JPS6330808A - Optical semiconductor element module - Google Patents

Abstract

PURPOSE:To obtain an optical semiconductor element module having a high reliability of airtight sealing, and being excellent in a mounting property of a communication equipment, by fixing a coupling rod lens to a light leading out hole of a metallic member provided by passing through a side wall of a container, sealing airtightly said lens, and placing coaxially an optical semiconductor element and an optical fiber on both its sides. CONSTITUTION:A metallic member 8 passes through a side wall 9-2 of a box type container, fixed in the front end and the rear end of the container, and in the inside of the metallic member 8, the side face is metallized and a rod lens 10 is welded and fixed by solder, and sealed airtightly. In opposition to a groove provided on a part of the metallic member 8, a semiconductor laser chip 1 is mounted so as to be opposed to the end face of the rod lens 10 through a heat sink 2 and a chip carrier 3. A quartz fiber provided on the center of an optical fiber covered wire 12 is protected by a ceramic capillary provided on a light incident end face part, and a ferrule 16, the tip position is adjusted to an optimum position, and thereafter, fixed to the outside end of the metallic member 8 through a slide ring 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical semiconductor element module, and particularly to a semiconductor laser module for optical fiber communication.

[Conventional technology]

Conventionally, various types of semiconductor laser modules (hereinafter referred to as modules) for optical fiber communication have been devised, but they can be broadly divided into coaxial type modules that perform optical coupling via rod lenses and modules with a tip processed. There are two types of flat modules that perform direct coupling using fibers. The advantages and problems of these modules will be explained below.

The first type of coaxial type module was the earliest one to be considered, and is a cylindrical package (container) with a window glass, for example, as shown in the structure shown in JP-A No. 57-211289. 〉A laser diode (hereinafter referred to as Ll) that is hermetically sealed inside is first manufactured, and then the L
In order to efficiently couple the light emitted from D to the fiber, the LD, lens, and fiber mounted on a coaxial member are mutually adjusted and then fixed. In general, coupling between an LD and a fiber (especially a single mode fiber) requires extremely strict positional accuracy, so coupling efficiency etc. may fluctuate due to temperature changes, and progressive deterioration of coupling efficiency may occur due to changes over time. However, in the case of this coaxial type module, since the structure is symmetrical with respect to the central axis of the module, the fluctuation factors are canceled out within the cross section, and a stable connection is obtained. However, this structure assumes the use of an LD assembled in a cylindrical package in advance, so it is not possible to construct a high value-added composite module with peripheral circuits and elements mounted in the same package. Can not. Another disadvantage is that since the outer shape of the module is cylindrical, it is difficult to mount it in communication equipment.

The second type of flat module, as shown at the 975 National Conference of the Institute of Electronics and Communication Engineers in 1985, has an LD mounted inside a box-shaped case, and a tipped fiber introduced through the side wall of the case. , near the tip of the fiber
This is a method of fixing with a fixative near D. In the case of this module, since a box-shaped case is used, a DIP type package used for integrated circuits can be adopted, and it can be directly mounted on a printed circuit board. Furthermore, if the area inside the case is increased, peripheral circuits and elements can be easily mounted in the same package. However, in the case of this module, since the fiber coating tends to adsorb gas, it is not possible to perform an airtightness test using helium gas or radioactive gas, and the reliability of hermetic sealing is difficult. Another disadvantage of this module is that coupling efficiency must be sacrificed in order to achieve stable coupling, especially when a single mode fiber is used. Also,
It is known that it is possible to construct a module with excellent transmission characteristics by incorporating an isolator inside the module, but in the case of this module, it is not possible to insert an isolator because the LD and the fiber tip are close to each other. .

[Problem that the invention seeks to solve]

The problems of the two types of modules explained above can be summarized as follows.

First, coaxial modules have the disadvantages of (a) not being suitable for compounding, and (b) poor mounting performance. Next, in flat modules, (a) the reliability of hermetic sealing is low;
(b) There is a drawback that the coupling efficiency must be kept low in order to stabilize the coupling. Furthermore, (c) there is a drawback that an isolator cannot be built-in.

The purpose of the present invention is to provide an optical semiconductor element module in which the coupling between an optical semiconductor element and a fiber is highly efficient and stable, the reliability of hermetic sealing is high, and the ease of mounting in communication equipment is excellent. be.

Another object of the present invention is to provide a high-value-added optical semiconductor element module that can incorporate peripheral circuits.

A further object of the present invention is to provide an optical semiconductor element module with excellent transmission characteristics.

[Means for solving problems]

The optical semiconductor element module of the present invention includes a metal member including a flat part on which an optical semiconductor element is mounted, and a light guide hole arranged parallel to the flat part with a predetermined height difference, and the light guide hole is located on a side wall of the metal member. through you to support the metal member.
a container to be fixed; a lens fixed within the light guide hole to hermetically seal it; and a lens disposed at one end of the light guide hole of the metal member and optically coupled to the optical semiconductor element via the lens. This includes an optical fiber.

〔Example〕

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

Figure 1 (a> is a plan view of an embodiment of the present invention, Figure 1 (b)
) is a cross-sectional view taken along the line x-x' of Figure 1 (a).
For simplicity, the plan view shows the state with M9-3 removed, and the cross-sectional view shows the semiconductor laser chip 1, heat sink 2, chip carrier 3, monitor photodiode 11, rod lens 10, and optical fiber coated wire. 12, pigtail 13
is not cut.

In this embodiment, a semiconductor laser chip 1, which is an optical semiconductor element, is mounted via a heat sink 2 and a chip carrier 3, and a first flat part 4 is arranged parallel to the first flat part 4 with a predetermined height difference. A pipe-shaped metal member 8 includes a second flat portion 5, a groove 6 provided in the second flat portion 5, and a light guide hole 7 provided in series with the groove 6; A container (consisting of a bottom plate 9-1, a side wall 9-2, and i) that penetrates the side wall 9-2 to support and fix the metal member 8, and a container that is fixed in the light guide hole 7 and hermetically seals it. A rod lens 10 is arranged at one end of the light guide hole 7 of the metal member 8, and a semiconductor laser chip 7 is provided through the rod lens 10.
and an optical fiber 12 that is optically coupled to the optical fiber.

Specifically, the metal member 8 passes through the side wall 9-2 of the box-shaped container and is fixed at the front and rear ends of the container. Inside the metal member 8, metallized side surfaces are applied, and a rod lens 10 is fused and fixed with solder, and the metal member 8 is hermetically sealed. A portion of the metal member 8 is cut away leaving a portion of the cross section inside the container to reach the light exit hole?
A semiconductor laser chip 1 is mounted facing the rod lens 6 via a heat sink 2 and a chip carrier 3 so as to face the end surface of the rod lens 10. A monitoring photodiode 11 is mounted behind the semiconductor laser chip 1. Leads 14 extend laterally from both sides of the container, and the chip carrier 3 and photodiode 11 are connected to the leads 14 by bonding wires 15. In addition, there is a lid 9 on the top surface.
-3 and seal it airtight by seam welding. From now on
After the above work is completed, an airtightness test will be conducted.

A quartz fiber is provided through the center of the optical fiber coated wire 12, and the quartz fiber is protected by a ceramic capillary and a ferrule 16 provided at the light incident end face, and after adjusting the tip position to an optimal position, It is fixed to the outer end of the metal member 8 via a slide ring 17. When fixing, the joints between the ferrule 16 and the slide ring 17, and between the slide ring 17 and the metal member 8 are spot welded at two to three places at the same time using a YAG laser. Further, this fixed portion and the ferrule 16 are protected by a protective sleeve 18. As a result of the above operations, the light emitted from the semiconductor laser chip 1 is outputted to the outside through the pigtail 13.

Further, by inserting an optical isolator 19 between the rod lens 10 and the optical fiber coated wire 12, it is possible to eliminate the influence of reflected return light and configure a module with excellent transmission characteristics.

Generally, in a semiconductor laser module, it is desirable to efficiently couple the optical output emitted from the semiconductor laser to a fiber, but for this purpose, it is necessary to arrange the semiconductor laser lens and the optical fiber at optimal positions. In particular, in the case of a semiconductor laser module with a single mode fiber, it is necessary not only to focus the emitted light accurately into the core of the optical fiber, but also to prevent the coupling efficiency from decreasing due to positional or angular misalignment, and to ensure that the end face of the semiconductor laser chip It is necessary to convert the spot diameter of the near-field image of the fiber into the spot diameter of the guided mode of the fiber, and when designing the module, care must be taken to ensure that these conditions are satisfied with good reproducibility. In the case of the embodiment shown in FIGS. 1(a) and 1(b), the assembly procedure of the optical system is to mount the Wooden lens and semiconductor laser chip inside the container as the first step, and then as the second step to mount the optical system. While measuring the coupled power to maximize the power of the light coupled to the fiber, adjust the fiber tip position forward and backward (in the optical axis direction), up and down, and left and right (perpendicular to the optical axis) to maximize the power. After adjusting in three directions, the fiber is fixed. In this case, focusing the focused light beam on the core is
Accuracy can be achieved by adjusting the position of the optical fiber tip in three directions, but in order to eliminate angular deviation and optimize the conversion rate (image magnification) of the spot system, the relative position of the semiconductor laser and rod lens must be adjusted. It is necessary to accurately arrange the elements, and in this embodiment, design measures have been taken to improve the reproducibility of the arrangement. First, in order to accurately fix the rod lens, a positioning step is provided at the portion where the rod lens is inserted, so that the tip position of the rod lens is automatically determined. Further, when fixing the chip carrier 3, positioning is similarly performed using the stepped portion. As a result, the distance between the semiconductor laser chip and the rod lens and the height of the semiconductor laser chip with respect to the central axis of the lens are automatically determined by the dimensions of the component. In addition, in order to suppress the lateral displacement of the semiconductor laser chip, it is necessary to adjust and fix the semiconductor laser chip so that it is located on the extension of the central axis of the lens while observing with a microscope with a hairline or other sight. Bye.

The module having the structure described above has the following advantages.

First, it is assembled in a box-shaped container equipped with a heat dissipation flange, and has a pin arrangement similar to that of a DIP package widely used for integrated circuits, making it easy to mount in communication equipment. ing.

Second, the reliability of hermetic sealing is high. With this module, the airtightness test can be performed before the coated optical fiber is attached, that is, after the coupling rod lens is fixed.
There are no inconveniences caused by adsorbed gas on the optical fiber coated wire.

In addition, in this module, the coupling system from the semiconductor laser to the optical fiber has a configuration based on a coaxial structure, so the coupling is highly efficient and stable.

Additionally, since an isolator can be installed between the semiconductor laser and the fiber, it is possible to construct a module with excellent transmission characteristics that eliminates the effects of reflected return light, which was not possible with conventional flat modules. be.

FIG. 2 is a plan view of another embodiment of the invention.

However, although the lid is not shown, it is actually installed.

This embodiment is the same as the embodiment shown in FIGS. 1(a) and 1(b) except that a peripheral circuit board 20 is built in.The peripheral circuit board 20 includes compensation for increasing the response speed of the semiconductor laser. At least one of a circuit, a drive circuit for driving the semiconductor laser, or an APC circuit for keeping the output level of the semiconductor laser constant is provided in a monolithic or hybrid type and is connected to the semiconductor laser and the photodiode. It is clear that added value is high because the peripheral circuits are mounted in the same container.

Although the above description has been made using a semiconductor laser as an example of an optical semiconductor element, the present invention can also be applied to a transmitter module using an LED and a photodetector module using an avalanche photodiode. Further, instead of the rod lens, a spherical lens, a spherical lens, or a compound lens system may be used as long as airtightness is not lost.

〔Effect of the invention〕

As explained above, the present invention fixes a coupling rod lens to the light guide hole of a metal member provided through the side wall of a container, hermetically seals it, and connects an optical semiconductor element and an optical fiber on both sides of the coupling rod lens. By coaxially arranging the optical semiconductor element and optical fiber, the coupling between the optical semiconductor element and the optical fiber is highly efficient and stable, the hermetic seal is highly reliable, and the optical semiconductor element module has excellent mountability when mounted in communication equipment. This has the effect that it can be obtained. Further, by mounting peripheral circuits in the same container, added value can be increased, and by incorporating an optical isolator, a semiconductor optical device module with excellent transmission characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of an embodiment of the present invention, and FIG. 1(b) is a plan view of an embodiment of the present invention.
) is a sectional view taken along line xx' of FIG. 1 (a), and FIG. 2 is a plan view of an embodiment of the pond of the present invention. 3... Chip carrier, 4... First flat part, 5
...second flat part, 6...groove, 7...light guide hole,
8... Metal member, 9-1... Bottom plate of container, 9-2.
・Side wall of container, 9-3... Lid of container, 10... Rod lens, 11... Hole diode for monitor, 1
2... Optical fiber coated wire, 13... Pigtail, 1
4... Lead, 15... Bonding wire, 16...
・Ferrule, 17...Slide ring, 18...
Protective sleeve, 1... Optical isolator, 20...
Peripheral circuit board. District Z

Claims (2)

[Claims] (1) A metal member including a flat part on which an optical semiconductor element is mounted and a light guide hole arranged parallel to the flat part with a predetermined height difference, and the light guide hole penetrates through the side wall of the metal member. a container that supports and fixes the member; a lens that is fixed in the light guide hole and hermetically seals it; and a container that is disposed at one end of the light guide hole of the metal member and that communicates with the optical semiconductor element through the lens. 1. An optical semiconductor element module comprising: an optical fiber that is coupled to the optical fiber; (2) The optical semiconductor element module according to claim (1), wherein an optical isolator is inserted between the lens and the optical fiber.