JPH0511125U - Optical isolator - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an optical isolator having high extinction performance and low insertion loss, which enables easy assembly and joining of parts. In an optical isolator 10 including a polarizer 1, a Faraday rotator 3, an analyzer 2, and a cylindrical magnet 4 for applying a magnetic field to the Faraday rotator 3, the polarizer 1 (or the analyzer 2) is a metal member 5 ( Alternatively, the metal members 11 and 12 (or the metal member 15) are arranged inside the metal member 6).
And 16) and fixed. Metal members 5, 1
1, 12 and the gap between the polarizer 1 (or the metal members 6, 1)
The gaps 5 and 16 and the analyzer 2) are filled with solder. The Faraday rotator 3 is arranged inside the cylindrical magnet 4 and is fixed by being sandwiched between two metal members 13 and 14. The gap between the cylindrical magnet 4, the metal members 13 and 14, and the Faraday rotator 3 is filled with solder. The metal member 5, the metal member 6, and the cylindrical magnet 4 are provided with holes 20 into which solder is inserted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention is an optical component used in, for example, an optical communication system or an optical measuring instrument. An optical isolator to prevent the light emitted from the source from returning to the light source by being reflected at the end face of the optical system. It is related to the rater.

[0002]

[Prior art]

  When trying to transmit the light from the light source through the optical system, it was reflected by the end surface of the optical system. Light returns to the light source. For example, signal transmission by optical fiber, from laser light source The emitted light is projected onto the fiber end face through a lens, and most of it is transmitted as transmitted light. The laser enters the inside of the fiber, but is reflected by the end surface of the lens or fiber and is reflected by the laser. After returning to the light source, the end face of the light is reflected again and becomes noise. like this Optical isolators are used to eliminate noise. Optical isolators , The ability to extinguish the reflected light returning to the light source, that is, the extinction performance is high, and the loss of light transmittance It is required to be small, that is, to have low insertion loss.

[0003]   FIG. 5 shows a sectional view of the optical isolator. In the figure, an optical element, a polarizer 1 and a fiber The Laday rotator 3 and the analyzer 2 are arranged in this order, and the metal members 5 and 6 serving as holding jigs. And a magnet 4 for applying a magnetic field to the Faraday rotator 3 and assembled into an outer cylinder 7. It is stored. In the optical isolator shown in the figure, the boundary portion of each component is shown in, for example, a portion. Although they are joined by solder as described above, they are often joined by an adhesive.

[0004]   When soldering each component of the optical isolator, make sure that the optical element A thin metal film must be formed on the side surface of the child. Forming a metal thin film is complicated Therefore, the optical surface of the optical element becomes dirty and the insertion loss of the optical isolator increases. Well In addition, since the parts of the optical isolator have different thermal expansion coefficients, when the solder solidifies The shrinkage of the strain causes non-uniform mechanical strain in the optical element. When mechanical strain occurs The optical axis shifts and the insertion loss of the optical isolator increases, and the Faraday rotator undergoes double bending. Folding occurs and the extinction performance of the optical isolator deteriorates.

[0005]   If the optical isolators are bonded with adhesive, the adhesive will be Outgassing causes clouding of the optical element surface, increasing insertion loss of the optical isolator To do. Solder glass is often used as an adhesive, but it melts solder glass In order to do so, it must be hot. As mentioned above, the coefficient of thermal expansion of each component Due to the difference, non-uniform mechanical strain is caused by shrinkage when the solder glass solidifies. Occurs.

[0006]

[Problems to be solved by the device]

  As a measure for avoiding the mechanical strain that occurs when the adhesive is solidified, as described in 2-245720 has an optical element inside the pipe with a coil spring or O-ring. A method of pressing and fixing is disclosed. However, coil springs and O-rings If it is pressed down, the position of the optical element is displaced due to the deformation.

[0007]   The present invention has been made to solve the above problems, and has high extinction performance and insertion loss. Optical isolator with low loss, which enables easy assembly and joining of parts. The purpose is to provide data.

[0008]

[Means for Solving the Problems]

  The optical isolator of the present invention, which has been made to achieve the above-mentioned object, is compared with the embodiment. A description will be given according to the corresponding FIG.

[0009]   In the figure, a polarizer 1, a Faraday rotator 3, an analyzer 2 and a Faraday rotator 3 are shown. In the optical isolator 10 including the cylindrical magnet 4 for applying a magnetic field, the polarizer 1 is made of gold. It is arranged inside the metal member 5 and is sandwiched and fixed by the metal members 11 and 12. . The gap between the metal members 5, 11, 12 and the polarizer 1 is filled with solder. Analyzer 2 is disposed inside the metal member 6 and is sandwiched and fixed by the metal members 15 and 16. ing. The gap between the metal members 6, 15, 16 and the analyzer 2 is filled with solder. The Faraday rotator 3 is arranged inside the cylindrical magnet 4 and has two metal members 13 and 14 It is fixed by being sandwiched between. Cylindrical magnet 4, metal members 13 and 14, and Faraday The gap of the rotor 3 is filled with solder.

[0010]   In the optical isolator shown in FIG. 1, the polarizer 1 (or the analyzer 2) has a cylindrical metal part. Inside the material 5 (or the metal member 6), the metal members 11 and 12 (or the metal member 15) And 16) are fixed by being sandwiched between them, but they are biased by an integrally formed metal member. The photon 1 and the analyzer 2 may be fixed.

[0011]   Assemble the parts described above by applying solder to the boundary with other parts. After that, the solder is melted and the gap is filled with the solder. As shown in FIG. 1, metal member 5, metal A hole 20 for inserting solder is provided in the member 6 and the cylindrical magnet 4, and the solder is inserted in the hole 20. It will be easier to work if you place them. If you do not want to make a hole 20 in the cylindrical magnet 4, For example, the holes 20 may be provided in the metal members 11, 12, 13, 14, 15, 16 respectively. Yes.

[0012]

[Action]

  The optical element is fixed by a metal member, and the optical element and Since the metal members are not directly joined with solder, when the solder solidifies No uniform mechanical strain occurs. Also, by filling the gaps between the parts with solder, The structure of the isolator is stable and the position of the optical element does not shift even after a long time. The characteristics of the optical isolator do not deteriorate.

[0013]

【Example】

  Embodiments of the present invention will be described below.

[0014]   FIG. 1 is a sectional view of an optical isolator of one embodiment to which the present invention is applied.

[0015]   The optical isolator 10 shown in the figure includes a polarizer 1, a Faraday rotator 3, an analyzer 2, and a fiber. Cylindrical magnet 4 for applying a magnetic field to Laday rotator 3 and metal members 5, 6, 11, 12 , 13, 14, 15, 16 are placed inside the assembly outer cylinder 7, and the gaps between the parts are soldered. It is buried and formed integrally. Provided on the metal member 5, the metal member 6, and the cylindrical magnet 4. The hole 20 is a hole into which solder is inserted.

[0016]   The polarizer 1 is a glass polarizing plate on the inner peripheral surface of the metal member 5, and the analyzer 2 is a glass polarizing plate. The metal member 6 is formed into a cylindrical shape having an outer diameter that can be accommodated on the inner peripheral surface. Faraday rotator 3 is A smut-substituted rare earth iron garnet crystal is formed into a cylindrical shape that can be housed in the cylindrical magnet 4. Money The metal members 5, 6, 11, 12, 13, 14, 15, 16 are all solderable tin , Silver, gold, palladium, copper and alloys based on these metals Form. The metal member 5 (or the metal member 6) has the same outer diameter as that of the cylindrical magnet 4 and has an uneven width. Photon 1 (or analyzer 2) and metal members 11 and 12 (or metal members 15 and 16) ) Equal to the sum of the widths. The width of the cylindrical magnet 4 is the Faraday rotator 3, and It is equal to the sum of the widths of the metal members 13, 14. In addition, the width of the outer cylinder 7 depends on the metal member 5 and the cylindrical magnet. The stone 4 and the metal member 6 are formed to have the same width.

[0017]   The metal member 5, the metal member 6, and the cylindrical magnet 4 have four holes 20 at the left and right ends, respectively. It is provided at a position symmetrical in the radial direction and in a direction perpendicular to the optical axis. Half each hole 20 Insert the rice field.

[0018]   Polarizer 1 (or analyzer 2) is placed inside metal member 5 (or metal member 6) Then, sandwich it from both sides with the metal members 11 and 12 (or the metal members 15 and 16) to fix it. Set. The Faraday rotator 3 is arranged inside the cylindrical magnet 4, and the metal member 13 is inserted from both sides. , 14, and fix. Next, melt the solder inserted in each hole 20 , The gap between the metal members 5, 11, 12 and the polarizer 1, and the metal members 6, 15, 16 and And the gap between the analyzer 2 is filled with solder. Also, the cylindrical magnet 4, the metal members 13 and 14, and The gap between the Faraday rotator 3 and the Faraday rotator 3 is also filled with solder.

[0019]   The entire parts described above are arranged inside the outer cylinder 7 in the order shown in FIG. , And the outer cylinder 7 and the metal member 16 are joined and fixed by soldering to complete the optical isolator 10. To achieve.

[0020]   The metal member for fixing the polarizer 1 and the analyzer 2 is formed as shown in FIGS. May be. Although illustrated in the case of the polarizer 1, the same applies to the case of the analyzer 2. Figure In the case of the tilted polarizer 1, the polarizer 2 is arranged inside the metal member 5 and is tilted. The metal members 11 and 12 thus formed are sandwiched and fixed. Figure 3 is a metal member 5 is integrally formed, and the polarizer 1 is fixed inside the metal member 5. Figure 4 is metal One side of the member 5 is opened, the polarizer 1 is placed inside the metal member 5, and the metal member 11 is used. It is fixed.

[0021]   If the metal member is a metal that is difficult to solder, apply gold plating on the surface in advance. It is advisable to form a metal film. In addition to gold, for example, tin, silver, palladium, copper plating But it's okay. The method of forming the metal film is not limited to plating, but may be vacuum deposition or sputtering. The method can also be used.

[0022]

[Effect of device]

  As described above in detail, the optical isolator of the present invention is an optical isolator for soldering. It is easy to manufacture because it is not necessary to form a metal thin film on the optical element. Optical element is thermal expansion Because it is fixed without being joined to other parts with different numbers by soldering, distortion does not occur, The characteristics of the optical isolator do not deteriorate. Also, since no adhesive is used, optical isolation The weather resistance of the data is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical isolator of one embodiment to which the present invention is applied.

FIG. 2 is a cross-sectional view showing that an inclined optical element is fixed by a metal member.

FIG. 3 is a cross-sectional view showing that an optical element is fixed by a metal member integrally formed.

FIG. 4 is a cross-sectional view showing that the optical element is fixed by two metal members.

FIG. 5 is a sectional view of a conventional optical isolator.

[Explanation of symbols]

1 is a polarizer, 2 is an analyzer, 3 is a Faraday rotator, 4 is a cylindrical magnet, 5 and 6 are metal members, 7 is an outer cylinder, 10 is an optical isolator, 11, 12, 13, 14, 15, 16 are The metal member 20 is a hole.

Claims (2)

[Scope of utility model registration request] 1. An optical isolator comprising a polarizer, a Faraday rotator, an analyzer and a magnet for applying a magnetic field to the Faraday rotator, wherein the polarizer and the analyzer are each fixed by at least one metal member and The gap between the polarizer and the gap between the metal member and the analyzer are filled with solder, the Faraday rotator is placed inside the magnet, and is fixed by being sandwiched between two metal members. The magnet, the metal member, and the Faraday rotation An optical isolator characterized in that the gap between the child is filled with solder. 2. The optical isolator according to claim 1, wherein the metal member, or the metal member and the magnet are provided with holes through which solder is inserted.