JP2007171999A - Package for housing optical element, and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package for housing an optical element and an optical module, capable of making a coupling efficiency of optical signals between the optical element and two or more optical fibers favorable, and letting the optical element operate normally and stably for a long term. <P>SOLUTION: The package for housing the optical element is provided with a substrate 1 having a mounting part 1a for mounting the optical element on the upper face, and a frame body 2 which is attached to the upper face of the substrate 1 so as to surround the mounting part 1a and to which a lid body is brazed on the upper face of the side part, and the frame body 2 has on its upper face of the side part two or more optical fiber introduction parts 2a consisting of almost U-shaped cross-sectional grooves for making the optical fibers to be optically coupled to the optical element pass therethrough and brazing them, and one optical fiber is made to pass through each optical fiber introduction part 2a, respectively, and is brazed thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wavelength multiplexer / demultiplexer that multiplexes or demultiplexes optical signals of different wavelengths, or an optical element storage package for accommodating an optical passive device (hereinafter referred to as an optical element) such as an optical switch, and the like. The present invention relates to an optical module that is optically coupled to an optical fiber after accommodating an optical element.

  The example of the conventional package for optical element accommodation is shown with a perspective view. An example of an optical module in which an optical element such as a wavelength multiplexer / demultiplexer is accommodated in this optical element accommodation package and optically coupled to an optical fiber is shown in a perspective view.

  The optical element storage package has a mounting part 11a on which the optical element 17 is mounted on the upper surface, and a flange part 11b provided on the outer peripheral part so as to be screwed to an external circuit board (not shown). An optical fiber introducing portion (including a base 11 having a through hole for introducing an optical fiber 18 into a substantially central portion of one opposite side surface, which is attached to the upper surface of the base 11 so as to surround the mounting portion 11a. (Hereinafter referred to as “introducing portion”) 12a, and a frame 12 having a pipe attachment portion (hereinafter referred to as “attachment portion”) 12b on the outer side surface opposite to the introduction portion 12a, and the attachment portion 12b. It is mainly composed of a pipe 13 that is joined and leads the optical fiber 18 to the introduction part 12a.

  In the optical module, an optical element 17 and an optical fiber aligner (hereinafter referred to as an aligner) 16 are placed on the upper surface of the placement portion 11a via a holding base 15, and the optical fiber 18 leads the introduction portion 12c. And is optically coupled to the optical element 17 by moving the optical fiber 18 back and forth along a substantially V-shaped V-groove 16a on the upper surface of the aligner 16.

Further, after optical coupling, the holder 13a is welded to the front end surface of the pipe 13 by YAG welding or the like, and the lid 19 is YAG welded or brazed to the upper surface of the frame body 12, whereby the inside of the optical element storage package is hermetically sealed. The optical module sealed in is completed. This optical module houses the optical element 17 in an airtight manner, and is used for high-speed optical communication and the like.
JP-A-6-3565 JP-A-7-198973 Japanese Patent Laid-Open No. 2001-21818

  However, when a plurality of optical fibers 18 are introduced into the optical element storage package in order to optically transmit a large amount of information, the plurality of optical fibers 18 are introduced into the optical element storage package, and further, Optical coupling to the element 17 is very complicated in work.

Specifically, since the part where the optical fiber 18 is stably placed and fixed is only the part of the V-groove 16a of the aligner 16, when there are a plurality of optical fibers 18, even if the first optical fiber 18 is Even if optical coupling is possible, the optical coupling of the first optical fiber 18 is impaired when the other optical fibers 18 are optically coupled, that is, the optical axes of the optical fibers 18 may be misaligned. There was a problem that it was very difficult to match.

In addition, since the work is very complicated, there is a problem that the optical fiber 18 is likely to be broken during the work.

  Further, even if the plurality of optical fibers 18 and the optical element 17 can be optically coupled, the step of YAG welding the holder 13 a to the tip surface of the pipe 13 and the lid 19 are joined to the upper surface of the frame 12. 2 steps are required, and the heat history at that time generates a stress that distorts the optical fiber 18 and the optical coupling between the optical element 17 and the optical fiber 18 is slightly deteriorated. There was also.

  Therefore, the conventional optical element storage package and optical module have a problem that the operability of the optical element 17 cannot be improved, and a large amount of information may not be optically transmitted.

  The present invention has been completed in view of the above-described problems, and the object thereof is to improve the optical signal coupling efficiency between a plurality of optical fibers and optical elements. An object of the present invention is to provide an optical element storage package and an optical module that can be operated normally and stably.

  The present invention includes a base having a mounting portion on which an optical element is mounted on the upper surface, and the upper surface of the base so as to surround the mounting portion, and a lid is brazed to the upper surface of the side portion. A plurality of optical fibers each having a substantially U-shaped cross section for brazing through an optical fiber optically coupled to the optical element on the upper surface of the side portion. Each of the optical fiber introducing portions has an introducing portion, and one optical fiber is passed through and brazed to each of the optical fiber introducing portions.

  Further, the optical element storage package, the optical element placed on the placement portion, the optical fiber brazed through each of the optical fiber introduction portions, and the brazing on the upper surface of the frame body And a lid that hermetically seals the optical element and the optical fiber introduction part.

  According to the present invention, it is not necessary to introduce an optical fiber into the optical element housing package via a pipe as in the prior art, and the optical fiber is temporarily fixed to the introduction portion and placed inside the package. Since optical coupling with an optical element can be performed accurately, the workability of optical coupling between a single optical fiber and an optical element can be made extremely efficient, and a single optical fiber can be stably fixed and held. can do.

  According to the present invention, after optically coupling a plurality of optical fibers and optical elements as in the prior art, a step of YAG welding the holder to the tip surface of the pipe, and a step of joining the lid to the upper surface of the frame Two steps are not required, and the thermal history at that time does not generate stress that distorts the optical fiber, and optical coupling between the optical element and the optical fiber is not deteriorated. It is possible to provide an optical module that can be excellent and capable of optically transmitting a large amount of information.

  The optical element storage package of the present invention will be described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of an embodiment of an optical element storage package according to the present invention, and FIG.

  1 and 2, reference numeral 1 denotes a base body, and reference numeral 2 denotes a frame body. The base body 1 and the frame body 2 basically constitute a container for accommodating an optical element.

  The substrate 1 functions as a support member for supporting the optical element and a substantially rectangular heat radiating plate for dissipating heat emitted from the optical element, and a mounting for mounting the optical element on a substantially central portion of the upper surface thereof. It has a placement part 1a.

Further, the outer periphery of the base body 1 has a flange portion 1b in which a screw hole is provided by extending the base body 1 to the outside of the frame body 2 so that it can be screwed to an external circuit board (not shown). It is preferable.

  The substrate 1 is a plate-like body made of a metal material such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or a copper (Cu) -tungsten (W) alloy, and is made of, for example, an Fe-Ni-Co alloy. In the case of forming, the ingot is manufactured into a predetermined shape by performing a metal processing method such as rolling or punching.

  The surface of the substrate 1 is a metal having excellent corrosion resistance and wettability with a brazing material, specifically, a Ni layer having a thickness of 0.5 μm to 9 μm and an Au layer having a thickness of 0.5 μm to 5 μm. Are preferably deposited sequentially by a plating method, whereby the base 1 can be effectively prevented from being oxidatively corroded, and the optical element and the frame 2 are firmly bonded to the upper surface of the base 1 with a brazing material. It can be fixed.

  The base body 1 is joined to a frame-shaped frame body 2 such as a quadrangle so as to surround the mounting portion 1 a on which the optical element is mounted, and the optical element is accommodated inside the frame body 2. A void is formed for this purpose.

  The frame body 2 is made of a metal material like the base body 1 and has a substantially U-shaped cross section for brazing through an optical fiber to a substantially central portion of the upper surface of the side portion by the same processing method as the base body 1. It is processed into one having at least one optical fiber introducing portion 2a.

  When the frame body 2 is made of, for example, an Fe—Ni—Co alloy, the frame body 2 is manufactured in a predetermined frame shape by applying a metal processing method such as rolling or punching to the ingot.

In addition, the frame 2 is attached to the base body 1 with a silver (Ag) brazing material having an appropriate volume in which the upper surface of the base body 1 and the lower surface of the frame body 2 are laid on the upper surface of the base body 1. It is performed by brazing and joining via a brazing material such as.

Further, similarly to the substrate 1, it is preferable that a Ni layer having a thickness of 0.5 μm to 9 μm and an Au layer having a thickness of 0.5 μm to 5 μm are sequentially deposited on the surface of the frame 2 by a plating method.

  The optical fiber introducing portion 2a in the optical element storage package of the present invention is composed of a groove having a substantially U-shaped cross section for brazing through one optical fiber.

This optical fiber introducing portion 2a has a function of stably fixing and holding the optical fiber, and even when the base 1 is screwed to the external circuit board by the flange portion 1b, the optical fiber introducing portion 2a is generated in the flange portion 1b by screwing. Thus, the stress transmitted to the optical fiber can be made extremely small.

Furthermore, since the optical fiber introducing portion 2a has a shape capable of covering the outer peripheral surface of the optical fiber with the brazing material substantially uniformly when it is fixed by brazing through the optical fiber inside, the brazing material is melted. As a result, the air present in the optical fiber introduction portion 2a that causes a void in the brazing material that is generated when sealing between the outer peripheral surface of the optical fiber and the optical fiber introduction portion 2a is made easier to escape to the outside. Since there is an action, there is no void generation in the brazing material, and there is also a function of improving the hermetic sealing in the optical fiber introducing portion 2a.

  As shown in the partially enlarged perspective view of the optical fiber introducing portion 2a, when the diameter of the optical fiber introduced through the optical fiber introducing portion 2a is r (μm), the width A of the opening is r + 5 μm to It is preferable that r + 200 μm and the depth B is r + 5 μm to r + 200 μm.

  When the width A of the opening is less than r + 5 μm, it is impossible to braze so as to cover the outer peripheral surface of the optical fiber substantially uniformly, and it becomes impossible to eliminate voids in the brazing material. It becomes difficult to stop the optical element, and it becomes difficult to hermetically seal the optical element.

On the other hand, when the width A of the opening exceeds r + 200 μm, it is difficult to stably fix the optical fiber to the substantially central portion of the optical fiber introduction portion 2a. Therefore, the center of the cross section of the optical fiber in the optical fiber introduction portion 2a A center point of the cross section of the optical fiber mounted and fixed in the V-groove of the optical fiber aligner mounted on the mounting portion 1a with the optical element on the mounting portion 1a, which functions as an optical axis adjustment Causes misalignment.

For this reason, stress is easily generated in the optical fiber, and the optical fiber is easily broken. This causes a problem that the reliability of the optical module using the optical element storage package becomes very low.

  Further, when the depth B is less than r + 5 μm, it is impossible to braze so as to cover the outer peripheral surface of the optical fiber substantially uniformly, and it becomes impossible to eliminate voids in the brazing material. It becomes impossible to make the hermetic seal good, and it becomes difficult to hermetically seal the optical element.

On the other hand, when the depth B exceeds r + 200 μm, distortion caused by warping or twisting of the frame body 2 and the base body 1 due to the difference in coefficient of thermal expansion when the frame body 2 is joined to the upper surface of the base body 1 is screwed. Since the stress to return to the flat state by stopping is transmitted from the base body 1 to the optical fiber 8 through the optical fiber introducing portion 2a and the brazing material of the frame body 2, the base body 1 is transferred to the external circuit board by the flange portion 1b. When the screw is fixed, a stress that easily breaks the optical fiber is transmitted from the base 1 to the optical fiber 8 through the optical fiber introducing portion 2a and the brazing material. The problem is that the reliability of the module becomes very low.

  The depth of the optical fiber introducing portion 2a, that is, the thickness of the frame body 2 is preferably about 0.7 to 1.8 mm.

When the depth is less than 0.7 mm, it is difficult to stably fix and hold the optical fiber. On the other hand, when the depth exceeds 1.8 mm, the brazing area of the portion where the optical fiber is fixed and held becomes wide. Therefore, the residual stress generated after brazing between the optical fiber and the optical fiber introducing portion 2a becomes very large, and when an external force is applied to the optical fiber, the brazing material around the optical fiber in the optical fiber introducing portion 2c is cracked. Such mechanical breakdown tends to occur, and it tends to be difficult to hermetically seal the optical element.

  Using such an optical element storage package of the present invention, as shown in a perspective view of an example of the embodiment, the optical element 7 and the aligner 6 are placed on the upper surface of the mounting portion 1 a via the holding table 5. The optical fiber 8 is brazed through the optical fiber introducing portion 2a and introduced from the outside to the optical element 7, and the end of the optical fiber 8 is connected to the substantially V-shaped upper surface of the aligner 6. It is optically coupled to the optical element 7 by placing it in the V-shaped groove 6a and moving it back and forth along it.

Further, a lid body 9 having a lower surface clad with a low-temperature brazing material 9a such as gold (Au) -tin (Sn) brazing material is brazed on the upper surface of the frame body 2 including the optical fiber introducing portion 2a. Thus, the optical module of the present invention in which the inside of the optical element storage package is hermetically sealed is completed.

  In this optical module, the protective film (resin or the like) located at the optical fiber introduction part 2a of the optical fiber 8 introduced through the optical fiber introduction part 2a is peeled off to remove quartz glass (core fiber of the optical fiber 8). And a plating film of Ni, Au or the like is sequentially deposited on the entire outer periphery of the core of the exposed optical fiber 8 so that the outer peripheral surface of the optical fiber 8 is interposed between the plating film and the brazing material. The optical fiber introduction part 2a and the lid 9 are satisfactorily brazed, and the optical fiber introduction part 2a is hermetically sealed.

In this optical module, as in the prior art, after optically coupling a plurality of optical fibers and optical elements, a step of YAG welding the holder to the tip surface of the pipe, and a step of joining the lid to the upper surface of the frame 2 is not necessary, and the thermal history at that time does not generate stress that distorts the optical fiber, so that the optical coupling between the optical element and the optical fiber is not deteriorated. Therefore, it is possible to optically transmit a large amount of information.

It is a perspective view which shows an example of embodiment of the optical element storage package of this invention. It is a partial expansion perspective view of the peripheral part of the optical fiber introducing | transducing part of the optical element storage package shown in FIG. It is a perspective view which shows an example of embodiment of the optical module of this invention. It is a perspective view which shows the other example of embodiment of the optical element storage package of this invention. It is a perspective view which shows the other example of embodiment of the optical module of this invention. It is a perspective view which shows the example of the conventional package for optical element accommodation. It is a perspective view which shows the example of the conventional optical module.

Explanation of symbols

1: Base 1a: Placement part 1b: Flange part 2: Frame body 2a: Optical fiber introduction part 7: Optical element 8: Optical fiber 9: Lid

Claims (2)

A base body having a mounting portion on which an optical element is mounted; and a frame body attached to the upper surface of the base body so as to surround the mounting portion and having a lid brazed on the upper surface of the side portion; Comprising
The frame includes a plurality of optical fiber introduction portions each having a substantially U-shaped cross section for brazing through an optical fiber optically coupled to the optical element on an upper surface of the side portion. An optical element storage package in which one optical fiber is passed through the optical fiber introduction portion and brazed.   The optical element storage package according to claim 1, an optical element placed on the placement portion, an optical fiber brazed through each of the optical fiber introduction portions, and an upper surface of the frame body An optical module comprising: a brazed lid that hermetically seals the optical element and the optical fiber introduction portion.

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