JP2010078670A - Polymer optical waveguide and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer optical waveguide in which the generation of cracks which is likely to take place at the boundary of two kinds of clad parts exposed on the surface (surface in the direction parallel to the advancing direction of waveguide light) of an optical waveguide is prevented, flexible performance is ensured, a highly accurate mounting and a machining, or the like, of surface at 45° at an end part are easy, and which has high bending durability. <P>SOLUTION: The polymer optical waveguide 10 includes a plurality of core parts 14, 15; a clad part which encloses at least the core part 14, in which the light propagates among the plurality of core parts, along the direction in which the light propagates; a first clad part 16, having a bending elasticity larger than that of the core parts as a clad part located among the plurality of core parts at least at one end part; and second clad parts 12, 17, 18 having a bending elasticity smaller than that of the first clad part as clad parts, located extending over the plurality of core parts. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polymer optical waveguide and a method for manufacturing the same.

Polymer optical waveguides with high flexibility are used in optical interconnection in which signal transmission is performed by light within information devices and between devices. For example, it has followability to twist and bend like a flexible printed circuit board used for electric wiring for the purpose of applying signal transmission by light to an operating part represented by a hinge of a notebook type personal computer or a folding cellular phone. A flexible type polymer optical waveguide has been proposed (see Patent Document 1).
In this flexible type polymer optical waveguide (flexible optical waveguide), a core through which light is propagated and a clad provided around the core are both made of a material having a low bending elastic modulus such as a gel material, Overall flexibility.

  However, when a high flexibility is given to the entire polymer optical waveguide, deformation easily occurs due to external forces such as pick-up and bonding in the mounting process. For this reason, when optically coupling with a light emitting element or a light receiving element, the shape of the optical waveguide is not maintained, and it becomes difficult to mount with sufficient accuracy. Further, by having flexibility, it is difficult to form a flat surface with high accuracy even in a process of producing a 45 ° micromirror surface by a dicing saw.

In order to realize both the flexibility and mounting accuracy of the optical waveguide, the clad part is composed of a soft clad material and a hard clad material, and the soft clad part has at least one end on the light propagation direction side from the soft clad part. A polymer optical waveguide provided with a hard clad portion having a high bending elastic modulus is disclosed (see Patent Document 2). In this optical waveguide, the clad portion is constituted by two kinds of materials having different bending elastic moduli, so that both flexibility in following bending and twisting and high mounting accuracy can be achieved.
JP 2003-207659 A JP 2007-33830 A

  This project prevents the occurrence of cracks that are likely to occur at the boundary between the two types of cladding exposed on the surface of the optical waveguide (surface parallel to the traveling direction of the guided light), and ensures high performance while ensuring flexible performance. The main object is to provide a polymer optical waveguide that is easy to mount and 45 ° surface processing at the end, and that has high bending durability.

The invention of claim 1 includes: a plurality of core portions extending in a light propagation direction; and the core portion surrounding at least a core portion in which light propagates among the plurality of core portions along the light propagation direction. A cladding portion having a low refractive index, and a first cladding portion having a higher bending elastic modulus than the core portion as a cladding portion located between the plurality of core portions at at least one end portion. The polymer optical waveguide is characterized in that a second clad part having a lower bending elastic modulus than the first clad part is provided as a clad part located across the plurality of core parts. .
The invention according to claim 2 forms a groove by cutting a polymer film in which a core layer and a cladding layer having a refractive index lower than that of the core layer are laminated with a dicing saw from the core layer side in a thickness direction. And forming a first clad part having a higher bending elastic modulus than the core part as a clad part positioned between the plurality of core parts at at least one end. And a step of forming a second clad part having a lower bending elastic modulus than the first clad part as a clad part located across the plurality of core parts. It is a manufacturing method of an optical waveguide.

According to the first aspect of the present invention, compared to the case where the present configuration is not provided, the occurrence of cracks that are likely to occur at the boundary between the two types of clad portions exposed on the surface of the optical waveguide is prevented, and while ensuring flexible performance, A polymer optical waveguide that is easy to mount with precision and has 45 ° surface processing at the end and has bending durability can be obtained.
According to the second aspect of the invention, compared to the case without this configuration, cracks are likely to occur at the boundary between the two types of clad portions exposed on the surface of the optical waveguide (surface in a direction parallel to the traveling direction of the guided light). A high-precision material with a simple process and high material that prevents bending and secures flexible performance, facilitates high-precision mounting and 45 ° surface processing of the end, and has bending durability. It can be manufactured with efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that members having substantially the same functions and actions are given the same reference numerals or symbols throughout the drawings as appropriate, and repeated descriptions are omitted as appropriate.

<Optical waveguide>
FIG. 1 is a schematic view showing the structure of the polymer optical waveguide of the first embodiment. 2A shows a cross section taken along line AA in FIG. 1, and FIG. 2B shows a part of the cross section taken along line BB in FIG. The optical waveguide 10 surrounds the core portion 14 along the direction in which the light propagates and a plurality of core portions 14 through which light propagates, and the cladding portions 12, 16, 17, 18 having a refractive index smaller than that of the core portion 14. Embedded polymer optical waveguide.

The clad part is divided into a hard clad part (first clad part, hereinafter referred to as “hard clad (part)”) 16 and a soft clad part (second clad part, hereinafter referred to as “soft clad”) which are distinguished by flexural modulus. (Referred to as (part) ”) 12, 17, and 18. A hard clad positioned between the core portions 14 and 15 at each end in the longitudinal direction (light propagation direction) of the optical waveguide 10 and having a higher bending elastic modulus than the core portion 14 at a portion sandwiched between the core portions. A clad portion that is provided over the plurality of core portions 14 and 15, that is, a surface in contact with the plurality of core portions 14 and 15 (upper and lower sides of the core portions 14 and 15 and the hard clad portion 16 in FIG. 1). Or the clad portion sandwiched between the core portions 14 and 15 corresponding to positions other than the end portion of the waveguide 10, the soft clad portions 12, 17, having a lower bending elastic modulus than the hard clad portion 16. 18 is provided. In the specification of the present application, the “cladding portion positioned across the plurality of core portions 14, 15” refers to the cladding portions 12, 17, 18 other than the hard cladding portion 16 provided at the end, regardless of the manufacturing method. means.
Further, on both side surfaces of the optical waveguide 10, a dummy core 15 that is formed of the same kind of resin as the core 14 through which light propagates and is not used as a core (waveguide core) 14 that propagates light when the optical waveguide 10 is used is exposed. is doing. As will be described later, the dummy core 15 remains when the core layer and the clad layer are cut by a dicing saw to form a core shape, and may be exposed on the side surface of the waveguide.

In addition, the term “plurality of cores” in this specification means that the dummy core 15 as described above is included in addition to the waveguide core 14. The “upper and lower surfaces” are surfaces parallel to both the direction in which the cores 14 and 15 are arranged in parallel and the light propagation direction, and the “side surface” is a plurality of cores 14 and 15 in parallel. The “end face” refers to the face where light enters and exits.
The “end portion” of the optical waveguide 10 in which the hard clad portion 16 is provided is a portion having a certain length from the end face toward the center portion, and the length in which the hard clad portion 16 is provided depends on the purpose. Just choose. Although depending on the length and width of the optical waveguide 16, usually, if the hard cladding 16 is provided between the core portions 14 and 15 having a length of 1 mm or more and 20 mm or less from the end surface, high-precision mounting and end portions are achieved. Thus, the polymer optical waveguide is surely easy to process at 45 °. However, the end of the optical waveguide 10 according to the present embodiment only needs to have a hardness capable of achieving the object of the present embodiment, and all the clads between the cores need to be hard clads. Absent. That is, if a hard clad is provided between some core portions at the end, high-precision mounting and 45 ° surface processing of the end are facilitated while ensuring flexible performance.

  As described above, since the hard clad 16 is disposed on both side surfaces of the core 14 at at least one end of the optical waveguide 10, the portion where the hard clad 16 is provided is caused by an external force in mounting work or end face shape processing. The deformation of the core portion 14 is suppressed, and the hard clad portion 16 is in contact with the side surface of the core portion 14 and is not provided on the upper and lower surfaces. Therefore, the total thickness of the optical waveguide 10 that causes a decrease in flexibility. The increase of is suppressed. On the other hand, the upper and lower surfaces of the core portion 14 and the hard clad portion 16 are integrally covered with the soft clad portions 12 and 18, respectively, and both main surfaces of the optical waveguide 10 are interfaced with different materials (the hard clad 16 and the soft clad 17. Therefore, the occurrence of cracks that cause breakage of the optical waveguide 10 is suppressed.

The core portion 14 and the soft clad portions 12, 17 and 18 need to be formed by selecting a material having a bending elastic modulus that realizes the flexibility required for the use of the optical waveguide 10. Although depending on the outer dimensions of the optical waveguide 10 to be described later, the flexural modulus of the material constituting each of the core portion 14 and the soft cladding portions 12, 17, 18 is 50 MPa to 1500 MPa, more preferably 200 MPa to 1000 MPa. . The flexural modulus is a value measured according to ASTM D790.
By having the core portion 14 and the soft clad portions 12, 17 and 18 each have a bending elastic modulus in the above range, the optical waveguide 10 exhibits flexibility except for the portion where the hard clad portion 16 is provided, and is excessive. Damage due to contact with other parts due to various deformations and deflection is suppressed.
On the other hand, since the hard clad part 16 provides a function as a reinforcing material for suppressing core deformation, the flexural modulus is preferably 1.5 GPa or more, more preferably 2 GPa or more.

Each material for the core and the clad is transparent to the wavelength used for the optical waveguide 10 and can set a desired refractive index difference between the core 14 and the clad 12, 16, 17, 18. There is no particular limitation. For example, an alicyclic olefin resin, an acrylic resin, an epoxy resin, a polyimide resin, or the like is used.
In order to exhibit optical characteristics as the optical waveguide 10, each of the claddings 12, 16, 17, and 18 needs to be made of a material having a refractive index lower than that of the core 14, and in particular, a refractive index with the optical waveguide core 14. In order to ensure the difference, the relative refractive index difference is 0.5% or more, preferably 1% or more. Further, it is desirable that the refractive index difference between the clads 12, 16, 17, and 18 is small, and the difference is within 0.05, preferably within 0.001, and more preferably no difference from the point of light confinement. This is desirable.

  The external dimensions of the optical waveguide 10 according to the present embodiment are not particularly limited, and may be set as appropriate according to the material, application, and the like. For example, to make the flexible optical waveguide 10, the thickness of the optical waveguide 10 is 50 μm. The thickness is preferably 500 μm or less and more preferably 70 μm or more and 300 μm or less. On the other hand, the width of the optical waveguide 10 is desirably 0.5 mm or more and 10 mm or less, and more desirably 1 mm or more and 5 mm or less. By setting the thickness and width of the optical waveguide 10 within the above ranges, it is easy to ensure flexibility and strength as the optical waveguide 10.

  On the other hand, the cross-sectional dimension of the hard clad 16 is set to a height sufficient to contact the entire core side surface in the height direction, and the width is 20 μm or more, more preferably 40 μm or more. By setting it as the above value, it becomes easy to secure a cross-sectional area equal to or larger than the core diameter of the multimode optical waveguide 10 so that the total cross-sectional area of the hard clad 16 provided on both side surfaces of the core can be secured. The strength is effective for suppressing deformation.

  In the optical waveguide 10 having such a configuration, even if the core portion 14 and the soft clad portion 17 have high flexibility, both side surfaces of the core portion 14 at the ends have an elastic modulus constituting the hard clad portion 16. Since it is in contact with high resin, deformation due to external force is suppressed in the portion where the hard clad portion 16 is provided. Further, the hard clad portion 16 is embedded in the optical waveguide 10 like the core 14, and both the main surfaces of the optical waveguide 10 are covered with the soft clad portion 17, so that there is no seam. Therefore, the occurrence of cracks due to insufficient bonding force between materials, which is a cause of breakage failure of the optical waveguide 10, is effectively prevented.

  Although the increase in the total thickness of the optical waveguide 10 increases the bending stress and decreases the bending durability, the hard clad 16 is in contact with the side surface of the core 14 and does not exist in the vertical direction. The presence of the reinforcing structure by the inner hard clad portion 16 does not increase the total thickness of the optical waveguide 10. That is, the hard clad portion 16 embedded in the optical waveguide 10 and in contact with the side surface of the core portion 14 does not deteriorate the bending durability of the optical waveguide 10 and suppresses deformation of the core 14 due to external force. Fulfill.

  The external force that causes deformation of the core is mainly the external force applied in the mounting process for joining the optical waveguide to the light emitting / receiving element, microlens array, package, etc., and the shape of the optical waveguide such as cutting with a dicing saw. It is an external force applied in the process of processing itself. Connection of optical components such as light emitting / receiving elements and optical waveguides requires extremely accurate alignment with an tolerance of about ± 5 μm. In addition to optical waveguides in various processes such as pick-up, installation, and pressure application during mounting operations The deformation of the core of the joint portion due to the applied external force causes a manufacturing defect of the optical waveguide module.

For example, a typical example of optical waveguide processing by a dicing saw is a 45 ° inclined surface for changing the traveling direction of signal light by 90 °. In order to suppress the occurrence of excessive loss when changing the traveling direction of light, flatness and smoothness of a 45 ° inclined surface are required. If the core is flexible enough to be deformed by an external force, a dicing blade that rotates at high speed passes through the core while deforming, making it difficult to achieve flatness and smoothness, making it difficult to manufacture a high-performance optical waveguide. It becomes.
However, even if the optical waveguide 10 according to this embodiment is cut into a 45 ° inclined surface by cutting the vicinity of the end portion with a dicing saw, the hard clad portions 16 are formed on both side surfaces of the core portion 14 in the vicinity of the end portion. Since it is provided, flatness and smoothness can be easily obtained, and an optical waveguide having a highly accurate 45 ° inclined surface can be obtained.

<Optical waveguide manufacturing method>
The method for manufacturing the optical waveguide of the present embodiment is not particularly limited. However, if the optical waveguide has a linear core, for example, the manufacturing process as shown in FIGS. Manufactured with precision.
First, as shown in FIG. 3A, a polymer film 10A having a two-layer structure in which a cladding layer 12A and a core layer 14A are laminated is prepared. For example, a lower cladding polymer layer 12A and a core polymer layer 14A are sequentially laminated on a flat support substrate (not shown) such as glass or silicon. The method of laminating the layers 12A and 14A is not particularly limited as long as they are integrally laminated so that no peeling occurs between the layers 12A and 14A. For example, a known method such as laminating or spin coating is adopted. The

The core portion 14 is formed by cutting the polymer film 10A from the core layer 14A side to form a groove portion. For example, as shown in FIG. 3 (B), at least the core layer 14A is removed by cutting at a predetermined depth in the thickness direction from the core layer 14A side with a dicing saw along the longitudinal direction of the polymer film 10A. . In order to form the core part 14 reliably, a part of the core layer 14A and the lower clad layer 12A may be cut and removed.
By performing such cutting with a dicing saw a plurality of times in the width direction of the polymer film 10A at a predetermined interval, a plurality of cutting grooves 20 parallel to each other are formed along the longitudinal direction of the polymer film 10A. Formed with. In addition, the width | variety, the number, and space | interval of the cutting groove 20 are not limited to what was shown to FIG. 3 (B), What is necessary is just to set suitably according to a use etc. For example, since the remaining portion of the core layer 14A becomes the core portion 14 or the dummy core portion 15, the interval and number of cutting may be set according to the core shape to be formed, the width, number, interval, and the like of the core 14. . For example, as shown in FIG. 5, the cutting grooves may be formed so that the interval between the core portions 14 becomes larger.

  Next, a hard clad portion 16 is formed in a cutting groove corresponding to a portion requiring reinforcement of the optical waveguide. For example, as shown in FIG. 3C, a plate-like silicone rubber 22 is brought into close contact with the upper surface of the polymer film 10A so as to cover a portion reinforced with a hard clad. The silicone rubber plate 22 is not particularly limited as long as it is permeable to ultraviolet light, is in close contact with the upper surface of the polymer film 10A, and does not damage the core portion 14, for example, transparent room temperature curing (RTV). A silicone rubber molded into a plate shape is used.

  Next, as shown in FIG. 4A, the ultraviolet curable hard clad resin solution 16A is dropped onto the end portion on the side to which the silicone rubber plate 22 is adhered. The hard clad resin solution 16 </ b> A dropped onto the end is injected into the space formed by the cutting groove 20 and the silicone rubber plate 22 by capillary action. It is possible to adjust the length of the hard clad portion 16 by controlling the width of the cutting groove 20, the viscosity of the hard clad resin liquid 16A, the filling time, and the like.

  After the hard clad resin liquid 16A is filled to a desired length of the cutting groove 20, the resin liquid 16A is cured by ultraviolet irradiation. After curing, the silicone rubber plate 22 is peeled from the polymer film 10A, so that the hard clad portion 16 is formed at a predetermined length at the end of each cutting groove 20 as shown in FIG. A molecular film 10A is obtained. In the polymer film 10A shown in FIG. 4B, the hard clad portion 16 is formed in the cutting groove 20 using the silicone rubber plate 22 at both ends. Note that the hard clad portion 16 may be formed only at one end depending on the application, such as when processing only one end into a 45 ° inclined surface.

  Finally, the soft clad parts 17 and 18 (the embedded clad part 17 and the upper clad part 18) are formed on the remaining part of the cutting groove 20 of the polymer film 10A and the upper surface of the core part 14 and the hard clad part 16. For example, a liquid soft clad resin is applied to the upper surface of the polymer film 10A by spin coating and then cured. As a result, as shown in FIG. 4C, the soft clad portions 17 and 18 are integrally formed on the groove portion 20 other than the portion where the hard clad portion 16 is already embedded, and the upper surface of the core portion 14 and the hard clad portion 16, respectively. Thus, an optical waveguide 10 that is formed automatically is obtained.

In addition, as another example of the manufacturing method of the polymer optical waveguide 10 according to the present embodiment, for example, Japanese Patent Application Laid-Open No. 2004-29507, Japanese Patent Application Laid-Open No. 2004-86144, and Japanese Patent Application Laid-Open No. 2004-86144 previously proposed by the present applicant. For example, a method for producing a polymer optical waveguide disclosed in Japanese Patent Application Laid-Open No. 2004-109927 may be used. According to these polymer optical waveguide manufacturing methods, it is possible to mass-produce optical waveguides very simply and at low cost by manufacturing the polymer optical waveguide using a mold called a micromold method. Moreover, despite the simple manufacturing method, an optical waveguide with a small optical waveguide loss can be manufactured stably. Furthermore, it is possible to produce an optical waveguide on a flexible plastic substrate that has been difficult to produce.
Also in the case where the polymer optical waveguide according to the present embodiment is manufactured by applying these manufacturing methods, the embedded cladding portion 16 at least at one end portion is formed of a hard cladding material, and the other cladding portion is a soft cladding. What is necessary is just to form with a material.

Hereinafter, although an example is described, the present invention is not limited to the following example at all.
<Example>
An epoxy ultraviolet curable resin having a refractive index of 1.60 and a flexural modulus of 500 MPa after curing as a core resin, and a refractive index of 1.55 and a flexural modulus of 300 MPa after curing as a soft cladding resin. Epoxy ultraviolet curable resins were further prepared as epoxy resins having a refractive index of 1.55, a viscosity of 640 mPa · s, and a flexural modulus after curing of 2.1 GPa as a hard clad resin.

  Spin coat soft resin for clad (thickness 20 μm) and core resin (thickness 40 μm) in this order on a borosilicate glass substrate with a side length of 120 mm and thickness of 3 mm, and cure each layer. A two-layer polymer film was obtained.

  Next, using a dicing saw with a blade having a thickness of 100 μm, cutting was performed so that the core portion having a width of 10 μm and a width of 40 μm was aligned at a pitch of 500 μm from the lowermost surface of the two-layer polymer film. .

  Next, two silicone rubber plates obtained by molding a thermosetting liquid dimethylsiloxane rubber (manufactured by Dow Corning Toray Co., Ltd .: SYLGARD 184) into a plate shape (150 mm × 30 mm × 7 mm) are each formed as a core layer of a two-layer polymer film. Adhered to the top. At this time, the positions of the end portions of the respective silicone rubber plates were made to coincide with the positions of the respective end portions in the longitudinal direction of the polymer film.

  Next, a hard clad resin is applied to the cutting groove exposed on the end face of the polymer film and left for about 10 minutes. After confirming that 10 mm or more is filled from the end face, the hard clad resin is cured by ultraviolet irradiation. I let you. After curing, the silicone rubber plate was peeled from the polymer film.

  Next, a soft clad resin was applied so as to cover the upper surface (core layer upper surface) of the polymer film, vacuum defoamed in an atmosphere of 10 Pa, spin-coated, and then cured by ultraviolet irradiation. Thereby, a buried type waveguide structure was formed.

  Finally, using a dicing saw, the polymer is formed into a length of 110 mm, a width of 0.9 mm, and a thickness of 70 μm, peeled from the borosilicate glass substrate, and the hard clad portion is in contact with the core portion side surface at both ends in the longitudinal direction. An optical waveguide film was produced.

Next, a silicon substrate having a length of 5 mm and a width of 5 mm in which a cross-shaped alignment mark having a width of 5 μm was formed in the center was prepared, and the mounting accuracy of the produced polymer optical waveguide film was confirmed. A polymer optical waveguide film was mounted on a silicon substrate by passive alignment by image recognition using a die bonder having a mounting accuracy of ± 1 μm in an unloaded state. The bonding load was 1.0 N, and an ultraviolet curable resin previously applied on the silicon substrate was cured by ultraviolet irradiation, and the polymer optical waveguide film was bonded onto the silicon substrate.
When the above mounting accuracy was confirmed five times, the deviation of the core from the ideal mounting position was within 5 μm. In addition, the position of the core at the end of the joint surface of the polymer optical waveguide film and the distance between the cores were not changed before and after mounting.

Next, using a dicing saw equipped with a 45 ° angled Si blade, both ends of the polymer optical waveguide film were cut at an angle of 45 ° with respect to the optical axis, and a core having a 45 ° mirror surface. Was exposed.
The core shape of the 45 ° mirror surface was flat, and the centerline average roughness (Ra) measured with a confocal microscope was 70 nm or less. When VCSEL light having a wavelength of 850 nm was introduced through a single mode optical fiber and the loss of the waveguide was evaluated, the excess loss at the 45 ° mirror surface was 0.9 dB.
Thus, by providing the hard clad portions at both ends of the polymer optical waveguide film, a highly accurate 45 ° mirror surface can be formed.

<Comparative example>
A polymer optical waveguide film having a length of 110 mm, a width of 0.9 mm, and a thickness of 70 μm was produced in the same manner as in the above example except that the hard clad portion was not formed.
When a mounting accuracy confirmation experiment similar to that of the example was performed, a positional deviation of 10 μm or more occurred in 2 out of 5 trials, and the mounting accuracy was unstable.
In addition, when trying to form a 45 ° mirror surface using a blade similar to that in the example, the processed surface deviates from an ideal shape and is deformed to a shape with a hollow center portion. The measured center line average roughness (Ra) was 600 nm or more at the best value.

The present invention is not limited to the above embodiments and examples, and may be modified as appropriate. For example, the number of core portions in the optical waveguide, the distance between the core portions, and the like are not limited, and may be formed as required. Moreover, it is good also as an optical waveguide of the structure where the several core is laminated | stacked on the thickness direction of the optical waveguide.
Further, for example, the clad may be exposed on the side surface of the optical waveguide instead of the dummy core.

  Further, it may be a single core optical waveguide. For example, in the optical waveguide shown in FIG. 6, dummy cores 15 are formed on both sides of one core 14 through which light propagates via clads 16 and 17. Even in such a single-core optical waveguide, at least one end portion has a hard clad 16 between the core portions 14 and 15 as shown in FIG. Except for the end portions that are provided, it is only necessary to provide soft claddings 12, 18, and 17 that are located across the core portions 14 and 15 as shown in FIG. 7B.

1 is a perspective view schematically showing a polymer optical waveguide according to a first embodiment. It is a figure showing roughly the polymer optical waveguide concerning a 1st embodiment. (A) Sectional view taken along line AA in FIG. 1 (B) Partial sectional view taken along line BB in FIG. It is a figure which shows the process of the first half which manufactures the optical waveguide which concerns on 1st Embodiment. It is a figure which shows the process of the latter half which manufactures the optical waveguide which concerns on 1st Embodiment. It is a figure which shows the end surface of the other example of a polymer optical waveguide. 1 is a perspective view schematically showing a single core polymer optical waveguide. FIG. It is the schematic which shows the cross section of the polymer optical waveguide shown in FIG. (A) Sectional view on plane A in FIG. 6 (B) Sectional view on plane B in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Polymer optical waveguide 10A Polymer film 12, 17, 18 Soft clad part (2nd clad part)
14 Core part 15 Dummy core part 16 Hard clad part (1st clad part)
20 Cutting groove 22 Silicone rubber plate

Claims (2)

A plurality of core portions extending in a light propagation direction, and a cladding portion having a lower refractive index than the core portion surrounding at least a core portion where light propagates along the light propagation direction among the plurality of core portions. And having
As a clad portion located between the plurality of core portions at at least one end portion, the clad portion has a first clad portion having a higher bending elastic modulus than the core portion and is located across the plurality of core portions. A polymer optical waveguide characterized in that a second clad part having a lower flexural modulus than that of the first clad part is provided as a part. A polymer film in which a core layer and a clad layer having a refractive index lower than that of the core layer are laminated is cut with a dicing saw in a thickness direction from the core layer side to form a plurality of core portions. Forming, and
Forming a first clad portion having a higher flexural modulus than the core portion as a clad portion located between the plurality of core portions at at least one end; and
Forming a second clad portion having a lower bending elastic modulus than the first clad portion as a clad portion located across the plurality of core portions. Production method.

Images