a cross-sectional configuration diagram of a conventional integrated product on the LD side in an LD module. 1... LD (semiconductor laser), 2... LD mount, 3... lens, 4...
・Lens holder, 5...hole, 6...protrusion,
7...Spacer. 4: Lens holder Honkomyo's Atsushi Tarube Diagram 1st Figure 1

Claims (1)

[Claims] A semiconductor laser module in which an LD mount (2) to which a semiconductor laser (1) is fixed and a lens holder (4) to which a lens (3) is fixed are arranged in a predetermined positional relationship, A hole (5) is provided in the lens holder (4), and a spacer (7) having a protrusion (6) having a shape corresponding to the shape of the hole (5) is slidably brought into close contact with the LD mount (2). A semiconductor laser module characterized in that an LD mount (2), a spacer (7) and a lens holder (4) are laser welded with the projection (6) of the spacer fitted into the hole (5) of the lens holder. Lens fixed structure.