JP2002243990A - Optical module and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module that is inexpensive, thin and excellent in mounting property as well as productivity and suitable for a surface type optical element module for high-speed operation, and its manufacturing method. SOLUTION: By integrating a mirror 3-1 and a lens 7-1 which are optical path converting elements, the module is simplified. In order to realize a thin PD/VCSEL module whose optical path is bent by a 45 deg. mirror 5-1, the mirror 5-1 is assembled in the lens 7-1 and an optical axis is adjusted in a surface direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module operated in a high frequency range used for optical communication and measurement.
In particular, the present invention relates to a structure of an optical module for mass-production at low cost using a thin package and a manufacturing method thereof.

[0002]

FIG. 3 shows a conventional high-speed photodiode (P).
D) An example of a module structure is shown. Here, 1 is a planar PD element (PD chip), 2 is a submount, 3 is a high-frequency line, 4 is a metal carrier, 5 is a mirror, 6 is a metal package with a high-frequency coaxial connector, and 7 is an optical coupling lens. , 8 is a ferrule in which the optical fiber is fixed internally, and 9 is a lid for hermetic sealing.

In order to assemble this, first, the PD element 1,
The submount 2 and the high-frequency line 3 are mounted on the carrier 4 with a solder material such as gold tin. The mirror 5 is fixed on the carrier 1 with an adhesive or YAG laser welding on the upper part of the PD element 1 via a member (not shown in the figure) for holding the mirror having an appropriate shape. The lens 7 is optically aligned with the optical fiber of the ferrule 8 disposed at a predetermined position, and is fixed to the carrier 4 by welding. Thereafter, the carrier 4 is fixed to the package 6 with solder or the like. Then, the lid 9 is seam-welded to the package 6 and hermetically sealed. Finally, the ferrule 8 is aligned and fixed to the package 6 by welding.

[0004] If an electric preamplifier (preamplifier) is mounted in place of the high-frequency line 3 in the above process, a module with a built-in preamplifier can be obtained.

[0005]

In the above-described conventional structure shown in FIG. 3, the working distance (WD) of the lens 7 needs a certain length in order to insert the mirror 5 between the optical element 1 and the lens 7. Become. For this reason, as the optical coupling lens 7, an aspherical lens having a low image magnification and a large aperture is mainly used.

However, the light receiving diameter of the high-speed PD element 1 is generally small, so that the image magnification must be increased.
Therefore, in order to secure WD, the lens diameter of the lens 7 must be increased.

On the other hand, it is required to reduce the height of the module as much as possible to improve the mounting density.
If the lens diameter is large, the module thickness cannot be reduced.

The conventional structure has a disadvantage that the manufacturing process is complicated and the number of parts is large, which is disadvantageous for mass production.

The present invention has been made in view of the above points, and has as its object to provide a low-cost, thin, high-speed surface light source that is excellent in productivity and mountability. An object of the present invention is to provide an optical module suitable for an element module and a method for manufacturing the same.

[0010]

According to a first aspect of the present invention, there is provided an optical module comprising: a planar optical element for inputting / outputting an optical signal in a direction perpendicular to an element substrate; An optical module for coupling, wherein the planar optical element and the optical fiber are arranged in a direction parallel to a bottom surface of a module package, and an optical lens for optically coupling the optical fiber and the planar optical element to each other. And a mirror surface integrated with the optical lens and bending a light path passing through the optical lens in a direction perpendicular to the planar optical element.

Here, the optical lens is provided via the mirror surface formed on the back side of the optical lens or the mirror surface formed on the slope of the projection on the back side of the package sealing lid. It can be characterized in that it is integrally fixed to the slope of the projection of the stopper for stopping.

Further, the optical lens may be a hemispherical lens.

Further, the optical lens may be a refractive index distribution type lens in which a high refractive index layer is distributed in a hemispherical shape.

[0014] The optical lens may be an aspheric lens with a mirror having the mirror surface formed inside so that the light incident and exit directions are at right angles.

Further, a lens fixing plate arranged and fixed inside the module package is used in place of the package sealing lid.

According to another aspect of the present invention, there is provided a method of manufacturing an optical module, comprising: fixing an optical fiber in a direction parallel to a bottom surface of a module package; Mounting the input / output planar optical element on the element substrate at a predetermined position of the module package in a direction parallel to the bottom surface of the module package; and optically coupling the optical fiber and the planar optical element to each other. And a step of finely adjusting and fixing a mirror surface for bending an optical path passing through the optical lens in a direction perpendicular to the planar optical element in a direction parallel to the bottom surface of the module package. It is characterized by the following.

Here, the optical lens is sealed with the package through the mirror surface formed on the back side of the optical lens or the mirror surface formed on the slope of the projection on the back side of the package sealing lid. Fixing the package sealing lid integrally with the slope of the projection, and finely adjusting the package sealing lid in a direction parallel to the bottom surface of the module package. Performing optical axis alignment and fixing the package sealing lid to the module package.

(Operation) With the above configuration, according to the present invention, a low-cost and thin high-speed PD module or surface light emitting element module can be easily realized.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 schematically shows a configuration of a hemispherical lens PD module according to a first embodiment of the present invention. Here, 1-1 is a planar PD element as a planar optical element for inputting and outputting an optical signal in a direction perpendicular to the element substrate, 2-1 is a submount as an element substrate, and 5-1 is an optical path. A mirror surface bent in a direction perpendicular to the PD device 1-1, 6-1 is a ceramic package with high-frequency wiring as a module package, and 7-1 optically couples the optical fiber and the planar PD device 1-1 to each other. 8-1 is a ferrule internally fixing the optical fiber, 9-1 is a metal lid for hermetic sealing, and 10
-1 is a preamplifier IC (integrated circuit).

The optical module of FIG. 1 is assembled in the following steps. First, the ferrule 8-1 is fixed to the package 6-1 with low melting point glass or brazing material. Next, the PD element 1-1 is mounted on the package 6-1 with AuS.
Fix with n solder. Next, the hemispherical lens 1 is fixed to the protrusion (triangular block) of the lid with solder or an adhesive. Further, light is input from an optical fiber by an external light source to PD1.
-1 with lens at the position where the current output of -1 is maximum
And the lid 9-1 is fixed to the package 6-1 by the YAG laser. Finally, the lid 9-1 and the package 6-1 are hermetically sealed with resin.

Here, the hemispherical lens 7-1 with a non-reflective coating on the entire circumference is cut in half and used to suppress the reflection on the spherical surface.

The optical axes of the PD element 1-1 and the optical fiber of the ferrule 8-1 are aligned by sliding the lens fixed to the lid 9-1 in the horizontal direction with respect to the bottom surface of the package 6-1. For this reason, since the optical fiber can be fixed to the package 6-1 in advance, the thickness can be reduced, and the number of parts is small. Therefore, it is suitable for mass production to reduce the cost. Since the optical axis adjustment is performed only in the horizontal XY directions, the process is simple and automation is easy.

Although a spherical lens is cheaper and easier to obtain than an aspherical lens, since a WD cannot be taken long in principle,
A configuration in which a mirror is inserted between the optical device and the surface optical device is impossible. In contrast, the present invention solves this problem by forming a mirror surface in the lens. Mirror surface 5-1
Can be realized simply by fixing the lens 5-1 to the gold-plated lid 9-1 with an optical adhesive, but in order to obtain complete total reflection, a dielectric film is formed on the lens 7-1 by vapor deposition. It is also possible.

In the present embodiment, the hermetic sealing is performed with a resin. However, a lens fixing plate (not shown) is housed in a package, and a hermetic lid 9-1 is disposed above the lens fixing plate.
It is also possible to adopt a configuration in which the lid is strictly sealed by resistance welding or the like.

Further, the ferrule portion 8-1 can be a small-sized optical connector having a module structure of a type that does not directly emit an optical fiber.

Further, an array module can be manufactured by using a bar-shaped (rod-shaped) PD array element having a plurality of PD elements formed in the lateral direction and an array fiber. Examples of the lens in this case include a rod lens (which is also cut in half and includes a mirror surface), an aspheric lens array, and a refractive index distribution lens in which a high refractive index layer is distributed in a hemispherical shape according to the element pitch. Will be adopted.
In the array module, the requirements for the mounting angle accuracy of the PD element and the optical fiber become strict, but the basic assembly can be performed by exactly the same process.

(Second Embodiment) FIG. 2 schematically shows the configuration of an aspheric lens VCSEL module according to a second embodiment of the present invention. Here, 1-2 is a surface emitting laser diode element (VCSEL element), 2-2 is a submount, 5-2 is a mirror surface, 6-2 is a ceramic package with high frequency wiring, and 7-2 is an aspherical lens. , 8-2 denotes a ferrule in which an optical fiber is fixed internally, 9-2 denotes a metal lid, and 10-2 denotes a laser driver IC.
The aspherical lens 7-2 is an optical lens with a mirror having a pair of aspherical lenses and having a mirror surface 5-2 formed on the inner side so that the light incident and exit directions are at right angles.

In this embodiment, a surface emitting laser diode (V
This is an example in which the CSEL) element 1-2 is modularized. Although the aspheric lens 7-2 is used to increase the optical coupling, the assembling procedure is basically the same as that of the present invention described above except that the surface-emitting laser diode element 1-2 is adjusted to emit light. This is the same as the first embodiment.

The aspherical lens 7-2 has a special shape in which the lens surface 5-2 is in a right angle direction. However, once the mold is raised, the manufacturing method is the same as that of a normal one. If it becomes possible, cost reduction can be expected. The aspherical lens 7-2 in FIG. 2 is a dice obtained by diagonally cutting a dice, and a lens optimally designed is formed on the two surfaces. Note that one side may be flat depending on the optical design.

Naturally, if the requirement for the optical coupling efficiency is not severe, a hemispherical lens may be used as in the above-described first embodiment of the present invention.

[0032]

As described above, according to the present invention,
Since the optical path changing element and the lens are integrated, the module can be simplified, and a high-speed photodiode module or a surface-emitting laser diode module can be significantly reduced in cost and small in size and thickness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a configuration of a photodiode module according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically illustrating a configuration of a surface emitting laser diode module according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically illustrating a configuration example of a conventional photodiode module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1-1 PD element 1-2 VCSEL element 2, 2-1, 2-2 Submount 3 High frequency line 4 Carrier 5 Mirror 5-1, 5-2 Mirror surface 6 Package 6-1, 6-2 High frequency electrode Attached and ceramic package 7 Aspherical lens 7-1 Hemispherical lens 7-2 Aspherical lens with mirror 8, 8-1, 8-2 Ferrule 9, 9-1, 9-2 Lid 10-1 Preamplifier circuit 10-2 Laser Driver IC

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H037 AA01 BA03 BA12 CA13 CA15 CA16 CA19 CA38 DA05 DA06 DA18 DA36 5F073 AB17 AB27 AB28 AB29 BA01 BA09 EA14 FA08 FA23 FA29 5F088 BA02 BB01 BB06 JA03 JA12 JA14 JA20

Claims (10)

[Claims] 1. An optical module for optically coupling an optical fiber and a planar optical element for inputting and outputting an optical signal in a direction perpendicular to an element substrate, wherein the planar optical element and the optical fiber are module-packaged. An optical lens for optically coupling the optical fiber and the planar optical element to each other; and an optical path integrated with the optical lens and passing through the optical lens. An optical module having a mirror surface bent in a direction perpendicular to the mirror. 2. The package sealing of the optical lens through the mirror surface formed on the back side of the optical lens or the mirror surface formed on the slope of the projection on the back side of the package sealing lid. The optical module according to claim 1, wherein the optical module is integrally fixed to an inclined surface of the projection of the cover. 3. The optical module according to claim 1, wherein the optical lens is a hemispherical lens. 4. The optical module according to claim 1, wherein the optical lens is a gradient index lens in which a high refractive index layer is distributed in a hemispherical shape. 5. The optical module according to claim 1, wherein the optical lens is an aspheric lens with a mirror that forms the mirror surface on the inner side so that a light incident / exit direction becomes a right angle. 6. The optical module according to claim 2, wherein a lens fixing plate disposed and fixed inside the module package is used instead of the package sealing lid. 7. A step of fixing an optical fiber in a direction parallel to a bottom surface of a module package, and a step of setting a planar optical element for inputting / outputting an optical signal in a direction perpendicular to an element substrate in a direction parallel to the bottom surface of the module package. Mounting the module package on the element substrate at a predetermined position of the module package, an optical lens for optically coupling the optical fiber and the planar optical element to each other, and an optical path passing through the optical lens to the planar optical element. Finely adjusting and fixing a mirror surface bent in a direction perpendicular to the direction parallel to the bottom surface of the module package. 8. The optical lens for sealing the package through the mirror surface formed on the back side of the optical lens or the mirror surface formed on the slope of the projection on the back side of the package sealing lid. Fixing the package sealing lid integrally with the slope of the projection of the lid in the direction parallel to the bottom surface of the module package; 8. The method for manufacturing an optical module according to claim 7, further comprising: performing axis alignment and fixing the package sealing lid to the module package. 9. The optical lens is a hemispherical lens, or a gradient index lens having a high refractive index layer distributed in a hemispherical shape, or the mirror surface is formed on the inner side so that the light incident and exit directions are at right angles. The method for manufacturing an optical module according to claim 7, wherein one of the optical lenses is used. 10. The method for manufacturing an optical module according to claim 8, wherein a lens fixing plate arranged and fixed inside the module package is used instead of the package sealing lid.