JP2017211414A - Optical path conversion mirror with optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical path conversion mirror with optical waveguide capable of efficiently branching a beam of light transmitted on a core layer at desired ratio.SOLUTION: The optical path conversion mirror with optical waveguide which has a first core layer 1 on which a beam incident light transmits and an optical path conversion mirror. The optical path conversion mirror with optical waveguide includes: a second core layer 2 disposed above a part of a first core layer; and optical path conversion mirrors 6, 7 which are positioned on the optical path of the light transmitting on the core layer being inclined with respect to the optical path. Two or more of at least one optical path conversion mirror 7 are disposed on the optical paths, which are disposed on a part or all the second core layer in a thickness direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical waveguide with an optical path conversion mirror.

  With the increase in information capacity, development of optical interconnection technology that uses optical signals not only for communication fields such as trunk lines and access systems, but also for information processing in routers and server devices is underway. In particular, as an optical transmission path for using light for short-distance signal transmission between boards in a router or a server device, optical fibers that have a higher degree of freedom in wiring and can be densified than optical fibers. It is desirable to use a waveguide. Among them, an optical waveguide using a polymer material excellent in processability and economy is promising. Under such circumstances, a part of the light propagating through the optical waveguide is branched, and the intensity of this light is measured to confirm the deterioration of the optical element over time and to detect an abnormality of the optical element as soon as possible. There is an increasing demand for using the light as a reference for alignment when mounting optical elements.

  As a technique for moving the light propagated using the optical path conversion mirror to another optical path, for example, Patent Document 1 discloses a method of moving the light propagated through the first core to the second core using two optical path conversion mirrors. Has been proposed. Further, as shown in FIG. 4 of Patent Document 1, it has been proposed to move more light by changing the angle of a part of the optical path conversion mirror.

JP 2012-198572 A

However, when this technique is used for the purpose of branching a part of the propagating light without reflecting it at the second mirror part, it is expected that the propagating ratio of the propagating light greatly changes depending on the position of the second mirror surface. It is difficult to obtain an arbitrary branching ratio, and it is necessary to perform mirror processing on both sides of the substrate, which increases the number of processes.
Further, when the angle of a part of the optical path conversion mirror is changed as shown in FIG. 4 of Patent Document 1, the propagation direction of the light path converted on the first mirror surface is different depending on the mirror angle, so the spot diameter is increased. It is difficult to propagate sufficient light to the light receiver. In addition, when condensing light using a lens, it is considered difficult to reduce the size because the lens diameter increases.

  The optical waveguide with an optical path conversion mirror of the present invention is provided in view of the solution of the above problem, and provides an optical waveguide with an optical path conversion mirror capable of efficiently branching light propagating through the core layer at an arbitrary ratio. The purpose is to do.

As a result of diligent research to solve the above problems, the inventors of the present invention are an optical waveguide having a first core layer through which incident light propagates and an optical path conversion mirror, and one of the first core layers. A second core layer at the top of the part, wherein the optical path conversion mirror is positioned on the optical path of light propagating through the core layer and is inclined with respect to the optical path, and two or more are disposed on the optical path The above-mentioned problem can be solved by providing an optical waveguide characterized in that at least one of the optical path conversion mirrors is installed for a part or all of the thickness direction of the second core layer. I found. The present invention has been completed based on such knowledge.
That is, the present invention relates to the following.
(1) An optical waveguide having a first core layer through which incident light propagates and an optical path conversion mirror, wherein the optical path has a second core layer above a part of the first core layer, Two or more conversion mirrors are located on an optical path of light propagating through the core layer and are inclined with respect to the optical path, and two or more conversion mirrors are disposed on the optical path, and at least one of the optical path conversion mirrors is the second core. An optical waveguide with an optical path conversion mirror, wherein the optical waveguide is installed for a part or all of the thickness direction of the layer.
(2) The optical waveguide with an optical path conversion mirror according to (1), wherein an upper surface, a lower surface and side surfaces of the core layer of the optical waveguide are covered with a cladding layer having a refractive index lower than that of the core layer.
(3) The optical waveguide with an optical path conversion mirror according to (1) or (2), wherein an inclination angle of the optical path conversion mirror is in a range of 43 ° to 47 °.
(4) The optical waveguide with an optical path conversion mirror according to any one of (1) to (3), wherein the optical waveguide is a polymer optical waveguide.
(5) The optical waveguide with an optical path conversion mirror according to any one of (1) to (4), having a lens on the optical path converted by the core layer of the optical waveguide and the optical path conversion mirror.

  The optical waveguide with an optical path conversion mirror of the present invention can efficiently branch light propagating through the core layer at an arbitrary ratio.

It is a side view which shows the one aspect | mode of the optical waveguide with a mirror of this invention. It is a side view which shows another aspect of the optical waveguide with a mirror of this invention. It is a side view which shows another aspect of the optical waveguide with a mirror of this invention. It is a side view which shows the one aspect | mode at the time of using the lens of the optical waveguide with a mirror of this invention. It is a perspective view which shows the shape of the 1st core layer in the comparative example 1 of this invention.

An optical waveguide with an optical path conversion mirror of the present invention will be described with reference to FIG.
The optical waveguide with an optical path conversion mirror of the present invention is an optical waveguide having an optical path conversion mirror and a first core layer 1 through which incident light propagates, wherein a part of the first core layer 1 is the first core layer 1. A portion thicker than the thickness of the core layer (second core layer 2), and the optical path conversion mirror is located on an optical path of light propagating through the core layer and is inclined with respect to the optical path An optical waveguide with an optical path conversion mirror, wherein two or more optical path conversion mirrors are arranged on the optical path, and at least one of the optical path conversion mirrors is installed for a part or all of the thickness direction of the second core layer. It is.
When the light propagating through the first core layer 1 reaches the core portion having the second core layer 2, part of the light is also propagated to the second core layer. By performing optical path conversion of this part of the light by the second optical path conversion mirror 7 formed in the second core layer, it is possible to branch the light that has propagated through the core layer. Furthermore, the propagation light can be branched at an arbitrary ratio by adjusting the depth at the time of manufacturing the optical path conversion mirror.

  Further, since the optical waveguide is covered with the clad layers 3 and 4 whose upper surface, lower surface and side surfaces of the core layers 1 and 2 are lower in refractive index than the core layer, scratches and foreign matter on the core layer and the optical path conversion mirror portion. It is possible to prevent contamination due to, for example, and suppress an increase in light loss.

  Further, when the inclination angle of the optical path conversion mirror is in the range of 43 ° to 47 °, preferably 45 °, the optical path converted light is substantially perpendicular to the propagation direction of the light propagating through the core layer. Therefore, the mounting of the optical element is facilitated.

  Further, since the optical waveguide is a polymer optical waveguide, the optical waveguide has flexibility, so that it is possible to prevent damage due to bending of the optical waveguide during handling.

Further, by having a lens on the optical path converted by the core layer of the optical waveguide and the optical path conversion mirror, the propagating light is condensed or collimated to reduce the optical loss in the optical waveguide with the optical path conversion mirror. In addition, the amount of light received by the optical element can be increased.
Hereinafter, each member used in the present invention will be described in detail.

[Optical path conversion mirror]
In the present invention, the optical path conversion mirror is an inclined surface having a certain angle produced by dicing or the like in order to change the propagation direction of light propagating through the core layer.
In the present invention, the angle of the optical path conversion mirror is not particularly limited as long as it can reflect light, but it is preferably between 40 ° and 50 ° from the viewpoint of performing optical path conversion of more propagated light. If the angle is 43 ° to 47 °, the angle of the light whose path has been changed becomes closer to a right angle, so that the light whose path has been changed becomes substantially perpendicular to the propagation direction of the light propagating through the core layer. Since it becomes easy, it is more preferable.
The number of optical path conversion mirrors is particularly limited as long as two or more optical path conversion mirrors are arranged on the optical path, and at least one of the optical path conversion mirrors is provided for a part or all of the thickness direction of the second core layer. Instead, three or more optical path conversion mirrors may be installed to further branch light in the first core layer, and may be similarly installed to branch in the second core layer. Further, in order to cope with a usage method in which the light propagation direction is switched as shown in FIG. 3, the second optical path conversion mirror 7 and the third optical path conversion mirror 8 are installed at both ends of the second core layer. It doesn't matter.

[Clad layer]
In the present invention, the clad layer is not necessarily required, but by having the clad layer, it is possible to protect the core layer from scratches and contamination by foreign substances.
The clad layer is formed on the upper surface, the lower surface, and the side surface of the core layer.
The clad layer forming material used in the present invention is not particularly limited as long as it has a lower refractive index than the core layer, and a thermosetting resin composition or a photosensitive resin composition can be suitably used. . In the lower clad layer and the upper clad layer, the clad layer forming material may contain the same or different components, and the refractive indexes of the materials may be the same or different.

[First core layer]
In the present invention, the first core layer is formed on the lower clad layer, and is a layer through which light incident on the optical waveguide with an optical path conversion mirror from the light source is propagated.
The first core layer forming material is not particularly limited as long as it is a material having a higher refractive index than that of the cladding layer, and a thermosetting resin composition or a photosensitive resin composition can be suitably used.

[Second core layer]
In the present invention, the second core layer is a layer that is formed on a part of the first core layer and through which light is propagated.
The material for forming the second core layer is not particularly limited as long as the material has a higher refractive index than that of the cladding layer, and a thermosetting resin composition or a photosensitive resin composition can be suitably used.
In the first core layer and the second core layer, the components contained in the forming material may be the same or different, and the refractive index of the material is higher if the refractive index is higher than the refractive index of the cladding layer. May be the same or different. However, when the refractive index of the material forming the first core layer and the second core layer is different, total reflection occurs at the interface between the first core layer and the second core layer depending on the combination of refractive indexes, Since it is considered that a necessary branching ratio cannot be obtained, it is preferable to use the same material as the material for forming the first core layer and the second core layer.

〔lens〕
In the present invention, the lens is a member that is installed on the optical path converted by the core layer of the optical waveguide and the optical path conversion mirror and used for collecting or collimating the propagating light.
The shape of the lens is not particularly limited as long as the propagating light can be condensed or collimated.
The diameter and thickness of the lens are not particularly limited as long as the propagation light can be collected and thick, but the focal length of the lens is calculated by the distance between the lens upper surface and the optical element and the diameter and thickness of the lens. Are equal to each other, it is preferable because light can be collected on the light receiving portion of the optical element and more light can be received. Further, from the viewpoint of miniaturization, it is preferable that the lens has a smaller diameter and thickness on the premise that a sufficient amount of light can be collected in the light receiving unit.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
Example 1
(Production of optical waveguide)
Thickness as the substrate 5: 25 μm, length 140 mm, width 140 mm size polyimide substrate (Toray Dupont Co., Ltd., trade name: Kapton EN) on the entire surface, PET film (Toyobo Co., Ltd. “Cosmo Shine A4100”, A clad layer-forming photosensitive resin in the form of a dry film (thickness: 50 μm) (product name; C73, refractive index after curing: 1.536) applied to a vacuum pressure laminator (product) Name: MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) was evacuated to 500 Pa or less, and then thermocompression bonded under the conditions of pressure 0.7 MPa, temperature 70 ° C., and pressurization time 30 seconds. Thereafter, using an ultraviolet exposure machine (trade name: EV-800, manufactured by Hitachi Via Mechanics Co., Ltd.), ultraviolet light (wavelength 365 nm) is irradiated through the PET film at 1 J / cm ² , and then the PET film is peeled off. The lower clad layer 3 having a thickness of 10 μm was prepared by heating and curing at 1 ° C. for 1 hour.

Next, a dry film-shaped first core layer forming resin (trade name; AD193, manufactured by Hitachi Chemical Co., Ltd.) coated on a PET film (Toyobo Co., Ltd. “Cosmo Shine A1517”, thickness: 16 μm) Is a vacuum pressure laminator (trade name: MVLP-500, manufactured by Meiki Seisakusho Co., Ltd., one side is a silicon rubber surface, the other side is a SUS403 surface (SUS surface is a PET film) Side)), and evacuated to 500 Pa or less, and then thermocompression bonded onto the lower cladding layer under the conditions of pressure 0.7 MPa, temperature 80 ° C., and pressurization time 30 seconds. Thereafter, the PET film was peeled off by irradiating 3 J / cm ² (wavelength 365 nm) through the negative photomask having an opening for forming the first core layer 1 using the above exposure machine.

Next, a second core layer forming resin similar to the first core layer forming resin is thermocompression-bonded onto the first core layer forming resin under the same conditions as described above, using the vacuum pressure laminator. did. Thereafter, 3J / cm ^{2 of} irradiation (wavelength 365 nm) is irradiated through the negative photomask having an opening for forming the second core layer using the above exposure machine, and then the PET film is peeled off. After developing with a mass% potassium carbonate aqueous solution, and further using the above exposure machine (wavelength 365 nm) to irradiate 4 J / cm ² with 4 J / cm ^{2, the} film was heat cured at 170 ° C. for 1 hour. Thus, the first core layer 1 and the second core layer 2 were formed.

  The height of the first core layer from the surface of the lower cladding layer was 45 μm, and the height of the second core layer from the surface of the first core layer was 20 μm.

  The obtained core layer was cut using a dicing saw (DAC552, manufactured by DISCO Corporation) having a dicing blade having a 45 ° inclined surface, and the first optical path conversion mirror 6 having a 45 ° inclined surface; The second optical path conversion mirror 7 is formed, the depth of the first optical path conversion mirror from the upper surface of the second core layer is 65 μm, and the depth of the second optical path conversion mirror from the upper surface of the second core layer is 20 μm. It was.

Next, a photosensitive resin for forming the upper clad layer 4 in the form of a dry film coated on a PET film (“Cosmo Shine A4100” manufactured by Toyobo Co., Ltd., thickness: 50 μm) (trade name; C73, manufactured by Hitachi Chemical Co., Ltd.) The refractive index after curing: 1.536) was evacuated to 500 Pa or less using a vacuum pressure laminator (trade name: MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.), and then pressure 0.7 MPa, temperature 70 Thermocompression bonding was performed on the light guide path main body forming surface side under the conditions of ° C and pressurization time of 30 seconds.
After that, through a negative photomask having a 100 μm-square light shielding part, alignment is performed so that the respective light shielding parts are arranged on the first optical path conversion mirror 6 and the second optical path conversion mirror 7, and the ultraviolet exposure described above Machine (trade name: EV-800, manufactured by Hitachi Via Mechanics Co., Ltd.), ultraviolet rays (wavelength 365 nm) were irradiated through the PET film at 0.5 J / cm ² , and then the PET film was peeled off to obtain 1% by mass. An upper clad layer having an opening 9 is developed with an aqueous potassium carbonate solution and further irradiated with 4 J / cm ² (wavelength 365 nm) using the above exposure apparatus, and then heat-cured at 170 ° C. for 1 hour. 4 was formed.

  The upper cladding layer 4 was 80 μm thick from the surface of the lower cladding layer 3. The total thickness of the obtained optical waveguide was 115 μm.

  Next, the outer shape is processed using a dicing saw (DAC552, manufactured by DISCO Corporation) equipped with a rectangular dicing blade, the length of the first core layer is 1500 μm, and the second end is in the range of 500 μm to 1000 μm from the core end face. The core layer was processed to exist.

  850 nm laser light emitted from a laser light source (FLS-300 manufactured by EXFO) is incident through the GI50 fiber from the end face of the core layer of the optical waveguide with an optical path conversion mirror obtained by the outer shape processing, and the first optical path The light that has undergone optical path conversion by the conversion mirror and the light that has undergone optical path conversion by the second optical path conversion mirror are received by an SI114 optical fiber placed at a height of 100 μm from the top surface of the substrate, directly above each optical path conversion mirror. By receiving with a light receiver (Q82214 manufactured by Advantest Corporation), the branching ratio of the propagation light was measured. As a result of measuring five samples prepared in this example, 50 to 55% of the total amount of light incident on the core layer is converted by the first optical path conversion mirror, and 15 to 20% is converted by the second optical path conversion mirror. It was found that the light was received by the SI114 fiber.

(Example 2)
In Example 1, a thickness of 55 μm and a diameter of 150 μm are formed on the opposite surface of the lower clad layer of the substrate on the optical axis of the light subjected to the optical path conversion in the first optical path conversion mirror and the second optical path conversion mirror after the outer shape processing. The lens 10 was installed (see FIG. 4).
The branching ratio was measured in the same manner as in Example 1 except that the height of the SI114 fiber was set to 100 μm from the upper surface of the lens in the sample in which the microlens was installed.
As a result of measuring five samples prepared in this example, 65 to 70% of the total amount of light incident on the core layer is converted by the first optical path conversion mirror, and 20 to 25% is optical path converted by the second optical path conversion mirror. It was found that the light was received by the SI114 fiber.

(Comparative Example 1)
In Example 1, only the first core layer is produced without producing the second core layer, and the second optical path conversion mirror 7 is formed on a part of the first core layer 1 in the width direction as shown in FIG. A sample was prepared by the same method except that the width of the first optical path conversion mirror was set to 30 μm and the width of the second optical path conversion mirror was set to 15 μm.
As a result of measuring five samples prepared in this comparative example, 35 to 50% of the total light amount incident on the core layer is converted by the first optical path conversion mirror, and 8 to 17% is optical path converted by the second optical path conversion mirror. It was found that the light was received by the SI114 fiber, and the amount of received light was smaller and the variation was larger than in Example 1. This is considered to be due to the fact that the width of the optical path conversion mirror, which was initially set due to the accuracy when processing the optical path conversion mirror, varies from sample to sample.

  The optical waveguide with an optical path conversion mirror of the present invention is an optical waveguide with an optical path conversion mirror capable of efficiently branching propagating light at an arbitrary ratio, and can be applied to confirming the lifetime of an optical element, alignment of optical element mounting, etc. It is.

1. First core layer2. Second core layer3. Lower clad layer 4. 4. Upper clad layer Substrate 6. First optical path conversion mirror 7. Second optical path conversion mirror 8. Third optical path conversion mirror 9. Opening 10. lens

Claims (5)

  An optical waveguide having a first core layer through which incident light propagates and an optical path conversion mirror, wherein the optical path conversion mirror has a second core layer above a part of the first core layer, , Located on the optical path of the light propagating through the core layer, and inclined with respect to the optical path, two or more disposed on the optical path, and at least one of the optical path conversion mirrors has a thickness of the second core layer An optical waveguide with an optical path conversion mirror, characterized in that the optical waveguide is installed for a part or all of directions.   2. The optical waveguide with an optical path conversion mirror according to claim 1, wherein an upper surface, a lower surface and a side surface of the core layer of the optical waveguide are covered with a cladding layer having a refractive index lower than that of the core layer.   The optical waveguide with an optical path conversion mirror according to claim 1 or 2, wherein an inclination angle of the optical path conversion mirror is in a range of 43 ° to 47 °.   The optical waveguide with an optical path conversion mirror according to any one of claims 1 to 3, wherein the optical waveguide is a polymer optical waveguide.   The optical waveguide with an optical path conversion mirror according to any one of claims 1 to 4, further comprising a lens on an optical path converted by the core layer of the optical waveguide and the optical path conversion mirror.

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