JPH08262373A - Optical isolator - Google Patents

Abstract

PURPOSE: To decrease the number of parts constituting a metal fusion type optical isolator and to reduce a manufacturing cost by forming stepped parts on optical elements, exposing a first solder material or metallized film to the side faces of the optical elements joined by soldering and soldering and joining magnets and the optical elements by a second solder material. CONSTITUTION: The respective sides which are the joint surfaces of the optical elements are previously provided with the stepped parts and thereafter, the metallized films 11 are formed. At this time, the metallized films 11 are formed on the side faces 13 and stepping surfaces 14 of the stepped parts as well, not only on the joint surfaces by providing the respective sides with the stepped parts. The polarize 1, the Faraday rotor 2 and the analyzer 3 are thereafter soldered and joined by the first solder material 8. At this time, the solder material 8 flows onto the metallized films 11 formed on the side faces 13 and stepping surfaces 14 of the stepped parts as well and, therefore, the first solder material 8 is exposed on the side faces of the joined optical elements. Next, the exposed first solder material 8 and the plating film 9 on the surfaces of the magnets 5 are joined by the second solder material 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical isolator utilizing the Faraday effect used in optical communication, optical measurement and the like, and more particularly to an optical isolator having a structure excellent in mass productivity.

[0002]

2. Description of the Related Art In recent years, an optical communication system using a semiconductor laser as a light source and an optical application device using a semiconductor laser have been used, and further, their applications and scales have been expanded.

In order to improve the accuracy and stability of these optical communication systems and optical application equipment, an optical isolator is used for the purpose of removing the returning light to the semiconductor laser. The structure of this optical isolator includes a polarizer, an analyzer, an optical element including a Faraday rotator, and a permanent magnet for generating a magnetic field.
And a holder for fixing and protecting them.

Conventionally, organic adhesives have been used as a method for fixing and adhering each optical element to a holder, but the stability of the adhesive strength is poor over a long period of time, and especially against environmental changes such as temperature and humidity. , The characteristics were deteriorated. Therefore, an optical isolator, such as a repeater for optical communication, which requires a high degree of reliability over a long period of time, has an optical isolator formed by a metal fusion method instead of the conventional fixing method using an organic adhesive. Proposed.

Here, a conventional metal fusion type optical isolator will be described. FIG. 4 shows a cross-sectional view of a conventional fused metal optical isolator. The optical element including the polarizer 1, the Faraday rotator 2 and the analyzer 3 and the polarizer side end holder 4 are simultaneously fixed by the solder material 7, and the magnet 5 is soldered and fixed to the analyzer side end holder 6. It The polarizer-side end holder 4 and the analyzer-side end holder 6 are joined by laser welding via the outer ring 12 to form a one-stage optical isolator. At this time, the solder fixing metallized film 11 of each optical element is formed in a portion where light does not pass.

[0006]

However, the conventional manufacturing method has serious problems in mass productivity and cost. That is, in order to fix each optical element and magnet constituting the optical isolator, it is necessary to use a polarizer side and an analyzer side end holder and an external holder (also referred to as an external ring), which increases the number of parts. Since the number of manufacturing steps also increases, the cost is increased.

A technical object of the present invention is to provide an optical isolator having a structure capable of reducing the manufacturing cost by reducing the number of parts constituting the metal fusion type optical isolator.

[0008]

According to the present invention, a plate-shaped polarizer to be joined in a metal fusion type optical isolator,
Faraday rotator, and at the time of joining the optical elements consisting of the analyzer, to form a step on at least one surface of the optical element, after forming a metallized film on the step portion and the joining surface, soldering the optical elements to each other, By using the structure in which the metal plating film of the metal-plated permanent magnet and the solder joint part of the optical element are soldered together, the number of parts of the optical isolator can be eliminated without using the end holders and external holders that were required in the past. And an inexpensive optical isolator can be provided.

[0009]

In the conventional optical isolator, the solder joint portion of the optical element is not exposed on the side surface of the joined optical element. Therefore, it is not possible to solder the optical element and the magnet by using this portion.

Therefore, by the following measures, the first
The solder joint surface is exposed on the side surface of the optical element joined by the solder material, and the magnet and the optical element are joined by the second solder material by using the first solder material exposed on the side surface. I made it possible.

That is, as shown in FIG. 1, a step portion S is provided in advance on each side which is a bonding surface of the optical element. Next, similarly to the conventional method, the metallized film 11 is formed. At this time, since the step portion S is provided, the metallized film is formed not only on the bonding surface but also on the side surface 13 and the step surface 14 of the step portion.

After that, a solder material (referred to as a first solder material)
The polarizer 1, the Faraday rotator 2, and the analyzer 3 are
To solder joint.

At this time, as shown in FIG. 2, the metallized film 1 formed on the side surface 13 and the step surface 14 of the step portion.
Since the first solder material 8 also flows over the first solder material 1, the first solder material 8 can be exposed on the side surface of the joined optical element.

Next, the exposed first solder material 8 and the plated film 9 on the surface of the magnet 5 are bonded with the second solder material 10 to manufacture a metal-bonded optical isolator without using each holder. be able to.

[0015]

EXAMPLES Hereinafter, examples will be described in detail.

(Example 1) Steps S are formed in advance on four sides of a bonding surface in a polarizer, an analyzer and a Faraday rotator having an antireflection film formed thereon, as shown in FIG.

After that, the metallized film 11 is formed on each joint surface and the step S. At this time, in the metallized film 11, Cr is 0.35 μm as a base film and Ni is 0.30 as an intermediate film.
35 μm, and Au as a bonding film was formed as a three-layer film of 0.15 μm.

After that, the optical element was solder-bonded by the first solder material (Au-Sn: melting point 280 ° C.) 8 (see FIG. 2).

Next, a Ni-plated film (film thickness 10 μm) 9 having a columnar shape as shown in FIG. 3 and having rectangular parallelepiped holes formed in the central axis direction and provided with escape grooves 15 at the four corners was applied. The optical element block which was bonded and integrated with the magnet 5 was inserted, and the magnet and the optical element were solder-bonded with the second solder material (Pb-Sn: 175 ° C.) 10 to manufacture an optical isolator.

As described above, the step portion is formed on the optical element, the first solder material or the metallized film is exposed on the side surface of the soldered optical element, and the second solder material is used to expose the magnet and the optical element. By solder joining the elements, an optical isolator can be manufactured without using an end holder and an external holder.

It is to be noted that the purpose of the present invention is to form a stepped portion on the optical element and expose the side surface of the optical element to which the first solder material or the metallized film is solder-bonded. , And the solder material,
It is not limited to the embodiments of the present invention.

[0022]

As described above, according to the structure of the present invention, the mass productivity of the highly reliable optical isolator is improved,
The cost can be reduced.

[Brief description of drawings]

FIG. 1 is an external perspective view illustrating the outline of an embodiment of the present invention.

FIG. 2 is a side sectional view showing an embodiment of the present invention.

FIG. 3 is a diagram illustrating a state in which an optical element is inserted into and bonded to a magnet used in the present invention. 3 (a) is a partially crushed external appearance perspective view, and FIG. 3 (b) is a sectional view.

FIG. 4 is a sectional view showing a conventional solder joint type optical isolator.

[Explanation of symbols]

 1 Polarizer 2 Garnet Single Crystal Plate 3 Analyzer 4 Polarizer Side End Holder 5 Magnet (Permanent Magnet) 6 Analyzer Side End Holder 7 Solder Material 8 First Solder Material 9 Ni Plating Film 10 Second Solder Material 11 metallized film 12 outer ring 13 side surface 14 step surface 15 relief groove S stepped portion

Claims (1)

[Claims] 1. In a metal fusion type optical isolator comprising an optical element consisting of a polarizer, a Faraday rotator, and an analyzer and a permanent magnet, at least one of the joining surfaces joining the optical elements is stepped. A metallized film is formed on the joint surface and the stepped portion, the optical elements are solder-bonded to each other at the metallized film portion, the permanent magnet is metal-plated, and the solder-bonded portion of the optical element is permanently bonded. An optical isolator characterized by being soldered to a plated portion of a magnet.