JPH0933859A - Optical isolator and manufacture of its optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the optical isolator which is made compact to a minimum necessary extent and also provide the manufacture of the optical element, used for the isolator, which is inexpensive and superior in mass-productivity. SOLUTION: Metallized films 8 are formed on a plarizer material plate 21, one surface of an analyzer material plate 23, and both the surfaces of a Faraday rotator material plate 22, grooves 12 are formed in a lattice shape on the surfaces where the metallized films are formed, and the Faraday rotator material plate 22 is sandwiched between the surfaces of the polarizer material plate 21 and analyzer material plate 23 where the metallized films 8 are formed. After they are put one over another, the grooves 12 and apertures 11 are arrayed on slanting lines crossing lines perpendicular to the respective material plates at an angle θ and then a solder material 5 is put in the grooves 12. After soldering adhesion, one group of a light transmission area for a polarizer, the light transmission area for the corresponding Faraday rotator, and the light transmission area for the analyzer, and the parts including the respective metallized films surrounding the group of the light transmission areas is cut as an optical element 9 for one isolator, thus obtaining the optical element for the optical isolator which is made compact to minimum necessary extent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical isolator using a Faraday effect used for optical communication, optical measurement and the like, which is small in size and excellent in mass productivity, and a method for manufacturing an optical element thereof.

[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 widely used, and 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 comprises an optical element consisting of a polarizer, an analyzer and a Faraday rotator, a permanent magnet for generating a magnetic field and a holder for fixing and protecting them.

Conventionally, as a method of adhesively fixing a polarizer, a Faraday rotator and an analyzer and an optical element and a holder, there are a fixing method using an organic adhesive and a metal fusion method.

Regarding the fixing method using an organic adhesive among the above-mentioned fixing methods, it has been found that the stability of the adhesive force over a long period of time is poor, especially against environmental changes such as temperature and humidity.

Therefore, an optical isolator such as a repeater for optical communication, which requires a high degree of reliability for a long period of time, is formed by a metal fusion method instead of the fixing method using the organic adhesive. Optical isolators are used.

Adhesive fixing by the metal fusion method in the optical isolator forms the metallization film 8 for metal fusion on the outer periphery of the polarizer 1, the analyzer 3, the Faraday rotator 2 and at least the light transmitting portion, and the polarizer 1 The Faraday rotator 2 and the analyzer 3 are bonded and fixed, and the optical element and the holder are bonded and fixed.

A non-reflective coating is previously formed on each surface of the polarizer 1, the analyzer 3, and the Faraday rotator 2 which constitute the optical element of the conventional optical isolator. As shown in FIG. Although light passes through with almost no reflection, there is light that is slightly reflected, and it is inevitable that this reflected light returns to the incident side.

Therefore, for applications in which even a slight amount of reflected light is unacceptable, a method of tilting the optical element or the optical isolator by about 2 to 9 ° with respect to the incident light is adopted.

That is, as shown in FIG. 4, the tilt holder 10 is inserted between the magnet 4 and the outer holder 6, or the optical isolator itself is tilted with respect to the optical axis of the incident light and fixed, and then reflected. A method is adopted in which the optical system is installed so that the light does not return to the incident side.

[0012]

However, in any conventional isolator, the solder-bonded optical element is used while being inclined with respect to the optical axis. Therefore, the outer shape of the optical isolator becomes larger than the area through which light can actually pass, which is a limit to downsizing.

In particular, when the tilt holder is inserted when the optical element is tilted with respect to the optical axis, the tilt holder needs to have a certain degree of thickness in view of processing accuracy and strength. There was a serious problem in cost reduction.

Further, in the conventional method for manufacturing an optical element of an isolator, a polarizer, an analyzer, and an optical element, which constitute one optical element, are made of optical materials such as a polarizer material plate, an analyzer material plate, and a Faraday rotator material plate. Faraday rotator is cut out, and then a polarizer, analyzer, and a metallized film are formed on each predetermined surface of the Faraday rotator, so that the polarizer, analyzer, and Faraday rotator are washed after cutting into one piece. However, it is difficult to metallize a large number of optical elements, and there are serious problems in mass productivity and cost reduction.

The problem to be solved by the present invention is to solve the above-mentioned problems and to provide an optical isolator which is miniaturized to the minimum necessary, and the optical used for the isolator. It is an object of the present invention to provide a manufacturing method of an element which is inexpensive and excellent in mass productivity.

[0016]

According to the present invention, in an optical isolator having an optical element consisting of a polarizer, a Faraday rotator, and an analyzer, one cross section by a predetermined plane including the optical axis of the optical element is Due to the parallelogram, it is possible to provide a miniaturized optical isolator characterized in that the light incident surface and the light emitting surface of the optical element are inclined at a predetermined angle from the right angle with respect to the optical axis.

Further, according to the present invention, the optical element comprising the polarizer of the optical isolator, the Faraday rotator, and the analyzer has a parallelogram in one cross section along a predetermined plane including the optical axis. In the method for manufacturing an optical element, wherein the light incident surface and the light emitting surface of the element are inclined at a predetermined angle from the right angle with respect to the optical axis, a parallel plate-shaped polarizer material plate having a size such that a plurality of polarizers can be taken out, Prepare a parallel plate-shaped Faraday rotator material plate of a size that can be taken out by the Faraday rotator and a parallel plate-shaped analyzer material plate of a size that can be taken by a plurality of analyzers, and set it on one surface of the polarizer material plate. A metallized film is formed on the one surface while leaving a light transmission region for the polarizer at each position having a space of Faraday rotator at each position having the predetermined space on both sides of the Faraday rotator plate. Of the metallized film is formed on both sides of the metallized film leaving the light transmissive region, and the metallized film is left on the one surface of the analyzer material plate with the light transmissive region for the analyzer being left. It is formed on one surface so that the Faraday rotator material plate is sandwiched between the polarizer material plate and the analyzer material plate, and the surface of the polarizer material plate on which the metallized film is formed and the Faraday rotation. One surface of the child material plate on which the metallized film is formed, and the surface of the analyzer material plate on which the metallized film is formed and the other surface of the Faraday rotator material plate on which the metallized film is formed face each other. For each of the light transmission regions for the polarizer of the plate, for each Faraday rotator material plate the midpoint of each light transmission region for the Faraday rotator material, and for the analyzer of the corresponding analyzer material plate The midpoint of each light transmission area is The photon material plate, the Faraday rotator material plate, and the light transmission region of the polarizer material plate and the Faraday rotation so as to be located on an inclined line that intersects the line orthogonal to the analyzer material plate at the predetermined angle. The light transmission region of the sub-material plate and the light transmission region of the analyzer material plate are respectively shifted, and the polarizer material plate, the Faraday rotator material plate, and the analyzer material plate are overlapped and bonded and fixed to each other. Forming a material laminate, each light transmission region for the polarizer from the optical material laminate, a corresponding light transmission region for the Faraday rotator, a set of corresponding light transmission regions for the analyzer, An optical element of an optical isolator, characterized in that a portion including each metallized film surrounding each of the pair of light transmitting regions is cut out with a cutting plane parallel to the inclined line as an optical element to obtain a plurality of optical elements. To provide a manufacturing method of be able to.

At this time, on one surface of the polarizer material plate,
After forming a metallized film on one surface of the analyzer material plate and on both surfaces of the Faraday rotator material plate, before stacking and fixing the polarizer material plate, the analyzer material plate, and the Faraday rotator material plate. Or a polarizer material plate, an analyzer material plate, a Faraday rotator material plate before forming a metallized film on one surface of the polarizer material plate, one surface of the analyzer material plate, or both surfaces of the Faraday rotator material plate. By forming the groove at a predetermined position above, it is possible to provide a method for manufacturing an optical element of an optical isolator that is inexpensive and excellent in mass productivity.

[0019]

As shown in FIG. 1 as an embodiment of the present invention, a hexahedron whose optical element has a parallelogram cross section and is soldered to a metal-plated magnet 4 to form a conventional hexagon, for example, as shown in FIG. Compared to the method of installing the optical isolator at a tilt, almost all the area other than the metallized film 8 portion can be used for the optical surface of the optical element. That is,
The product of the present invention can be made smaller than the same aperture 11.

Furthermore, since the tilt holder 10 for tilting and installing can be omitted, the size and cost can be reduced as compared with the conventional product.

Further, by forming grooves on the polarizer material plate 21, the analyzer material plate 23, and the Faraday rotator material plate 22, the polarizer material plate 21, the analyzer material plate 23, and the Faraday rotator material plate 22 are formed. Can be easily cut.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

[Embodiment 1] First, a plurality of polarizers 1
And a Faraday rotator material plate 22 having the same vertical and horizontal lengths and a predetermined thickness, and the Faraday rotator material plate 22 having a vertical and horizontal length and a predetermined thickness. An analyzer material plate 23 having the same length and width as the polarizer material plate 21 and having a predetermined thickness is prepared.

Next, the metallized film 8 is formed on one surface of the polarizer material plate 21, both surfaces of the Faraday rotator material plate 22, and one surface of the analyzer material plate 23. After that, the grooves 12 are formed in a lattice pattern on the surface of the polarizer material plate 21, the Faraday rotator material plate 22, and the analyzer material plate 23 on which the metallized film 8 is formed, and as shown in FIG. The Faraday rotator material plate 22 is sandwiched between the surface of the material plate 21 on which the metallized film 8 is formed and the surface of the analyzer material plate 23 on which the metallized film 8 is formed. Hereinafter, the polarizer material plate, the Faraday rotator material plate, and the analyzer material plate are collectively referred to as an optical material plate. Here, each optical material plate has a groove 12
Is formed so that the end portions of the optical material plates are aligned and the optical material plates face each other when they are stacked.

FIG. 5 is a schematic sectional view showing the present embodiment of the method for manufacturing an optical element of an optical isolator according to the present invention.

After overlapping, the groove 1 is formed as shown in FIG.
2 so that the position of 2 and the position of aperture 11 are displaced,
The ends of the polarizer material plate 21, the Faraday rotator material plate 22, and the analyzer material plate 23 are located on the inclined line that intersects a line orthogonal to each optical material plate at an angle θ. Then groove 12
Insert the solder material 5 into.

The inserted solder material 5 is heated in a heat treatment furnace to become liquid and then moves on the metallized film 8 by a capillary phenomenon as shown in FIG. Solder bonding is performed by only entering and then cooling. At this time, since the excess solder material 5 remains in the groove 12, the solder material 5 does not flow into the light transmitting portion to increase the incident loss.

Next, as shown by the dotted lines in FIG. 5B, each light transmission area for the polarizer 1, the corresponding light transmission area for the Faraday rotator 2, and the corresponding light for the analyzer 3 are shown. A portion including one set of transmission regions and each metallized film 8 surrounding each of the one set of light transmission regions is cut out as an optical element 9 for one set of optical isolators.

In this way, as shown in FIG. 5C, the optical element 9 for one set of a plurality of optical isolators can be obtained.

[Embodiment 2] First, Embodiment 1
Similarly, a polarizer material plate 21 having a size such that a plurality of polarizers 1 can be taken out and having a same vertical and horizontal length and a predetermined thickness, and a vertical and horizontal length equal to the polarizer material plate 21 and having a predetermined thickness. A Faraday rotator material plate 22 and an analyzer material plate 23 having the same vertical and horizontal lengths as the polarizer material plate 21 and a predetermined thickness are prepared.

Next, the metallized film 8 is formed on one surface of the polarizer material plate 21, both surfaces of the Faraday rotator material plate 22, and one surface of the analyzer material plate 23. After that, the grooves 12 are formed in a lattice pattern on the surface of the polarizer material plate 21, the Faraday rotator material plate 22, and the analyzer material plate 23 on which the metallized film 8 is formed, and as shown in FIG. The Faraday rotator material plate 22 is sandwiched between the surface of the material plate 21 on which the metallized film 8 is formed and the surface of the analyzer material plate 23 on which the metallized film 8 is formed. Here, as shown in FIG. 6A, the grooves 12 of each optical material plate are arranged on an inclined line that intersects a line orthogonal to each optical material plate at an angle θ when the ends of each optical material plate are aligned. To form.

FIG. 6 is a schematic sectional view showing the present embodiment of the method for manufacturing an optical element of an optical isolator according to the present invention.

After overlapping, the solder material 5 is inserted into the groove 12. The inserted solder material 5 is heated and becomes liquid in a heat treatment furnace, and then moves on the metallized film 8 by a capillary phenomenon as shown in FIG. 6 (b) to enter an amount necessary for solder bonding, Then, by cooling, solder bonding is performed.

Next, as shown by the dotted lines in FIG. 6B, each light transmission region for the polarizer 1, the corresponding light transmission region for the Faraday rotator 2, and the corresponding light for the analyzer 3 are shown. A portion including one set of transmission regions and each metallized film 8 surrounding each of the one set of light transmission regions is cut out as an optical element 9 for one set of optical isolators.

In this way, as shown in FIG. 6C, the optical element 9 for one set of a plurality of optical isolators can be obtained.

[Embodiment 3] FIG. 7 is a schematic sectional view showing the present embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

In the first embodiment, the polarizer material plate 2 is used.
Before the metallized film 8 is formed on one side of the Faraday rotator material plate 22, both sides of the Faraday rotator material plate 22, and one side of the analyzer material plate 23, one side of the polarizer material plate 21, both sides of the Faraday rotator material plate 22, and the detection side. The groove 12 is formed on one surface of the photon material plate 23. Here, the groove 12 is formed so as to be in a position facing each other when the end portions of the optical material plates are aligned and the optical material plates are stacked.

After that, the same steps as those in the first embodiment are performed to obtain the optical element 9 for one set of a plurality of optical isolators.

[Fourth Embodiment] FIG. 8 is a schematic sectional view showing the present embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

In the second embodiment, the polarizer material plate 2 is used.
Before the metallized film 8 is formed on one side of the Faraday rotator material plate 22, both sides of the Faraday rotator material plate 22, and one side of the analyzer material plate 23, one side of the polarizer material plate 21, both sides of the Faraday rotator material plate 22, and the detection side. The groove 12 is formed on one surface of the photon material plate 23. Here, as shown in FIG. 8A, the grooves 12 of each optical material plate are arranged on an inclined line that intersects a line orthogonal to each optical material plate at an angle θ when the ends of each optical material plate are aligned. To form.

After that, the same steps as those in the first embodiment are performed to obtain the optical element 9 for one set of a plurality of optical isolators.

In the embodiment of the present invention, the figure is shown in which the solder material 5 is inserted into the groove 12 and soldered.
A thin film made of a solder material may be formed on the metallized film by a vapor deposition method, a sputtering method or an ion plating method and soldered, and the method of installing the solder material is not limited to the embodiment of the present invention.

In the cross-sectional view showing the embodiment of the present invention, the shape of the groove 12 is rectangular, but the solder material 5 can be inserted, the excess solder material 5 can be held at the time of solder bonding, and cutting can be performed. Since it is only necessary to reduce the vibration due to cutting at the time of,
It may be a polygon such as a triangle or a trapezoid, or a semicircle or an ellipse, and the shape of the groove 12 is not limited to the embodiment of the present invention.

Further, in the embodiment of the present invention, the fixing method by soldering, which is the metal fusion method, has been described, but the fixing method by an organic adhesive may be used for adhesion and fixing.

In the embodiment of the present invention, the groove 12 may be displaced only in the X-axis direction in FIG.
It may be only the axial direction or any direction sandwiched between the X axis and the Y axis.

[0046]

EXAMPLES In the embodiment of the present invention, the polarizer material plate 21 and the analyzer material plate 23 are optical material plates made of rutile single crystal. As the Faraday rotator material plate 22, an optical material plate made of garnet single crystal was used. Each of the polarizer material plate 21, the Faraday rotator material plate 22, and the analyzer material plate 23 had a vertical and horizontal size of 11 mm × 11 mm. , The polarizer material plate 21
The thickness of the analyzer material plate 23 was 0.4 mm, and the thickness of the Faraday rotator was 0.485 mm. Further, an angle θ formed by a line intersecting with each optical material plate at right angles and an inclined line intersecting with each other was set to 4 degrees.

[0047]

As described above, according to the present invention, it is possible to manufacture a large number of small-sized, low-cost and highly reliable optical isolators.

[Brief description of drawings]

FIG. 1 is a sectional view showing a section including an optical axis according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a method for manufacturing an optical element of an optical isolator according to the present invention.

FIG. 3 is a sectional view showing a section including an optical axis of a conventional optical isolator.

FIG. 4 is a cross-sectional view showing a cross section including an optical axis of an optical isolator tilted by using a conventional tilt holder.

FIG. 5 is a schematic cross-sectional view showing an embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

FIG. 6 is a schematic cross-sectional view showing an embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

FIG. 7 is a schematic cross-sectional view showing an embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

FIG. 8 is a schematic sectional view showing an embodiment of a method for manufacturing an optical element of an optical isolator according to the present invention.

[Explanation of symbols]

 1 Polarizer 2 Faraday rotator 3 Analyzer 4 Magnet 5 Solder material 6 External holder 7 End holder 8 Metallized film 9 Optical element for one set of optical isolator 10 Tilt holder 11 Aperture 12 Groove 21 Polarizer material plate 22 Faraday rotator Material plate 23 Analyzer material plate

Claims (4)

[Claims] 1. An optical isolator having an optical element including a polarizer, a Faraday rotator, and an analyzer,
One cross section of a predetermined plane including the optical axis of the optical element is a parallelogram, so that the light entrance surface and the light exit surface of the optical element are inclined at a predetermined angle from the right angle with respect to the optical axis. Optical isolator. 2. A light-incident surface of the optical element and a light-incident surface of the optical element comprising a polarizer, a Faraday rotator, and an analyzer, and a cross section of a predetermined plane including the optical axis of the optical element is a parallelogram. In the method for manufacturing the optical element, wherein the light emitting surface is inclined at a predetermined angle from the right angle with respect to the optical axis, a parallel plate-shaped polarizer material plate having a size capable of taking out a plurality of polarizers, and a size capable of taking out a plurality of Faraday rotators. A parallel plate-shaped Faraday rotator material plate and a parallel plate-shaped analyzer material plate of a size that allows a plurality of analyzers to be taken out, each having a predetermined interval on one surface of the polarizer material plate. A light-transmitting region for the Faraday rotator is formed at each position on the both sides of the Faraday rotator plate, leaving a light-transmitting region for the polarizer at the position on the one surface. Leave me Talize film is formed on both sides,
A metallization film is formed on the one surface of the analyzer material plate, leaving a light transmitting region for the analyzer at each position having the predetermined distance, and the polarizer material plate and the analyzer material plate are formed. By so that the Faraday rotator material plate is sandwiched, and
A surface of the polarizer material plate on which the metallized film is formed and one surface of the Faraday rotator material plate on which the metallized film is formed;
And the surface of the analyzer material plate on which the metallized film is formed and the other surface of the Faraday rotator material plate on which the metallized film is formed are opposed to each other, and each of the light transmission regions for the polarizer of the polarizer material plate is The midpoint, the midpoint of each light transmission region for the Faraday rotator of the corresponding Faraday rotator material plate, and the midpoint of each light transmission region for the analyzer of the corresponding analyzer material plate is the polarized light. Child material plate, the Faraday rotator material plate,
And a light transmitting region of the polarizer material plate, a light transmitting region of the Faraday rotator material plate, and the detector so as to be located on an inclined line that intersects the line orthogonal to the analyzer material plate at the predetermined angle. The light transmission regions of the photon material plates are respectively shifted, the polarizer material plate, the Faraday rotator material plate, and the analyzer material plate are overlapped and bonded and fixed to form an optical material laminated plate,
From the optical material laminated plate, each light transmission region for the polarizer, a corresponding light transmission region for the Faraday rotator, a set of corresponding light transmission regions for the analyzer, and a set of the light transmission regions. A method for manufacturing an optical element of an optical isolator, characterized in that a portion including each metallized film surrounding each of the above is cut out by a cutting plane parallel to the inclined line as an optical element to obtain a plurality of optical elements. 3. The polarizer material plate according to claim 2, wherein a metallized film is formed on one surface of the polarizer material plate, both surfaces of the Faraday rotator material plate, and one surface of the analyzer material plate. Before superposing the Faraday rotator material plate and the analyzer material plate, at least one of the surface of the polarizer material plate on which the metallized film is formed and the one surface of the Faraday rotator material plate on which the metallized film is formed. At a predetermined position between the light transmission regions on the surface of the analyzer material plate and on at least one of the surface of the Faraday rotator material plate on which the metallized film is formed and the other surface of the Faraday rotator material plate on which the metallized film is formed. A method for manufacturing an optical element of an optical isolator, which comprises forming a groove in the substrate. 4. The polarizer material plate according to claim 2, wherein a metallized film is formed on one surface of the polarizer material plate, both surfaces of the Faraday rotator material plate, and one surface of the analyzer material plate. At a predetermined position on at least one surface on one surface and one surface of the Faraday rotator material plate, and on at least one surface on one surface of the analyzer material plate and the other one surface of the Faraday rotator material plate. A method for manufacturing an optical element of an optical isolator, which comprises forming a groove.