JPH11174247A - High polymer optical waveguide and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce crosstalk, transmission loss and coupling loss. SOLUTION: This optical waveguide is provided with a structure for which a second groove part 11 provided with the cross sectional area of a desired optical waveguide core part dimension is formed at the center of the bottom part of a wide and shallow first groove part 10. That is, the opining width of the first groove part 10 is wider than the opening width of the second groove part 11 and a depth from the surface of a high polymer clad substrate to the bottom part of the first groove part 10 is shallower than the depth from the bottom part of the first groove part 10 to the bottom part of the second groove part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor, an optical communication component, a CD and an LD used in a document reading optical system such as a facsimile, a copying machine or a scanner.
The present invention relates to a polymer optical waveguide used for an optical component in an optical disc pickup, such as an optical disc pickup, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, polymer optical waveguides using a polymer material are cheaper and more suitable for mass production than those using an inorganic material. Have been done. One of them is to drop a core material in a monomer state, which has a higher refractive index than the substrate when cured, on the polymer clad substrate surface with fine grooves formed on the surface, and then sweep the surface using a squeegee etc. Thus, there is a method of manufacturing a polymer optical waveguide in which such a material is injected only into a groove, polymerized and cured. Even if the waveguide substrate has a large area and the waveguide pattern is complicated and densely packed, this manufacturing method can produce a large number of substrates at low cost by manufacturing a substrate having grooves formed by injection molding or the like. Since it can be produced, a low-cost image sensor can be provided.

[0003]

However, when such a conventional technique is used, a waveguide is formed by filling a core material in a groove of the manufactured clad substrate, and a process of manufacturing a clad substrate having fine grooves on the surface is performed. There is a problem in the fabrication process.

[0004] In the former waveguide forming process, there arises a problem of unswept core material and gouging of the core material. That is, if the core material is to be packed exactly 100% in the groove of each waveguide in the sample plane, the core material is likely to be left unswept on the clad substrate surface. as a result,
The unswept portion of the core material causes crosstalk of light between the waveguide cores, causing a reduction in the resolution of the image sensor.

On the other hand, if the remaining material is swept so as to ensure that no unswept residue is present, the core material is excessively cut off, and the cross section of the core is cut away from the upper portion of the groove into a curved shape. Become. As a result, the complicated cross-sectional shape due to the dent causes a decrease in light transmittance, and 10
Since there is no 0% core, the small cross-sectional area of the core results in a decrease in light intensity at the joint between the waveguide and another optical element.

The depth of the recess tends to be substantially constant regardless of the depth of the groove when the squeegee conditions are the same. In other words, in the case of a waveguide requiring a small core cross section, the groove on the surface of the clad substrate is inevitably shallow. At the same depth, almost no core material fills the grooves. And, if the filling state of the core material varies in the sample, it causes variation in the optical characteristics of the waveguide.

In the latter manufacturing process, when a clad substrate having a groove formed on the surface is manufactured by a method using a mold such as injection molding, it is difficult to release the resin poured into the mold without deforming the mold. In particular, this is a serious problem when fabricating a waveguide pattern in which grooves are densely packed in a wide area, which results in deformation of the grooves and the substrate itself during release. When such deformation occurs, it also causes an increase in unswept core material, a variation in the filling rate of the core material, a decrease in transmittance of guided light, and an increase in variation.

As described above, when manufacturing a method of manufacturing a polymer optical waveguide, there is a problem associated with mold release of a resin in a process of manufacturing a clad substrate, and in a process of forming a waveguide, unremoved core material and core There was a problem of removing the material. For this reason, it is a very important issue how to correct such mold release of the resin, unsweeping of the core material, and digging, and to manufacture a waveguide with less crosstalk, transmission loss and coupling loss.

Therefore, the present invention solves the above-mentioned problems,
It is an object of the present invention to provide a polymer optical waveguide capable of reducing crosstalk, transmission loss, and coupling loss, and a method for manufacturing the same.

[0010]

According to a first aspect of the present invention, there is provided a polymer optical waveguide in which a groove is formed in a surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core. is there. The groove includes a first groove formed on the outermost surface of the polymer clad substrate, and a second groove formed at a bottom of the first groove and having a desired width of the optical waveguide core. The opening width of the first groove is wider than the opening width of the second groove, and the depth from the surface of the polymer clad substrate to the bottom of the first groove is from the bottom of the first groove to the second groove. Characterized by being shallower than the depth to the bottom.

According to a second aspect of the present invention, in the polymer optical waveguide according to the first aspect, the side walls of the first groove and the second groove have an inclination angle of 90 degrees or more and less than 180 degrees with respect to the bottom. It is characterized by having.

A third aspect of the present invention is a method for manufacturing a polymer optical waveguide, wherein a groove is formed on the surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core.
This manufacturing method comprises the steps of: preparing a master master having the same shape as the polymer clad substrate having the grooves formed therein; forming a mold based on the master master; It comprises a step of forming a polymer clad substrate by molding, and a step of forming an optical waveguide on the polymer clad substrate. Then, in the mold making step, the resist film applied to the glass substrate is exposed for a short time through a first photomask having a window opened by a width wider than the width of the optical waveguide core portion, and then developed to obtain a resist film. Forming a first groove, exposing and developing the bottom of the first groove through a second photomask having a window opened by the width of the optical waveguide core, and forming a second groove on the bottom of the first groove; Is formed.

According to a fourth aspect of the present invention, in the mold forming step, the resist film applied to the glass substrate is exposed through a first photomask having a window having a width wider than the width of the optical waveguide core. Forming a second groove at the bottom of the first groove by further exposing the exposed portion by the first photomask through a second photomask having a window opened by the width of the optical waveguide core, and then developing the exposed portion. It is characterized by.

According to a fifth aspect of the present invention, in the mold making step, the resist film applied to the glass substrate is exposed and developed for a short time through a second photomask having a window opened by the width of the optical waveguide core. Forming a second groove, and positioning the first photomask having a window opened by a width wider than the width of the optical waveguide core so that the second groove is located in the window; Through this, a first groove portion is formed by exposing and developing for a shorter time than the exposure time of the second photomask.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure of the polymer optical waveguide used in the first embodiment will be described. FIG.
It is a diagram showing a structure of a polymer optical waveguide according to the present invention,
(A) shows a structure filled with a core material, and (b)
Indicates a structure not filled with a core material. The polymer optical waveguide has a second shallow section having a desired optical waveguide core dimension at the center of the bottom of the wide and shallow first groove 10.
Has a structure in which the groove 11 is formed. That is, the first
The opening width of the groove 10 is wider than the opening width of the second groove 11, and the depth from the surface of the polymer clad substrate to the bottom of the first groove 10 is the second from the bottom of the first groove 10 to the second. It is shallower than the depth to the bottom of the groove 11.

The cross-sectional shape of the optical waveguide core formed in the second groove 11 is substantially trapezoidal as shown. Angle of inclination α of first groove 10 with respect to the bottom of the side wall
Is at least 90 degrees and less than 180 degrees at the bottom of the groove. The inclination angle θ of the second groove 11 with respect to the bottom of the side wall is not less than 90 degrees and not more than 120 degrees.

Next, a process for manufacturing a polymer clad substrate used in the polymer optical waveguide shown in FIG. 1A will be described. When preparing a polymer clad substrate, first, a master master having the same shape as the polymer clad substrate is prepared, and a mold is formed using the master master. Then, a polymer clad substrate is formed using a mold.

FIG. 2 is a view showing a process of manufacturing a polymer clad substrate used in the polymer optical waveguide shown in FIG. First, as shown in FIG.
m, a positive photoresist film 31 is applied on a glass substrate 32 by a spin coating method, and then, as shown in FIG.
3 is brought into close contact with the resist surface, through which ultraviolet light is irradiated for exposure. Here, the amount of exposure is the same as that of the resist film 31.
Is a value for developing to a depth of 1 μm, which is 20 mJ / cm ^{2 at} a wavelength of 350 nm. That is, the amount of ultraviolet irradiation at the time of the exposure is adjusted so that the depth when the resist film 31 is developed becomes the depth of the first groove 41.

Next, development rinsing is performed on the substrate, and a width of 10 μm and a depth of 1 μm as shown in FIG.
Is formed in the resist film. The first groove 35 is formed by the first groove 1 shown in FIG.
It corresponds to 0. The second photomask 36 in which the window 37 is opened by the width of the waveguide core is used.
Position so that it is in the center of the bottom of the groove 35 of
This is brought into close contact with the resist surface and exposed (FIG. 2
(D)). However, the width of the window 37 is 8 μm, and the exposure amount is 170 mJ / cm ^{2 at} a wavelength of 350 nm in depth.
And After that, when this is developed, as shown in FIG. 2E, the second groove 38 having a cross section of 8 μm in width and 8 μm in depth becomes a first groove 35 having a width of 10 μm and 1 μm in depth.
Is formed in the central portion. The second groove 38 corresponds to the second groove 11 that forms the waveguide core shown in FIG. Here, the exposure amount is from 90 degrees to 120 degrees.
The angle is adjusted so as to be a desired angle between degrees. In the present embodiment, θ is adjusted to be 102 degrees, and the interval between adjacent second groove portions 38 is adjusted to be 14 μm.

Using this resist pattern as a master master plate, a mold 39 shown in FIG. 2F is manufactured, and a polymer clad substrate 61 is manufactured by an injection molding method using a PMMA material. Thus, as shown in FIG. 2 (g), the polymer clad substrate 61 has a 10 μm wide, 1 μm deep first groove 10 at the center of the second groove 10 μm wide, 8 μm deep.
Of the groove 11.

Next, a method for manufacturing a polymer optical waveguide using the polymer clad substrate 61 will be described. FIG.
FIG. 3 is a diagram showing a method for producing a polymer optical waveguide using a polymer clad substrate. First, as shown in FIG.
A core material 62 in a monomer state is dropped on the surface of the PMMA substrate 61 on which fine grooves have been formed.
3 and the core material is filled only in the grooves as shown in FIG. The core material is a UV curable resin, J.S.
-91 was used. Then, after the core material is filled, the core material is polymerized by irradiating the entire surface of the substrate with ultraviolet rays 64 as shown in FIG. After the core material is cured, a clad material 65 in a monomer state is applied to the substrate surface as shown in FIG. Thereafter, as shown in FIG. 4E, the PMMA substrate 66 is adhered using the clad material 65 as an adhesive and the PMMA substrate 66 as a reinforcing material, and the clad layer is cured by irradiation with ultraviolet light to form the PMMA substrate 61.
Glue. The cladding material 65 used was SK9 from Summers Optical. Through the above series of steps, a buried polymer optical waveguide can be manufactured.

(Second Embodiment) In the first embodiment, development is performed each time photoresist exposure is performed. However, the photoresist development step can be omitted. Therefore, a second embodiment in which the photoresist developing step is omitted will be described next.

FIG. 4 is a view showing a process of manufacturing a polymer clad substrate used in the second embodiment. As shown in FIG. 1A, first, a positive photoresist film 31 having a thickness of 9 μm is applied on a glass substrate 32 by a spin coating method, and then, as shown in FIG. A first photomask 33 having a window 34 with a width of 10 μm is brought into close contact with the resist surface and exposed through this. Here, this exposure amount is a value for developing the resist film to a depth of 1 μm, and is 20 mJ / cm ^{2 at} a wavelength of 350 nm. Next, the second photomask 36 having the window 37 opened by the width of the waveguide core is aligned so that the window 37 is located at the center of the groove, and this is brought into close contact with the resist surface. Exposure is performed (FIG. 4C). However, the width of the window 37 is 8
μm, and the exposure amount is 1 at a wavelength of 350 nm in depth.
70 mJ / cm ² . Thereafter, when this is developed, as shown in FIG. 4D, a second groove 38 having a cross section of 8 μm in width and 8 μm in depth forms a 10 μm in width and 1 μm in depth.
Is formed at the center of the first groove 35. Θ is 102 degrees, and the interval between adjacent second grooves 38 is 14 degrees.
μm. Using this resist pattern as a master master plate, a mold 39 shown in FIG. 4E is manufactured, and a polymer clad substrate 61 is manufactured by an injection molding method using a PMMA material. Thus, as shown in FIG. 4F, the polymer clad substrate 61 has a 10 μm wide, 1 μm deep first groove 10 at the center of the second clad having a width of 8 μm and a depth of 8 μm.
Of the groove 11.

As described above, the manufacturing process of the polymer clad substrate is different from the manufacturing process described in the first embodiment.
The photoresist developing step shown in FIG. 3C can be omitted, and the photoresist step can be simplified. In addition,
When manufacturing a polymer optical waveguide using such a polymer clad substrate, the process shown in FIG. 2 is used as in the first embodiment.

(Third Embodiment) In the first embodiment,
Although the second shallow groove portion 38 is formed after the first and wide first shallow groove portion 35 is formed, the order of forming such grooves may be changed. Therefore, a third embodiment in which the second groove 38 is formed first will be described.

FIG. 5 is a view showing a process of manufacturing a polymer clad substrate used in the third embodiment. As shown in FIG. 3A, first, a positive photoresist film 31 having a thickness of 9 μm is applied on a glass substrate 32 by a spin coating method, and then, as shown in FIG. The second photomask 36 having the window 37 opened by the width of the core is brought into close contact with the resist surface and exposed. The width of the window 37 is 8 μm. Then, as shown in FIG. 4C, the substrate is subjected to a developing process to form a second groove 38 in the resist film 31. After that, the first photomask 33 having the window 34 with a width of 10 μm is positioned so that the second groove 38 is located at the center of the window 34, and this is brought into close contact with the resist surface and is exposed ( FIG. 5D). However, the exposure amount is a value for developing the resist film to a depth of 1 μm, and is 20 mJ / cm ² at a wavelength of 350 nm. Then, by developing this, the first groove 35 becomes the second groove 38.
And a width of 8 μm as shown in FIG.
The second groove 38 having a width of 10 μm and a depth of 1 μm is located at the center of the first groove 35 having a width of 10 μm and a depth of 1 μm. In addition,
is 102 degrees, and the interval between adjacent second grooves 38 is 14 μm. Using this resist pattern as a master master plate, a mold 39 shown in FIG. 5F is manufactured, and the polymer clad substrate 6 is formed by an injection molding method using a PMMA material.
Prepare No. 1. Thus, as shown in FIG. 4E, the polymer clad substrate 61 has a width of 10 μm and a depth of 1 μm.
The second groove 11 having a width of 8 μm and a depth of 8 μm is provided at the center of the first groove 10 of m.

As described above, the manufacturing process of the polymer clad substrate is different from the manufacturing process described in the first embodiment in that in the process of performing the photoresist exposure and the photoresist development, a groove having a width of 8 μm and a depth of 8 μm is formed. With a width of 10 μm and a depth of 1
It is formed before the groove of μm. When a polymer optical waveguide is manufactured using such a polymer clad substrate, the steps shown in FIG. 2 are used as in the first and second embodiments.

(Fourth Embodiment) In the first to third embodiments, the case where the polymer optical waveguide shown in FIG. 1 is formed is shown. It can also be applied when doing so. Therefore, in the following, FIG.
An embodiment using the structure of the polymer optical waveguide shown in FIG. In addition, this embodiment described below
These correspond to the first to third embodiments, respectively.

First, FIG. 6 on which the present embodiment is based
The structure of the polymer optical waveguide shown in FIG. FIG.
In the polymer optical waveguide shown in (a), a second groove 11 having a cross-sectional area of a desired optical waveguide core dimension is formed at the center of a wide and shallow first groove 12 having a gentle inclination angle. Having a structure. The difference from the first embodiment shown in FIG.
The point that the bottom part of the first groove 12 is the opening of the second groove 11. Therefore, there is no portion forming the bottom of the first groove 12, and the side wall of the second groove 11 is connected to the side wall of the first groove 12. As shown in FIG. 6A, the cross-sectional shape of the core portion of the optical waveguide is trapezoidal, and the inclination angle θ of the side wall of the groove 11 is not less than 90 degrees and not more than 120 degrees at the bottom of the groove. The inclination angle β of the groove side wall at the bottom of the groove is 90 degrees or more and θ or more at the bottom of the groove (FIG. 6B).

Next, a fourth embodiment will be described with reference to FIGS. In the present embodiment, as in the first embodiment, a polymer clad substrate having fine grooves provided on its surface is manufactured by the steps shown in FIGS. 2 and 3 and then the core material is filled with a squeegee. After that, the upper reinforcing material is bonded to produce a buried optical waveguide. However, in the process of forming the first groove 35 (FIG. 2B) in the preparation of the master master, the first photomask 33 is formed.
Exposure is performed with a gap of 50 μm between the resist and the resist surface. For this reason, a wide groove in which the inclination angle β is 165 degrees, which is gentler than the core groove, is formed. After that, using the process shown in FIG.
A clad substrate having a groove 11 formed on the surface is formed by injection molding, and an optical waveguide is manufactured in the process of FIG.

Similarly, in FIGS. 4 and 5, in the step of forming the first groove 35 in the master master, the distance between the first photomask 33 and the resist surface is 5 mm.
Exposure is performed with a gap of 0 μm. For this reason,
A wide groove having an inclination angle β of 165 degrees which is gentler than the core groove is formed. Thus, the polymer clad substrate having the structure shown in FIG. 6 can also be manufactured by the polymer clad substrate manufacturing method described in the first to third embodiments.

In the conventional and the polymer clad substrates of the above embodiments, squeegee conditions are set so as to minimize the upper dent. FIG. 7 shows a state in which the core groove is filled with the core material in the polymer clad substrate. When the conventional groove structure shown in FIG. 7A is employed, a large amount of core material is left unsweeped. As shown in FIGS. 7B and 7C, in the polymer clad substrate of the present embodiment, the core material left unsweeped only slightly remains at both ends of the first grooves 10, 12.
Further, the remaining unswept portion is formed in the core portion (the second groove portion 1).
Since the state is separated from 1), the occurrence of crosstalk is eliminated.

Further, the squeegee condition is set so as to completely eliminate unscanned portions and prevent crosstalk. FIG.
In the conventional structure shown in (a), the core material is greatly digged. However, in the polymer clad substrate of the present embodiment, the core material filled in the first grooves 10 and 12 is digged, and the second grooves 11 are in a state where there is little digging. The depth of the dent 11 is shallow as shown in FIGS. 8B and 8C. For this reason, the transmittance is increased, and the loss at the coupling portion with other optical components is reduced.

Similarly, when the core section of the second groove portion 11 is small, when squeegeeing is performed so as not to cause crosstalk by completely eliminating unswept, the conventional groove structure shown in FIG. The core portion is recessed to near the bottom of the second groove portion 11. However, in the case of the polymer clad substrate of the present embodiment, if the squeegee conditions are set so that the depth position of the dent is the depth of the first groove portions 10 and 12, it will be shown in FIGS. 9B and 9C. As described above, the core material can be almost completely filled in the second groove portion 11.

In the polymer optical waveguides of the first to fourth embodiments, the width of the opening of the groove is formed wider than the width of the bottom, so that the polymer clad substrate is manufactured by a method using a mold. In this case, it is possible to easily release the resin poured into the mold without deformation, and to prevent deformation of the groove and the substrate itself, which are likely to occur at the time of release. In addition, it is possible to prevent an increase in unswept core material due to the deformation, a decrease in transmittance of guided light, and an increase in variation thereof.

The optical waveguide of the above embodiment has a wavelength of 532n.
m laser was incident, and the transmission loss excluding the incident and output loss was measured.
Good characteristics of 0.1 db / cm were obtained.

[0038]

According to the present invention, a first groove is formed at the outermost surface of the polymer clad substrate, and a second groove having a desired optical waveguide core width is formed at the bottom of the first groove. And the first
The opening width of the groove is wider than the opening width of the second groove, and the depth from the surface of the polymer clad substrate to the bottom of the first groove is from the bottom of the first groove to the bottom of the second groove. Shallower than the depth of the Therefore, when the core material is filled in the second groove, in order to make the cross-sectional area of the core as large as possible, when the squeegee is made to reduce the upper dent as much as possible,
Since the unswept core material only slightly remains at both ends of the first groove portion and is separated from the core portion, crosstalk between the cores can be eliminated. Further, when squeegeeing is performed so as to eliminate crosstalk by completely removing the unsweepable portion, the core material filled in the first groove portion is digged, and the amount of digging in the second groove portion can be reduced. Has a small cross-sectional shape of the core, the transmittance is high, and the loss at the joint with other optical components can be reduced.

According to the second aspect of the present invention, the opening width of the first groove is wider than the opening width of the second groove, and the inclination angle with respect to the bottom of the side wall is 90 degrees or more. In the case of manufacturing using a mold, the resin poured into the mold can be released without deformation, and deformation of the groove or the substrate itself, which is likely to occur at the time of release, can be prevented. In addition, it is possible to prevent an increase in unswept core material due to the deformation, a decrease in transmittance of guided light, and an increase in variation thereof.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a polymer optical waveguide according to the present invention.

FIG. 2 is a diagram illustrating a process of manufacturing a polymer clad substrate used in the first embodiment.

FIG. 3 is a view showing a manufacturing process of a polymer optical waveguide.

FIG. 4 is a view showing a process of manufacturing a polymer clad substrate used in a second embodiment.

FIG. 5 is a view showing a process of manufacturing a polymer clad substrate used in a third embodiment.

FIG. 6 is a diagram showing another structure of the polymer optical waveguide according to the present invention.

FIG. 7 is a diagram showing a state in which a core material is filled into a polymer clad surface core groove when a cross-sectional area of a core portion is increased.

FIG. 8 is a diagram showing a state in which the core material is filled into the polymer-clad surface core groove when the remaining unswept core material is reduced.

FIG. 9 is a diagram showing a state in which a core material is filled in a polymer clad surface core groove when the core has a small core cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st groove part 11 2nd groove part 31 Positive photoresist film 32 Glass substrate 33 1st photomask 34 1st photomask window 36 2nd photomask 37 2nd photomask window

Claims (5)

[Claims] 1. A polymer optical waveguide in which a groove is formed on a surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core portion. A first groove formed on the outermost surface, and a second groove formed at the bottom of the first groove and having a desired width of the optical waveguide core, the opening width of the first groove is: It is wider than the opening width of the second groove, and the depth from the surface of the polymer clad substrate to the bottom of the first groove is shallower than the depth from the bottom of the first groove to the bottom of the second groove. Characteristic polymer optical waveguide. 2. The polymer optical waveguide according to claim 1, wherein side walls of the first groove and the second groove have an inclination angle of 90 degrees or more and less than 180 degrees with respect to the bottom. 3. A method for producing a polymer optical waveguide in which a groove is formed on the surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core. A step of creating a master master having the same shape as the clad substrate, a step of creating a mold based on the master original, and a step of forming a polymer clad substrate by molding with a polymer clad material using the mold. A step of forming an optical waveguide on the polymer clad substrate. In the mold forming step, a first window having a window opened by a width wider than the width of the optical waveguide core portion with respect to the resist film applied to the glass substrate. After short-time exposure through a photomask, development is performed to form a first groove, and the bottom of the first groove is exposed and developed through a second photomask having a window opened by the width of the optical waveguide core. Forming a second groove at the bottom of the first groove. 4. A method of manufacturing a polymer optical waveguide, wherein a groove is formed on a surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core. A step of creating a master master having the same shape as the clad substrate, a step of creating a mold based on the master original, and a step of forming a polymer clad substrate by molding with a polymer clad material using the mold. A step of forming an optical waveguide on the polymer clad substrate. In the mold forming step, a first window having a window opened by a width wider than the width of the optical waveguide core portion with respect to the resist film applied to the glass substrate. Exposure is performed through a photomask, the exposed portion of the first photomask is further exposed through a second photomask having a window opened by the width of the optical waveguide core, and then developed to form a bottom of the first groove. Forming a second groove in the portion. 5. A method of manufacturing a polymer optical waveguide in which a groove is formed on a surface of a polymer clad substrate, and a core material is injected into the groove to form an optical waveguide core. A step of creating a master master having the same shape as the clad substrate, a step of creating a mold based on the master original, and a step of forming a polymer clad substrate by molding with a polymer clad material using the mold. Forming a light guide on the polymer clad substrate. In the mold making step, a second photomask having a window opened by the width of the light guide core is passed through a resist film applied to a glass substrate. Exposure and development are performed for a short time to form a second groove, and a first photomask having a window opened by a width larger than the width of the optical waveguide core is placed so that the second groove is located in the window. position A method of manufacturing a polymer optical waveguide, comprising: performing alignment, and exposing and developing through this process for a time shorter than the exposure time of the second photomask to form a first groove.