JP4599569B2 - Array type optical element connection method - Google Patents

Description

  The present invention relates to a method for connecting an array type optical element, and more specifically, an array type optical element in which optical functional elements such as lenses, filters, and apertures are integrated, and a plurality of light emitting elements or light receiving elements are integrated. The present invention relates to a method for connecting an optical module or a planar lightwave circuit in which a plurality of optical elements are integrated.

  In recent years, with the spread of optical fiber transmission, a technique for integrating a large number of optical elements at a high density has been demanded. In particular, in the wavelength division multiplexing transmission system, since optical signals of a plurality of wavelengths are handled at once, it is necessary to integrate optical elements having the same function by the number of wavelengths. For example, an optical module in which a plurality of light emitting elements or light receiving elements are accommodated in one package is known (see, for example, Patent Document 1).

  Also known is a planar lightwave circuit (hereinafter referred to as PLC: Planar Lightwave Circuit) in which an optical waveguide and an optical device comprising an optical waveguide are integrated on a silicon substrate or a quartz substrate. In the PLC, for example, optical functional elements such as a multiplexer / demultiplexer, a branching / coupling device, and an optical modulator are formed, and optical functional elements of a plurality of channels can be integrated. Patent Document 1 discloses that the optical module and the PLC module are connected to form an optical transceiver in a transmission terminal station. These optical modules and PLC modules have high productivity and reliability, and are excellent in terms of integration and high functionality.

JP 2006-128514 A JP 2005-70073 A

The above-described connection between the optical module and the PLC, and the connection between the optical fiber and the optical module or the PLC module are required to combine a plurality of optical signals together and with high coupling efficiency. Therefore, for example, an optical element such as a microarray lens for collimating or condensing the optical signal emitted from the optical fiber and coupling it to the optical module is used. The microarray lens, for example, forms a part having a different refractive index on a part of a glass substrate to give a lens effect (for example, see Patent Document 2), or forms a minute hemispherical structure on a glass substrate by etching. It is produced by.

  In order to couple these microarray lenses and optical modules, it is necessary to align the optical axes of the individual lenses with the optical axes of a plurality of light emitting elements or light receiving elements (hereinafter referred to as alignment). However, since the optical axis of the microarray lens manufactured on the glass substrate cannot be visually confirmed, it is necessary to previously form alignment markers on each of the microarray lens and the optical module. In addition, a method of supplying power to an optical module and performing alignment using a light source or an optical monitor (hereinafter referred to as active alignment) makes it difficult to optically couple the microarray lens to the light source or the optical monitor, which increases productivity. There was a problem of being inferior.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a method of connecting an array type optical element that allows easy alignment between individual optical elements and individual light emitting elements or light receiving elements. It is to provide.

  In order to achieve the above object, the present invention provides an array type optical element for joining an array type optical element having a plurality of optical elements arranged in an array to an optical module. In this connection method, a plurality of parallel V-grooves are formed on one surface of the first substrate, an optical element is disposed in the V-groove, and the surface of the first substrate on which the V-groove is formed and the second substrate Is a step of temporarily fixing to the block an array type optical element obtained by cutting the block bonded with a desired width in a plane perpendicular to the optical axis of the optical element, the optical element being perpendicular to the optical axis of the optical element. A first step of matching and temporarily fixing the optical axis of the optical element of the array type optical element and the optical axis of the optical element of the block by matching four sides surrounding the surface; and the array type optical element The end face and multiple channel optical elements were accommodated A second step of applying an adhesive to at least one of the lids of the module; and a third step of causing the optical axis of the optical element and the optical axis of the optical element of the array type optical element to coincide with each other to cure the adhesive. And a fourth step of separating the temporarily fixed array type optical element and the block.

In the first step, the array-type optical element and a part of the outer edge of the block can be temporarily bonded by bonding with an adhesive. In the third step, when the optical element accommodated in the optical module is a light emitting element , an optical monitor is connected to the optical element fixed to the block, the light emitting element is operated, and the optical monitor When the output is maximum, the adhesive is solidified , or when the optical element accommodated in the optical module is a light receiving element, a light source is connected to the optical element fixed to the block, and the light receiving element is operated. the output of connected optical monitor to the light receiving element is at maximum, may Rukoto to solidify the adhesive.

  The first substrate and the second substrate are preferably any one of (1) carbon-containing glass, (2) a resin containing any of carbon, silicon, and titanium oxide, and (3) ceramic. Is fixed by a carbon-containing thermosetting epoxy resin.

  The first substrate and the second substrate may be made of metal, and the optical element is fixed by solder.

  As the optical element, a graded index optical fiber or a step index optical fiber can be used.

  As described above, according to the present invention, alignment between individual optical elements and individual light emitting elements or light receiving elements can be easily performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, a four-channel microarray lens will be described as an example of an array type optical element. For example, as other optical elements, there are an optical filter, an aperture, and the like, but the alignment method can be applied in common.

  FIG. 1 shows the structure of a microarray lens according to an embodiment of the present invention. FIG. 1 shows one surface perpendicular to the optical axis of the microarray lens. The microarray lens 10 includes a first substrate 11 having a plurality of (four) V-grooves formed on one side, a second substrate 12 bonded to the side on which the V-groove is formed, and two sides of the V-groove. And an optical element 13 which is fixed in contact with one side of the second substrate 12 and serves as a microlens for each channel. Note that a gap between the V groove and the optical element 13 is filled with an adhesive 14.

  The optical element 13 has a refractive index profile in which the refractive index changes in the radial direction, and a GRIN lens, a graded index (GI) optical fiber, a step index (SI) optical fiber, or the like can be applied. As the adhesive 14, a UV curable or thermosetting epoxy resin or the like can be used.

  The microarray lens 10 uses, for example, a first substrate 11 using a GI optical fiber having a diameter of 125 μm as the optical element 13 and having V grooves formed at intervals of 250 μm. The GI type optical fiber is used by dividing the same optical fiber core wire into four. This is because the characteristics of the optical element to be the microarray lens are less varied between the channels.

  FIG. 2 shows a method for manufacturing a microarray lens according to an embodiment of the present invention. First, a plurality of parallel V-grooves are formed on one surface of the first substrate 11 (FIG. 2A). Accordingly, the optical axes of the optical elements of the individual channels are parallel to each other. Next, the adhesive 14 is applied to the surface on which the V-groove is formed, and the GI type optical fiber 15 is disposed as the optical element 13 in the V-groove (FIG. 2B). As described above, the GI type optical fiber uses the same optical fiber core wire divided into four. The surface of the first substrate 11 on which the V-groove is formed and the second substrate 12 are joined to cure the adhesive 14 (FIG. 2C). Finally, using a dicing saw, the microarray lenses 10a and 10b are cut out by cutting with a desired width on a plane perpendicular to the optical axis of the GI optical fiber 15 (FIG. 2 (d)). The block after cutting out the microarray lenses 10a and 10b is hereinafter referred to as a fiber block 21.

  Optical characteristics such as focus and NA can be adjusted by the refractive index profile of the optical element 13 and the lens length (equal to the width of the substrate to be cut).

  FIG. 3 shows the configuration of the optical module. As an example, the optical module 30 includes four light emitting elements or light receiving elements (hereinafter referred to as optical elements) 35 having a light emitting surface or a light receiving surface (hereinafter referred to as a light receiving / emitting surface) 34. The optical element 35 is sealed by a box-shaped housing 32 and a lid 33 made of sapphire glass that enables input and output of optical signals to and from the light receiving and emitting surface 34 (see, for example, Patent Document 1). Since the casing 32 and the lid 33 are joined by metal solder and have high airtightness, the casing 32 and the lid 33 are protected from the external environment and ensure the reliability of the optical element 35. The optical element 35 is fixed to the housing 32 with metal solder or the like with the light emitting / receiving surface 34 facing the lid 33, and is connected to the metal wiring 37 of the housing 32 by a bonding wire 36. The metal wiring 37 extends through the housing 32 to the back and side surfaces of the housing 32. A lead pin 38 is fixed to the metal wiring 37 on the back surface of the housing 32 by welding (such as brazing).

  FIG. 4 shows a method for connecting an optical module and a PLC module via a microarray lens. The optical module 30 is fixed so that the mounting surface of the mounting board 51 and the optical axis of the optical element 35 of the optical module 30 are parallel to each other. Since the metal wiring 37 of the optical module 30 and the electrode 52 formed on the mounting board 51 are fixed by metal solder or the like via the lead pins 38, the optical module 30 can be firmly fixed on the mounting board 51. .

  The optical element 35 of the optical module 30 has its light emitting / receiving surface 34 optically coupled to the optical waveguide 43 of the PLC module 40 via the optical element 13 of the microarray lens 10. The microarray lens 10 is bonded to the lid 33 of the optical module 30 using an adhesive or the like on one surface perpendicular to the optical axis of the optical element 13.

  In the PLC module 40, a PLC 42 is bonded on a substrate 41, and an optical waveguide 43 and an optical functional element are formed on the PLC 42. On the surface including the end face of the optical waveguide of the PLC 42, a sheath 44 as a reinforcing plate is joined on the PLC 42. The PLC 40 module is bonded to the other surface perpendicular to the optical axis of the optical element 13 on the surface including the end surface of the optical waveguide 43 using an adhesive or the like.

  Here, a method of bonding the microarray lens to the optical module will be described. The fiber block 21 is a block after the microarray lenses 10a and 10b are cut out in FIG. First, the microarray lens 10 and the fiber block 21 are temporarily fixed with their optical axes aligned. Since the microarray lens 10 is cut out from the fiber block 21, optical axis alignment can be easily performed by aligning four sides surrounding one surface perpendicular to the optical axis of the optical element 13 ( Hereinafter referred to as physical alignment).

  FIG. 5 shows a method of alignment between the microarray lens and the optical module. In FIG. 2, the surface perpendicular to the optical axis of the optical element 13 is a square, but any one of the four corners may be cut out in the optical axis direction (FIG. 5A). Further, if the groove 16 is formed in any one of the four sides in the optical axis direction, physical alignment is facilitated (FIG. 5B). Furthermore, physical alignment may be performed by forming through holes 17a and 17b in the optical axis direction of the substrate 12 (or 11) and inserting guide pins into the through holes 17a and 17b (FIG. 5 ( c)).

  FIG. 6 shows a temporary fixing method between the microarray lens and the optical module. In the temporary fixing, a part of the outer edge of the microarray lens 10 and the fiber block 21 is bonded with adhesives 61a and 61b (FIG. 6A). Further, clamps 62a and 62b for fixing the microarray lens 10 may be attached to the fiber block 21 (FIG. 6B). The microarray lens 10 and the fiber block 21 are brought into close contact with each other by the elasticity of the leaf spring of the clamp 62.

  Further, the guide pins 18a and 18b are press-fitted into the through holes 17a and 17b shown in FIG. 5C to fix the microarray lens 10 and the fiber block 21 (FIG. 6C). A vacuum suction device is connected to the through holes 17a and 17b on the opposite side of the surface of the fiber block 21 where the microarray lens 10 is temporarily fixed. The through-holes of the microarray lens 10 may be filled with an epoxy resin or the like, and the microarray lens 10 and the fiber block 21 may be fixed by vacuum suction.

  FIG. 7 shows a connection method between the microarray lens and the optical module in the first embodiment. The microarray lens 10 is connected to the optical module 30 fixed on the mounting board 51. First, an adhesive is applied to the other end face of the microarray lens 10 or the lid 33 of the optical module 30. As the adhesive, an ultraviolet curable adhesive or a thermosetting adhesive is used. Next, the fiber block 21 to which the microarray lens 10 is temporarily fixed is brought into contact with the optical module 30 (FIG. 7A).

  At this time, in order to perform alignment by active alignment, power is supplied to the mounting board 51 of the optical module 30 to operate the built-in optical element. On the other hand, a light source or an optical monitor is connected to the optical fiber fixed to the fiber block 21. Positioning is performed while observing the output of the light emitting element with an optical monitor connected to the optical fiber or observing the output of the light source with an optical monitor connected to the light receiving element. When the output of the light monitor is maximum, the adhesive is cured.

  After the adhesive is solidified, the microarray lens 10 and the fiber block 21 are separated by peeling off the temporarily fixed adhesives 61a and 61b or releasing the clamp (FIG. 7B). In this way, alignment between individual optical elements of the microarray lens 10 and individual light emitting elements or light receiving elements can be easily performed.

  Similarly, the connection between the optical module 30 to which the microarray lens 10 is bonded and the PLC module 40 is performed by operating an optical element built in the optical module 30 and connecting a light source or an optical monitor to the PLC module 40. An adhesive is applied to one end face of the microarray lens 10 or the end face of the PLC module 40, and alignment is performed while observing with an optical monitor. When the output of the light monitor is maximum, the adhesive is cured. In this way, the connection shown in FIG. 4 can be performed.

  In the microarray lens 10 shown in FIG. 1, the first substrate 11 and the second substrate 12 are made of carbon-containing glass and have light shielding properties. The adhesive 14 is also a light-shielding adhesive using a carbon-containing thermosetting epoxy resin. Further, an Fe—Ni alloy is used as the first substrate 11 and the second substrate 12, and AuSn solder is used as the adhesive 14. With this configuration, light is prevented from transmitting except for the opening of the optical element 13. Thereby, the light reflected by the lid 33, the light reflected by the optical element 35, and the like can be prevented from entering the PLC. Further, it is possible to prevent light leaked from a part other than the optical waveguide 43 of the PLC 42 from entering the optical element 35.

  When carbon-containing glass is used as the first substrate 11 and the second substrate 12, and a quartz glass optical fiber is used as the optical element 13, the difference in thermal expansion coefficient between the first substrate 11, the second substrate 12, and the optical element 13 is small. Therefore, thermal distortion can be prevented. In addition, the 1st board | substrate 11 and the 2nd board | substrate 12 can also use resin typified by the acrylic or epoxy containing not only carbon containing glass but carbon, silicon, and titanium oxide.

  Further, as the first substrate 11 and the second substrate 12, ceramics typified by alumina or the like may be used. When resin is used as the first substrate 11 and the second substrate 12 and a plastic optical fiber is used as the optical element 13, the difference in thermal expansion coefficient between the first substrate 11, the second substrate 12 and the optical element 13 is small. Distortion can be prevented.

  When an Fe—Ni alloy is used as the first substrate 11 and the second substrate 12 and a quartz glass optical fiber is used as the optical element 13, the difference in thermal expansion coefficient between the first substrate 11 and the second substrate 12 and the optical element 13 is Since it is small, thermal distortion can be prevented. The first substrate 11 and the second substrate 12 may use not only an Fe—Ni alloy but also a Cu alloy such as an Fe—Ni—Co alloy, CuW, or CuMo. Further, not only AuSn but also SnPb, SnAgCu, AgCu or the like can be used as the solder.

  FIG. 8 shows a connection method between the microarray lens and the PLC module in the second embodiment. First, an adhesive is applied to the other end surface of the microarray lens 10 or the end surface including the sheath 44 of the PLC module 40. As the adhesive, an ultraviolet curable adhesive or a thermosetting adhesive is used. Next, the fiber block 21 to which the microarray lens 10 is temporarily fixed is brought into contact with the PLC module 40 (FIG. 8A).

  At this time, in order to perform alignment by active alignment, an optical signal is input to the optical waveguide 43 of the PLC module 40 to operate the built-in optical functional element. On the other hand, an optical monitor is connected to the optical fiber fixed to the fiber block 21. Positioning is performed while observing the output from the PLC module 40 with an optical monitor connected to the optical fiber. When the output of the light monitor is maximum, the adhesive is cured.

  After the adhesive has solidified, the microarray lens 10 and the fiber block 21 are separated by peeling off the temporarily fixed adhesive 61 or releasing the clamp (FIG. 8B). In this way, alignment between the individual optical elements of the microarray lens 10 and the individual optical waveguides can be easily performed.

  Similarly, the connection between the PLC module 40 to which the microarray lens 10 is bonded and the optical module 30 is performed by operating an optical element built in the optical module 30 and connecting a light source or an optical monitor to the PLC module 40. An adhesive is applied to one end face of the microarray lens 10 or the lid 33 of the optical module 30, and alignment is performed while observing with an optical monitor. When the output of the light monitor is maximum, the adhesive is cured. In this way, the connection shown in FIG. 4 can be performed.

It is a figure which shows the structure of the microarray lens concerning one Embodiment of this invention. It is a figure which shows the manufacturing method of the microarray lens concerning one Embodiment of this invention. It is a figure which shows the structure of an optical module. It is a figure which shows the method of connecting an optical module and a PLC module via a microarray lens. It is a figure which shows the method of alignment between a microarray lens and an optical module. It is a figure which shows the method of the temporary fix | stop between a microarray lens and an optical module. 6 is a diagram illustrating a connection method between the microarray lens and the optical module in Embodiment 1. FIG. It is a figure which shows the connection method between the microarray lens and PLC module in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Microarray lens 11 1st board | substrate 12 2nd board | substrate 13 Optical element 14 Adhesive 15 Optical fiber 16 Groove 17 Through-hole 18 Guide pin 21 Fiber block 61 Adhesive 62 Clamp

Claims (10)

In a method of connecting an array type optical element for joining an array type optical element having a plurality of optical elements arranged in an array to an optical module,
A block in which a plurality of parallel V-grooves are formed on one surface of the first substrate, an optical element is disposed in the V-groove, and the surface of the first substrate on which the V-groove is formed and the second substrate are joined. A step of temporarily fixing an array type optical element cut at a desired width on a surface perpendicular to the optical axis of the optical element to the block, the four sides surrounding the surface perpendicular to the optical axis of the optical element; By first aligning the optical axis of the optical element of the array-type optical element with the optical axis of the optical element of the block by matching,
A second step of applying an adhesive to at least one of the end face of the array-type optical element and the lid of the optical module containing the optical elements of a plurality of channels;
A third step of matching the optical axis of the optical element and the optical axis of the optical element of the array-type optical element, and curing the adhesive;
A method of connecting array optical elements, comprising: a fourth step of separating the temporarily stopped array optical elements and the blocks. In the third step, when the optical element accommodated in the optical module is a light emitting element , an optical monitor is connected to the optical element fixed to the block, the light emitting element is operated, and the optical monitor Solidify the adhesive when the output is maximum , or
When the optical element accommodated in the optical module is a light receiving element, a light source is connected to the optical element fixed to the block, the light receiving element is operated, and the output of the optical monitor connected to the light receiving element is at maximum, a method of connecting an array type optical element according to claim 1, characterized in Rukoto to solidify the adhesive. In a method for connecting an array type optical element for joining an array type optical element in which a plurality of optical elements are arranged in an array to a PLC module,
A block in which a plurality of parallel V-grooves are formed on one surface of the first substrate, an optical element is disposed in the V-groove, and the surface of the first substrate on which the V-groove is formed and the second substrate are joined. A step of temporarily fixing an array type optical element cut at a desired width on a surface perpendicular to the optical axis of the optical element to the block, the four sides surrounding the surface perpendicular to the optical axis of the optical element; By first aligning the optical axis of the optical element of the array-type optical element with the optical axis of the optical element of the block by matching,
A second step of applying an adhesive to at least one of the end face of the array-type optical element and the end face of the PLC module in which the optical waveguides of a plurality of channels are formed;
A third step of causing the optical axis of the optical waveguide and the optical axis of the optical element of the array-type optical element to coincide with each other, and curing the adhesive;
A method of connecting array optical elements, comprising: a fourth step of separating the temporarily stopped array optical elements and the blocks.   In the third step, an optical signal is input to an optical waveguide formed in the PLC module, an optical monitor is connected to an optical element fixed to the block, and when the output of the optical monitor is maximum, bonding is performed. The method for connecting array type optical elements according to claim 3, wherein the agent is solidified.   5. The array type optical element according to claim 1, wherein in the first step, the array type optical element and a part of an outer edge of the block are temporarily bonded by bonding with an adhesive. How to connect the elements.   The first substrate and the second substrate are any one of (1) carbon-containing glass, (2) a resin containing any of carbon, silicon, and titanium oxide, and (3) ceramic. Item 6. The method for connecting an array type optical element according to any one of Items 1 to 5.   7. The array type optical element connection method according to claim 6, wherein the optical element is fixed by a carbon-containing thermosetting epoxy resin.   6. The array type optical element connection method according to claim 1, wherein the first substrate and the second substrate are made of metal.   9. The array type optical element connection method according to claim 8, wherein the optical element is fixed by solder.   10. The optical element according to claim 1, wherein the optical element is one of a graded index optical fiber having a refractive index profile in which a refractive index changes in a radial direction, and a step index optical fiber. The connection method of the array type optical element of description.

Images