JP2016173479A - Optical component manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide optical components applicable to high output light, such as compact light isolators, and a manufacturing method for such components.SOLUTION: According to an optical component manufacturing method, each of optical elements 12, 14 and 16 has front and rear faces disposed forward and backward in the optical path direction and side faces surrounding the front and rear faces. The front and rear faces have optical path areas where light passes and non-optical path areas where light does not pass, and in at least one of the opposing front and rear faces of each of adjoining optical elements 12, 14 and 16, concaves 19 linked to the side faces are disposed. At least two of the planar-shaped optical elements 12, 14 and 16 are made ready, and arranged in a predetermined sequence. The front and rear faces of the adjoining ones of the optical elements 12, 14 and 16 are pressed against each other. The concaves 19 are filled with energy-settable adhesive from the side faces, and setting energy is applied to the adhesive to set it.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing an optical component used in an optical communication device or the like, and an optical component.

  In general, optical components and optical modules used for optical communication include optical connectors, optical isolators, LD (Laser diode) modules for transmitting optical signals, and PD (Photo diode) modules for receiving optical signals. It has been known.

  An optical isolator is a component used in an optical communication system to prevent return light of an optical fiber. The returning light can be caused by the traveling light being inconsistent in refractive index between the materials in contact with each other, fiber misalignment or mode mismatching. The return light causes a decrease in system performance and adversely affects a transmission source such as a laser beam.

  In the polarization-dependent optical isolator, a polarizer such as a polarizing glass sheet is used to sandwich the Faraday rotator. Light travels through the first polarizer, then through the Faraday rotator, and then through the second polarizer. The isolator is disposed between the optical fiber and the lens or between the two lenses.

  The signal light emitted from the light source passes through the first polarizer. Next, the polarization of the light that has passed through the first polarizer is rotated 45 ° by the Faraday rotator, and then passes through the second polarizer whose polarization direction is shifted by 45 ° with respect to the first polarizer. Come out. In the case of the reverse direction, the return light is polarized by the second polarizer and then rotated 45 ° in the same direction by the Faraday rotator to become polarized light that is shifted by 90 ° with respect to the first polarizer. Thus, no signal is returned to the light source.

  In contrast to the polarization-dependent isolator, a polarization-independent optical isolator is also known. The polarization-independent isolator can be a wedge or flat birefringent material, or a prism with a thin film coating, and has a Faraday rotator sandwiched between two beam splitters.

  A Faraday rotator is typically made by surrounding a piece of garnet with a magnet so that a magnetic field is applied to optically activate the crystal. This type of garnet is referred to as a non-latching type. Another type of Faraday rotator is permanently magnetized and does not require an external magnetic field. This type of garnet is called a latch type.

  The various components of both polarization-dependent and polarization-independent optical isolators are generally joined by mechanical assemblies or by polymeric adhesives. As another alternative method, there is also known a method in which large material sheets are collectively assembled with an adhesive, that is, laminated.

  An optical component such as an optical isolator is configured by combining optical elements such as a Faraday rotator and a polarizer as described above. A fixing member or an adhesive is used for fixing the optical element. For example, Japanese Unexamined Patent Application Publication No. 2007-309967 discloses an optical isolator in which optical elements are bonded together using an optical adhesive and integrated. The optical adhesive is applied with a uniform thickness over the entire surface including the surface of the light passage portion of the optical element.

  In this optical isolator, a first polarizer having an antireflection film formed on a predetermined surface, a second polarizer, and a Faraday rotator having antireflection films formed on both surfaces are prepared. Apply the adhesive to the Faraday rotator side surface and the Faraday rotator side surface of the polarizer 2 and align the polarization surfaces of the first and second polarizers appropriately. It is manufactured by a procedure in which a predetermined pressure is applied and a block composed of three combined optical elements is heated to a predetermined temperature for a predetermined time to thermally cure the adhesive.

  As the optical adhesive, a thermosetting adhesive or an ultraviolet curable adhesive that has a low shrinkage at the time of adhesive curing and is less affected by heat and has high stability is used.

  The optical isolator as described above is an optical isolator conventionally used, and is usually used in many optical communication systems using light having an output of about several tens of milliwatts.

  On the other hand, in an optical communication system using an optical amplifier or the like, high-power laser light of about several hundred milliwatts is used. When an optical isolator having an optical adhesive on the optical path surface is used in an optical communication system using high-power laser light, there is a possibility that the adhesive may be altered, resulting in a problem in reliability.

  On the other hand, Japanese Patent Application Laid-Open No. 2005-181760 discloses an optical isolator having no adhesive on the optical path surface. This optical isolator has a structure in which a plate-shaped polarizer and a plate-shaped Faraday rotator are arranged and both ends thereof are held by a pair of substrates, and a groove-shaped recess is formed on each of two opposing mounting substrates. An optical isolator is disclosed which is formed and held with an adhesive while holding the ends of a polarizer and a Faraday rotator in a recess.

  This optical isolator prepares two substrates for holding a first polarizer, a Faraday rotator, and a second polarizer, and forms a recess on the opposing surfaces of the two substrates and applies an adhesive. The both ends of the first polarizer, the Faraday rotator, and the second polarizer are sandwiched between the recesses of the two substrates, and the adhesive is cured by heating to a predetermined temperature for a predetermined time. Manufactured in a procedure.

  Japanese Patent Application Laid-Open No. 4-333818 discloses an optical isolator using a glass material such as a low-melting glass instead of an adhesive. In this optical isolator, a polarizer and a Faraday rotator are fixed to each other with a first glass material at each outer peripheral portion, and the Faraday rotator and an analyzer are fixed to a magnet with a second glass material at each outer peripheral portion. It is configured as follows.

  This optical isolator is prepared in advance as a glass tablet in which the first and second glass materials are formed in a lattice shape, and is a glass tablet between the polarizer and the Faraday rotator and between the Faraday rotator and the analyzer. After aligning so that the glass tablet is inserted into each of the lattice-shaped grooves formed in the polarizer and the analyzer, the optical element is joined by heating the glass material at a predetermined temperature, and then the optical Manufactured by a procedure of cutting an element into individual pieces.

JP 2007-309967 A JP 2005-181760 A JP-A-4-333818

  The optical isolator disclosed in Patent Document 1 is obtained by bonding optical elements together using an optical adhesive and integrating them, and includes a joint surface between a first polarizer and a Faraday rotator, a Faraday rotator and a second one. An adhesive is applied to the bonding surface of the polarizer. Therefore, this optical isolator is not a problem as long as it is used in an optical communication system using light with an output of about several tens of milliwatts, but when used in a communication system using high-power laser light, There is a possibility of deterioration, causing a problem in reliability.

  FIG. 10 is a diagram showing a configuration of a conventional optical isolator disclosed in Patent Document 2. In FIG. This optical isolator 1 is composed of two polarizers 2 between two opposing mounting substrates 4 and one Faraday rotator 3 arranged between these polarizers 2 in total. The optical element is configured by being stacked via the gap 5.

  However, with this configuration, the distance (thickness) in the optical path direction (optical axis direction) of the stacked optical elements increases. In addition, there is a problem that a fixing member for fixing the optical element becomes an obstacle and hinders downsizing of the optical component.

  Also, according to the optical isolator disclosed in Patent Document 3, ideally, no gap is formed between the flat-plate Faraday rotator and the polarizer. However, in practice, it is difficult to fill the lattice-shaped grooves with the low melting point glass without excess or deficiency, no matter how accurately the glass tablet and the grooves are processed. For example, when there is a lot of glass material for the groove, it overflows from the groove and flows out between the flat plate Faraday rotator and the polarizer, resulting in a gap between the flat plate Faraday rotator and the polarizer, On the contrary, when there is little glass material with respect to a groove part, joining shortage will arise.

  Accordingly, the present invention provides an optical component such as a small optical isolator that can be applied to high output light, and a method for manufacturing the same. In addition, an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive and a manufacturing method thereof are provided.

In the first invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a recess connected to the side surface,
The following steps are provided.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) A step of applying curing energy to the adhesive after the step (3) to cure the adhesive.

In the second invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a recess connected to the side surface,
The following steps are provided.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), applying an energy curable adhesive to the side surface and filling the concave portion with the adhesive from the side surface;
(4) After the step (3), placing a flat plate on the side surface;
(5) After the step (4), applying curing energy to the adhesive to cure the adhesive applied to the side surface and the adhesive filled in the recess.

In the third invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and back surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and back surfaces facing the adjacent optical element is provided with a recess connected to the side surface. And
An optical component manufacturing method comprising the following steps.
(1) preparing at least two optical materials from which at least two of the flat optical elements can be taken out, and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) After the step (3), applying curing energy to the adhesive to cure the adhesive;
(5) After the step (4), cutting the optical material to obtain individual optical components.

  According to a fourth invention of the present application, in any one of the first to third inventions, the concave portion is provided in a non-optical path area of the front and rear surfaces.

  According to a fifth invention of the present application, in any one of the first to fourth inventions, the concave portion is composed of at least one groove, and the groove has a width of 0.005 mm to 0.5 mm, a depth of The thickness is 0.001 mm to 0.1 mm.

According to a sixth invention of the present application, in any one of the first to fifth inventions, the adhesive has a viscosity of 10 to 10 ⁵ mPa · s at room temperature.

In a seventh invention of the present application, in any one of the first to sixth inventions, the pressure at which the optical path surface of the at least two flat optical elements is pressed is 10 ⁴ Pa to 10 ^7. It is characterized by Pa.

  According to an eighth invention of the present application, in any one of the first to seventh inventions, an antireflection film is provided on at least one of the flat optical elements.

  The ninth invention of the present application is characterized by an optical isolator manufactured by the manufacturing method of any one of the first to eighth inventions of the present application.

  According to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

It is a figure which shows the structure of one Example of the optical component manufactured by the manufacturing method of this invention. It is a schematic diagram explaining the preparatory process of the optical material containing a flat optical element. It is a figure which shows the optical material manufactured by the preparatory process of FIG. It is process drawing which shows the manufacturing method of the optical component of this invention. It is a figure which shows the relationship between the pressing force at the time of press contact, and the result of having evaluated the press contact state. It is a figure which shows the structure of the other Example of the optical component manufactured by the manufacturing method of this invention. It is a figure which shows the structure of the optical isolator module to which the structure of the optical component of FIG. 1 is applied. It is the figure which contrasted the dimension of the optical component of this invention, and the optical component of a comparative example. It is a figure which shows the other structure of the optical isolator module to which the optical component manufactured by the manufacturing method of this invention is applied. It is a figure which shows the structure of the conventional optical isolator.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on an Example with reference to FIGS. However, the present invention is not limited to these examples.

  FIG. 1 is a cross-sectional view showing the configuration of an embodiment of an optical component manufactured by the manufacturing method of the present invention. FIG. 1 (a) is a plan view of the optical component 10, and FIG. It is AA sectional drawing in a). As shown in FIG. 1, the optical component 10 is configured by laminating a plurality of flat optical elements 12, 14, and 16. When the optical component 10 is an optical isolator, a polarizer (optical element 12), a Faraday rotator (optical element 14), and a polarizer (optical element 16) functioning as an analyzer are stacked in order from the direction in which communication light is transmitted. Configure.

  Each of the optical elements 12, 14, and 16 includes front and rear surfaces 12a, 14a, and 16a provided before and after the optical path direction (arrow B direction in the drawing), and side surfaces 12b and 14b that surround the front and rear surfaces 12a, 14a, and 16a. 16b, and the front and rear surfaces 12a, 14a, 16a have optical path regions 12c, 14c, 16c through which light passes and non-optical path regions 12d, 14d, 16d through which light does not pass.

Here, the optical path area is a region (indicated by a dotted line in the figure) in which the intensity of light is 1 / e ² or more with respect to the maximum intensity e near the center of the light in the Gaussian intensity distribution light. Area).

  A concave portion 19 connected to the side surfaces 12b, 14b, 16b is provided on at least one of the front and rear surfaces 12a, 14a, 16a facing each other of the adjacent optical elements 12, 14, 16. In FIG. 1, the front and rear surfaces 12a and 16a of the optical elements 12 and 16 facing the optical element 14 are provided with recesses 19 connected to the side surfaces 12b and 16b, respectively. The recess 19 is filled with an energy curable adhesive 18 as will be described later. Further, flat plates 20 are provided on both side surfaces of the optical elements 12, 14, and 16, respectively. The flat plate 20 is bonded to both side surfaces of the optical elements 12, 14, 16 by an energy curable adhesive 18, and the optical elements 12, 14, 16 are held on the flat plate 20.

  As described above, the optical component 10 manufactured by the manufacturing method according to the present invention is formed by laminating at least two plate-like optical elements, and each optical element is provided on the front and rear surfaces provided in the front and rear directions in the optical path direction. , And a side surface surrounding the front and rear surfaces, the front and rear surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and rear surfaces facing each other adjacent optical elements, A recess connected to the side surface is provided.

Hereinafter, an embodiment of a manufacturing method according to the present invention for manufacturing the optical component 10 as described above will be described.
A substrate as shown in FIG. 2A is “substrate-like optical material”, a large plate as shown in FIG. 2B is “large plate-like optical material”, and a strip as shown in FIG. 2C. The optical material cut into a shape is referred to as a “strip-shaped optical material”. The strip-shaped optical material is further cut into individual optical elements.

  FIG. 2 is a schematic diagram illustrating a preparation process of an optical material including a flat optical element used in the manufacturing method of the present invention, and FIG. 3 is a strip-shaped optical material manufactured by the preparation process of FIG. FIG. 2A shows a substrate-like optical material such as a polarizer and a Faraday rotator, FIG. 2B shows a large plate-like optical material in which concave portions are formed on the optical material on the substrate, and FIG. It is a figure which shows the cutting process which cut | disconnects a large plate-shaped optical material in strip shape. 3A shows a strip-shaped optical material for a polarizer, and FIG. 3B shows a strip-shaped optical material for a Faraday rotator.

  As shown in FIG. 2 (a), the substrate-like optical materials 312 and 316 are flat plate-shaped glass materials for a polarizer having a square of 11 mm and a thickness of 0.2 mm. The optical materials 312 and 316 are polished to a predetermined flatness. The flatness by polishing is, for example, λ / 2 to λ / 10 (λ = 633 nm).

  As shown in FIG. 2B, the substrate-like optical materials 312 and 316 used for the polarizer are processed into a large plate-like optical material 212 and 216 by processing the concave portions 219 in a lattice shape by a dicing machine. As shown in FIG. 2C, the large plate-shaped optical materials 112 and 116 are cut into strips to form strip-shaped optical materials 112 and 116. A substrate-like optical material 314 for a Faraday rotator is a flat-plate-permanently magnetized latch-type garnet material having a square of 11 mm and a thickness of 0.4 mm. The substrate-like optical material 314 for the Faraday rotator is cut into a strip shape without being processed into a concave portion, and becomes a strip-like optical material 114.

  FIG. 3A shows a plan view (upper) and a side view (lower) of strip-shaped optical materials 112 and 116 for a polarizer, and FIG. 3B shows a Faraday rotator. A plan view (upper stage) and a side view (lower stage) of the strip-shaped optical material 114 for use are shown.

  FIG. 4 is a process diagram showing a method for manufacturing an optical component according to the present invention, and (a) to (i) in the figure are views showing states of optical materials in each manufacturing process. In FIGS. 4A to 4I, a plan view is shown in the upper stage and a side view is shown in the lower stage as needed to facilitate understanding.

As shown in FIG. 4A, the strip-shaped optical materials 112 and 116 for the polarizer and the strip-shaped optical material 114 for the Faraday rotator are placed on the gripper 24 from below as shown in FIG. The material 114 and the optical material 116 are arranged so that the front and rear surfaces are in contact with each other in this order. Next, as shown in FIG. 4B, the gripping tool 25 is stacked on the optical materials 112, 114, and 116 arranged in a stacked manner, and a predetermined pressure (for example, 10 ⁵ Pa) is applied to the gripping tools 24, 25. And the optical materials 112, 114, and 116 are pressed.

  The pressure contact here is to press the front and back surfaces of adjacent optical materials or optical components in contact with each other. In the present invention, even the press contact is not intended to contact at the nanometer level, and the non-contact level (for example, 0.01 mm or less) that does not affect the use of the optical component of the present invention. It does not exclude the presence of ultrathin films such as fine gaps between optical materials and refractive index matching agents. By this pressure contact, it is possible to prevent the adhesive filled in the concave portion from flowing out between the front and back surfaces of the adjacent optical material or optical component.

FIG. 5 is a diagram showing the results of evaluating the pressing force when pressing the optical materials 112, 114, and 116 and the pressing state of the strip-shaped optical material. As shown in FIG. 5, when the pressing force at the time of pressure contact is 10 ³ Pa or less, when applying the adhesive from the side surface and filling the concave portion 119 with the adhesive, a part of the adhesive is removed from the concave portion 119. Since the flow was confirmed to the interface between the front and back surfaces of the adjacent strip-shaped optical material, it cannot be said that the pressure contact state is good. At 2 * 10 ⁷ Pa or higher, the optical materials 112, 114, and 116 are not in a good pressure contact state because fine damage such as cracks and chips occurred. At 10 ⁴ Pa to 10 ⁷ Pa, no adhesive flowed out from the recesses, and no fine damage of the optical material was confirmed, which is considered to be a good pressure contact state.

When the press contact is completed, as shown in FIG. 4C, the adhesive 18 is applied to the side surfaces of the optical materials 112, 114, and 116 that are press contacted. The adhesive 18 is filled in the recess 119 using a capillary phenomenon. In order to fill the recess 119 with the adhesive 18 without excess or deficiency, the adhesive 18 has a viscosity of 10 ² mPa · s to 10 ⁴ mPa · s at normal temperature (23 ± 5 ° C.) (Japanese Industrial Standard JIS K7117). -2 / corresponding international standard ISO 3219). The viscosity of the adhesive used in this example is 250 mPa · s.

  FIG. 4D shows a state where the filling of the adhesive 18 into the recess 119 is completed. In this embodiment, an ultraviolet curable epoxy adhesive is used as the adhesive 18 filling the recess 119. However, an energy curable adhesive that cures with other curing energy (such as thermosetting) may be used. .

  When the filling of the adhesive 18 into the recess 119 is completed, as shown in FIG. 4E, the flat plate 120 is disposed on the side surface of the pressed optical material 112, 114, 116. In order to bond the side surface of the optical material 112, 114, 116 and the flat plate 120, there is an amount of adhesive between the optical material 112, 114, 116 and the flat plate 120 so that the adhesive spreads over the entire flat plate 120. is necessary.

  Thereafter, as shown in FIG. 4 (f), the adhesive 18 is applied to the opposite side surfaces of the pressed optical materials 112, 114, and 116 to dispose the flat plate 120. In the present embodiment, the flat plate 120 is made of borosilicate glass, and the thickness of the adhesive 18 is about 1 to 5 μm. The flat plate 120 may be made of a material that does not transmit ultraviolet rays, such as metal or ceramic.

Thereafter, as shown in FIG. 4G, ultraviolet rays are irradiated from one side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached. The ultraviolet irradiation conditions were 10 mW / cm ² and the irradiation time was 5 minutes. Thereafter, ultraviolet rays are also irradiated from the other side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached (see FIG. 4H). The conditions for ultraviolet irradiation are the same. Thus, the adhesive 18 was hardened by irradiating with ultraviolet rays from both sides for a total of 10 minutes. When the adhesive 18 is a thermosetting type, it is cured at a predetermined temperature for a predetermined time. The predetermined temperature is not necessarily high, and may be room temperature or lower.

  Thereafter, as shown in a plan view (i1) of FIG. 4 (i), each optical component is cut to obtain the optical component 10 of FIG. Referring to the side view (i2) of FIG. 4 (i), the cutting line 21 is slightly inclined. The inclination angle is 6 to 8 degrees from the vertical direction. This inclination is adapted to the inclination of the ferrule to which the optical component is attached.

In the optical component 10, flat plates 20 are bonded to both sides of the optical elements 12, 14, 16 by an adhesive 18.
One side of the front and rear surfaces of the optical elements 12, 14, 16 (see 12a, 14a, 16a in FIG. 1) is preferably less than 1 mm. In this embodiment, the length of one side of the front and rear surfaces is about 0.7 mm.
The width of the recess 19 is preferably in the range of 0.005 mm to 0.2 mm and the depth is in the range of 0.005 mm to 0.05 mm. In this embodiment, the width of the recess 19 is 0.05 mm and the depth is 0. .02 mm.
Moreover, the recessed part 19 can be made into various shapes, The cross-sectional shape may be U-shape, U-shape, arc shape, etc.

  6A and 6B are diagrams showing the configuration of another embodiment of the optical component of the present invention. FIG. 6A is a plan view of the optical component 100, and FIG. The optical component 100 of FIG. 6 has a flat plate 20 disposed on all four side surfaces of the optical elements 12, 14, and 16.

An energy curable adhesive is applied between each side surface of the optical elements 12, 14, and 16 where the flat plate 20 is not provided and the flat plate 20, and then the applied adhesive is cured by applying curing energy. Thereby, the optical elements 10, 12, and 14 are held by the flat plate 20 on the four side surfaces. For the flat plate 20, for example, a glass plate is used. In addition, the dimension described in the drawing is an example, and the corresponding part of the optical component 10 in FIG. 1 may have the same dimension.
In addition, unlike the configurations of FIGS. 1 and 6, a configuration in which the flat plate 20 is not provided on all four side surfaces may be employed.

  FIG. 7 is a diagram showing the structure of the optical isolator module of the present invention. 7A is a top view of the optical isolator module 40, and FIG. 7B is a cross-sectional view of the optical isolator module 40 taken along the line DD. In this optical isolator module 40, an optical isolator 30 having the same configuration as that shown in FIG. 1 is bonded on an ferrule 44 via a glass spacer 42 with an adhesive.

  The ferrule 44 holds and protects the optical fiber 45 and is made of zirconia or the like having sufficient mechanical strength. Laser light passing through the optical fiber 45 enters the optical isolator 30 as indicated by an arrow B in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line 46. The beam diameter of the traveling laser light gradually increases according to the traveling distance as shown in the figure.

  As shown in FIG. 7B, the optical isolator 30 includes a polarizing glass 32, a Faraday rotator 34, and a polarizing glass 36.

  The polarizing glasses 32 and 36 and the Faraday rotator 34 have front and rear surfaces provided in the front and rear direction of the optical path and side surfaces surrounding the front and rear surfaces, as described in FIG. 1, and light passes through the front and rear surfaces. A concave portion 39 connected to the side surface is provided on at least one of the front and rear surfaces of the adjacent optical elements that have an optical path region and a non-optical path region through which light does not pass.

  The polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are arranged in a predetermined order, and after being pressed against each other, the concave portion 39 is filled with an energy curable adhesive 18, and a curing energy is applied to the adhesive 18 for bonding. Bonding is performed by curing the agent 18. Further, the polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are held by a flat plate 20 made of a glass material fixed to both side surfaces by an energy curable adhesive 18.

  FIG. 8 is a diagram comparing the dimensions of the optical component of the present invention and the optical component of the comparative example. (A) shows the structure of the optical isolator module shown in FIG. 7, (b) is an optical isolator module using the optical isolator of patent document 2 as a comparative example.

  8A and 8B, the thicknesses of the polarizing glasses 12 and 16 and the Faraday rotator 14 are compared as the same dimensions. The optical isolator is bonded to the end face of the ferrule 44 that holds the optical fiber 45. Laser light is incident on the optical isolator from the end of the optical fiber 45 and travels in the optical isolator as indicated by a dotted line 46 while being refracted in accordance with the refractive indexes of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16. The beam diameter of the laser light gradually increases according to the travel distance as shown in the figure.

  In the optical isolator module of the present invention shown in FIG. 8A, the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 are in pressure contact with the front and back surfaces adjacent to each other, and the traveling direction of the laser light The length L1 is 1 mm. Considering the beam diameter of the laser beam that expands while traveling this length L1 (1 mm), the width x1 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 0.7 mm.

  On the other hand, in the comparative example shown in FIG. 8B, there are gaps among the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16, respectively, and the optical isolator module of the present invention shown in FIG. In contrast, the length L2 in the traveling direction of the laser light is 1.4 mm. In consideration of the beam diameter of the laser light that expands while traveling this length, the width x2 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 1.0 mm.

  Accordingly, when the dimensional ratio of the optical isolator of the present invention and the optical isolator of the comparative example is converted into a volume ratio, 0.7 * 0.7 * 1.0 / (1.0 * 1.0 * 1.4) = 0. The volume of the optical component of the present invention is about 1/3 that of the optical component of the comparative example, and it can be seen that the optical component (optical isolator) can be downsized.

FIG. 9 is a diagram showing an example of the structure of a polarization-independent optical isolator module. 9A is a top view of the optical isolator 50, and FIG. 9B is a cross-sectional view of the optical isolator module 60 taken along line E-E. In this optical isolator module 60, a polarization-independent optical isolator 50 is bonded on a ferrule 63 via a glass spacer 70 with an adhesive.

  Laser light emitted from one optical fiber 61 enters the optical isolator 50 as indicated by an arrow C in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line. The light emitted from the optical isolator 50 is collimated by the lens 64 and reflected by the mirror 65, passes through the lens 64 again, enters the optical isolator 50, travels, and enters the other optical fiber 62.

  As shown in FIG. 9, the optical isolator module 60 includes a flat plate birefringent crystal 52 functioning as a polarizer, two half-wave plates 57 and 58 having a function of rotating the polarization direction, and permanent magnetized. A Faraday rotator 54 made of a latch-type garnet crystal and a birefringent crystal 56 functioning as a polarizer are stacked and pressed together. Each optical element of the birefringent crystal 52, the Faraday rotator 54, the half-wave plates 57 and 58, and the birefringent crystal 56 has, for example, a predetermined size in a lattice shape from a flat plate of 11 mm in length and width as described above. The one cut into two is used as one optical element. A YVO4 is used as the birefringent crystal, and a quartz plate or the like is used as the half-wave plate.

  The birefringent crystals 52 and 56 and the Faraday rotator 54 have front and rear surfaces provided in the front and rear direction of the optical path, and side surfaces surrounding the front and rear surfaces, and the front and rear surfaces have an optical path region through which light passes and light does not pass. The front and rear surfaces of the birefringent crystal 52 facing the half-wave plates 57 and 58, the front and rear surfaces of the Faraday rotator facing the half-wave plates 57 and 58, and the birefringent crystal 56. Concave portions 51 connected to the side surfaces are provided on the front and rear surfaces facing the Faraday rotator 54.

  The birefringent crystal 52, the half-wave plates 57 and 58, the Faraday rotator 54, and the birefringent crystal 56 are arranged in a predetermined order, and after being pressed, the recess 51 is filled with the energy curable adhesive 18. Bonding is performed by applying curing energy to the adhesive 18 and curing the adhesive 18. In addition, the birefringent crystal 52, the Faraday rotator 54, and the birefringent crystal 56 are glass materials fixed to the both side surfaces thereof, and the half-wave plates 57 and 58 are fixed to the one side surfaces thereof by the energy curable adhesive 18. It is hold | maintained by the flat plate 59 which consists of.

  The above description describes an example in which a large plate optical material is cut into a strip-shaped optical material, then bonded by pressure welding, adhesive filling, and adhesive curing, and finally cut into individual optical elements. However, the present invention is not limited to this. The manufacturing method according to the present invention can be applied to any state of the optical material of the large plate, the state of the strip-shaped optical material, and the state of the individual optical element.

  Further, the width of the optical material to be cut into strips may be cut so as to include one row of individual optical elements, or may be cut to include a plurality of rows of individual optical elements. Even in such a case, other appropriate processes may be added between the processes of pressure contact of the basic optical element, filling of the adhesive, and curing of the adhesive.

  As described above, according to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

  The above-described embodiment is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

10, 100 ... optical components 12, 14, 16 ... optical elements 112, 114, 116 ... strip-shaped optical material 212, 216 ... large plate-shaped optical material 312, 314, 316,. The substrate-like optical materials 12a, 14a, 16a ... the front and back surfaces 112a, 114a, 116a in the optical element ... the front and back surfaces 12b, 14b, 16b in the strip-like optical material ... the side surfaces 112b, 114b, 116b .. Side surfaces 12c, 14c, 16c in the strip-shaped optical material. Optical path regions 12d, 14d, 16d ... Non-optical path region 18 ... Adhesive 19 ... Concave portion 119 in the optical element ... Strip shape Recessed portion 219 in the optical material of the plate 20: Recessed portion 20 in the large plate-shaped optical material ... Flat plate 120 arranged on the side surface of the optical element ... Arranged on the side surface of the strip-shaped optical material Flat plate 21... Cutting line 23... 24, 25... Gripping tool 30... Polarization-dependent optical isolator 32. ... Recess 40 ... Polarization-dependent optical isolator module 45 ... Optical fiber 46 ... Dotted line 50 indicating laser light ... Polarization-independent optical isolator 51 ... Recess 52 ... Birefringence Crystal 54 ... Faraday rotator 56 ... Birefringent crystal 57 ... Half-wave plate 58 ... Half-wave plate 59 ... Flat plate 60 ... Polarization-independent optical isolator module 61 ... Optical fiber 62 ... Optical fiber 63 ... Ferrule 64 ... Lens 65 ... Mirror 70 ... Glass spacer

  The present invention relates to a method for manufacturing an optical component used in an optical communication device or the like, and an optical component.

  In general, optical components and optical modules used for optical communication include optical connectors, optical isolators, LD (Laser diode) modules for transmitting optical signals, and PD (Photo diode) modules for receiving optical signals. It has been known.

  An optical isolator is a component used in an optical communication system to prevent return light of an optical fiber. The returning light can be caused by the traveling light being inconsistent in refractive index between the materials in contact with each other, fiber misalignment or mode mismatching. The return light causes a decrease in system performance and adversely affects a transmission source such as a laser beam.

  In the polarization-dependent optical isolator, a polarizer such as a polarizing glass sheet is used to sandwich the Faraday rotator. Light travels through the first polarizer, then through the Faraday rotator, and then through the second polarizer. The isolator is disposed between the optical fiber and the lens or between the two lenses.

  The signal light emitted from the light source passes through the first polarizer. Next, the polarization of the light that has passed through the first polarizer is rotated 45 ° by the Faraday rotator, and then passes through the second polarizer whose polarization direction is shifted by 45 ° with respect to the first polarizer. Come out. In the case of the reverse direction, the return light is polarized by the second polarizer and then rotated 45 ° in the same direction by the Faraday rotator to become polarized light that is shifted by 90 ° with respect to the first polarizer. Thus, no signal is returned to the light source.

  In contrast to the polarization-dependent isolator, a polarization-independent optical isolator is also known. The polarization-independent isolator can be a wedge or flat birefringent material, or a prism with a thin film coating, and has a Faraday rotator sandwiched between two beam splitters.

  A Faraday rotator is typically made by surrounding a piece of garnet with a magnet so that a magnetic field is applied to optically activate the crystal. This type of garnet is referred to as a non-latching type. Another type of Faraday rotator is permanently magnetized and does not require an external magnetic field. This type of garnet is called a latch type.

  The various components of both polarization-dependent and polarization-independent optical isolators are generally joined by mechanical assemblies or by polymeric adhesives. As another alternative method, there is also known a method in which large material sheets are collectively assembled with an adhesive, that is, laminated.

  An optical component such as an optical isolator is configured by combining optical elements such as a Faraday rotator and a polarizer as described above. A fixing member or an adhesive is used for fixing the optical element. For example, Japanese Unexamined Patent Application Publication No. 2007-309967 discloses an optical isolator in which optical elements are bonded together using an optical adhesive and integrated. The optical adhesive is applied with a uniform thickness over the entire surface including the surface of the light passage portion of the optical element.

  In this optical isolator, a first polarizer having an antireflection film formed on a predetermined surface, a second polarizer, and a Faraday rotator having antireflection films formed on both surfaces are prepared. Apply the adhesive to the Faraday rotator side surface and the Faraday rotator side surface of the polarizer 2 and align the polarization surfaces of the first and second polarizers appropriately. It is manufactured by a procedure in which a predetermined pressure is applied and a block composed of three combined optical elements is heated to a predetermined temperature for a predetermined time to thermally cure the adhesive.

  As the optical adhesive, a thermosetting adhesive or an ultraviolet curable adhesive that has a low shrinkage at the time of adhesive curing and is less affected by heat and has high stability is used.

  The optical isolator as described above is an optical isolator conventionally used, and is usually used in many optical communication systems using light having an output of about several tens of milliwatts.

  On the other hand, in an optical communication system using an optical amplifier or the like, high-power laser light of about several hundred milliwatts is used. When an optical isolator having an optical adhesive on the optical path surface is used in an optical communication system using high-power laser light, there is a possibility that the adhesive may be altered, resulting in a problem in reliability.

  On the other hand, Japanese Patent Application Laid-Open No. 2005-181760 discloses an optical isolator having no adhesive on the optical path surface. This optical isolator has a structure in which a plate-shaped polarizer and a plate-shaped Faraday rotator are arranged and both ends thereof are held by a pair of substrates, and a groove-shaped recess is formed on each of two opposing mounting substrates. An optical isolator is disclosed which is formed and held with an adhesive while holding the ends of a polarizer and a Faraday rotator in a recess.

  This optical isolator prepares two substrates for holding a first polarizer, a Faraday rotator, and a second polarizer, and forms a recess on the opposing surfaces of the two substrates and applies an adhesive. The both ends of the first polarizer, the Faraday rotator, and the second polarizer are sandwiched between the recesses of the two substrates, and the adhesive is cured by heating to a predetermined temperature for a predetermined time. Manufactured in a procedure.

  Japanese Patent Application Laid-Open No. 4-333818 discloses an optical isolator using a glass material such as a low-melting glass instead of an adhesive. In this optical isolator, a polarizer and a Faraday rotator are fixed to each other with a first glass material at each outer peripheral portion, and the Faraday rotator and an analyzer are fixed to a magnet with a second glass material at each outer peripheral portion. It is configured as follows.

  This optical isolator is prepared in advance as a glass tablet in which the first and second glass materials are formed in a lattice shape, and is a glass tablet between the polarizer and the Faraday rotator and between the Faraday rotator and the analyzer. After aligning so that the glass tablet is inserted into each of the lattice-shaped grooves formed in the polarizer and the analyzer, the optical element is joined by heating the glass material at a predetermined temperature, and then the optical Manufactured by a procedure of cutting an element into individual pieces.

JP 2007-309967 A JP 2005-181760 A JP-A-4-333818

  The optical isolator disclosed in Patent Document 1 is obtained by bonding optical elements together using an optical adhesive and integrating them, and includes a joint surface between a first polarizer and a Faraday rotator, a Faraday rotator and a second one. An adhesive is applied to the bonding surface of the polarizer. Therefore, this optical isolator is not a problem as long as it is used in an optical communication system using light with an output of about several tens of milliwatts, but when used in a communication system using high-power laser light, There is a possibility of deterioration, causing a problem in reliability.

  FIG. 10 is a diagram showing a configuration of a conventional optical isolator disclosed in Patent Document 2. In FIG. This optical isolator 1 is composed of two polarizers 2 between two opposing mounting substrates 4 and one Faraday rotator 3 arranged between these polarizers 2 in total. The optical element is configured by being stacked via the gap 5.

  However, with this configuration, the distance (thickness) in the optical path direction (optical axis direction) of the stacked optical elements increases. In addition, there is a problem that a fixing member for fixing the optical element becomes an obstacle and hinders downsizing of the optical component.

  Also, according to the optical isolator disclosed in Patent Document 3, ideally, no gap is formed between the flat-plate Faraday rotator and the polarizer. However, in practice, it is difficult to fill the lattice-shaped grooves with the low melting point glass without excess or deficiency, no matter how accurately the glass tablet and the grooves are processed. For example, if there is a lot of glass material for the groove, it overflows from the groove and flows out between the flat plate Faraday rotator and the polarizer, resulting in a gap between the flat plate Faraday rotator and the polarizer, On the contrary, when there is little glass material with respect to a groove part, joining shortage will arise.

  Accordingly, the present invention provides an optical component such as a small optical isolator that can be applied to high output light, and a method for manufacturing the same. In addition, an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive and a manufacturing method thereof are provided.

In the first invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a recess connected to the side surface,
The following steps are provided.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) A step of applying curing energy to the adhesive after the step (3) to cure the adhesive.

In the second invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a recess connected to the side surface,
The following steps are provided.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), applying an energy curable adhesive to the side surface and filling the concave portion with the adhesive from the side surface;
(4) After the step (3), placing a flat plate on the side surface;
(5) After the step (4), applying curing energy to the adhesive to cure the adhesive applied to the side surface and the adhesive filled in the recess.

In the third invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and back surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and back surfaces facing the adjacent optical element is provided with a recess connected to the side surface. And
An optical component manufacturing method comprising the following steps.
(1) preparing at least two optical materials from which at least two of the flat optical elements can be taken out, and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) After the step (3), applying curing energy to the adhesive to cure the adhesive;
(5) After the step (4), cutting the optical material to obtain individual optical components.

  According to a fourth invention of the present application, in any one of the first to third inventions, the concave portion is provided in a non-optical path area of the front and rear surfaces.

  According to a fifth invention of the present application, in any one of the first to fourth inventions, the concave portion is composed of at least one groove, and the groove has a width of 0.005 mm to 0.5 mm, a depth of The thickness is 0.001 mm to 0.1 mm.

According to a sixth invention of the present application, in any one of the first to fifth inventions, the adhesive has a viscosity of 10 to 10 ⁵ mPa · s at room temperature.

In a seventh invention of the present application, in any one of the first to sixth inventions, the pressure at which the optical path surfaces of the at least two flat optical elements are in pressure contact is 10 ⁴ Pa to 10 ^8. It is characterized by Pa .

  According to an eighth invention of the present application, in any one of the first to seventh inventions, an antireflection film is provided on at least one of the flat optical elements.

  The ninth invention of the present application is characterized by an optical isolator manufactured by the manufacturing method of any one of the first to eighth inventions of the present application.

  According to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

It is a figure which shows the structure of one Example of the optical component manufactured by the manufacturing method of this invention. It is a schematic diagram explaining the preparatory process of the optical material containing a flat optical element. It is a figure which shows the optical material manufactured by the preparatory process of FIG. It is process drawing which shows the manufacturing method of the optical component of this invention. It is a figure which shows the relationship between the pressing force at the time of press contact, and the result of having evaluated the press contact state. It is a figure which shows the structure of the other Example of the optical component manufactured by the manufacturing method of this invention. It is a figure which shows the structure of the optical isolator module to which the structure of the optical component of FIG. 1 is applied. It is the figure which contrasted the dimension of the optical component of this invention, and the optical component of a comparative example. It is a figure which shows the other structure of the optical isolator module to which the optical component manufactured by the manufacturing method of this invention is applied. It is a figure which shows the structure of the conventional optical isolator.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on an Example with reference to FIGS. However, the present invention is not limited to these examples.

  FIG. 1 is a cross-sectional view showing the configuration of an embodiment of an optical component manufactured by the manufacturing method of the present invention. FIG. 1 (a) is a plan view of the optical component 10, and FIG. It is AA sectional drawing in a). As shown in FIG. 1, the optical component 10 is configured by laminating a plurality of flat optical elements 12, 14, and 16. When the optical component 10 is an optical isolator, a polarizer (optical element 12), a Faraday rotator (optical element 14), and a polarizer (optical element 16) functioning as an analyzer are stacked in order from the direction in which communication light is transmitted. Configure.

  Each of the optical elements 12, 14, and 16 includes front and rear surfaces 12a, 14a, and 16a provided before and after the optical path direction (arrow B direction in the drawing), and side surfaces 12b and 14b that surround the front and rear surfaces 12a, 14a, and 16a. 16b, and the front and rear surfaces 12a, 14a, 16a have optical path regions 12c, 14c, 16c through which light passes and non-optical path regions 12d, 14d, 16d through which light does not pass.

Here, the optical path area is a region (indicated by a dotted line in the figure) in which the intensity of light is 1 / e ² or more with respect to the maximum intensity e near the center of the light in the Gaussian intensity distribution light. Area).

  A concave portion 19 connected to the side surfaces 12b, 14b, 16b is provided on at least one of the front and rear surfaces 12a, 14a, 16a facing each other of the adjacent optical elements 12, 14, 16. In FIG. 1, the front and rear surfaces 12a and 16a of the optical elements 12 and 16 facing the optical element 14 are provided with recesses 19 connected to the side surfaces 12b and 16b, respectively. The recess 19 is filled with an energy curable adhesive 18 as will be described later. Further, flat plates 20 are provided on both side surfaces of the optical elements 12, 14, and 16, respectively. The flat plate 20 is bonded to both side surfaces of the optical elements 12, 14, 16 by an energy curable adhesive 18, and the optical elements 12, 14, 16 are held on the flat plate 20.

  As described above, the optical component 10 manufactured by the manufacturing method according to the present invention is formed by laminating at least two plate-like optical elements, and each optical element is provided on the front and rear surfaces provided in the front and rear directions in the optical path direction. , And a side surface surrounding the front and rear surfaces, the front and rear surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and rear surfaces facing each other adjacent optical elements, A recess connected to the side surface is provided.

Hereinafter, an embodiment of a manufacturing method according to the present invention for manufacturing the optical component 10 as described above will be described.
A substrate as shown in FIG. 2A is “substrate-like optical material”, a large plate as shown in FIG. 2B is “large plate-like optical material”, and a strip as shown in FIG. 2C. The optical material cut into a shape is referred to as a “strip-shaped optical material”. The strip-shaped optical material is further cut into individual optical elements.

  FIG. 2 is a schematic diagram illustrating a preparation process of an optical material including a flat optical element used in the manufacturing method of the present invention, and FIG. 3 is a strip-shaped optical material manufactured by the preparation process of FIG. FIG. 2A shows a substrate-like optical material such as a polarizer and a Faraday rotator, FIG. 2B shows a large plate-like optical material in which concave portions are formed on the optical material on the substrate, and FIG. It is a figure which shows the cutting process which cut | disconnects a large plate-shaped optical material in strip shape. 3A shows a strip-shaped optical material for a polarizer, and FIG. 3B shows a strip-shaped optical material for a Faraday rotator.

  As shown in FIG. 2 (a), the substrate-like optical materials 312 and 316 are flat plate-shaped glass materials for a polarizer having a square of 11 mm and a thickness of 0.2 mm. The optical materials 312 and 316 are polished to a predetermined flatness. The flatness by polishing is, for example, λ / 2 to λ / 10 (λ = 633 nm).

  As shown in FIG. 2B, the substrate-like optical materials 312 and 316 used for the polarizer are processed into a large plate-like optical material 212 and 216 by processing the concave portions 219 in a lattice shape by a dicing machine. As shown in FIG. 2C, the large plate-shaped optical materials 112 and 116 are cut into strips to form strip-shaped optical materials 112 and 116. A substrate-like optical material 314 for a Faraday rotator is a flat-plate-permanently magnetized latch-type garnet material having a square of 11 mm and a thickness of 0.4 mm. The substrate-like optical material 314 for the Faraday rotator is cut into a strip shape without being processed into a concave portion, and becomes a strip-like optical material 114.

  FIG. 3A shows a plan view (upper) and a side view (lower) of strip-shaped optical materials 112 and 116 for a polarizer, and FIG. 3B shows a Faraday rotator. A plan view (upper stage) and a side view (lower stage) of the strip-shaped optical material 114 for use are shown.

  FIG. 4 is a process diagram showing a method for manufacturing an optical component according to the present invention, and (a) to (i) in the figure are views showing states of optical materials in each manufacturing process. In FIGS. 4A to 4I, a plan view is shown in the upper stage and a side view is shown in the lower stage as needed to facilitate understanding.

As shown in FIG. 4A, the strip-shaped optical materials 112 and 116 for the polarizer and the strip-shaped optical material 114 for the Faraday rotator are placed on the gripper 24 from below as shown in FIG. The material 114 and the optical material 116 are arranged so that the front and rear surfaces are in contact with each other in this order. Next, as shown in FIG. 4B, the gripping tool 25 is stacked on the optical materials 112, 114, and 116 arranged in a stacked manner, and a predetermined pressure (for example, 10 ⁵ Pa) is applied to the gripping tools 24, 25. And the optical materials 112, 114, and 116 are pressed.

  The pressure contact here is to press the front and back surfaces of adjacent optical materials or optical components in contact with each other. In the present invention, even the press contact is not intended to contact at the nanometer level, and the non-contact level (for example, 0.01 mm or less) that does not affect the use of the optical component of the present invention. It does not exclude the presence of ultrathin films such as fine gaps between optical materials and refractive index matching agents. By this pressure contact, it is possible to prevent the adhesive filled in the concave portion from flowing out between the front and back surfaces of the adjacent optical material or optical component.

FIG. 5 is a diagram showing the results of evaluating the pressing force when pressing the optical materials 112, 114, and 116 and the pressing state of the strip-shaped optical material. As shown in FIG. 5, when the pressing force at the time of pressure contact is 10 ³ Pa or less, when applying the adhesive from the side surface and filling the concave portion 119 with the adhesive, a part of the adhesive is removed from the concave portion 119. Since the flow was confirmed to the interface between the front and back surfaces of the adjacent strip-shaped optical material, it cannot be said that the pressure contact state is good. When the pressure is 2 * 10 ⁸ Pa or more, the optical materials 112, 114, and 116 are slightly damaged such as cracks and chips, and thus cannot be said to be in a good pressure contact state. From 10 ⁴ Pa to 10 ⁸ Pa , the adhesive did not flow out from the recesses, and fine damage to the optical material was not confirmed.

When the press contact is completed, as shown in FIG. 4C, the adhesive 18 is applied to the side surfaces of the optical materials 112, 114, and 116 that are press contacted. The adhesive 18 is filled in the recess 119 using a capillary phenomenon. In order to fill the recess 119 with the adhesive 18 without excess or deficiency, the adhesive 18 has a viscosity of 10 ² mPa · s to 10 ⁴ mPa · s at normal temperature (23 ± 5 ° C.) (Japanese Industrial Standard JIS K7117). -2 / corresponding international standard ISO 3219). The viscosity of the adhesive used in this example is 250 mPa · s.

  FIG. 4D shows a state where the filling of the adhesive 18 into the recess 119 is completed. In this embodiment, an ultraviolet curable epoxy adhesive is used as the adhesive 18 filling the recess 119. However, an energy curable adhesive that cures with other curing energy (such as thermosetting) may be used. .

  When the filling of the adhesive 18 into the recess 119 is completed, as shown in FIG. 4E, the flat plate 120 is disposed on the side surface of the pressed optical material 112, 114, 116. In order to bond the side surface of the optical material 112, 114, 116 and the flat plate 120, there is an amount of adhesive between the optical material 112, 114, 116 and the flat plate 120 so that the adhesive spreads over the entire flat plate 120. is necessary.

  Thereafter, as shown in FIG. 4 (f), the adhesive 18 is applied to the opposite side surfaces of the pressed optical materials 112, 114, and 116 to dispose the flat plate 120. In the present embodiment, the flat plate 120 is made of borosilicate glass, and the thickness of the adhesive 18 is about 1 to 5 μm. The flat plate 120 may be made of a material that does not transmit ultraviolet rays, such as metal or ceramic.

Thereafter, as shown in FIG. 4G, ultraviolet rays are irradiated from one side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached. The ultraviolet irradiation conditions were 10 mW / cm ² and the irradiation time was 5 minutes. Thereafter, ultraviolet rays are also irradiated from the other side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached (see FIG. 4H). The conditions for ultraviolet irradiation are the same. Thus, the adhesive 18 was hardened by irradiating with ultraviolet rays from both sides for a total of 10 minutes. When the adhesive 18 is a thermosetting type, it is cured at a predetermined temperature for a predetermined time. The predetermined temperature is not necessarily high, and may be room temperature or lower.

  Thereafter, as shown in a plan view (i1) of FIG. 4 (i), each optical component is cut to obtain the optical component 10 of FIG. Referring to the side view (i2) of FIG. 4 (i), the cutting line 21 is slightly inclined. The inclination angle is 6 to 8 degrees from the vertical direction. This inclination is adapted to the inclination of the ferrule to which the optical component is attached.

In the optical component 10, flat plates 20 are bonded to both sides of the optical elements 12, 14, 16 by an adhesive 18.
One side of the front and rear surfaces of the optical elements 12, 14, 16 (see 12a, 14a, 16a in FIG. 1) is preferably less than 1 mm. In this embodiment, the length of one side of the front and rear surfaces is about 0.7 mm.
The width of the recess 19 is preferably in the range of 0.005 mm to 0.2 mm and the depth is in the range of 0.005 mm to 0.05 mm. In this embodiment, the width of the recess 19 is 0.05 mm and the depth is 0. .02 mm.
Moreover, the recessed part 19 can be made into various shapes, The cross-sectional shape may be U-shape, U-shape, arc shape, etc.

  6A and 6B are diagrams showing the configuration of another embodiment of the optical component of the present invention. FIG. 6A is a plan view of the optical component 100, and FIG. The optical component 100 of FIG. 6 has a flat plate 20 disposed on all four side surfaces of the optical elements 12, 14, and 16.

An energy curable adhesive is applied between each side surface of the optical elements 12, 14, and 16 where the flat plate 20 is not provided and the flat plate 20, and then the applied adhesive is cured by applying curing energy. Thereby, the optical elements 10, 12, and 14 are held by the flat plate 20 on the four side surfaces. For the flat plate 20, for example, a glass plate is used. In addition, the dimension described in the drawing is an example, and the corresponding part of the optical component 10 in FIG. 1 may have the same dimension.
In addition, unlike the configurations of FIGS. 1 and 6, a configuration in which the flat plate 20 is not provided on all four side surfaces may be employed.

  FIG. 7 is a diagram showing the structure of the optical isolator module of the present invention. 7A is a top view of the optical isolator module 40, and FIG. 7B is a cross-sectional view of the optical isolator module 40 taken along the line DD. In this optical isolator module 40, an optical isolator 30 having the same configuration as that shown in FIG. 1 is bonded on an ferrule 44 via a glass spacer 42 with an adhesive.

  The ferrule 44 holds and protects the optical fiber 45 and is made of zirconia or the like having sufficient mechanical strength. Laser light passing through the optical fiber 45 enters the optical isolator 30 as indicated by an arrow B in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line 46. The beam diameter of the traveling laser light gradually increases according to the traveling distance as shown in the figure.

  As shown in FIG. 7B, the optical isolator 30 includes a polarizing glass 32, a Faraday rotator 34, and a polarizing glass 36.

  The polarizing glasses 32 and 36 and the Faraday rotator 34 have front and rear surfaces provided in the front and rear direction of the optical path and side surfaces surrounding the front and rear surfaces, as described in FIG. 1, and light passes through the front and rear surfaces. A concave portion 39 connected to the side surface is provided on at least one of the front and rear surfaces of the adjacent optical elements that have an optical path region and a non-optical path region through which light does not pass.

  The polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are arranged in a predetermined order, and after being pressed against each other, the concave portion 39 is filled with an energy curable adhesive 18, and a curing energy is applied to the adhesive 18 for bonding. Bonding is performed by curing the agent 18. Further, the polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are held by a flat plate 20 made of a glass material fixed to both side surfaces by an energy curable adhesive 18.

  FIG. 8 is a diagram comparing the dimensions of the optical component of the present invention and the optical component of the comparative example. (A) shows the structure of the optical isolator module shown in FIG. 7, (b) is an optical isolator module using the optical isolator of patent document 2 as a comparative example.

  8A and 8B, the thicknesses of the polarizing glasses 12 and 16 and the Faraday rotator 14 are compared as the same dimensions. The optical isolator is bonded to the end face of the ferrule 44 that holds the optical fiber 45. Laser light is incident on the optical isolator from the end of the optical fiber 45 and travels in the optical isolator as indicated by a dotted line 46 while being refracted in accordance with the refractive indexes of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16. The beam diameter of the laser light gradually increases according to the travel distance as shown in the figure.

  In the optical isolator module of the present invention shown in FIG. 8A, the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 are in pressure contact with the front and back surfaces adjacent to each other, and the traveling direction of the laser light The length L1 is 1 mm. Considering the beam diameter of the laser beam that expands while traveling this length L1 (1 mm), the width x1 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 0.7 mm.

  On the other hand, in the comparative example shown in FIG. 8B, there are gaps among the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16, respectively, and the optical isolator module of the present invention shown in FIG. In contrast, the length L2 in the traveling direction of the laser light is 1.4 mm. In consideration of the beam diameter of the laser light that expands while traveling this length, the width x2 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 1.0 mm.

  Accordingly, when the dimensional ratio of the optical isolator of the present invention and the optical isolator of the comparative example is converted into a volume ratio, 0.7 * 0.7 * 1.0 / (1.0 * 1.0 * 1.4) = 0. The volume of the optical component of the present invention is about 1/3 that of the optical component of the comparative example, and it can be seen that the optical component (optical isolator) can be downsized.

FIG. 9 is a diagram showing an example of the structure of a polarization-independent optical isolator module. 9A is a top view of the optical isolator 50, and FIG. 9B is a cross-sectional view of the optical isolator module 60 taken along line E-E. In this optical isolator module 60, a polarization-independent optical isolator 50 is bonded on a ferrule 63 via a glass spacer 70 with an adhesive.

  Laser light emitted from one optical fiber 61 enters the optical isolator 50 as indicated by an arrow C in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line. The light emitted from the optical isolator 50 is collimated by the lens 64 and reflected by the mirror 65, passes through the lens 64 again, enters the optical isolator 50, travels, and enters the other optical fiber 62.

  As shown in FIG. 9, the optical isolator module 60 includes a flat plate birefringent crystal 52 functioning as a polarizer, two half-wave plates 57 and 58 having a function of rotating the polarization direction, and permanent magnetized. A Faraday rotator 54 made of a latch-type garnet crystal and a birefringent crystal 56 functioning as a polarizer are stacked and pressed together. Each optical element of the birefringent crystal 52, the Faraday rotator 54, the half-wave plates 57 and 58, and the birefringent crystal 56 has, for example, a predetermined size in a lattice shape from a flat plate of 11 mm in length and width as described above. The one cut into two is used as one optical element. A YVO4 is used as the birefringent crystal, and a quartz plate or the like is used as the half-wave plate.

  The birefringent crystals 52 and 56 and the Faraday rotator 54 have front and rear surfaces provided in the front and rear direction of the optical path, and side surfaces surrounding the front and rear surfaces, and the front and rear surfaces have an optical path region through which light passes and light does not pass. The front and rear surfaces of the birefringent crystal 52 facing the half-wave plates 57 and 58, the front and rear surfaces of the Faraday rotator facing the half-wave plates 57 and 58, and the birefringent crystal 56. Concave portions 51 connected to the side surfaces are provided on the front and rear surfaces facing the Faraday rotator 54.

  The birefringent crystal 52, the half-wave plates 57 and 58, the Faraday rotator 54, and the birefringent crystal 56 are arranged in a predetermined order, and after being pressed, the recess 51 is filled with the energy curable adhesive 18. Bonding is performed by applying curing energy to the adhesive 18 and curing the adhesive 18. In addition, the birefringent crystal 52, the Faraday rotator 54, and the birefringent crystal 56 are glass materials fixed to the both side surfaces thereof, and the half-wave plates 57 and 58 are fixed to the one side surfaces thereof by the energy curable adhesive 18. It is hold | maintained by the flat plate 59 which consists of.

  The above description describes an example in which a large plate optical material is cut into a strip-shaped optical material, then bonded by pressure welding, adhesive filling, and adhesive curing, and finally cut into individual optical elements. However, the present invention is not limited to this. The manufacturing method according to the present invention can be applied to any state of the optical material of the large plate, the state of the strip-shaped optical material, and the state of the individual optical element.

  Further, the width of the optical material to be cut into strips may be cut so as to include one row of individual optical elements, or may be cut to include a plurality of rows of individual optical elements. Even in such a case, other appropriate processes may be added between the processes of pressure contact of the basic optical element, filling of the adhesive, and curing of the adhesive.

  As described above, according to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

  The above-described embodiment is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

10, 100 ... optical components 12, 14, 16 ... optical elements 112, 114, 116 ... strip-shaped optical material 212, 216 ... large plate-shaped optical material 312, 314, 316,. The substrate-like optical materials 12a, 14a, 16a ... the front and back surfaces 112a, 114a, 116a in the optical element ... the front and back surfaces 12b, 14b, 16b in the strip-like optical material ... the side surfaces 112b, 114b, 116b .. Side surfaces 12c, 14c, 16c in the strip-shaped optical material. Optical path regions 12d, 14d, 16d ... Non-optical path region 18 ... Adhesive 19 ... Concave portion 119 in the optical element ... Strip shape Recessed portion 219 in the optical material of the plate 20: Recessed portion 20 in the large plate-shaped optical material ... Flat plate 120 arranged on the side surface of the optical element ... Arranged on the side surface of the strip-shaped optical material Flat plate 21... Cutting line 23... 24, 25... Gripping tool 30... Polarization-dependent optical isolator 32. ... Recess 40 ... Polarization-dependent optical isolator module 45 ... Optical fiber 46 ... Dotted line 50 indicating laser light ... Polarization-independent optical isolator 51 ... Recess 52 ... Birefringence Crystal 54 ... Faraday rotator 56 ... Birefringent crystal 57 ... Half-wave plate 58 ... Half-wave plate 59 ... Flat plate 60 ... Polarization-independent optical isolator module 61 ... Optical fiber 62 ... Optical fiber 63 ... Ferrule 64 ... Lens 65 ... Mirror 70 ... Glass spacer

  The present invention relates to a method for manufacturing an optical component used in an optical communication device or the like.

  In general, optical components and optical modules used for optical communication include optical connectors, optical isolators, LD (Laser diode) modules for transmitting optical signals, and PD (Photo diode) modules for receiving optical signals. It has been known.

  An optical isolator is a component used in an optical communication system to prevent return light of an optical fiber. The returning light can be caused by the traveling light being inconsistent in refractive index between the materials in contact with each other, fiber misalignment or mode mismatching. The return light causes a decrease in system performance and adversely affects a transmission source such as a laser beam.

  In the polarization-dependent optical isolator, a polarizer such as a polarizing glass sheet is used to sandwich the Faraday rotator. Light travels through the first polarizer, then through the Faraday rotator, and then through the second polarizer. The isolator is disposed between the optical fiber and the lens or between the two lenses.

  The signal light emitted from the light source passes through the first polarizer. Next, the polarization of the light that has passed through the first polarizer is rotated 45 ° by the Faraday rotator, and then passes through the second polarizer whose polarization direction is shifted by 45 ° with respect to the first polarizer. Come out. In the case of the reverse direction, the return light is polarized by the second polarizer and then rotated 45 ° in the same direction by the Faraday rotator to become polarized light that is shifted by 90 ° with respect to the first polarizer. Thus, no signal is returned to the light source.

  In contrast to the polarization-dependent isolator, a polarization-independent optical isolator is also known. The polarization-independent isolator can be a wedge or flat birefringent material, or a prism with a thin film coating, and has a Faraday rotator sandwiched between two beam splitters.

  A Faraday rotator is typically made by surrounding a piece of garnet with a magnet so that a magnetic field is applied to optically activate the crystal. This type of garnet is referred to as a non-latching type. Another type of Faraday rotator is permanently magnetized and does not require an external magnetic field. This type of garnet is called a latch type.

  The various components of both polarization-dependent and polarization-independent optical isolators are generally joined by mechanical assemblies or by polymeric adhesives. As another alternative method, there is also known a method in which large material sheets are collectively assembled with an adhesive, that is, laminated.

  An optical component such as an optical isolator is configured by combining optical elements such as a Faraday rotator and a polarizer as described above. A fixing member or an adhesive is used for fixing the optical element. For example, Japanese Unexamined Patent Application Publication No. 2007-309967 discloses an optical isolator in which optical elements are bonded together using an optical adhesive and integrated. The optical adhesive is applied with a uniform thickness over the entire surface including the surface of the light passage portion of the optical element.

  In this optical isolator, a first polarizer having an antireflection film formed on a predetermined surface, a second polarizer, and a Faraday rotator having antireflection films formed on both surfaces are prepared. Apply the adhesive to the Faraday rotator side surface and the Faraday rotator side surface of the polarizer 2 and align the polarization surfaces of the first and second polarizers appropriately. It is manufactured by a procedure in which a predetermined pressure is applied and a block composed of three combined optical elements is heated to a predetermined temperature for a predetermined time to thermally cure the adhesive.

  As the optical adhesive, a thermosetting adhesive or an ultraviolet curable adhesive that has a low shrinkage at the time of adhesive curing and is less affected by heat and has high stability is used.

  The optical isolator as described above is an optical isolator conventionally used, and is usually used in many optical communication systems using light having an output of about several tens of milliwatts.

  On the other hand, in an optical communication system using an optical amplifier or the like, high-power laser light of about several hundred milliwatts is used. When an optical isolator having an optical adhesive on the optical path surface is used in an optical communication system using high-power laser light, there is a possibility that the adhesive may be altered, resulting in a problem in reliability.

  On the other hand, Japanese Patent Application Laid-Open No. 2005-181760 discloses an optical isolator having no adhesive on the optical path surface. This optical isolator has a structure in which a plate-shaped polarizer and a plate-shaped Faraday rotator are arranged and both ends thereof are held by a pair of substrates, and a groove-shaped recess is formed on each of two opposing mounting substrates. An optical isolator is disclosed which is formed and held with an adhesive while holding the ends of a polarizer and a Faraday rotator in a recess.

  This optical isolator prepares two substrates for holding a first polarizer, a Faraday rotator, and a second polarizer, and forms a recess on the opposing surfaces of the two substrates and applies an adhesive. The both ends of the first polarizer, the Faraday rotator, and the second polarizer are sandwiched between the recesses of the two substrates, and the adhesive is cured by heating to a predetermined temperature for a predetermined time. Manufactured in a procedure.

  Japanese Patent Application Laid-Open No. 4-333818 discloses an optical isolator using a glass material such as a low-melting glass instead of an adhesive. In this optical isolator, a polarizer and a Faraday rotator are fixed to each other with a first glass material at each outer peripheral portion, and the Faraday rotator and an analyzer are fixed to a magnet with a second glass material at each outer peripheral portion. It is configured as follows.

  This optical isolator is prepared in advance as a glass tablet in which the first and second glass materials are formed in a lattice shape, and is a glass tablet between the polarizer and the Faraday rotator and between the Faraday rotator and the analyzer. After aligning so that the glass tablet is inserted into each of the lattice-shaped grooves formed in the polarizer and the analyzer, the optical element is joined by heating the glass material at a predetermined temperature, and then the optical Manufactured by a procedure of cutting an element into individual pieces.

JP 2007-309967 A JP 2005-181760 A JP-A-4-333818

  The optical isolator disclosed in Patent Document 1 is obtained by bonding optical elements together using an optical adhesive and integrating them, and includes a joint surface between a first polarizer and a Faraday rotator, a Faraday rotator and a second one. An adhesive is applied to the bonding surface of the polarizer. Therefore, this optical isolator is not a problem as long as it is used in an optical communication system using light with an output of about several tens of milliwatts, but when used in a communication system using high-power laser light, There is a possibility of deterioration, causing a problem in reliability.

  FIG. 10 is a diagram showing a configuration of a conventional optical isolator disclosed in Patent Document 2. In FIG. This optical isolator 1 is composed of two polarizers 2 between two opposing mounting substrates 4 and one Faraday rotator 3 arranged between these polarizers 2 in total. The optical element is configured by being stacked via the gap 5.

  However, with this configuration, the distance (thickness) in the optical path direction (optical axis direction) of the stacked optical elements increases. In addition, there is a problem that a fixing member for fixing the optical element becomes an obstacle and hinders downsizing of the optical component.

  Also, according to the optical isolator disclosed in Patent Document 3, ideally, no gap is formed between the flat-plate Faraday rotator and the polarizer. However, in practice, it is difficult to fill the lattice-shaped grooves with the low melting point glass without excess or deficiency, no matter how accurately the glass tablet and the grooves are processed. For example, if there is a lot of glass material for the groove, it overflows from the groove and flows out between the flat plate Faraday rotator and the polarizer, resulting in a gap between the flat plate Faraday rotator and the polarizer, On the contrary, when there is little glass material with respect to a groove part, joining shortage will arise.

  Accordingly, the present invention provides an optical component such as a small optical isolator that can be applied to high output light, and a method for manufacturing the same. Further, the present invention provides a method for manufacturing an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

In the first invention of the present application,
A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and back surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and back surfaces facing the adjacent optical element is provided with a recess connected to the side surface. The following steps are provided.
(1) preparing at least two optical materials from which at least two of the flat optical elements can be taken out, and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) After the step (3), applying curing energy to the adhesive to cure the adhesive;
(5) After the step (4), cutting the optical material to obtain individual optical components.

  According to a second invention of the present application, in the first invention, the concave portion is provided in a non-optical path region of the front and rear surfaces.

  In a third invention of the present application, in any one of the first invention and the second invention, the concave portion is composed of at least one groove, and the groove has a width of 0.005 mm to 0.5 mm, a depth of The thickness is 0.001 mm to 0.1 mm.

According to a fourth invention of the present application, in any one of the first to third inventions, the adhesive has a viscosity of 10 to 10 ⁵ mPa · s at room temperature.

According to a fifth invention of the present application, in any one of the first to fourth inventions, the pressure for press-contacting the optical path surface of the at least two flat optical elements is 10 ⁴ Pa to 10 ^8. It is characterized by Pa.

  According to a sixth invention of the present application, in any one of the first to fifth inventions, an antireflection film is provided on at least one of the flat optical elements.

  According to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

It is a figure which shows the structure of one Example of the optical component manufactured by the manufacturing method of this invention. It is a schematic diagram explaining the preparatory process of the optical material containing a flat optical element. It is a figure which shows the optical material manufactured by the preparatory process of FIG. It is process drawing which shows the manufacturing method of the optical component of this invention. It is a figure which shows the relationship between the pressing force at the time of press contact, and the result of having evaluated the press contact state. It is a figure which shows the structure of the other Example of the optical component manufactured by the manufacturing method of this invention. It is a figure which shows the structure of the optical isolator module to which the structure of the optical component of FIG. 1 is applied. It is the figure which contrasted the dimension of the optical component of this invention, and the optical component of a comparative example. It is a figure which shows the other structure of the optical isolator module to which the optical component manufactured by the manufacturing method of this invention is applied. It is a figure which shows the structure of the conventional optical isolator.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on an Example with reference to FIGS. However, the present invention is not limited to these examples.

  FIG. 1 is a cross-sectional view showing the configuration of an embodiment of an optical component manufactured by the manufacturing method of the present invention. FIG. 1 (a) is a plan view of the optical component 10, and FIG. It is AA sectional drawing in a). As shown in FIG. 1, the optical component 10 is configured by laminating a plurality of flat optical elements 12, 14, and 16. When the optical component 10 is an optical isolator, a polarizer (optical element 12), a Faraday rotator (optical element 14), and a polarizer (optical element 16) functioning as an analyzer are stacked in order from the direction in which communication light is transmitted. Configure.

  Each of the optical elements 12, 14, and 16 includes front and rear surfaces 12a, 14a, and 16a provided before and after the optical path direction (arrow B direction in the drawing), and side surfaces 12b and 14b that surround the front and rear surfaces 12a, 14a, and 16a. 16b, and the front and rear surfaces 12a, 14a, 16a have optical path regions 12c, 14c, 16c through which light passes and non-optical path regions 12d, 14d, 16d through which light does not pass.

Here, the optical path area is a region (indicated by a dotted line in the figure) in which the intensity of light is 1 / e ² or more with respect to the maximum intensity e near the center of the light in the Gaussian intensity distribution light. Area).

  A concave portion 19 connected to the side surfaces 12b, 14b, 16b is provided on at least one of the front and rear surfaces 12a, 14a, 16a facing each other of the adjacent optical elements 12, 14, 16. In FIG. 1, the front and rear surfaces 12a and 16a of the optical elements 12 and 16 facing the optical element 14 are provided with recesses 19 connected to the side surfaces 12b and 16b, respectively. The recess 19 is filled with an energy curable adhesive 18 as will be described later. Further, flat plates 20 are provided on both side surfaces of the optical elements 12, 14, and 16, respectively. The flat plate 20 is bonded to both side surfaces of the optical elements 12, 14, 16 by an energy curable adhesive 18, and the optical elements 12, 14, 16 are held on the flat plate 20.

  As described above, the optical component 10 manufactured by the manufacturing method according to the present invention is formed by laminating at least two plate-like optical elements, and each optical element is provided on the front and rear surfaces provided in the front and rear directions in the optical path direction. , And a side surface surrounding the front and rear surfaces, the front and rear surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass, and at least one of the front and rear surfaces facing each other adjacent optical elements, A recess connected to the side surface is provided.

Hereinafter, an embodiment of a manufacturing method according to the present invention for manufacturing the optical component 10 as described above will be described.
A substrate as shown in FIG. 2A is “substrate-like optical material”, a large plate as shown in FIG. 2B is “large plate-like optical material”, and a strip as shown in FIG. 2C. The optical material cut into a shape is referred to as a “strip-shaped optical material”. The strip-shaped optical material is further cut into individual optical elements.

  FIG. 2 is a schematic diagram illustrating a preparation process of an optical material including a flat optical element used in the manufacturing method of the present invention, and FIG. 3 is a strip-shaped optical material manufactured by the preparation process of FIG. FIG. 2A shows a substrate-like optical material such as a polarizer and a Faraday rotator, FIG. 2B shows a large plate-like optical material in which concave portions are formed on the optical material on the substrate, and FIG. It is a figure which shows the cutting process which cut | disconnects a large plate-shaped optical material in strip shape. 3A shows a strip-shaped optical material for a polarizer, and FIG. 3B shows a strip-shaped optical material for a Faraday rotator.

  As shown in FIG. 2 (a), the substrate-like optical materials 312 and 316 are flat plate-shaped glass materials for a polarizer having a square of 11 mm and a thickness of 0.2 mm. The optical materials 312 and 316 are polished to a predetermined flatness. The flatness by polishing is, for example, λ / 2 to λ / 10 (λ = 633 nm).

  As shown in FIG. 2B, the substrate-like optical materials 312 and 316 used for the polarizer are processed into a large plate-like optical material 212 and 216 by processing the concave portions 219 in a lattice shape by a dicing machine. As shown in FIG. 2C, the large plate-shaped optical materials 112 and 116 are cut into strips to form strip-shaped optical materials 112 and 116. A substrate-like optical material 314 for a Faraday rotator is a flat-plate-permanently magnetized latch-type garnet material having a square of 11 mm and a thickness of 0.4 mm. The substrate-like optical material 314 for the Faraday rotator is cut into a strip shape without being processed into a concave portion, and becomes a strip-like optical material 114.

  FIG. 3A shows a plan view (upper) and a side view (lower) of strip-shaped optical materials 112 and 116 for a polarizer, and FIG. 3B shows a Faraday rotator. A plan view (upper stage) and a side view (lower stage) of the strip-shaped optical material 114 for use are shown.

  FIG. 4 is a process diagram showing a method for manufacturing an optical component according to the present invention, and (a) to (i) in the figure are views showing states of optical materials in each manufacturing process. In FIGS. 4A to 4I, a plan view is shown in the upper stage and a side view is shown in the lower stage as needed to facilitate understanding.

As shown in FIG. 4A, the strip-shaped optical materials 112 and 116 for the polarizer and the strip-shaped optical material 114 for the Faraday rotator are placed on the gripper 24 from below as shown in FIG. The material 114 and the optical material 116 are arranged so that the front and rear surfaces are in contact with each other in this order. Next, as shown in FIG. 4B, the gripping tool 25 is stacked on the optical materials 112, 114, and 116 arranged in a stacked manner, and a predetermined pressure (for example, 10 ⁵ Pa) is applied to the gripping tools 24, 25. And the optical materials 112, 114, and 116 are pressed.

  The pressure contact here is to press the front and back surfaces of adjacent optical materials or optical components in contact with each other. In the present invention, even the press contact is not intended to contact at the nanometer level, and the non-contact level (for example, 0.01 mm or less) that does not affect the use of the optical component of the present invention. It does not exclude the presence of ultrathin films such as fine gaps between optical materials and refractive index matching agents. By this pressure contact, it is possible to prevent the adhesive filled in the concave portion from flowing out between the front and back surfaces of the adjacent optical material or optical component.

FIG. 5 is a diagram showing the results of evaluating the pressing force when pressing the optical materials 112, 114, and 116 and the pressing state of the strip-shaped optical material. As shown in FIG. 5, when the pressing force at the time of pressure contact is 10 ³ Pa or less, when applying the adhesive from the side surface and filling the concave portion 119 with the adhesive, a part of the adhesive is removed from the concave portion 119. Since the flow was confirmed to the interface between the front and back surfaces of the adjacent strip-shaped optical material, it cannot be said that the pressure contact state is good. When the pressure is 2 * 10 ⁸ Pa or more, the optical materials 112, 114, and 116 are slightly damaged such as cracks and chips, and thus cannot be said to be in a good pressure contact state. At 10 ⁴ Pa to 10 ⁸ Pa, the adhesive did not flow out from the recesses, and no fine damage to the optical material was confirmed.

When the press contact is completed, as shown in FIG. 4C, the adhesive 18 is applied to the side surfaces of the optical materials 112, 114, and 116 that are press contacted. The adhesive 18 is filled in the recess 119 using a capillary phenomenon. In order to fill the recess 119 with the adhesive 18 without excess or deficiency, the adhesive 18 has a viscosity of 10 ² mPa · s to 10 ⁴ mPa · s at normal temperature (23 ± 5 ° C.) (Japanese Industrial Standard JIS K7117). -2 / corresponding international standard ISO 3219). The viscosity of the adhesive used in this example is 250 mPa · s.

  FIG. 4D shows a state where the filling of the adhesive 18 into the recess 119 is completed. In this embodiment, an ultraviolet curable epoxy adhesive is used as the adhesive 18 filling the recess 119. However, an energy curable adhesive that cures with other curing energy (such as thermosetting) may be used. .

  When the filling of the adhesive 18 into the recess 119 is completed, as shown in FIG. 4E, the flat plate 120 is disposed on the side surface of the pressed optical material 112, 114, 116. In order to bond the side surface of the optical material 112, 114, 116 and the flat plate 120, there is an amount of adhesive between the optical material 112, 114, 116 and the flat plate 120 so that the adhesive spreads over the entire flat plate 120. is necessary.

  Thereafter, as shown in FIG. 4 (f), the adhesive 18 is applied to the opposite side surfaces of the pressed optical materials 112, 114, and 116 to dispose the flat plate 120. In the present embodiment, the flat plate 120 is made of borosilicate glass, and the thickness of the adhesive 18 is about 1 to 5 μm. The flat plate 120 may be made of a material that does not transmit ultraviolet rays, such as metal or ceramic.

Thereafter, as shown in FIG. 4G, ultraviolet rays are irradiated from one side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached. The ultraviolet irradiation conditions were 10 mW / cm ² and the irradiation time was 5 minutes. Thereafter, ultraviolet rays are also irradiated from the other side surface of the optical material 112, 114, 116 to which the flat plate 120 is attached (see FIG. 4H). The conditions for ultraviolet irradiation are the same. Thus, the adhesive 18 was hardened by irradiating with ultraviolet rays from both sides for a total of 10 minutes. When the adhesive 18 is a thermosetting type, it is cured at a predetermined temperature for a predetermined time. The predetermined temperature is not necessarily high, and may be room temperature or lower.

  Thereafter, as shown in a plan view (i1) of FIG. 4 (i), each optical component is cut to obtain the optical component 10 of FIG. Referring to the side view (i2) of FIG. 4 (i), the cutting line 21 is slightly inclined. The inclination angle is 6 to 8 degrees from the vertical direction. This inclination is adapted to the inclination of the ferrule to which the optical component is attached.

In the optical component 10, flat plates 20 are bonded to both sides of the optical elements 12, 14, 16 by an adhesive 18.
One side of the front and rear surfaces of the optical elements 12, 14, 16 (see 12a, 14a, 16a in FIG. 1) is preferably less than 1 mm. In this embodiment, the length of one side of the front and rear surfaces is about 0.7 mm.
The width of the recess 19 is preferably in the range of 0.005 mm to 0.2 mm and the depth is in the range of 0.005 mm to 0.05 mm. In this embodiment, the width of the recess 19 is 0.05 mm and the depth is 0. .02 mm.
Moreover, the recessed part 19 can be made into various shapes, The cross-sectional shape may be U-shape, U-shape, arc shape, etc.

  6A and 6B are diagrams showing the configuration of another embodiment of the optical component of the present invention. FIG. 6A is a plan view of the optical component 100, and FIG. The optical component 100 of FIG. 6 has a flat plate 20 disposed on all four side surfaces of the optical elements 12, 14, and 16.

An energy curable adhesive is applied between each side surface of the optical elements 12, 14, and 16 where the flat plate 20 is not provided and the flat plate 20, and then the applied adhesive is cured by applying curing energy. Thereby, the optical elements 10, 12, and 14 are held by the flat plate 20 on the four side surfaces. For the flat plate 20, for example, a glass plate is used. In addition, the dimension described in the drawing is an example, and the corresponding part of the optical component 10 in FIG. 1 may have the same dimension.
In addition, unlike the configurations of FIGS. 1 and 6, a configuration in which the flat plate 20 is not provided on all four side surfaces may be employed.

  FIG. 7 is a diagram showing the structure of the optical isolator module of the present invention. 7A is a top view of the optical isolator module 40, and FIG. 7B is a cross-sectional view of the optical isolator module 40 taken along the line DD. In this optical isolator module 40, an optical isolator 30 having the same configuration as that shown in FIG. 1 is bonded on an ferrule 44 via a glass spacer 42 with an adhesive.

  The ferrule 44 holds and protects the optical fiber 45 and is made of zirconia or the like having sufficient mechanical strength. Laser light passing through the optical fiber 45 enters the optical isolator 30 as indicated by an arrow B in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line 46. The beam diameter of the traveling laser light gradually increases according to the traveling distance as shown in the figure.

  As shown in FIG. 7B, the optical isolator 30 includes a polarizing glass 32, a Faraday rotator 34, and a polarizing glass 36.

  The polarizing glasses 32 and 36 and the Faraday rotator 34 have front and rear surfaces provided in the front and rear direction of the optical path and side surfaces surrounding the front and rear surfaces, as described in FIG. 1, and light passes through the front and rear surfaces. A concave portion 39 connected to the side surface is provided on at least one of the front and rear surfaces of the adjacent optical elements that have an optical path region and a non-optical path region through which light does not pass.

  The polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are arranged in a predetermined order, and after being pressed against each other, the concave portion 39 is filled with an energy curable adhesive 18, and a curing energy is applied to the adhesive 18 for bonding. Bonding is performed by curing the agent 18. Further, the polarizing glass 32, the Faraday rotator 34, and the polarizing glass 36 are held by a flat plate 20 made of a glass material fixed to both side surfaces by an energy curable adhesive 18.

  FIG. 8 is a diagram comparing the dimensions of the optical component of the present invention and the optical component of the comparative example. (A) shows the structure of the optical isolator module shown in FIG. 7, (b) is an optical isolator module using the optical isolator of patent document 2 as a comparative example.

  8A and 8B, the thicknesses of the polarizing glasses 12 and 16 and the Faraday rotator 14 are compared as the same dimensions. The optical isolator is bonded to the end face of the ferrule 44 that holds the optical fiber 45. Laser light is incident on the optical isolator from the end of the optical fiber 45 and travels in the optical isolator as indicated by a dotted line 46 while being refracted in accordance with the refractive indexes of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16. The beam diameter of the laser light gradually increases according to the travel distance as shown in the figure.

  In the optical isolator module of the present invention shown in FIG. 8A, the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 are in pressure contact with the front and back surfaces adjacent to each other, and the traveling direction of the laser light The length L1 is 1 mm. Considering the beam diameter of the laser beam that expands while traveling this length L1 (1 mm), the width x1 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 0.7 mm.

  On the other hand, in the comparative example shown in FIG. 8B, there are gaps among the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16, respectively, and the optical isolator module of the present invention shown in FIG. In contrast, the length L2 in the traveling direction of the laser light is 1.4 mm. In consideration of the beam diameter of the laser light that expands while traveling this length, the width x2 of one side of the polarizing glass 12, the Faraday rotator 14, and the polarizing glass 16 is 1.0 mm.

  Accordingly, when the dimensional ratio of the optical isolator of the present invention and the optical isolator of the comparative example is converted into a volume ratio, 0.7 * 0.7 * 1.0 / (1.0 * 1.0 * 1.4) = 0. The volume of the optical component of the present invention is about 1/3 that of the optical component of the comparative example, and it can be seen that the optical component (optical isolator) can be downsized.

FIG. 9 is a diagram showing an example of the structure of a polarization-independent optical isolator module. 9A is a top view of the optical isolator 50, and FIG. 9B is a cross-sectional view of the optical isolator module 60 taken along line E-E. In this optical isolator module 60, a polarization-independent optical isolator 50 is bonded on a ferrule 63 via a glass spacer 70 with an adhesive.

  Laser light emitted from one optical fiber 61 enters the optical isolator 50 as indicated by an arrow C in the figure. The incident laser light travels in the optical isolator as indicated by a dotted line. The light emitted from the optical isolator 50 is collimated by the lens 64 and reflected by the mirror 65, passes through the lens 64 again, enters the optical isolator 50, travels, and enters the other optical fiber 62.

  As shown in FIG. 9, the optical isolator module 60 includes a flat plate birefringent crystal 52 functioning as a polarizer, two half-wave plates 57 and 58 having a function of rotating the polarization direction, and permanent magnetized. A Faraday rotator 54 made of a latch-type garnet crystal and a birefringent crystal 56 functioning as a polarizer are stacked and pressed together. Each optical element of the birefringent crystal 52, the Faraday rotator 54, the half-wave plates 57 and 58, and the birefringent crystal 56 has, for example, a predetermined size in a lattice shape from a flat plate of 11 mm in length and width as described above. The one cut into two is used as one optical element. A YVO4 is used as the birefringent crystal, and a quartz plate or the like is used as the half-wave plate.

  The birefringent crystals 52 and 56 and the Faraday rotator 54 have front and rear surfaces provided in the front and rear direction of the optical path, and side surfaces surrounding the front and rear surfaces, and the front and rear surfaces have an optical path region through which light passes and light does not pass. The front and rear surfaces of the birefringent crystal 52 facing the half-wave plates 57 and 58, the front and rear surfaces of the Faraday rotator facing the half-wave plates 57 and 58, and the birefringent crystal 56. Concave portions 51 connected to the side surfaces are provided on the front and rear surfaces facing the Faraday rotator 54.

  The birefringent crystal 52, the half-wave plates 57 and 58, the Faraday rotator 54, and the birefringent crystal 56 are arranged in a predetermined order, and after being pressed, the recess 51 is filled with the energy curable adhesive 18. Bonding is performed by applying curing energy to the adhesive 18 and curing the adhesive 18. In addition, the birefringent crystal 52, the Faraday rotator 54, and the birefringent crystal 56 are glass materials fixed to the both side surfaces thereof, and the half-wave plates 57 and 58 are fixed to the one side surfaces thereof by the energy curable adhesive 18. It is hold | maintained by the flat plate 59 which consists of.

  The above description describes an example in which a large plate optical material is cut into a strip-shaped optical material, then bonded by pressure welding, adhesive filling, and adhesive curing, and finally cut into individual optical elements. However, the present invention is not limited to this. The manufacturing method according to the present invention can be applied to any state of the optical material of the large plate, the state of the strip-shaped optical material, and the state of the individual optical element.

  Further, the width of the optical material to be cut into strips may be cut so as to include one row of individual optical elements, or may be cut to include a plurality of rows of individual optical elements. Even in such a case, other appropriate processes may be added between the processes of pressure contact of the basic optical element, filling of the adhesive, and curing of the adhesive.

  As described above, according to the present invention, it is possible to provide an optical component such as a small optical isolator that can be applied to high output light. In addition, it is possible to provide an optical component such as an optical isolator that can be manufactured by a general-purpose manufacturing facility and is inexpensive.

  The above-described embodiment is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

10, 100 ... optical components 12, 14, 16 ... optical elements 112, 114, 116 ... strip-shaped optical material 212, 216 ... large plate-shaped optical material 312, 314, 316,. The substrate-like optical materials 12a, 14a, 16a ... the front and back surfaces 112a, 114a, 116a in the optical element ... the front and back surfaces 12b, 14b, 16b in the strip-like optical material ... the side surfaces 112b, 114b, 116b .. Side surfaces 12c, 14c, 16c in the strip-shaped optical material. Optical path regions 12d, 14d, 16d ... Non-optical path region 18 ... Adhesive 19 ... Concave portion 119 in the optical element ... Strip shape Recessed portion 219 in the optical material of the plate 20: Recessed portion 20 in the large plate-shaped optical material ... Flat plate 120 arranged on the side surface of the optical element ... Arranged on the side surface of the strip-shaped optical material Flat plate 21... Cutting line 23... 24, 25... Gripping tool 30... Polarization-dependent optical isolator 32. ... Recess 40 ... Polarization-dependent optical isolator module 45 ... Optical fiber 46 ... Dotted line 50 indicating laser light ... Polarization-independent optical isolator 51 ... Recess 52 ... Birefringence Crystal 54 ... Faraday rotator 56 ... Birefringent crystal 57 ... Half-wave plate 58 ... Half-wave plate 59 ... Flat plate 60 ... Polarization-independent optical isolator module 61 ... Optical fiber 62 ... Optical fiber 63 ... Ferrule 64 ... Lens 65 ... Mirror 70 ... Glass spacer

Claims (9)

A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a concave portion connected to the side surface,
An optical component manufacturing method comprising the following steps.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) A step of applying curing energy to the adhesive after the step (3) to cure the adhesive. A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear direction of the optical path, and side surfaces surrounding the front and rear surfaces, and the front and rear surfaces have an optical path region through which light passes and a non-optical path region through which light does not pass. Have
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a concave portion connected to the side surface,
An optical component manufacturing method comprising the following steps.
(1) preparing at least two plate-like optical elements and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), applying an energy curable adhesive to the side surface and filling the concave portion with the adhesive from the side surface;
(4) After the step (3), placing a flat plate on the side surface;
(5) After the step (4), applying curing energy to the adhesive to cure the adhesive applied to the side surface and the adhesive filled in the recess. A method of manufacturing an optical component in which at least two flat optical elements are laminated,
Each of the optical elements has front and rear surfaces provided in the front and rear directions in the optical path direction, and side surfaces surrounding the front and rear surfaces,
The front and rear surfaces have an optical path area through which light passes and a non-optical path area through which light does not pass,
At least one of the front and back surfaces facing each other of the adjacent optical elements is provided with a concave portion connected to the side surface,
An optical component manufacturing method comprising the following steps.
(1) preparing at least two optical materials from which at least two of the flat optical elements can be taken out, and arranging them in a predetermined order;
(2) a step of pressing the front and back surfaces of the adjacent optical elements together;
(3) After the step (2), filling the concave portion with an energy curable adhesive from the side surface;
(4) After the step (3), applying curing energy to the adhesive to cure the adhesive;
(5) After the step (4), cutting the optical material to obtain individual optical components.   4. The method of manufacturing an optical component according to claim 1, wherein the concave portion is provided in a non-optical path area of the front and rear surfaces. 5.   The said recessed part consists of at least 1 groove | channel, The width | variety of the said groove | channel is 0.005 mm-0.5 mm, The depth is 0.001 mm-0.1 mm, Any one of Claim 1 thru | or 4 characterized by the above-mentioned. The manufacturing method of the optical component of Claim 1. The method for manufacturing an optical component according to claim 1, wherein the adhesive has a viscosity of 10 to 10 ⁵ mPa · s at room temperature. The optical component according to any one of claims 1 to 6, wherein a pressure for pressing the optical path surface of the at least two flat optical elements is 10 ⁴ Pa to 10 ⁷ Pa. Manufacturing method.   The method of manufacturing an optical component according to any one of claims 1 to 7, wherein an antireflection film is applied to at least one of the flat optical elements.   An optical isolator manufactured by the manufacturing method according to claim 1.