JP2000338347A - Optical module and production of optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module having an optical waveguide capable of perpendicularly bending the course of the optical waveguide. SOLUTION: This optical module has the optical waveguide 13 which is coupled to perpendicular mirror finished surfaces 12 of a perpendicular mirror finished surface film and changes the course 90 deg. by reflecting a luminous flux at the perpendicular mirror finished surfaces 12 between an optical element tip 14 and an optical fiber 15. The greater part of the optical waveguide 13 is formed of a lower clad layer 20, a core layer 21 and an upper clad layer 22 laminated on a substrate 10. The 90 deg. bending part of the optical waveguide 13 is composed of the perpendicular mirror finished surfaces 12 on the substrate 10 and upper and lower connecting layers 19. The light advancing through the optical waveguide 13 is reflected by the perpendicular mirror finished surfaces 12 of the perpendicular mirror finished surface film and is bent 90 deg. in the optical path which is then introduced to the next waveguide part of the optical waveguide 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module and a method for manufacturing an optical waveguide, and more particularly, to an optical module having an optical waveguide capable of easily bending the optical waveguide and a method for manufacturing the optical waveguide.

[0002]

2. Description of the Related Art A typical polymer optical waveguide conventionally known has a lower cladding layer, a core layer and an upper cladding layer formed on a substrate, and the core layer has a narrow cross section having a substantially square cross section. This is a structure in which a stripline shape is formed, and a side face of the stripline shape is filled with a cladding layer to form an optical waveguide (Japanese Patent Laid-Open No. 6-273631: title of the invention, "optical waveguide"). Here, a resin having a lower refractive index is used for the cladding layer than for the core layer.

Further, a core layer is formed on a transfer mold, a clad layer is applied thereon, the clad layer and the core layer are peeled off from the transfer mold, and a clad layer is further applied to a portion where the core layer is exposed. An optical waveguide manufactured by the method described above is also known (Japanese Patent Application Laid-Open No. 9-281351: title of the invention "Method for Manufacturing Polymer Optical Waveguide"). This optical waveguide also forms a thin stripline-shaped core layer having a substantially square cross section. Further, there is also known an optical waveguide in which a thin stripline-shaped optical waveguide is formed (Japanese Patent Application Laid-Open No. H10-14872).
No. 9: title of invention "Method for forming ridge pattern of polymer optical waveguide core").

[0004]

In the above-mentioned conventional optical waveguide, it is necessary to bend the light path at a right angle or at an angle close to the right angle in order to transmit light within a limited area as short as possible. . In this case, in the conventional optical waveguide, as shown in the plan view of FIG. 16A and the sectional view of FIG. 16B, the lower clad layer 2, the core layer 3, and the upper clad layer 4 are formed on the substrate 1. A method is used in which a bent portion 5 that changes the course by gradually bending the strip-line-shaped core layer 3 of the optical waveguide formed with a radius having a radius of 500 times or more the width of the strip-line shape is used.

For this reason, the single-mode optical waveguide has a strip line shape width of about 10 μm. In that case, a 5-mm radius is required to bend the direction of light at a right angle. A large area is occupied on the substrate to bend the stripline shape, and there is a problem that the mounting area of other chip components on the substrate is narrowed and the mounting density is reduced.

[0006] The present invention has been made in view of the above points,
It is an object of the present invention to provide an optical module having an optical waveguide capable of bending a path of the optical waveguide at a right angle, and a method for manufacturing the optical waveguide.

[0007]

To achieve the above object, an optical module according to the present invention comprises a flat vertical mirror film having a vertical mirror surface formed on a front surface and a back surface bonded to a substrate; Upper and lower connection layers formed on the film,
A first optical waveguide comprising a lower clad layer, a core layer, and an upper clad layer, which is laminated on the substrate from which the vertical mirror film and the upper and lower connection layers have been removed and exposed,
And one end of each core layer of the second optical waveguide is connected to the upper and lower connection layers on the remaining vertical mirror film obliquely to the mirror surface and symmetrically to each other, and Each of the upper cladding layers of the optical waveguide is integrally connected via an opening between one end of each core layer.

In order to achieve the above object, the method of manufacturing an optical waveguide according to the present invention comprises: a first step of forming a flat vertical mirror film having a mirror surface perpendicular to the surface;
A second step of forming a vertical mirror-finished film on the substrate, a third step of removing at least a portion of the vertical mirror-finished film that forms an optical waveguide to expose the substrate, and a third step of exposing the substrate. A fourth step of forming each lower clad layer of the first and second optical waveguides on the substrate and up to the height of the surface of the vertical mirror film left unremoved in the third step; A fifth step of forming the upper and lower connection layers at predetermined positions on the surface of the vertical mirror-finished film, and the first and the second mirrors are inclined and symmetrically with respect to the mirror surface of the vertical mirror film on which the upper and lower connection layers are formed. A sixth step of forming each core layer of the second optical waveguide, and a seventh step of commonly forming an upper cladding layer on each core layer of the first and second optical waveguides. It is characterized by.

In the method for manufacturing an optical module and an optical waveguide according to the present invention, light from a core layer of the first optical waveguide or the second optical waveguide is reflected by a vertical mirror surface via upper and lower connection layers,
The optical path can be changed, for example, by 90 degrees and led to the second optical waveguide or the core layer of the first optical waveguide through the upper and lower connection layers.

In order to achieve the above object, an optical module according to the present invention comprises a core layer having a lower clad layer formed on a substrate, a mirror surface perpendicular to the front surface, and a back surface bonded to the lower clad layer. An upper clad layer is formed by laminating a flat mirror-shaped film consisting of only a flat mirror film and a core layer with an exposed substrate and a core layer being removed by removing portions other than the central portion of the optical waveguide of the vertical mirror-finished film and the lower clad layer. And a first optical waveguide comprising a core layer and an upper cladding layer. One end of each core layer of the first and second optical waveguides is the same as the core layer of the remaining vertical mirror film. It is formed and integrated at the height position, and is connected obliquely to the mirror surface and symmetrically to each other.

In order to achieve the above object, a method of manufacturing an optical waveguide according to the present invention is directed to a first method of forming a flat vertical mirror film having only a core layer and having a mirror surface perpendicular to the surface. Step, a second step of forming a lower clad layer on the substrate, a third step of forming a vertical mirror film on the lower clad layer, and removing at least a portion of the vertical mirror film that forms an optical waveguide. Forming a core layer on the lower clad layer exposed in the fourth step, and leaving the core layer without being removed in the fourth step. The cores of the first and second optical waveguides are formed obliquely and symmetrically with respect to the mirror surface of the vertical mirror film at the height of the surface of the vertical mirror film. Fifth integrated with the layer Characterized in that it comprises a degree, and a sixth step of forming a upper cladding layer in common on the first and the core layer of the second optical waveguide.

In the method for manufacturing an optical module and an optical waveguide of the present invention, the core layer of the vertical mirror film, the first and second
Both core layers can be integrally formed by adjusting the height of the core layer of the optical waveguide.

Further, in order to achieve the above object, the present invention relates to a method for producing a flat vertical mirror film comprising a core layer made of a material whose refractive index is increased by X-ray exposure and having a mirror surface perpendicular to the surface. A second step of forming a lower cladding layer on a substrate, a third step of forming a vertical mirror film on the lower cladding layer, and a step of manufacturing a vertical mirror film. A fourth step of removing only the intersection of the first optical waveguide and the second optical waveguide with the mirror surface of the vertical mirror film, and a first mirror film of the vertical mirror film remaining without being removed by the fourth step. Optical waveguide and second
By exposing X-rays at an angle to the mirror surface and at a position symmetrical to each other with respect to the mirror surface to be the optical waveguide of
A fifth step of forming each core layer of the first and second optical waveguides on the lower cladding layer, and a fifth step of commonly forming the upper cladding layer on each core layer of the first and second optical waveguides. 6 steps. According to the present invention, the removed portion of the vertical mirror film can be only the intersection of the vertical mirror surface and the optical waveguide in the optical waveguide region.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are a plan view and a sectional view, respectively, of a first embodiment of an optical module according to the present invention. As shown in FIGS. 3A and 3B, a vertical mirror surface of a vertical mirror film is coupled between the optical element chip 14 and the optical fiber 15, and the light flux is reflected by the vertical mirror surface 12 to change the course by 90 degrees. An optical module having an optical waveguide 13 is formed, and dotted lines I and II of the optical waveguide 13 are provided.
The portion excluding the 90-degree bent portion shown by is formed in a removed portion 17 from which the vertical mirror film 11 has been removed.

FIG. 1B is a cross-sectional view taken along a dashed line in FIG. 1A. Most of the optical waveguide 13 is a lower clad layer 20, a core layer 21, and an upper clad layer 2 laminated on a substrate 10.
2, the 90-degree bent portion of the optical waveguide 13 is formed between the vertical mirror surface 12 on the substrate 10 and the upper and lower connection layers 1.
The upper and lower connection layers 19 are connected to the core layer 21 and are connected to the upper cladding layer 22 through openings formed in the core layer 21.

The vertical mirror film 11 is a two-layer plate-like film in which a core layer is formed on a clad layer as described later.
As shown in (a), they are formed in an oblique lattice shape. The optical element chip 14 is connected to the wiring 16 via the bump 14. Further, the optical fiber 15 is
The core 23 of the optical fiber 15 is connected to the core layer 21.

Next, a method of manufacturing the optical module according to the present embodiment will be described with reference to FIGS. FIG. 8A shows an optical waveguide in the form of a strip line having a core layer width of 10 μm, a light exit port of about 10 μm of a chip of an optical element (laser diode) with a spot size conversion element or about 10 μm of a single mode optical fiber.
FIG. 4B is a plan view showing that the laser light is guided by connecting to a core having a diameter of 1 μm. FIG. 4B is a diagram illustrating a UV-curable epoxy resin having a refractive index of 1.50 applied on the core layer in a thickness of 30 μm. FIG. 4 is a cross-sectional view showing that an ultraviolet ray is used to expose and cure an optical fiber and an optical element other than the chip mounting part by using an ultraviolet mask, remove an uncured part, and form an upper cladding layer.

First, a 30 μm thick polyimide film having a thickness of 30 μm and a polyimide film having a refractive index of 1.535 and a thickness of 10 μm was formed on a polyimide film having a refractive index of 1.50 and a thickness of 20 μm. obtain. Next, the 30 μm
As shown in the perspective view of FIG. 2, the thick plate-like polyimide film is cut into, for example, bands 6a, 6b, and 6c each having a width of 3 mm, and one cross section along each cutting line 8 of the bands 6a, 6b, and 6c is cut. After mirror polishing by a method such as electrolytic polishing, aluminum is deposited to form first vertical mirror surfaces 7a, 7b and 7c. Next, the strips 6a, 6b, and 6c are adhered again at the cut surfaces (vertical mirror surfaces 7b and 7c and the cut surface which has not been mirror-polished), and one flat film as shown in FIG. obtain.

Next, the flat film is cut again into strips having a width of 3 mm along a cutting line 9 perpendicular to the direction of the vertical mirror surfaces 7a, 7b, 7c of the bonded strips 6a, 6b, 6c. Then, one section is mirror-polished and aluminum is vapor-deposited on the section in the same manner as described above to form second vertical mirror surfaces 51a, 51b and 51c as shown in FIG. 3B. Then, the cross sections are bonded again to obtain a flat film 52 as shown in FIG. In this way, a flat film (vertical mirror film) 52 having a vertical mirror surface formed in a lattice shape is formed.

Subsequently, the periphery of the vertical mirror film 52 is cut along a third cutting line 53 inclined by 45 degrees with respect to the longitudinal direction of the vertical mirror surface, so that the mirror surface perpendicular to the film surface is obliquely gridded. FIG. 4 (b) shows the 30
A vertical mirror film 54 having a thickness of μm (this corresponds to the vertical mirror film 11 in FIG. 1) is prepared.

Next, the silicon substrate 10 shown in FIG.
The installation part of the optical fiber is made of hydrofluoric acid, nitric acid, sulfuric acid,
Chemical etching with an acidic aqueous solution of acetic acid
A V-groove 18 (18 in FIGS. 1 and 8) shown in FIG. When a single-mode optical fiber having a diameter of 125 μm is installed in the V-groove 18, the V-groove 18 is processed so that the core of the optical fiber is positioned at a height of 30 μm above the upper surface of the silicon substrate 10. That is, the silicon substrate 10
The V-groove 18 is machined to a depth that matches the upper surface of the above-mentioned 30 μm-thick vertical mirror film 54 to be adhered.

The vertical mirror film 54 previously prepared is bonded on the silicon substrate 10 with an epoxy resin adhesive to obtain an element having a structure shown in FIGS. 4C and 5C. FIG. 5C is a cross-sectional view taken along a dashed line in FIG. 4C. Subsequently, as shown in FIG. 5D, the silicon substrate 10 to which the vertical mirror film 54 is adhered is coated with an alkali-resistant etching resist, and the mask pattern is exposed to the etching resist and developed. An etching resist pattern 55 is formed. 80 parts of 50% aqueous potassium hydroxide solution and 20 parts of ethanol
Part, immersed in an alkaline etching solution consisting of 10 parts of hydrazine hydrate, and subjected to an etching treatment at 60 ° C. for 5 minutes to install an optical fiber, a mounting area of a square optical element chip of about 1 mm, and an optical element. By removing the wiring portion and the portion where the optical waveguide is formed (17 in FIG. 1A), FIG.
An element having a cross section shown in FIG. Thereafter, the etching resist 55 is peeled off by a known means as shown in FIG. The vertical mirror surface 56 in FIGS. 5E and 5F is one of the vertical mirror surfaces 7a to 7c and 51a to 51c.

Next, in the mounting region of the chip of the optical element exposed earlier, the component terminals for setting the micro bumps of the chip of the optical element and the wiring pattern drawn therefrom are indicated by 57 in FIG. 6A. Then, a copper plating pattern having a thickness of 4 μm is formed. Next, as shown in FIG. 6 (b), the liquid epoxy oligomer and the light were adjusted so that the refractive index after curing was 1.50 until the top surface of the vertical mirror surface was completely filled in the removed portion of the vertical mirror film. The solution 58 containing the polymerization initiator is filled.

After the injection of the solution, an ultraviolet mask is set on the platform, and ultraviolet light is irradiated from above to cure the liquid oligomer in accordance with the pattern of the ultraviolet mask. As shown in the cross-sectional view of FIG.
The remaining portion of the vertical mirror film (3 in the plan view of FIG.
0), and a pattern for masking the mounting area of the optical element chip and the installation area of the optical fiber is formed, and ultraviolet light is applied to portions other than the masked portion to be cured. The masked portion, that is, the mounting area of the chip of the optical element is then removed by phenomena of the oligomer with an isopropanol solution, and FIG.
As shown in (1), a pattern of the lower cladding layer 20 is formed by the oligomer 59 after curing.

Next, an ultraviolet curable resin having a refractive index of 1.530 is applied thereon by spin coating to a thickness of 1 μm. Then, at the point where the optical path of the optical waveguide is to be vertically folded by an ultraviolet mask, as shown in FIGS. A thin film obtained by exposing the pattern and curing the resin is formed as shown in FIG. This film is
The upper and lower connection layers 19, and then the core layer 2 formed thereon
A directional coupler is formed between the substrate 1 and the resin layer having a refractive index of 1.535 on the lattice pattern.

Next, an ultraviolet curable resin having a refractive index of 1.535 and a thickness of 10 μm is formed on the lower cladding layer 20 (the oligomer 59 after curing), and the pattern of the core layer 21 of the optical waveguide is formed. The pattern is transferred and exposed to ultraviolet light to cure the resin, and the uncured portion is dissolved and removed by a development process to form a resin core layer 21 as shown in FIG.

Next, as shown in FIGS. 7 (b) and 8 (b), an ultraviolet curable epoxy resin having a refractive index of 1.50 is applied on the core layer 21 to a thickness of 30 μm. Using a mask, a portion other than the chip mounting portion of the optical fiber and the optical element is exposed to ultraviolet light and cured, and the uncured portion is removed to form the upper cladding layer 22.

The component terminals (3 in FIG. 8 (a)) of the mounting area (31 in FIG. 8 (a)) of the chip of the optical element thus exposed.
2) On top, as shown in FIGS. 1 (b) and 7 (c), an optical element chip 14 having a small solder bump 24 having a diameter of about 26 μm formed on a terminal by an optical element chip with a spot size conversion element is mounted. Then, the solder pump 24 of the chip of the optical element is connected to the component terminal of the copper pattern exposed in the region. The chip 14 of the optical element is self-aligned to the component terminal by the minute solder bump 24,
The exit of the chip 14 of the optical element is aligned with the height of the core layer 21. Further, the single mode optical fiber 15 is installed at the position of the V groove 18 and the core 2 of the optical fiber 15 is provided.
3 is aligned with the core layer 21.

The core layer 21 thus formed is formed as shown in FIG.
As shown in (a), the optical waveguides 28a and 28b having a width of 10 μm and having a width of about 10 μm are formed on a chip (14 in FIG. 1) of an optical element (laser diode) with a spot size conversion element. Approximately 10 μm of exit port or single mode optical fiber (15 in FIG. 1)
1 (b) and guides the laser beam.

Further, at the end of the strip-line optical waveguides 28a and 28b, as shown in FIG.
Parabolic optical waveguides 29a and 29b are formed with a parabola whose distance from the bottom to the opening is 1.43 mm and the width of the opening is 60 μm. That is, the bottoms of the parabolic optical waveguides 29a and 29b are connected to the stripline optical waveguides 28a and 28b. The stripline-shaped optical waveguide 28a and the parabolic-shaped optical waveguide 29a are the first
And the strip-line-shaped optical waveguide 28b and the parabolic-shaped optical waveguide 29b constitute a second optical waveguide.

The parabolic optical waveguides 29a and 29b overlap the stripline optical waveguides 28a and 28b with a length of 40 μm up to the connection portion, and have a width of 20 μm 120 μm from the connection portion. The width becomes 60 μm at 1390 μm ahead. FIG.
As shown in (a), parabolic optical waveguides 29a,
An opening of 9b with a width of 60 μm is connected to the vertical mirror surface 12 of the vertical mirror film. The vertical mirror surface 12 of the vertical mirror film is
The light flux is reflected and the light path is set to 9 on the XY coordinate plane of the folded substrate surface.
Bend 0 degrees. The light beam reflected by the vertical mirror surface 12 of the vertical mirror film is guided to a parabolic opening having a width of 60 μm, and the parabolic bottom is formed 1.43 mm ahead of the opening along the optical path of the light beam. The bottom of
It is connected to the second stripline-shaped optical waveguides 28a and 28b whose traveling direction makes an angle of 90 degrees with the traveling direction of the first spotline-shaped optical waveguide.

The parabolic optical waveguides 29a and 29b
Is used, even if the position of the vertical mirror 12 is shifted in parallel, the light is always focused on the strip line located at the focal point of the parabola. High degree. The first optical waveguides 28a and 28b and the second optical waveguides 29a and 29b constitute the optical waveguide 13 of FIG. 1 described above.

In this manner, the light beam emitted from the light emitting port of the chip 14 of the optical device with the spot size conversion element or the core 23 of the single mode optical fiber 15 is guided to the strip line optical waveguide 28a or 28b. Then, the light is guided from the optical waveguide 28a or 28b to the parabolic optical waveguide 29a or 29b, and the light emitted from the opening of the parabolic optical waveguide 29a or 29b is reflected by the vertical mirror surface 12 of the vertical mirror film to make the optical path 90 °.
And the optical path is changed to the next parabolic optical waveguide 29.
b or 29a, the light beam guided to the bottom of the parabolic shape is applied to the second stripline-shaped optical waveguide 28b.
Alternatively, the laser light is guided to the second stripline-shaped optical waveguide 28b or 28a which forms an angle of 90 degrees with the stripline-shaped optical waveguide 28a or 28b.

As a method of forming the above optical waveguide, the photocurable resin is exposed to ultraviolet light to be cured, and the uncured portion is dissolved and removed to form the core layer 21, on which the low refractive index clad layer 22 is formed. Was formed, but in order to form the core layer 21,
It is also possible to form the core layer 21 and the (side surface) cladding layer 22 by exposing a material whose refractive index changes by light exposure to change the refractive index depending on the location of the film surface.

Further, it is also possible to produce an optical module using a vertical mirror film having only one vertical mirror surface. The substrate of this embodiment is not limited to a silicon substrate, and can be manufactured by coating a metal substrate with an insulating resin and using a ceramic substrate, a glass substrate, or an organic resin substrate. It can be manufactured as well.

Further, even if the direction of the vertical mirror surface of the vertical mirror film is not necessarily 45 degrees in the vertical and horizontal directions of the optical module, the optical waveguide connected to the chip of the optical element or the opening of the optical fiber is formed by the vertical mirror surface of the vertical mirror film. The first optical waveguide is formed to be connected in an oblique direction to the first mirror, and the angle of the vertical mirror is set so that the second mirror is formed at a position symmetrical to the first mirror with respect to the vertical mirror of the vertical mirror film. As long as it is installed, the angle of the vertical mirror surface can be arranged at any angle.

Next, the operation of this embodiment will be described. First, with reference to FIG. 8, a description will be given of the operation of converting a light beam at the XY coordinates on the substrate surface.

An optical waveguide 28a having a stripline shape,
If the diameter of 28b is d (= 10 μm), the spread angle (half angle) of the light emitted from the mouth is calculated as (4 / π) × λ / d radian. That is, light having a wavelength λ of 1.3 μm is converted into a parabolic optical waveguide 29 having a diameter of about d = 10 μm.
a, 29b, the spread angle of the light is 0.1 mm.
17 radians (9.7 degrees), a parabolic 1.4
At the position of the opening 3 mm ahead, the width of the light beam is 243 μm (= 0.
17 x 1.43 mm).

Since the width of the openings of the parabolic optical waveguides 29a and 29b is 60 μm, the light beam is reflected on the parabolic side surface. Then, the divergence angle of the light beam is corrected, and the divergence angle is set to 0.028 in a parabolic 60 μm opening.
Radians. The spread angle is 2.8 μm at 100 μm ahead, which is only about 5% of the luminous flux having a width of 60 μm, and has little effect on the optical path 100 μm ahead.

Next, with reference to FIG. 8B, the operation of converting a light beam observed from an XZ coordinate plane representing a cross section of the substrate surface will be described. The luminous flux entering the parabolic optical waveguide (first optical waveguide) on the substrate surface and transmitting in the Z direction is a direction composed of the upper and lower connection layers 19 having a thickness of 2 μm in the upper and lower connection regions and the core layer 26 of a vertical mirror film. Guided to a vertical mirror film by a sex coupler.

In the directional coupler, when the relative refractive index difference between the core layer 26 and the upper and lower connection layers 19 is about 0.01, the refractive index of the upper and lower connection layers 19 is adjusted to the core layer (the core layer 21 of the optical waveguide). If the relative refractive index of the value obtained by dividing by the refractive index of the core layer 26 of the vertical mirror film is equal to n, the refractive index of light is λ, and the thickness of the upper and lower connection layers 19 is d, Generally, exp (−2 × π × ((1-n ² ) ^1/2 ) × d / λ)
The evanescent light attenuated at a rate of about
Ooze and transmit.

If the refractive index of the core layer is 1.535 and the refractive index of the upper and lower connection layers 19 is 1.530, n = 0.996
7 and λ = 1.3 μm, the light is reduced by half at d = 1.8 μm and reduced to 1/10 or less at d = 6 μm by the above directional coupler. Therefore, the vertical mirror film core layer 2 is separated from the optical waveguide through the upper and lower connection layers 19.
6 has a mode coupling constant κ at which light seeps. When the thickness of the core layer 21 of the optical waveguide is equal to the thickness of the core layer 26 of the vertical mirror-finished film, and the thickness is t, the value of the mode coupling constant κ is about the following equation 1.

Κ〜 (λ / t ² ) × exp (−2π ((1-n ² ) ^1/2 ) × d / λ) (Equation 1) Then, transfer from the core layer 21 to the vertical mirror-finished film. The light flux periodically fluctuates in accordance with the length z of the upper and lower connection layers 19 in the light traveling direction. Then, the distance z represented by the following equation 2
, The total luminous flux is completely transferred from one of the core layer 21 of the optical waveguide and the core layer 26 of the vertical mirror film to the other core layer.

Z = (π / 2) / κ (Equation 2) Here, n is set to 0.9967, and the wavelength λ is set to 1.3.
When t = 10 μm and d = 1 μm with light of μm, Equation 1
And z = 229 μm is obtained from Equation 2. Therefore, the region of the upper and lower connection layers 19 is formed to have a distance of 229 μm in the light traveling direction. As shown in FIG. 8A, when light is incident on the region of the upper and lower connection layers 19 at an oblique angle of 45 degrees, the upper and lower connection layer regions are separated from the mirror surfaces 12 to 16 of the vertical mirror film.
What is necessary is just to form a region having a width of 2 μm.

As a result, the light beam passes through the directional coupler to the core layer 26 of the vertical mirror film, is reflected by the vertical mirror surface 12 of the vertical mirror film, and then again passes through the directional coupler. The transition is made to the core layer 21 of the optical waveguide.

Further, in this optical module, as shown by 40 in FIG. 9, the optical waveguides cross each other, and the core layers of those optical waveguides can be integrated at the intersection. This is because the light beams traveling in the intersecting optical waveguides travel in directions independent of each other as shown by arrows, and the rate at which signals are mixed in the light beams by the intersection is negligibly small. In FIG. 9, the portion indicated by the dotted line III has the configuration shown in FIG.

Next, a second embodiment of the present invention will be described. FIG. 10A is a plan view of a main part of an optical module according to a second embodiment of the present invention, and FIG. 10B is a cross-sectional view of the optical module according to the second embodiment of the present invention. . In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the second embodiment shown in FIG. 10, as shown in FIG. 10B, the core layer formed by the remaining portion 42 of the vertical mirror film having the vertical mirror surface 46 is formed at the same height as the core layer 44. -It is characterized by being a core layer of the body.

Next, the manufacturing method of the present embodiment will be described with reference to FIGS. First, a plate on which a thin film of polyimide resin having a refractive index of 1.535 or a polycarbonate resin having a thickness of 10 μm (this is referred to as a core layer of a vertical mirror film) is cut into a strip having a width of several millimeters and the end face is polished, Aluminum is deposited on the end surface to form a mirror surface. Next, a band having the above-mentioned mirror surface formed on the end face is attached with the end face abutting on a plane. In this way, a vertical mirror-finished film having a mirror surface perpendicular to the film surface formed in a diagonal lattice pattern is prepared.

Next, as shown in FIG. 11A, a V-groove 18 is formed on the portion of the silicon substrate 10 where the optical fiber is to be provided by chemical etching. Next, the silicon substrate 1
The component terminals on which the micro bumps of the optical element chip 14 are placed and the wiring patterns 16 drawn therefrom are placed on the
It is formed with a μm copper plating pattern.

Next, as shown in FIG. 11 (b), an ultraviolet curable epoxy resin 60 having a refractive index of 1.50 is applied to a thickness of 26 μm thereon, and a portion other than the optical module mounting portion and the optical fiber installation position is applied. The portion is exposed using an ultraviolet mask 61 and then cured to form an ultraviolet cured portion as a lower cladding layer 43 as shown in FIG.

Next, as shown in FIG. 11D, an ultraviolet-curable epoxy resin having a refractive index of 1.50 was applied on top of this by several μm.
m, and the vertical mirror film 62 previously formed is bonded with the resin. Subsequently, the thickness of 10 μm
The vertical mirror-finished film 62 is chemically etched with an alkaline aqueous solution to remove a portion where the optical fiber 15 is mounted, a portion where the optical element chip 14 is mounted, and a portion where the optical waveguide is formed.
As shown in FIG. 11E, the vertical mirror film remaining portion 42 having the vertical mirror surface 46 is left at other positions.

Next, as shown in FIG. 12A, the liquid level is adjusted to the full surface of the remaining portion 42 of the vertical mirror film after chemical etching, and the refractive index after curing is 1.535.
After the solution 63 containing the liquid epoxy oligomer and the photopolymerization initiator to be filled is filled in the portion where the vertical mirror film is removed, ultraviolet rays are irradiated from above using the ultraviolet mask 64 to cure the resin into the shape of the core layer of the optical waveguide. The uncured portion of the ultraviolet curable resin of the core layer and the lower cladding layer
The uncured portion of the ultraviolet curable epoxy resin of No. 3 is dissolved and removed, and the core layer 44 and the lower cladding layer 43 are formed together. As shown in FIGS. 10 (b) and 12 (b), the core layer 44 formed in this manner is the same as the core layer formed at the same height as the core layer of the remaining portion 42 of the vertical mirror film. Become.

Next, as shown in FIG. 12C, an ultraviolet curable epoxy resin 65 having a refractive index of 1.50 is applied on the core layer 44 to a thickness of 30 μm, and the optical element chip mounting area is UV light is exposed through an ultraviolet mask 66 for shielding the resin, thereby curing the resin in a portion other than the mounting region of the chip of the optical element. Next, the uncured portion of the ultraviolet curable resin is dissolved and removed, and the upper clad layer 45 is formed as shown in FIG.
It is formed as shown in FIG.

As shown in FIGS. 10 (b) and 12 (e), the terminal of the optical element chip having the spot size conversion element has a diameter of about 26 μm on the component terminal in the mounting area of the chip of the optical element chip thus exposed. The chip 14 of the optical element on which the small solder bump 24 is formed is mounted, the single mode optical fiber 15 is provided at the position of the V groove 18, and the core 23 of the optical fiber 15 is aligned with the core layer 44.

As shown in FIG. 10A, the core layer 44 is formed by connecting stripline-shaped optical waveguides 47a and 47b each having a width of 10 μm to an optical element (laser diode) with a spot size conversion element. 14 light exit port of about 10 μm or single mode optical fiber 1
5 is connected to the core 23 having a diameter of about 10 μm to guide laser light.

The shape of the core layer 44 of the optical waveguide is the same as in the first embodiment, and the light beam emitted from the light exit of the chip 14 of the optical element with the spot size conversion element or the core 23 of the single mode optical fiber 15 is used. Is guided to the stripline-shaped optical waveguide 47a or 47b, and then guided from the optical waveguide 47a or 47b to the parabolic optical waveguide 48a or 48b, and emitted light from the opening of the parabolic optical waveguide 48a or 48b The light reflected by the vertical mirror surface 46 of the core layer portion of the vertical mirror surface film, bending the optical path by 90 degrees, receiving the optical path at the opening of the next parabolic optical waveguide 48b or 48a, and guiding the light flux guided to the bottom of the parabolic shape By leading the light to the second stripline-shaped optical waveguide 47b or 47a, the stripline-shaped optical waveguide 47 is formed. Or 47b and the second strip line shaped optical waveguide 47b or 47 at an angle of 90 degrees
Guide laser light to a.

Next, a third embodiment of the present invention will be described. FIG. 13 and FIG. 14 are explanatory views in each step of the third embodiment of the method of manufacturing an optical waveguide according to the present invention. In the figure, the same components as those in FIGS. 10 to 12 are denoted by the same reference numerals. In the present embodiment, similarly to the second embodiment, as shown in FIG.
A UV-curable epoxy resin having a refractive index of 1.50 is applied to a thickness of 26 μm on the silicon substrate 10 on which is formed, and the portions other than the mounting portion of the optical element chip and the installation portion of the optical fiber are exposed and cured using an ultraviolet mask. Then, the lower clad layer 69 is formed. Next, a polyimide vertical mirror film 70 having a refractive index of 1.535 is formed on the lower cladding layer 69 with an ultraviolet curable epoxy resin adhesive having a refractive index of 1.50.
Paste.

Next, as shown in FIG. 13B, a copper pattern 72 is plated on the vertical mirror film 70 having a vertical mirror surface 71 by 10 μm, a photoresist is applied thereon, and the mask pattern is exposed. The copper is etched using the developed etching resist to form a copper pattern 73 as shown in FIG. Subsequently, FIG.
As shown in (d), the copper pattern 73 is used as a mask to irradiate a carbon dioxide gas laser beam to evaporate and remove a vertical mirror surface portion intersecting the optical waveguide forming position.

Next, the removed portion is filled with a polyimide precursor solution 74 having a refractive index of 1.535 as shown in FIG.
For 1 hour, at 250 ° C. for 30 minutes, and at 350 ° C. for 1 hour to form a polyimide 75 as shown in FIG. Next, as shown in FIG. 14A, using the copper pattern 73 as a mask, the polyimide 75 at the mounting part of the optical element chip and the part where the optical fiber is installed is applied to the second laser light
To remove.

Next, as shown in FIG. 14A, the uncured ultraviolet-curable epoxy resin under the window opened by the irradiation of the second laser light 76 is dissolved and removed. Lower cladding layer 6 for mounting part and optical fiber installation part
9 is removed. Thereafter, as shown in FIG.
The copper pattern 73 is removed by etching.

Next, as shown in FIG. 14C, an X-ray 77 having a peak energy of 100 eV is exposed on the polyimide 75 using an X-ray mask pattern to increase the refractive index in the polyimide film. Optical waveguide core layer 7
8 are formed. Next, an ultraviolet-curable epoxy resin having a refractive index of 1.50 is applied thereon so that the height above the vertical mirror-finished film is 30 μm.
Ultraviolet light is exposed using an ultraviolet mask that shields the chip mounting area of the optical element, and the ultraviolet curable epoxy resin in a part other than the chip mounting area of the optical element is cured. Then, as shown in FIG. 14D, the uncured portion is dissolved and removed to form the upper cladding layer 79.

FIG. 15 shows a third optical module according to the present invention.
1 shows a plan view of the embodiment. In the figure, the same components as those in FIGS. 1A, 13 and 14 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 15, the optical waveguide 13 is formed on the substrate 10 as shown in FIG.
This is a laminated structure of the lower cladding layer 69, the core layer 78, and the upper cladding layer 79. In the region of the optical waveguide 13, only the intersection 81 between the vertical mirror surface 71 and the optical waveguide 13 has the vertical mirror film 70 removed. This is a portion filled with polyimide 75. Further, a removed portion 82 of the lower cladding layer 69 is formed in a mounting portion of the optical element chip 14 and a setting portion of the optical fiber 15. The area indicated by the dotted line I in FIG. 15 has a planar structure similar to the planar structure shown in FIG.

In this embodiment, the removed portion of the polyimide vertical mirror film is to remove only the intersection 81 between the vertical mirror surface and the optical waveguide in the region of the optical waveguide 13 except for the position of the optical element chip and the optical fiber. Therefore, the amount of the waste liquid from which the polyimide is removed can be reduced because the removed portion is small.

The present invention is not limited to the above-described embodiment.
May not have the oblique lattice shape shown in FIG. 1 or FIG. 4 (b), and may have, for example, a structure in which vertical mirror surfaces are formed in parallel.

[0065]

As described above, according to the present invention,
Create a vertical mirror film with a mirror surface perpendicular to the substrate surface formed in a diagonal lattice shape, guide the light from the core layer to the vertical mirror film via the upper and lower connection layers, reflect it at the vertical mirror surface and refract the optical path Therefore, the light can be easily guided to the optical waveguide in the perpendicular direction.

Further, according to the present invention, since the height of the core layer of the vertical mirror film and the core layer of the optical waveguide are matched to form the two core layers, the formation of the upper and lower connection layers becomes unnecessary and the production becomes easier. The manufacturing cost of the optical module can be reduced.

Further, according to the present invention, the removed portion of the vertical mirror film is formed so as to remove only the intersection of the vertical mirror surface and the optical waveguide in the region of the optical waveguide except for the position of the optical element chip and the optical fiber. As a result, the removed portion is small, and the amount of waste liquid from which the polyimide has been removed can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for producing a vertical mirror-finished film used in the present invention.

FIG. 3 is an explanatory view (1) of each step of the first embodiment of the manufacturing method of the present invention.

FIG. 4 is an explanatory view (2) of each step of the first embodiment of the manufacturing method of the present invention.

FIG. 5 is an explanatory view (3) of each step of the first embodiment of the manufacturing method of the present invention.

FIG. 6 is an explanatory view (No. 4) of each step of the first embodiment of the manufacturing method of the present invention.

FIG. 7 is an explanatory view (No. 5) of each step of the first embodiment of the manufacturing method of the present invention.

FIG. 8 is a plan view and a cross-sectional view of a main part according to the first embodiment of the present invention.

FIG. 9 is a diagram showing that optical waveguides cross each other, and that the core layers of those optical waveguides can be integrated at an intersection.

FIG. 10 is a plan view of a main part according to a second embodiment of the present invention and a cross-sectional view of the entire configuration.

FIG. 11 is an explanatory view (1) of each step of the second embodiment of the manufacturing method of the present invention.

FIG. 12 is an explanatory view (2) of each step of the second embodiment of the manufacturing method of the present invention.

FIG. 13 is an explanatory view (1) of each step of the third embodiment of the manufacturing method of the present invention.

FIG. 14 is an explanatory view (2) of each step of the third embodiment of the manufacturing method of the present invention.

FIG. 15 is a plan view of a third embodiment of the present invention.

FIG. 16 is a plan view and a cross-sectional view of an example of a conventional optical module in a case where a light path is bent in a right angle direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Substrate 11, 54, 62, 70 Vertical mirror surface film 12, 46, 56, 71 Vertical mirror surface 13 Optical waveguide 14 Optical element chip 15 Optical fiber 16 Wiring 17 Vertical mirror film removal part 18 V groove 19 Upper and lower connection layers 20, 43, 69 Lower cladding layer 21, 44, 78 Core layer 22, 45, 79 Upper cladding layer 23 Core of optical fiber 25 Cladding layer of vertical mirror film 26 Core layer of vertical mirror film 28a, 28b, 47a, 47b Stripline optical waveguide 29a, 29b, 48a, 48b Parabolic optical waveguide 30, 42 Vertical mirror film residual portion 58 Liquid oligomer 59 Cured oligomer 75 Polyimide 81 Vertical mirror film removal, Polyimide filling portion 82 Lower cladding layer removing portion

Claims (11)

[Claims] 1. A flat vertical mirror film having a vertical mirror surface formed on a front surface and a back surface bonded to a substrate, an upper and lower connection layer formed on the vertical mirror film, the vertical mirror film and an upper and lower connection A first and a second optical waveguide comprising a lower cladding layer, a core layer, and an upper cladding layer, which are laminated on the substrate where the layer is removed and exposed, wherein the first and second optical waveguides are One end of each core layer is connected to the upper and lower connection layers on the remaining vertical mirror film obliquely to the mirror surface and symmetrically to each other, and the first and second optical waveguides are connected to each other. An optical module, wherein each upper clad layer is integrally connected via an opening between one ends of the respective core layers. 2. The perpendicular mirror film, wherein the mirror surface is formed in a cross section perpendicular to the surface of a two-layer film in which a core layer is formed on a clad layer, and the upper and lower connection layers are 2. The optical module according to claim 1, wherein the first and second optical waveguides are made of a material having a lower refractive index than a refractive index of each core layer. 3. A flat vertical mirror-finished film consisting of only a core layer, wherein a mirror surface perpendicular to the front surface is formed on the substrate on which the lower cladding layer is formed, and a back surface is adhered to the lower cladding layer. An upper clad layer is laminated on the substrate and the core layer, in which a portion other than the center portion of the optical waveguide of the film and the lower clad layer is removed and exposed, and the lower clad layer, the core layer and the upper clad layer are formed. A first and a second optical waveguide, wherein one end of each of the core layers of the first and the second optical waveguide is formed at the same height position as the core layer of the remaining vertical mirror film. Along with being integrated,
An optical module, which is obliquely connected to the mirror surface and symmetrically connected to each other. 4. The first and second optical waveguides are respectively connected to a vertical mirror surface of the vertical mirror film via a stripline-shaped first optical waveguide portion and a parabolic second optical waveguide portion. 2. The method according to claim 1, wherein
Or the optical module of 3. 5. The light guide according to claim 1, wherein the first and second optical waveguides are formed such that a light beam traveling through the core layer of the first or second optical waveguide is reflected by the vertical mirror surface and formed at a right angle or an angle close thereto. The optical module according to claim 1, wherein the optical module is formed so that an optical path is changed so as to advance in the core layer of the second optical waveguide or the first optical waveguide. 6. A first step of forming a flat vertical mirror film having a mirror surface perpendicular to a surface thereof, a second step of forming the vertical mirror film on a substrate, and a step of forming the vertical mirror film on a substrate. A third step of exposing the substrate by removing at least a portion where the optical waveguide is formed; and a step of removing the substrate on the substrate exposed by the third step and remaining without being removed by the third step. A fourth step of forming each of the lower cladding layers of the first and second optical waveguides up to the height of the surface of the vertical mirror-finished film, and connecting vertically to a predetermined position on the surface of the left vertical mirror-finished film. A fifth step of forming a layer; and forming the core layers of the first and second optical waveguides obliquely and symmetrically with respect to the mirror surface of the vertical mirror film on which the upper and lower connection layers are formed. The sixth to form each Step and the first and seventh step of the manufacturing method of the optical waveguide, which comprises a forming the upper cladding layer in common on each core layer of the second optical waveguide. 7. The vertical mirror-finished film in which the mirror surface is formed in a cross section perpendicular to the surface of a two-layer film in which a core layer is formed on a clad layer, 7. The optical waveguide according to claim 6, wherein in the fifth step, the upper and lower connection layers are formed of a material having a lower refractive index than the refractive index of each core layer of the first and second optical waveguides. Manufacturing method. 8. A first method for producing a flat vertical mirror-finished film having only a core layer and having a mirror surface perpendicular to the surface.
A second step of forming a lower clad layer on a substrate; a third step of forming the vertical mirror film on the lower clad layer; and forming at least an optical waveguide among the vertical mirror films. A fourth step of exposing the lower cladding layer by removing a portion to be formed, and forming a core layer on the lower cladding layer exposed by the fourth step, and forming the core layer by the fourth step. Formed as the respective core layers of the first and second optical waveguides at the height of the surface of the vertical mirror film left unremoved and obliquely and symmetrically with respect to the mirror surface of the vertical mirror film. A fifth step of integrating with the core layer of the vertical mirror film, and a sixth step of commonly forming an upper clad layer on each core layer of the first and second optical waveguides. Manufacture of an optical waveguide characterized by including Method. 9. A first step of forming a flat vertical mirror film having only a core layer of a material whose refractive index is increased by X-ray exposure and having a vertical mirror surface formed on a surface thereof, and a lower cladding film on the substrate. A second step of forming a layer; a third step of forming the vertical mirror film on the lower clad layer; and a first optical waveguide and a second optical waveguide to be manufactured among the vertical mirror films. A fourth step of removing only a portion of the vertical mirror film that intersects with the mirror, and the first optical waveguide and the second light guide of the vertical mirror film remaining without being removed in the fourth step. Each of the core layers of the first and second optical waveguides is exposed to X-rays at a position oblique to the mirror surface and symmetrical to each other with respect to the mirror surface, thereby increasing the refractive index. A fifth step of forming on the layer; Method of manufacturing an optical waveguide, which comprises a sixth step of forming a upper cladding layer in common on the first and the core layer of the second optical waveguide. 10. The first and second optical waveguides are respectively connected to a vertical mirror surface of the vertical mirror film from a stripline-shaped first optical waveguide portion through a parabolic second optical waveguide portion. The method for manufacturing an optical waveguide according to any one of claims 6 to 9, wherein: 11. The first and second optical waveguides are arranged such that a light beam traveling through the core layer of the first optical waveguide or the second optical waveguide is reflected by the vertical mirror surface and forms a right angle or an angle close thereto. The optical path can be changed to the second optical waveguide or the first optical waveguide.
The optical module according to any one of claims 6 to 9, wherein the optical module is formed so as to advance in a core layer of the optical waveguide.