JPH04168404A - Manufacture of wave-guiding channel type optical module - Google Patents

Abstract

PURPOSE:To satisfactorily fix an optical element loading stem to a box body and improve the position precision by using a recessed part having a soldering layer as the surface for welding the optical element loading stem to the box body, and welding this by heating. CONSTITUTION:The optical axis fitting of a LD stem 2 integrated with a LD element 3 is conducted, and the stem 2 is laser-welded and fixed to a box body 1. On the surface for welding the stem 2 and the body 1, a recessed part is provided, and a soldering layer having a determined thickness is preliminarily provided thereon. Then, the connecting part 6 between the stem 2 and the box body 1 is heated at high frequency for soldering. The reason for this is that, when a solder is placed on the whole connecting surface of the stem, and the stem 2 is not in contact with the box body 1 at all, there is the possibility that only the solder is welded at the time of laser welding, and the stem 2 is not welded. Thus, the LD 3 and a glass wave-guiding channel can be fixed with highly precisely fitting their optical axes to each other, and the exothermic of the LD also can be effectively removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a waveguide type optical module.

[Prior Art] An optical module using an optical fiber or glass waveguide type has a structure in which an LD (laser diode) or LED (light emitting diode) and an optical fiber or glass waveguide are optically coupled through a lens or directly. It has become.

A conventional optical module has a structure as shown in FIG. 3(a) or (b). In the same figure, 1 is a metal box, 2 is an L
In the D stem, 3 is an LD chip, and 4 is an optical fiber. In the conventional example shown in FIG. 4A, the LD stem 2 is first fixed to the box 1 with solder or a YAG laser, and then the optical axis of the optical fiber 4 is aligned and fixed. Further, in the conventional example shown in FIG. 2B, the glass waveguide 5 is first fixed in the box 1 by YAG laser welding, and then the LD stem 2 is aligned with its optical axis and fixed by solder or YAG laser welding. In these figures, reference numeral 6 indicates a location where the box 1 and the LD stem 2 are fixed.

In the case of the optical fiber type optical module shown in Figure (a), the LD
After the system 2 is fixed, the optical axis can be adjusted with respect to the optical fiber 4. However, in the case of the glass waveguide type shown in figure (b),
It is difficult to align the optical axis by moving the glass waveguide 5, and it is necessary to fix the LD stem 2 with an accuracy of several microns with respect to the optical axis.

[Problems to be Solved by the Invention] As described above, solder or YAG laser welding is used as a conventional method for fixing the LD stem of an optical module. When fixing with solder, non-uniform stress is applied to the stem when the solder solidifies, causing optical axis deviation of about 5 to 7 μm at the minimum. Further, when there is a temperature change outside, there is a problem in that optical axis deviation occurs due to a creep phenomenon or linear expansion of the solder.

In addition, in laser welding, since the weld is a spot, a gap is created between the stem box and the thermal resistance of this part is large, and the heat generated by the LD is not efficiently removed outside the box, resulting in stable characteristics of the LD. There is a problem that it becomes impossible to obtain.

The present invention has been made in view of the above points, and provides a method for manufacturing a waveguide type optical module that makes it possible to fix the stem with high precision and with high reliability so as to prevent positional shift even due to temperature fluctuations. The purpose is to

[Means for Solving the Problems] The above object is to provide a concave portion in the surface of the optical element-mounted stem to be welded to the box, provide a solder layer of a predetermined thickness in the concave portion in advance, and connect the stem to the same edge portion of the stem. This is achieved by laser welding the contact portion with the box and then heat welding the solder layer to solder the stem and the metal box.

[Function] With the above means installed, the stem can be well fixed to the metal box by laser welding and soldering, and the position can be fixed with high precision, and the thermal lightning conduction of the LD can be prevented. can do well.

[Example] The present invention will be described below based on the illustrated example. 1st
An embodiment of the invention is shown in FIG. 2 and FIG.

It should be noted that the same parts as in the prior art have been given the same reference numerals, so their explanation will be omitted. In this embodiment, a recess 2a is provided on the surface of the LD system 2 to be welded to the box 1, and a solder layer 7 of a predetermined thickness is provided in advance in the recess 2a. After the peripheral edge of the LD stem 2 is laser welded to the box 1, the solder layer 7 is heated and the LD
The recess 2a of the stem 2 was soldered to the metal case 1.

By doing this, the LD stem 2 and the metal box 1
The laser welding and soldering have made it possible to fix the laser diode well, making it possible to fix the position with high precision and to improve the heat conduction of the LD. It is possible to improve reliability without causing problems.

That is, the glass waveguide 5 is fixed to the box 1 by laser welding. Next, the LD stem 2 integrated with the LD element 3
The optical axes of the LD stem 2 are aligned, and the contact portion between the peripheral edge of the LD stem 2 and the box 1 is fixed by laser welding.

For this purpose, the joint 6 between the LD stem 2 and the box 1 is heated to a temperature higher than the melting point of the solder 7 using a high-frequency heater (not shown) to perform soldering. At this time, the heating time is set to within 2 seconds in view of the heat resistance of the LD3. Furthermore, if the solder 7 is placed on the entire joint surface of the stem 2 and the stem 2 and the box 1 are not in contact at all, there is a risk that only the solder 7 will melt during laser welding and the stem body 2 will not melt ( (In other words, although the stem 2 and the box 1 are joined by the solder 7, the stem 2 and the box 1 are not directly laser welded.)
As shown in FIG. 2, the structure of the LD stem 2 was such that a recess 2a was provided on the surface to be joined to the box 1. Note that the recessed portion 2a may have a structure in which a plurality of grooves are provided or a lattice-like structure. The thickness of the solder layer 7 was set to about 10 uTrL to 100 um so that both sides of the desoldering D stem 2 and the box 1 were sufficiently wetted and no gaps were created when melted. In this case, wettability is further improved by applying solder plating to the side of the box 1.

In this way, according to this embodiment, the LD in the optical module
The optical axes of the optical axis and the glass waveguide can be aligned and fixed with high precision, and at the same time, the heat generated by the LD can be effectively removed.

In the case of laser welding, the position of laser irradiation is the joint inside the box, but this can also be done from outside the box through the wall of the box. In addition to a YAG laser, an electron beam can also be used as a heat source for spot welding.

Further, in this embodiment, the solder layer in the concave portion provided on the LD stem is molded, but it is also possible to form only the concave portion in the LD stem, and weld by sandwiching a solder foil that matches the depth of the concave portion.

Furthermore, it can also be used as a short LED of an LD as a light emitting element.

[Effects of the Invention] As described above, the present invention provides a stem case for mounting an optical element,
A concave portion is provided on the surface to be welded, a solder layer of a predetermined thickness is provided in advance in this concave portion, and after laser welding the stem and the casing, the solder layer is heated to bond the concave portion of the stem and the metal casing. Since the stem and metal box are soldered together, the position of the stem and metal box can be fixed with high precision, and the heat conduction of the optical element can be improved. A highly reliable waveguide type optical module can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional side view showing a waveguide type optical module manufactured according to the present invention, FIG. 2 is a perspective view showing an example of an LD stem used in the present invention, and FIGS. 3(a) and (b) are FIG. 2 is a vertical side view showing a conventional optical modicoll. 1: metal box, 2: LD stem, 2a: recess, 5 glass waveguide, 7: solder layer. 1st Bacteria 2 Lower Han 7th Layer 3rd Bacteria (α)

Claims (1)

[Claims] 1. A waveguide type optical module comprising the steps of fixing a glass waveguide inside a metal box, and then fixing a stem carrying an optical element whose optical axis is aligned with the glass waveguide inside the box by laser welding. In the manufacturing method, a recess is provided on the surface of the stem to be welded to the box, a solder layer of a predetermined thickness is provided in advance in the recess, and a contact area between the peripheral edge of the stem and the box is laser welded. After that, the solder layer is heated and melted to solder the concave portion of the stem and the case.