JP2005055796A - Optical connector provided with antireflection member and its forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a stable, high-performance and inexpensive antireflection film on the end face of a ferrule. <P>SOLUTION: The optical connector is formed in steps of: inserting an optical fiber 4 into a ferrule 2; depositing a proper amount of a UV-curing resin 52 on the end face of the ferrule 2 in at least a part where the optical fiber 4 is present; pressing a transparent die 54 having a rugged face comprising a continuous pattern of minute pyramid-like figures to the resin; and irradiating the resin with UV rays 55 through the die 54 to form the antireflection member having the rugged face transferred thereon on the end face of the ferrule 2 at least in a part where the optical fiber 4 is present. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical connector in which a reflection member such as an antireflection film is provided on an end face of a fiber strand inserted and fixed through a ferrule, and a method for forming the same.

  Conventionally, an optical connector 1 for an optical semiconductor module such as a laser diode or a photodiode is fixed by connecting the optical connector 1 to one end and inserting a ferrule 2 into the optical semiconductor module 7 as shown in FIG. Yes. As shown in FIG. 12, the optical connector 1 has an optical fiber 4 inserted and fixed to a ferrule 2. A flange 3 is attached to the ferrule 2. Light emitted from the laser diode 71 or the like of the optical semiconductor module 7 is incident on the optical fiber 4 inserted through the ferrule 2.

  An end surface including the end surface of the optical fiber 4 on the ferrule 2 side is usually provided with an antireflection film, that is, an AR coat 6 in order to prevent reflection of incident light. This prevents the amount of incident light from decreasing and is generally formed by depositing dielectrics in multiple layers.

A method of forming an antireflection film on the end face of the optical fiber 4 shown in FIG. 12 conventionally are various, Part 1 Tsunihikari fiber 4 inserted, fixed ferrule 2 film-forming source (e.g. silica: SiO ₂ And a tantalum oxide (Ta ₂ O ₅ ) in a chamber (not shown) in which evaporated atoms or molecules exist, and a multilayer film in which SiO ₂ and Ta ₂ O ₅ are alternately laminated on the end face of the optical fiber 4 In addition to forming the film, energy is given to the evaporated atoms or molecules by irradiating or accelerating O ₂ active molecules from the ion gun installed in the same chamber toward the end face of the optical fiber 4, and the denseness is high. A method for forming a film with strong adhesion (ion beam assisted deposition method: IAD method), a holder in which an optical fiber 4 is set in a chamber filled with a discharge gas, and a dome in the chamber as a cathode There is a method of accelerating ionized evaporated atoms or molecules and attaching them to the end face of an optical fiber (ion plating method).

  When the film is formed on the end face of the optical fiber by the conventional film forming method, gas is generated from the coating resin that protects the optical fiber in the film, the plating metal of the ferrule, etc., and these impurities are mixed in the film, There is a problem that a predetermined film cannot be obtained.

  As a method for solving such a problem, a fiber strand is inserted and fixed into the ferrule, the ferrule is set in a chamber of the film forming apparatus, and the end surface of the fiber strand protruding or exposed on the end surface of the ferrule is used. In the film forming method on the fiber end face for forming an antireflection film or the like, all or part of the gold-plated portion of the ferrule is previously coated with a substance other than the plating material, or the fiber strand is coated with solder for fixing to the ferrule. Alternatively, a film forming method has been proposed in which the gold plating is not exposed in the chamber by removing, covering with a shielding plate, or covering with a protective film (see Patent Document 1).

  However, when the above-described vapor deposition method is used, the film forming method is troublesome, and the workability is not so good because a vacuum vapor deposition apparatus is required. Furthermore, when the antireflection film is formed by vapor deposition, the thickness of the reflection film depends on the surface accuracy of the end surface on which the vapor deposition film is formed.

There is also a method in which AR deposition is performed on a substrate such as glass and the like and then attached to the end face of the ferrule. However, this method has a problem in that it is difficult for an operator to handle because the substrate is extremely fine with a size of several millimeters.
JP 2001-318244 A

  As described above, the formation of the reflective film on the conventional ferrule has a problem that the deposition workability and the mounting workability are complicated. An object of the present invention is to form a stable, high-performance and inexpensive antireflection film on the ferrule end face.

  The optical connector provided with the reflecting member of the present invention is made of an ultraviolet curable resin in which an optical fiber is inserted into a ferrule, and a concave and convex surface made of a continuous pattern having a fine conical shape is formed at least on the portion of the optical fiber portion of the ferrule end face. An antireflection member is provided.

  Further, in the method of forming an optical connector provided with the antireflection member of the present invention, an optical fiber is inserted into a ferrule, and an appropriate amount of ultraviolet curable resin is attached to at least a portion of the optical fiber portion of the ferrule end face, thereby forming a fine conical shape. Pressing a transparent mold having a concavo-convex surface formed of a continuous pattern, irradiating with ultraviolet rays through the mold, and forming an antireflection member to which the concavo-convex surface has been transferred at least at a portion of the optical fiber portion of the ferrule end surface It is characterized by.

  It is good to comprise so that an optical fiber may be fixed to a ferrule with formation of the said reflection preventing member.

    Moreover, it is good to provide a hollow in the site | part containing the optical fiber part of the said ferrule end surface.

  According to the method for forming an antireflection structure in an optical communication member according to the present invention, there is no performance variation such as film thickness variation during AR deposition, and the formation of the antireflection structure can be easily automated.

  Thus, according to the method for forming an antireflection film for an optical communication member in the present invention, stable performance can be obtained as compared with conventional AR deposition. Moreover, the thing of a low reflectance characteristic can be obtained easily.

  On the production side, according to the conventional vapor deposition method, there was a problem that the vapor deposition was also performed at a place other than the necessary part. .

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part as a prior art example.

  FIG. 1 is a perspective view showing an optical connector for an optical semiconductor module according to the present invention, and FIG. 2 is a sectional view thereof. As shown in FIGS. 1 and 2, the optical connector 1 includes a gold-plated ferrule 2, an optical fiber 4 that is inserted and fixed to the ferrule 2, and a flange 3. An antireflection film 5 which is a feature of the present invention is provided on the end face of the ferrule 2. The antireflection film 5 is formed by forming an uneven surface composed of a continuous pattern having a fine cone shape.

  FIG. 3 is a perspective view showing a schematic shape of the surface of the antireflection film 5, and FIG. 4 is a schematic diagram showing a pattern cross-sectional shape. As shown in FIG. 3, an uneven surface made of a continuous pattern in which fine cone-shaped projections 51 are continuously formed on the surface of an antireflection member main body 50 made of a translucent resin, for example, an ultraviolet curable resin. ing. The pattern shape of the protrusions 51 in this embodiment is a quadrangular pyramid shape, but may be a hexagonal pyramid shape or a conical shape.

  A ratio D / p of the pattern height D to the pattern pitch p shown in FIG. The pattern pitch p is preferably smaller than the wavelength of light used as the optical semiconductor module, and may be smaller than the value obtained by dividing the wavelength of light used by the refractive index of the ultraviolet curable resin. The aspect ratio is preferably 1 or more. An antireflection film 5 having such a pattern surface is formed on the end surface of the ferrule 2.

  In order to form the above-described antireflection film 5 on the end face of the ferrule 2, an appropriate amount of ultraviolet curable resin is deposited on the end face of the ferrule 2, and then a continuous pattern of fine cones as shown in FIGS. The antireflection film 5 is formed on the end face of the ferrule 2 by pressing a transparent mold formed on the surface and irradiating ultraviolet rays through the mold.

  In the above-described structure, the ferrule 2 and the optical fiber 4 are fixed without using solder or the like, and the antireflection film 5 is formed and the optical fiber 4 is fixed using the ultraviolet curable resin for forming the antireflection film 5. It can be done at the same time.

  Next, a method for forming the antireflection film 5 will be further described with reference to the drawings. FIG. 5 is a perspective view showing a jig 60 for forming the antireflection film 5 at the tip of the ferrule 2. As shown in FIG. 6, the jig 60 is provided with many holes 61 into which the flange 3 of the optical connector 1 is inserted. The optical connector 1 is inserted into the hole 61 of the jig 60.

  FIG. 6 is a schematic cross-sectional view showing a method for forming the antireflection film 5 on the tip of the ferrule 2 by using the jig 60 shown in FIG. As shown in FIG. 6A, the optical connector 1 is inserted into the hole 61 of the jig 60. At this time, the ferrule 2 and the optical fiber 4 may be already fixed by soldering or the like. In addition, in the case where the ferrule 2 and the optical fiber 4 are not fixed but are fixed simultaneously with the formation of the antireflection film 5, the optical fiber 4 is more than the ferrule 2. Temporarily fix it so that it does not fall out.

  Subsequently, as shown in FIG. 6B, an appropriate amount of ultraviolet curable resin 52 is attached to the tip of the ferrule 2. Thereafter, as shown in FIG. 6 (c), the transparent die 54 having a fine conical continuous pattern formed on the surface thereof is pressed, and at the same time, the ultraviolet ray 55 is irradiated from the back side of the die 54 and cured. Let

  FIG. 7 is an enlarged view of a portion where the mold is pressed against the tip of the ferrule 2. A pattern 54 a having a conical section is uniformly arranged on the mold 54. The pattern itself may have a quadrangular pyramid shape, a hexagonal pyramid shape, or a conical shape. The arrangement method may be one-dimensional or two-dimensional. Further, the pattern may be formed on the entire surface of the mold, but naturally the pattern may be formed only on a portion facing the tip surface of the ferrule 2.

  Regarding the pattern pitch p, the wavelength of light to be used may be made smaller than the value obtained by dividing the wavelength of the light used by the refractive index of the ultraviolet curable resin. The aspect ratio may be 1 or more. For example, if the wavelength used is 800 nm and the refractive index of the resin is 1.45, the pattern pitch p may be smaller than 550 nm. Desirably, the thickness is about 500 nm, which is about 90% of the calculated value. If the wavelength used is 1500 nm, the pattern pitch p is preferably about 930 nm.

  FIG. 8 is a schematic cross-sectional view showing another embodiment for forming the antireflection film 5, and a heater 56 is provided on the transparent mold side. By heating at the time of ultraviolet curing, the molding time can be shortened and the resin hardness of the pattern portion can be controlled. In addition, the heater 13 is arrange | positioned in places other than a pattern part.

  FIG. 9 is a schematic cross-sectional view showing still another embodiment for forming the antireflection film 5, and the vibrator 14 is provided on the jig 60 side. After the resin molding of the vibrator 62 is completed, the vibrator 62 is operated at a timing for separating the mold from the optical connector. The operation of the vibrator 62 facilitates separation of both.

  FIG. 10 is a cross-sectional view showing another embodiment of the optical connector for forming the antireflection film 5. In the structure shown in FIG. 10, a recess 21 is formed at the tip of the ferrule 2. By forming the recess 21, the optical fiber 4 and the antireflection film 5 can be fixed to the distal end of the optical fiber 4 with certainty.

  FIG. 11 is a cross-sectional view showing still another embodiment of the optical connector for forming the antireflection film 5. In order to prevent the reflected light when the laser light emitted from the optical semiconductor module 7 hits the tip of the ferrule 2 from being returned light, the tip of the ferrule 2 is inclined as shown in FIG. I am letting. In the example shown in FIG. 11, no dent is provided at the tip, but a dent may be provided as in FIG. 10.

  In the case of the optical connector having the configuration shown in FIG. 11, as the jig configuration shown in FIG. 5, an ultraviolet curable resin is used in the same process as shown in FIG. 6 by providing an inclined portion on the hole surface of the jig. The antireflection film 5 can be formed by a so-called 2P molding method in which ultraviolet rays are irradiated from the back side of the mold and cured.

  In the 2P molding method, resin molding can be performed on the end surface without being affected by the shape of the periphery of the end surface to be formed. Therefore, the desired antireflection film 5 can be provided without strictly requiring the surface accuracy of the end face of the ferrule 2.

  In the above-described embodiment, the antireflection film 5 is provided on the entire front surface of the ferrule 2. However, the antireflection film 5 is provided only in a portion including at least the portion of the optical fiber 4 of the ferrule 2. Also good.

It is a perspective view which shows the optical connector for optical semiconductor modules concerning this invention. It is sectional drawing which shows the optical connector for optical semiconductor modules concerning this invention. It is a perspective view which shows schematic shape of the surface of the anti-reflective film provided in the optical connector for optical semiconductor modules concerning this invention. It is a schematic diagram which shows the pattern cross-sectional shape of an antireflection film. It is a perspective view which shows the jig for forming an anti-reflective film in the front-end | tip part of a ferrule. It is typical sectional drawing which shows the method of forming an anti-reflective film in the front-end | tip part of a ferrule using a jig shown in FIG. 5 according to a process. It is an enlarged view of the part which pressed the metal mold | die to the front-end | tip part of the ferrule. It is a typical sectional view showing other embodiments for forming an antireflection film. It is typical sectional drawing which shows other embodiment for forming an antireflection film. It is sectional drawing which shows other embodiment of the optical connector which forms an antireflection film. It is sectional drawing which shows other embodiment of the optical connector which forms an antireflection film. It is a side view which shows the conventional optical connector. It is a schematic diagram which shows the conventional optical semiconductor module.

Explanation of symbols

1 Optical connector 2 Ferrule 3 Flange 4 Optical fiber 5 Antireflection film

Claims (4)

An optical fiber is inserted into the ferrule, and an antireflection member made of an ultraviolet curable resin is provided on at least a portion of the optical fiber portion of the ferrule end face, which is formed with an uneven surface made of a fine conical continuous pattern. An optical connector provided with an antireflection member. Insert an optical fiber through the ferrule, attach an appropriate amount of ultraviolet curable resin to at least the portion of the optical fiber portion of the ferrule end face, and press a transparent mold on which an uneven surface made of a continuous pattern of fine cones is formed, A method of forming an optical connector provided with an antireflection member, wherein ultraviolet rays are irradiated through a mold, and an antireflection member to which the uneven surface is transferred is formed at least at a portion of an optical fiber portion of a ferrule end face. The method of forming an optical connector provided with the antireflection member according to claim 2, wherein an optical fiber is fixed to the ferrule together with the formation of the antireflection member. 4. The method of forming an optical connector provided with an antireflection member according to claim 2, wherein a recess is provided in a portion including the optical fiber portion of the ferrule end face.