JP3456685B2 - Fabrication method of waveguide type optical element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a waveguide type optical element that constitutes an optical device used in the fields of optical communication and optical information processing.

[0002]

2. Description of the Related Art Conventionally, a waveguide type optical element of this type uses quartz glass, dielectric crystal LiNbO ₃ or the like as a material, and as a manufacturing method, photolithography or dry etching process often used in an LSI process. Microfabrication was performed by a combination of the above to manufacture a high-performance waveguide type optical element (for example, reference: Masao Kawachi Opticala
nd Quantum Electronics Volume 22 Page 391 (19
90 years))). However, the manufacturing process is complicated,
Due to the high cost of the manufacturing apparatus, it was decided that it was not suitable for mass production or that the element could not be manufactured at low cost. Further, even if the element is manufactured, thereafter, it is not suitable for mass production because precise adjustment is required for optical coupling with other optical components such as an optical fiber. In addition, although waveguide devices have been manufactured using cheaper materials and polymer materials (reference; Imamura et al., Electr
onics Lettes Vol. 27, page 1342 (1991)
In the same method as that for producing a glass waveguide, it is necessary to repeat the same patterning process for each substrate and the etching apparatus is expensive.
Even if the material is inexpensive, there is a drawback that the cost is not the same as that of the glass waveguide because the cost is not the same as that of the glass waveguide. Further, there is a problem that even if a device is manufactured in the same manner, thereafter, it is not suitable for mass production because precise adjustment is required for optical coupling with other optical components such as an optical fiber. In order to reduce the process cost or avoid the complexity of optical coupling, a method of producing a polymer waveguide by a polymer molding method suitable for mass production such as injection molding by transferring a mold has been proposed, but However, there was a drawback that the process was complicated.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, and it is possible to easily manufacture a high-performance waveguide type optical element at low cost, and to compare it with other optical parts. It is an object of the present invention to provide a method of manufacturing a waveguide type optical element, which can be manufactured by integrating a positioning portion such as a V-groove with a waveguide, which does not require a complicated positioning work when optically coupling.

[0004]

In order to solve the above-mentioned problems, a method of manufacturing a waveguide type optical element of the present invention is a process of applying a polymer material on a substrate to obtain a lower clad material , On top of the mold with a partially convex
To form a lower clad layer partially having a recess.
Extent, on the lower cladding layer, the lower class when cured
A step of applying a liquid photo-curable material that forms a resin having a higher refractive index than the head layer, and a coating film of the photo-curable material
Above, have a desired concave portion, only the concave shaped portion is a light passing
The other parts are covered with a mold that blocks light, and the concave shape is used.
A step of encapsulating the material to the light cured part, light is irradiated to the mold over, curing only the material of the photocurable enclosed in the concave portion of the mold, removing the mold
Removed by It includes a washing stream to step a solvent material to photocuring the liquid that was present in addition to the concave portion of the mold, the lower class
The core ridge of the optical waveguide is formed in accordance with the position of the recess formed in the pad layer .

In the present invention, the shape of the lower clad layer is formed.
The recess formed is a V-groove for aligning the optical fiber and
And / or rectangular grooves that align the optical components.

In the present invention , a mold having a concave portion and
Glass can be used or a polymer which is transparent at the wavelength to light cured.

In the present invention , the liquid photocurable material is an epoxy-based monomer or oligomer , or an unsaturated group.
Monomers or oligomers containing siloxane, and siloxane
From the group consisting of monomers or oligomers with bonds
Including a monomer or oligomer of choice and a photoinitiator,
It preferably has a viscosity of 10,000 cps or less at room temperature.

In the present invention, the lower clad material
Is an epoxy-based UV monomer, and the partial convex portion is
The mold that you have is a mold that allows the entire surface to transmit light, and the light passes through the mold.
To cure the epoxy UV monomer by light.
A lower clad layer having a concave portion is separately formed .

[0009]

[0010]

[0011]

[0012]

[0013]

In the present invention, a waveguide is basically manufactured by a molding process for transferring a pattern of a mold, which is a processing method suitable for mass production, from a polymer material which is an inexpensive material. The problem at this time is that since the polymer waveguide requires two kinds of materials, a core and a clad, for example, even if a clad material is used to form a core groove provided by molding, When filling the groove with the core material, in order to remove the excess core material after filling the groove,
A complicated process such as etching and polishing is required.

Therefore, in the manufacturing method of the present invention, it is possible to remove the excess portion of the treatment process with a solvent, that is, a process that can be removed with a solvent like the developing process in the photoresist step. , The die used is devised.

Further, the structure of a photo-curing type material as a molding processing material is a structure having an epoxy ring, an unsaturated group, silicone and the like and having little curing shrinkage, so that a processing error at the time of molding processing is reduced. .

Further, by devising the structure of the mold used in the present invention, the V-groove for mounting the waveguide and the optical fiber can be integrally formed, so that the waveguide and the optical fiber are optically coupled. Can be performed accurately and easily.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Guidelines for solving the above problems in the present invention will be briefly described.

(1) In the waveguide manufacturing process for manufacturing an element, a simple processing method suitable for mass production is used without using a large-scale device, and (2) a material is low in cost and processing is difficult. Easy to use polymeric material,
(3) When manufacturing a waveguide, use a mold in consideration of alignment with other optical components such as an optical fiber, and simplify the work for optical coupling as a post process as much as possible. To be

First, FIGS. 1 to 5 show the light applied to the present invention.
A rough procedure of a method for manufacturing a waveguide will be shown.

(A) A polymer film is applied onto the substrate 1 by means such as spin coating or dipping, and the cladding layer 2 is formed.
(Fig. 1).

(B) Next, a monomer or oligomer 3 which exhibits fluidity at room temperature is applied onto the clad layer 2 by means such as spin coating or dipping (FIG. 2).

(C) Next, a mold 4 having a desired shape
The substrate is covered with the above-mentioned monomer or oligomer 3
Is cured by light irradiation 5 to form the core portion 6 (FIG. 3).

(D) After removing the mold, the uncured material 3 is developed by a solvent and washed away (FIG. 4).

(E) After that, the polymer film 2 is covered again to form the waveguide element 7 composed of the core cladding (FIG. 5).

In the step (c), when the light-curable material is inserted into the groove, the viscosity of the material is 1000.
With a material of 0 cps or more, it is difficult to control the thickness of the core, so the viscosity of the material inserted into the groove is 1000 cp.
s or less is desirable.

The basic structure of the mold 4 used for producing the optical waveguide is shown in FIGS. 6 and 7. As the material of the mold 21, any material such as polymer and glass can be used as long as it can transmit light. FIG. 6 is an example seen from the upper surface of the mold. FIG. 7 is viewed from the side. The upper surface and side surfaces of the groove 22 for transferring the core portion have a structure through which light passes, and the other portion 23 is patterned with a material such as chrome used for a mask in a normal photo process so as not to transmit light. ing. Due to this structure, when a photo-curable material is irradiated through this mold with light, only the desired part is cured, and the ridge structure necessary for producing a channel structure waveguide is irradiated with light. In addition, it is possible to easily and accurately produce the film only by the developing process.

[0028]

The present invention will be described in detail below with reference to specific examples.

Reference Example 1 A method of manufacturing an optical waveguide applied to the present invention will be described. 8 to 12 show the manufacturing procedure.

First, a substrate 31 is prepared, and a polymer film 32 forming a clad layer is applied thereon by spin coating.
It is cured (refractive index 1.5). Next, an epoxy UV monomer (viscosity 1000 cp, see below formula of main component) 33 is applied (FIG. 8).

[0031]

[Chemical 1]

Next, the mold 34 is covered and UV light 35 is irradiated (FIG. 9). This monomer 33 is photo-cured by UV light, and the waveguide core 36 (n = 1.52, wavelength 1.31 μm).
m). Here, the mold 34 has a width of 50 μm and a height of 5
It is a glass mold having a recess of 0 μm and a length of 50 mm. As shown in the plan view (FIG. 10), the UV resin has a structure in which light does not pass except the recess. The core 36 is cured and has a convex shape (FIG. 11). Next, after washing away the portion that has not been cured by the light-shielding portion of the mold with a solvent, the polymer film 32 is covered again,
A waveguide type optical element 37 is manufactured (FIG. 12).

Using an LD light source (wavelength 1.31 μm),
When the waveguide loss of this waveguide type optical element 37 was measured, the waveguide loss was 0.3 dB / cm.

Reference Example 2 By the same operation as in Reference Example 1, a waveguide type optical element was produced using a monomer having the following unsaturated group as the main component of the monomer 33 (clad refractive index n = 1. 47, core refractive index n = 1.48, core width 7 μm, height 7 μm).

The waveguide loss of the device is 0.1 dB / cm.
Met.

[0036]

[Chemical 2]

[0037] However, n, m represents an integer of 1 or more, ginseng
For Remarks Example 2 is n = 1, m = 1.

Reference Example 3 In the same operation as in Reference Example 1, a waveguide type optical element (clad refractive index n = 1.50, core refraction n = 1.50, using the following oligomer having a siloxane bond as the main component of the monomer 33) was used. Ratio n = 1.51, core width 7 μm, height 7 μm) were manufactured.

The waveguide loss of the device is 0.1 dB / c.
m (wavelength 1.3 μm), 0.5 dB / cm (wavelength 1.5
5 μm).

[0040]

[Chemical 3]

[0041] However, n, m represents an integer of 1 or more, ginseng
In the case of Consideration 3 , n = 2 and m = 1.

Example 4 A method of manufacturing a waveguide type optical element with a V-groove by the method of the present invention will be described. 13-
FIG. 20 shows the manufacturing procedure.

First, the substrate 40 is prepared, and the epoxy UV monomer 41 is applied onto the substrate 40 (FIG. 13). Next, the cross-sectional structure is as shown in FIG. 14 with an opening of 60 ° and a height of 150μ.
A glass mold 42 having a V-shaped convex portion 43 of m, a width of 170 μm and a length of 20 mm is placed on the monomer 41, and the monomer 41 is photo-cured by UV light 44, and a cured film 45 (n =
1.51 and wavelength 1.31 μm). Monomer 41 is
Cured along the mold shape, V groove (opening angle 60 °, height 1
50 μm, length 20 mm) 46 is formed on the surface of the cured film 45 (FIG. 15). The mold 42 in this case is manufactured so that light is transmitted through the entire surface.

Next, as shown in FIG. 16, a mold 47 is formed in which a narrow groove portion 48 (depth 10 μm, width 10 μm, length 40 mm) is formed, and light cannot be transmitted except in the narrow groove portion. ,prepare. An epoxy-based UV monomer 49 that serves as a core is inserted into the narrow groove portion 48 of the mold 47, and is cured by light irradiation (FIG. 17). By this operation, the core ridge 400 is formed on the cured film 45. At this time, the cured film 4
5, the V groove 46 and the narrow groove portion 48 of the mold 47
Width of 10μm and height of 10μ
m core ridge 400 (n = 1.52, wavelength 1.31μ
m) is manufactured according to the position of the V groove 46 (FIG. 1).
8). The uncured portion was easily washed off with solvent.

Next, the epoxy UV monomer 41 is applied and cured again to form the upper clad layer, and the waveguide type optical element 401 with V-groove is manufactured (FIG. 19).

FIG. 20 is an external view of the completed waveguide type optics 401.
Shown in. When an optical fiber was fixed in this V groove 46 and the waveguide loss was measured using an LD light source (wavelength 1.31 μm), the connection loss with the fiber was 0.2 dB and the waveguide loss was 0.3 dB / cm. Met. Also, when the fine groove portion 48 has a depth of 40 μm, a width of 40 μm, and a length of 40 mm, a waveguide with a V groove is similarly formed, and the fiber connection loss is 0.1 d.
B, Waveguide loss 0.1 dB / cm (wavelength 0.85 μm)
Was observed.

Example 5 A method of manufacturing a waveguide type optical element with a wavelength filter according to the method of the present invention will be described. 21 to 28 show the manufacturing procedure thereof.

First, the substrate 50 is prepared, and the epoxy UV monomer 51 is applied onto the substrate 50 (FIG. 21). Next, as shown in FIG. 22, the sectional structure is a convex portion 53 (width 60 μm, height 1
Glass mold 52 having a size of 00 μm and a length of 3 mm)
On the monomer 51 and photocured using UV light 54, and a cured film 55 (n = 1.51, wavelength 1.31 μm).
m). The monomer 51 is cured along the shape of the mold, and has a groove for filter filling (width 60 μm, height 100 μm, length 3).
mm) 56 is formed on the surface of the cured film (FIG. 23).
The mold in this case is manufactured so that the entire surface can transmit light.

Next, as shown in FIG. 24, the sectional structure is a narrow groove portion 58 (depth 50 μm, width 50 μm, length 20 mm), narrow groove portion 59 (depth 50 μm, width 50 μm, length 20 m).
m) and the convex portion 500 (width 60 μm, height 100 μ
m, length 3 mm) is formed, and a mold 57 is prepared which is configured so that light cannot be transmitted except for the narrow groove portion. The epoxy-based UV monomer 501 serving as the core is inserted into the narrow groove portions 58 and 59 of the mold 57 and cured by UV light irradiation (FIG. 25). By this operation, the core ridges 502, 50
3 is formed on the cured film 55. At this time, by accurately aligning the groove 56 formed on the film 55 and the convex portion 500 of the mold 57, the core ridges 502 and 503 (n = 1.52, wavelength 1.31 μm) having a width of 50 μm and a height of 50 μm are formed.
m) is manufactured according to the position of the groove 56 (FIG. 2).
6).

Next, the wavelength filter 504 is placed in the groove 56.
(Multi-layer filter for 1.3 μm, height 200 μm, width 5
0 μm, length 3 mm) and then epoxy type U again
The V-monomer 51 is applied and cured to produce a waveguide type optical element 505 with a wavelength filter (FIG. 27).

FIG. 28 shows the appearance of the completed waveguide type optical element 505. When the waveguide loss was measured using an LD light source (wavelength 1.31 μm), the insertion loss was 0.2 dB and the waveguide loss was 0.3 dB / cm. Also, 1.55
When propagating through two wavelengths of μm and 1.30 μm, only light of 1.3 μm was observed, light of 1.55 μm was blocked, and the isolation was 50 dB or more.

(Embodiment 6) As in Embodiment 5, several wavelength filters are used, and wavelengths of 0.85 μm, 1.3 μm, 1.
When the separation of 55 μm was performed, it was found that the separation was possible from each port with an extinction ratio of 50 dB or more. FIG. 29 shows a plane configuration diagram of the produced waveguide type optical element. In the figure, 60 is a wavelength of 0.85 μm, 1.3 μm,
Port for incident light of 1.55 μm, 61 is wavelength 0.8
Filter that cuts light of 5 μm, 62 has wavelength of 1.3 μm
m is a filter that cuts light, and 63 is a cut filter.
Port for emitting 85 μm light, 64 for emitting cut 1.3 μm light, 65 for 1.55 μm
Is a light emission port.

In the above embodiment, 3 was used as the core material.
Although the type is limited, any material can be used as long as it is a material that can be cured using a photo-curing agent. Further, although the V-shaped groove is used as the groove shape for inserting the optical fiber in the fourth embodiment, it may not be the V-shaped groove as long as the shape allows the optical fiber to be inserted.

[0054]

As described above, according to the method of manufacturing a waveguide type optical element according to the present invention, a high performance optical element can be easily formed, and it is possible to connect an optical fiber and another optical element. However, since the waveguide and the groove for fixing another element can be sequentially formed with high precision, the effect of easily performing optical coupling with low loss is produced.

[Brief description of drawings]

FIG. 1 is a process drawing showing a basic process in manufacturing a waveguide type optical element of the present invention.

FIG. 2 is a process drawing showing a basic process in manufacturing a waveguide type optical element of the present invention.

FIG. 3 is a process drawing showing a basic process in manufacturing a waveguide type optical element of the present invention.

FIG. 4 is a process chart showing a basic process in manufacturing a waveguide type optical element of the present invention.

FIG. 5 is a process drawing showing a basic process in manufacturing a waveguide type optical element of the present invention.

FIG. 6 is a plan view showing an example of a mold used for producing the waveguide type optical element of the present invention.

FIG. 7 is a side view of the mold shown in FIG.

FIG. 8 is a process chart showing a basic process in manufacturing a waveguide type optical element of Reference Examples 1 to 3 .

FIG. 9 is a process chart showing a basic process in manufacturing a waveguide type optical element of Reference Examples 1 to 3 .

FIG. 10 is a process chart showing a basic process in manufacturing a waveguide type optical element of Reference Examples 1 to 3 .

FIG. 11 is a process chart showing a basic process in manufacturing a waveguide type optical element of Reference Examples 1 to 3 .

FIG. 12 is a process chart showing a basic process in manufacturing a waveguide type optical element of Reference Examples 1 to 3 .

FIG. 13 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 14 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 15 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 16 is a perspective view of a mold used for manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 17 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 18 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 19 is a process chart showing a basic process in manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 20 is a perspective view of an element obtained by manufacturing a waveguide type optical element with a V groove according to a fourth example of the present invention.

FIG. 21 is a process chart showing a basic process in manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 22 is a perspective view of a first mold used for manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 23 is a process chart showing a basic process in manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 24 is a perspective view of a second mold used for manufacturing a waveguide type optical element with a wavelength filter according to a fifth embodiment of the present invention.

FIG. 25 is a process chart showing a basic process in manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 26 is a process chart showing a basic process in manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 27 is a process chart showing a basic process in manufacturing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 28 is a perspective view of an element obtained by producing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

FIG. 29 is a plan configuration diagram of an element obtained by producing a waveguide type optical element with a wavelength filter according to a fifth example of the present invention.

[Explanation of symbols]

1 substrate 2 clad layer 3 monomer or oligomer showing fluidity at room temperature 4 mold 5 having desired shape 5 light irradiation 6 core part 7 waveguide element 21 mold 22 groove for transferring core part of mold 23 gold Portion other than groove 22 of mold 31 Substrate 32 Cladding layer 33 Epoxy UV monomer 34 Mold 35 UV light 36 Core having convex shape 37 Waveguide type optical element 40 Substrate 41 Epoxy UV monomer 42 Glass mold 43 Mold V-shaped convex part (opening angle 60 °, height 150
μm, width 170 μm, length 20 mm) 44 UV light 45 Cured resin (n = 1.51, wavelength 1.31μ
m) 46 V groove (opening angle 60 °, height 150 μm, length 20)
47) Mold 48 Fine groove of mold (depth 10 μm, width 10 μm, length 40 mm) 49 Epoxy UV monomer 50 serving as core 50 Substrate 51 Epoxy UV monomer 52 Glass mold 53 Convex part (width 100 μm, high) 100 μm long, 3 m long
m) 54 UV light 55 Photocured resin (n = 1.51, wavelength 1.31μ
m) 56 Filter filling groove (width 60μm, height 100μ
m, length 3 mm) 57 mold 58 mold fine groove (depth 50 μm, width 50 μm, length 20 mm) 59 mold fine groove (depth 50 μm, width 50 μm, length 20 mm) 60 wavelength 0.85 μm , A port for inputting light of 1.3 μm and 1.55 μm 61 A filter for cutting light of wavelength 0.85 μm 62 A filter for cutting light of wavelength 1.3 μm 63 A port for emitting light of cut wavelength 0.85 μm 64 Port 65 for Emitting Light of 1.3 μm Wavelength that is Cut Out 400 Emission Port of Light of Wavelength 1.55 μm 400 Core Ridge 401 V Waveguide Optical Element with V-groove 500 Convex Part (Width 60 μm, Height 100 μm, Length 3 m
m) 501 epoxy UV monomer 502 core ridge 503 core ridge 504 wavelength filter (multilayer film filter for 1.3 μm,
Height 200 μm, width 50 μm, length 3 mm) 505 Waveguide type optical element with wavelength filter

Continuation of front page (56) Reference JP-A-2-131202 (JP, A) JP-A-2-70412 (JP, A) JP-A 1-271710 (JP, A) JP-A-7-159630 (JP , A) JP 63-106949 (JP, A) JP 7-218739 (JP, A) JP 8-136762 (JP, A) JP 4-52606 (JP, A) JP 7-287141 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/12-6/138 G02B 6/30

Claims (4)

(57) [Claims] 1. A step of applying a polymer material onto a substrate to form a lower clad material, and a mold having a partially convex portion on the clad material.
Overlying to form a lower cladding layer with partial depressions
Step, the lower clad in the upper to the lower clad layer, the cured
A step of applying a liquid photo-curable material that forms a resin having a higher refractive index than the layer , and forming a desired concave portion on the coating film of the photo-curable material.
However, only the concave part allows light to pass through and the other parts block light.
Place the mold for the material of the photocurable the concave portion
A step of enclosing the light irradiating the mold over, curing only the material of the photocurable enclosed in the concave portion of the mold, removing the mold, the mold of the concave a material that photocuring of existing liquid other than parts include, washing stream to step a solvent, to the position of the formed in the lower clad layer recessed portion
A method of manufacturing a waveguide type optical element, which is characterized in that a core ridge of an optical waveguide is also formed. 2. The recess formed in the lower cladding layer
V-groove and / or optical component for aligning optical fiber
The waveguide according to claim 1, wherein the waveguide is a rectangular groove for aligning
Method of manufacturing mold optical element. 3. The liquid photocurable material is epoxy.
Monomer or oligomer, monomer having unsaturated group
Alternatively, oligomers and models having siloxane bonds
Mono selected from the group consisting of nomers or oligomers
The method for producing a waveguide type optical device according to claim 1, which comprises a polymer or an oligomer and a photoinitiator . 4. The epoxy-based U is used as the lower clad material.
The mold is made of V-monomer, and the mold partly has convex parts.
It is a mold that allows surface light transmission, and irradiates light through the mold to
Epoxy UV monomer is photo-cured and partially recessed
The lower clad layer for forming is formed according to claim 1 or 2.
For manufacturing a waveguide type optical element .