JPH0563769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention applies to optical fiber components such as light receiving elements mounted on optical modules used in optical communication systems such as optical data links and optical LANs. The present invention relates to an optical fiber fixing stand for optically coupling and fixing.

[Conventional technology]

As such an optical module, for example, an optical module in which an optical fiber is optically bonded to an optical operating component such as a semiconductor laser, a PIN photodiode, or an optical integrated circuit is known.

An example is shown in FIG. The illustrated optical module is a receiving optical module in which an optical fiber 1 and a PIN photodiode 2 are optically coupled, and the light emitted from the tip of the optical fiber 1 is used as a light receiving element.
The light is made to enter the light receiving section of the PIN photodiode 2.

In this optical module, the core portion of the optical fiber 1 is exposed at the tip portion 1a, and this exposed portion is formed with a so-called metallized fiber portion that is plated with metal. The tip end 1a of the optical fiber 1 on which the metallized fiber portion is formed is accurately positioned on the optical fiber fixing base 5 fixed on the metal package 3 near the PIN photodiode 2, and then soldered. attached and fixed in place. In addition,
The PIN photodiode 2 is fixed on a hybrid IC board 6 on which electronic components such as capacitors, resistors, and ICs (not shown) are mounted.

[Problem to be solved by the invention]

When fixing the optical fiber to the above-mentioned optical module, the tip 1a of the optical fiber 1 was fixed on the optical fiber fixing table 5, but filamentous solder or cream solder was used for this fixing. Ta.

When fixing optical fibers using thread-like solder, the thread-like solder may not be heated enough.
In such a case, the thread-like solder, which is still in a solid state, comes into contact with the tip 1a of the optical fiber 1, causing the tip 1a, which was once accurately positioned, to shift, resulting in poor workability. .

In addition, when cream solder is used, the flux in the cream solder may evaporate during soldering and adhere to the light receiving part of the PIN photodiode 2 placed oppositely, contaminating this part. It was hot.

The present invention has been made to solve the above problems, and its main purpose is to provide an optical fiber fixing stand that improves the workability of fixing optical fibers.

Another object of the present invention is to provide an optical fiber fixing stand that prevents flux from adhering to the light emitting/receiving surfaces of optically actuated components such as PIN photodiodes when fixing the optical fiber to an optical module. It is in.

[Means to solve the problem]

The optical fiber stand according to the present invention has been made in view of the above object, and is an optical fiber stand that supports and fixes the optical fiber in order to optically couple the optical fiber to an optically actuated component mounted on a substrate. The fiber fixing surface of the optical fiber fixing table is made of a brazing material, and a hollow part is formed between the fiber fixing surface and the optical fiber fixing surface for passing the optical fiber to be fixed therethrough. It is characterized by having a preformed body arranged therein.

Moreover, this preform can also be formed from a brazing material that does not contain flux.

[Effect]

By disposing this preform on the fiber fixing surface, a cavity is formed between the preform and the fiber fixing surface. After inserting the optical fiber to be fixed into this cavity and adjusting the optical axis, this preform is heated and melted, and then solidified to fix the optical fiber on the fiber fixing surface. . During this work, the operator does not touch the optical fiber, so there is no risk of the optical axis of the optical fiber being shifted, which would otherwise be caused by the operator touching the optical fiber.

〔Example〕

Below, regarding the fiber fixing base according to the present invention,
The explanation will be based on the attached drawings.

In FIG. 1, a PIN photodiode 2, which is an optically active component, and an optical fiber fixing base 5 are fixed on a hybrid IC board 6, which is a mounting board for an optical module.

This optical fiber fixing table 5 is provided with a preformed body 7 made of a flux-free brazing material on its upper fiber fixing surface 5b.

As shown in FIGS. 2 to 4, the preform 7 has a shape such as a U-shape, a U-shape, or a V-shape, which is bent so that a hollow part 7a is formed between it and the fiber fixing surface 5b. It is becoming. The preform 7 is fixed by having two recesses 5a formed in the fiber fixing surface 5b and fitting the two legs of the preform 7 into each recess 5a. Note that it is desirable that the melting point of the brazing material forming this preformed body 7 is lower than that of the brazing material used for die-bonding the fixing base 5.

Here, a method for fixing an optical fiber using the optical fiber fixing base 5 formed in this way will be explained in order of steps.

First, place the PIN on the hybrid IC board 6.
The optical fiber fixing base 5 is fixed at a position facing the photodiode 2, but prior to this step,
The fiber fixing surface 5b of the optical fiber fixing table 5 is plated in advance with a brazing material containing flux such as cream solder. In this process, the optical fiber 1 is soldered using the preformed body 7 in a later step, but this preformed body 7
Because it does not contain flux, it has poor solder wettability, and is used as a pretreatment to improve this.

Next, the optical fiber fixing base 5 with this plating is applied.
is fixed on the hybrid IC board 6. For this fixation, a filler metal with a relatively high melting point, e.g.
Die bonding is performed by brazing using Au-Sn solder at 280°C. Note that it is also possible to perform plating and die bonding of the optical fiber fixing base 5 at the same time using the same brazing material.

Next, the recess 5 formed in the fiber fixing surface 5b
The legs of the preformed body 7 are fitted into the holes a and fixed.
By fixing the preform 7 to the fiber fixing surface 5b in this manner, a hollow portion 7a is formed between the preform 7 and the fiber fixing surface 5b.

Next, the optical fiber 1 to be fixed is inserted into the hollow part 7a of the preform 7.
Bring the tip of the PIN photodiode 2 close to the PIN photodiode 2 to a predetermined distance. Thereafter, the optical axis of the optical fiber 1 is adjusted so that the optical axis coincides with the PIN photodiode 2. At this time, empty section 7
Since the inner diameter of a is sufficiently larger than the outer diameter of the optical fiber 1, by slightly shifting the position of the optical fiber 1 within this hollow part 7a,
The optical axis can be aligned with the PIN photodiode 2.

Next, after completing the optical axis adjustment of the optical fiber 1,
The optical fiber fixing table 5 and the preformed body 7 are heated to once melt the preformed body 7. After the preformed body 7 is melted, heating is stopped, and the melted preformed body 7 is cooled and solidified. Thereby, the optical fiber 1 is fixed to the optical fiber fixing base 5.

At this time, since the preformed body 7 is formed of a brazing material that does not contain flux, the preformed body 7 is heated and
There is no risk of flux occurring during melting,
It is possible to prevent flux from adhering to the light receiving surface of the PIN photodiode 2.

The optical fiber 1 shown in this embodiment is a metallized fiber whose tip is plated with metal in advance to make it suitable for brazing.

Further, in this embodiment, the leg portions of the preformed body 7 are 2
Both books fit into the recess 5a, but the cross section of the leg is formed into a prismatic shape such as a quadrangle, and the recess 5a
If a is also formed into a rectangular shape in accordance with these to prevent rotation of the preformed body 7 about its legs, the lengths of both legs are different and only one leg has the recess 5a.
It is also possible to use a J-shaped preform that fits.

Furthermore, in this embodiment, the optical fiber fixing base 5 is provided on the hybrid IC board 6;
It may be provided in the package 3 as conventionally.

〔Effect of the invention〕

As explained above, the optical fiber fixing stand according to the present invention employs a structure in which a preformed body is provided on the fiber fixing surface to form a cavity through which the optical fiber to be fixed is inserted. After inserting the optical fiber into the cavity and adjusting the optical axis, the preform can be melted and solidified, thereby fixing the optical fiber to the fiber fixing surface.

Therefore, during the fixing work of the optical fiber, the worker does not touch the optical fiber, so it is possible to avoid the optical axis shift of the optical fiber that would otherwise occur due to the worker touching the optical fiber. It becomes possible to improve the workability of fixing the optical fiber.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of an optical module equipped with an optical fiber fixing base according to the present invention, and FIG.
3 and 4 are elevational views showing an optical fiber fixing table according to the present invention, and FIG. 5 is a perspective view showing a conventional optical module. 1...Optical fiber, 2...PIN photodiode,
3... Package cage, 5... Optical fiber fixing stand, 5a...
Recessed portion, 5b...Fiber fixing surface, 6...Hybrid
IC substrate, 7... preformed body, 7a... empty part.

Claims (1)

[Scope of Claims] 1. An optical fiber fixing base that supports and fixes an optical fiber in order to optically couple the optical fiber to a photoactive component mounted on a substrate, the fiber of the optical fiber fixing base being On the fixed surface,
1. An optical fiber fixing stand comprising a preform formed of a brazing material and having a preform formed between the fiber fixing surface and a cavity through which an optical fiber to be fixed is inserted. 2. The optical fiber fixing stand according to claim 1, wherein the preform is made of a brazing material that does not contain flux.