Optical combiner and optical combiner method

Abstract

The present invention provides an optical combiner and an optical combining method capable of combining light of four or more wavelengths. An optical combiner (1) is capable of combining light of multiple wavelengths. The optical combiner comprises a plurality of coupling parts (10). The coupling parts (10) comprise a pair of main input paths (110, 120), a pair of main output paths (130, 140), and a main coupler (150). The main coupler (150) is arranged between the main input paths (110, 120) and the main output paths (130, 140), couples light incident on the main input paths (110, 120), and outputs the light to the main output paths (130, 140). One main input path (110, 120) of the coupling parts (10) is connected to the main output paths (130, 140) of the other coupling parts (10). The main coupler (150) has a coupling characteristic different from that of at least one other coupler (150).

Description

Technical Field

[0001] The present invention relates to an optical combiner and an optical combiner method. Background Art

[0002] Laser displays that allow users to see images by two-dimensionally scanning lasers are known. In laser displays, three colors of visible light, typically emitted by an R (red), G (green), and B (blue) light source, are brought close together and propagated to an image display unit. The image display unit projects an image onto a projection object using the two-dimensionally scanned and propagated light. For example, Patent Document 1 discloses an optical integrated circuit that brings lasers corresponding to the respective RGB colors close together and projects them.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-35876. Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, as mentioned above, Patent Document 1 is limited to combining (combining) three colors of RGB. In contrast, it would be better if four or more colors (four wavelengths) could be combined.

[0008] The present invention is made in view of the actual situation of the above-mentioned prior art, and its object is to provide an optical combiner and an optical combining method capable of combining light of four or more wavelengths.

[0009] Solutions for solving problems

[0010] The present invention relates to an optical combiner capable of combining light of multiple wavelengths. The optical combiner has multiple coupling sections, each of which has a pair of main input paths, a pair of main output paths, and a main coupler. The main coupler is arranged between the main input path and the main output path, couples light incident on the main input path, and outputs it to the main output path. The main input path of one of the coupling sections is connected to the main output path of the other coupling sections, and each main coupler has a coupling characteristic different from that of at least one other main coupler.

[0011] In addition, it is preferred to have: a standard unit with the multiple coupling parts as a group; and a sub-unit that can be connected to the standard unit, the sub-unit having: a pair of sub-input paths; a pair of sub-emission paths; and a sub-coupler, the sub-coupler couples the light incident on the sub-input paths and emits it to the sub-emission paths, the sub-input paths are configured to be connectable to the main emission path, and the sub-emission paths are configured to be connectable to the main input path.

[0012] Furthermore, it is preferable that the sub-injection path be configured to be connectable to the sub-emission path of another sub-unit.

[0013] Furthermore, it is preferable that the sub-emission path be configured to be connectable to the sub-injection path of another sub-unit.

[0014] In addition, it is preferred that the standard unit is composed of three coupling parts as a group, the other main emission path of the first coupling part is connected to one main injection path of the third coupling part, and one main emission path of the second coupling part is connected to another main injection path of the third coupling part, and the main coupler of the first coupling part, the main coupler of the second coupling part, and the main coupler of the third coupling part have different coupling characteristics.

[0015] In addition, it is preferred that either the light with the longest wavelength or the light with the second longest wavelength among the multiple wavelengths of light incident on the standard unit is incident on one of the main incident paths of the first coupling portion, and the remaining one of the light with the longest wavelength or the light with the second longest wavelength among the multiple wavelengths of light incident on the standard unit is incident on the other main incident path of the second coupling portion.

[0016] In addition, it is preferred that the main coupler of the first coupling part has a coupling characteristic of emitting light incident on any of the main input paths of the first coupling part toward the other main output path, the main coupler of the second coupling part has a coupling characteristic of emitting light incident on any of the main input paths of the second coupling part toward one main output path, and the main coupler of the third coupling part has a coupling characteristic of emitting light incident on any of the main input paths of the third coupling part toward any of the main output paths.

[0017] Furthermore, it is preferred that one of the sub-emission paths of the sub-unit is connected to the other main injection path of the first coupling portion, and the other sub-emission path of the sub-unit is connected to one main injection path of the second coupling portion.

[0018] Furthermore, it is preferable that the sub-coupler of the sub-unit has a coupling characteristic of emitting light incident on the pair of the sub-incident paths toward at least one of the sub-emission paths.

[0019] Furthermore, it is preferable that another of the sub-injection paths of the sub-unit is connected to one of the sub-emission paths of the other sub-unit.

[0020] Furthermore, it is preferred that one of the main emission paths of the third coupling portion is connected to another sub-injection path of the other sub-unit.

[0021] Furthermore, it is preferable that the sub-coupler of the sub-unit has a coupling characteristic of splitting at least one of the lights incident on the pair of the sub-incident paths and emitting the light to the pair of the sub-emission paths.

[0022] In addition, the present invention relates to an optical combining method for combining light of multiple wavelengths, including: a first combined light output step, combining a portion of the first light with the second light to output the first combined light; a second combined light output step, combining another portion of the first light with the third light to output the second combined light; a third combined light output step, combining the first combined light with the fourth light to output the third combined light; and a fourth combined light output step, combining the second combined light with the third combined light to output the fourth combined light.

[0023] Furthermore, assuming that the wavelength of the first light is λ1, the wavelength of the second light is λ2, the wavelength of the third light is λ3, and the wavelength of the fourth light is λ4, it is preferable that λ1<λ2<λ3<λ4.

[0024] Furthermore, the present invention relates to a method for combining light of multiple wavelengths, comprising the step of connecting an outgoing path of a coupling portion capable of combining at least two lights to an incoming path of another coupling portion.

[0025] Furthermore, assuming that the wavelength of the first light is λ1, the wavelength of the second light is λ2, the wavelength of the third light is λ3, and the wavelength of the fourth light is λ4, it is preferable that λ1<λ2<λ3<λ4.

[0026] Effects of the Invention

[0027] According to the present disclosure, an optical combiner and an optical combining method capable of combining light of four or more wavelengths can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram showing the relationship between the coupling section and incident light of the optical multiplexer according to the first embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram showing the relationship between the coupling section and incident light of the optical multiplexer according to the first embodiment.

[0030] Figure 3 This is a schematic diagram showing the structure of the optical multiplexer according to the first embodiment.

[0031] Figure 4 This is a schematic diagram showing the relationship between the wavelength of incident light and coupling characteristics of the optical multiplexer according to the first embodiment.

[0032] Figure 5 This is a table showing the wavelength of light incident on the optical multiplexer according to the first embodiment and the multiplexing efficiency.

[0033] Figure 6 This is a schematic diagram showing a path along which the first light incident on the optical multiplexer according to the first embodiment passes.

[0034] Figure 7 This is a schematic diagram showing a path along which the second light incident on the optical multiplexer according to the first embodiment passes.

[0035] Figure 8 This is a schematic diagram showing a path along which the third light incident on the optical multiplexer according to the first embodiment passes.

[0036] Figure 9 This is a schematic diagram showing a path along which the fourth light incident on the optical multiplexer according to the first embodiment passes.

[0037] Figure 10 It is a schematic diagram showing the structure of an optical multiplexer according to a second embodiment of the present invention.

[0038] Figure 11 This is a table showing the coupling characteristics of the wavelength of light incident on the optical multiplexer according to the second embodiment.

[0039] Figure 12 This is a table showing the wavelength of light incident on the optical multiplexer according to the second embodiment and the multiplexing efficiency.

[0040] Figure 13 This is a schematic diagram showing the structure of an optical multiplexer according to a third embodiment of the present invention.

[0041] Figure 14 This is a table showing the wavelength coupling characteristics of light incident on the optical multiplexer according to the third embodiment.

[0042] Figure 15 This is a table showing the wavelength of light incident on the optical multiplexer according to the third embodiment and the multiplexing efficiency. DETAILED DESCRIPTION

[0043] Below, refer to Figures 1 to 15 The optical multiplexer 1 and the optical multiplexing method according to each embodiment of the present invention will be described.

[0044] First, an overview of the optical multiplexer 1 and the optical multiplexing method according to each embodiment will be described.

[0045] The optical combiner 1 is a device that can combine multiple wavelengths of light. In particular, the optical combiner 1 is a device that can combine four or more types of light with different wavelengths. The optical combiner 1 has multiple Figure 1As shown, the optical multiplexer 1 includes a pair of main input paths 110 and 120, a pair of main output paths 130 and 140, and a main coupler 150. The optical multiplexer 1 combines light of multiple wavelengths using a combination of multiple coupling units 10. The optical multiplexer 1 has a structure in which multiple coupling units 10 are combined, for example.

[0046] Next, the structure of the coupling unit 10 will be described. Here, the coupling unit 10 is described using a directional coupler as an example. However, as long as light can be input from a pair of main input paths and output from a pair of main output paths, the coupling unit 10 can also be applied to couplers other than directional couplers. For example, the coupling unit 10 is not limited to a directional coupler and can also be a multimode interference type coupler other than a directional coupler. As long as light can be input from a pair of main input paths 110 and 120 and output from a pair of main output paths 130 and 140, any coupler can be used. A directional coupler is a coupler having a structure in which two optical waveguides are arranged close together and in parallel. A directional coupler is an optical coupler that utilizes the phenomenon that a light field leaking from an optical waveguide reaches an adjacent optical waveguide, and as the light propagates along the optical waveguide, the light is transferred to the adjacent optical waveguide or returns to the original optical waveguide.

[0047] Furthermore, multimode interference couplers are constructed using optical waveguides wider than the wavelength (multimode waveguides). Taking advantage of the large number of modes of light propagating through them, they connect the input and output waveguides to these multimode waveguides, thereby switching light. Multimode waveguides are not limited to simply wide waveguides; they also come in a variety of shapes, including those composed of multiple waveguides and those whose width varies along the propagation direction.

[0048] The pair of main incident paths 110 and 120 are each so-called optical waveguides. They are preferably, for example, single-mode optical waveguides or optical waveguides with the fundamental mode as the main component. The pair of main incident paths 110 and 120 each function as a propagation path for the incident light. In this embodiment, the pair of main incident paths 110 and 120 approach each other so that the distance between them decreases along the propagation direction from the incident entrance. A typical example is approaching in a curved shape toward each other.

[0049] The pair of main emission paths 130 and 140 are each a so-called optical waveguide. They function as propagation paths for the emitted light. In this embodiment, the pair of main emission paths 130 and 140 are separated so that the distance between them increases along the propagation direction toward the emission port. A typical example is a separation in which the main emission paths 130 and 140 are curved toward each other.

[0050] The main coupler 150 is a multiplexer that actually multiplexes the light incident along the main incident paths 110 and 120. The main coupler 150 is arranged between the main incident paths 110 and 120 and the main emission paths 130 and 140, and couples the light incident on the main incident paths 110 and 120 and emits it to the main emission paths 130 and 140. The main coupler 150 has a predetermined coupling characteristic. Figure 1 As shown, the main coupler 150 has the following coupling characteristics: for light of a predetermined wavelength λ, almost all of the light incident on one main incident path 110 is emitted to the other main emission path 140. In this embodiment, the length (coupling length) of the coupler 150 having this coupling characteristic is referred to as the "complete coupling length" of the predetermined wavelength. Figure 2 As shown, when the main coupler 150 is twice the length of the complete coupling length, it has the following coupling characteristics: almost all of the light of a predetermined wavelength λ incident on one main incident path 110 is emitted to one main emission path 130. Figure 2 In the case of , light with a wavelength λ incident on one main input path 110 propagates through main coupler 150 by first moving to the other main output path 140 and then to one main output path 130. When the length of main coupler 150 is 3L, light with a wavelength λ incident on one main input path 110 propagates through main coupler 150 by first moving to the other main output path 140 and then to one main output path 130 and then to the other main output path 140 again. In this way, the incident light is emitted from either or both of the pair of main output paths 130 and 140, depending on the fully coupled length determined by wavelength λ and the length of main coupler 150.

[0051] Here, one main incident path 110 or 120 of a coupling portion 10 is connected to the main emission paths 130 or 140 of another coupling portion 10. Thus, light incident on one coupling portion 10 passes through one or more coupling portions 10 and is finally emitted from one main emission path 130 or 140.

[0052] In the following embodiments, an example in which three coupling units 10 are connected in a predetermined combination is described as a standard unit 100. Furthermore, a coupling unit 10 configured to be detachably attached to and from the standard unit 100 is described as a subunit 21. Furthermore, in the following embodiments, by varying the connection combinations of the subunits 21 and the standard unit 100, light of various wavelengths can be multiplexed.

[0053] [First embodiment]

[0054] Next, refer to Figures 1 to 9 An optical multiplexer 1 and an optical multiplexing method according to a first embodiment of the present invention will be described.

[0055] like Figure 3 As shown, the optical combiner 1 includes a standard unit 100 and a subunit 21. In this embodiment, the optical combiner 1 combines four lights, namely, a first light (wavelength λ1), a second light (wavelength λ2), a third light (wavelength λ3), and a fourth light (wavelength λ4). Here, the wavelength relationship of the four lights is: λ1<λ2<λ3<λ4. In addition, in the following description, for a pair of main input paths 110, 120 and a pair of main output paths 130, 140, Figure 3 In the illustrated optical multiplexer 1 , the portion located on the upper side of the paper is referred to as “one”, and the portion located on the lower side of the paper is referred to as “the other”.

[0056] The standard unit 100 is composed of a plurality of coupling parts 10. In this embodiment, Figure 3 As shown, the standard cell 100 is composed of three coupling parts 10. Specifically, the standard cell 100 has a first coupling part 11, a second coupling part 12 and a third coupling part 13.

[0057] The first coupling unit 11 is configured to allow the third light to enter one of the pair of main incident paths 111 and 121. The main coupler 151 of the first coupling unit 11 has a coupling characteristic of emitting the light entering the main incident path 121 of the first coupling unit 11 to the other main emission path 141. Specifically, Figure 4 As shown, the length of the main coupler 151 of the first coupling section 11 is the complete coupling length for the third light, i.e., L / 2. Here, L is the complete coupling length for the wavelength λ2 of the second light. The other main outgoing paths 131 and 141 of the first coupling section 11 are connected to one main incoming path 113 and 123 of the third coupling section 13, described later. Specifically, with the longitudinal direction of the main coupler 151 as the boundary, the main outgoing path 141 of the main outgoing paths 131 and 141, which is located on the same side of the main incoming path 121 of the first coupling section 11 where the third light enters, is connected to one main incoming path 113 of the third coupling section 13. Furthermore, light with a wavelength second only to the longest wavelength among the multiple light beams (the third light in this embodiment) enters one main incoming path 111 of the first coupling section 11.

[0058] The second coupling section 12 is configured to allow the fourth light to enter the other of the pair of main input paths 112 and 122. The main coupler 152 of the second coupling section 12 has a coupling characteristic that allows the light entering the main input paths 112 and 122 of the second coupling section 12 to be emitted toward a single main output path 132. Specifically, the length of the main coupler 152 of the second coupling section 12 is L / 3, the complete coupling length for the fourth light. One main output path 132 of the second coupling section 12 is connected to the other main input path 123 of the third coupling section 13, described later. Specifically, the main output path 132 of the main output paths 132 and 142 located opposite the main input path 122 into which the fourth light enters is connected to the other main input path 123 of the third coupling section 13, with the longitudinal direction of the main coupler 152 serving as the boundary. Furthermore, the light with the longest wavelength among the plurality of light beams (the fourth light in this embodiment) enters the other main output path of the second coupling section 12.

[0059] The third coupling section 13 is connected to the first coupling section 11 and the second coupling section 12. Specifically, one main input path 113 of the third coupling section 13 is connected to the other main output path 141 of the first coupling section 11. Furthermore, another main input path 123 of the third coupling section 13 is connected to one main output path 132 of the second coupling section 12. The main coupler 153 of the third coupling section 13 has coupling characteristics that direct light incident on the main input paths 113 and 123 of the third coupling section 13 toward the one main output path 133. Specifically, the length of the main coupler 153 of the third coupling section 13 is the fully coupled length (L) of the second light.

[0060] The sub-unit 21 is configured to be connectable to the standard unit 100. The sub-unit 21 includes a pair of sub-injection paths 211 and 221, a pair of sub-output paths 231 and 241, and a sub-coupler 251. Figure 3 As shown, in this embodiment, a subunit 21 is provided. In addition, in this embodiment, the subunit 21 is coupled with the first coupling portion 11 and the second coupling portion 12.

[0061] A pair of sub-injection paths 211 and 221 are so-called optical waveguides. The pair of sub-injection paths 211 and 221 act as propagation paths of the incident light, respectively. In the present embodiment, the pair of sub-injection paths 211 and 221 respectively inject the first light and the second light. Specifically, the second light is injected on the first coupling part 11 side with the longitudinal direction of the sub-coupler 251 as the boundary. In addition, the first light is injected on the second coupling part 12 side. In the present embodiment, the sub-emission paths 231 and 241 are configured to be connected to the main injection paths 121 and 112. In the present embodiment, the pair of sub-injection paths 211 and 221 are close to each other in a manner that the distance between them decreases along the propagation direction from the injection port. The most representative example is that they are close to each other in a shape that bends in the direction of approaching each other.

[0062] The pair of sub-emission paths 231 and 241 are each a so-called optical waveguide. Each of the pair of sub-emission paths 231 and 241 functions as a propagation path for the emitted light. In this embodiment, the pair of sub-emission paths 231 and 241 are separated such that the distance between them increases in the propagation direction toward the emission outlet. A typical example is a separation in which the sub-emission paths 231 and 241 are curved toward each other.

[0063] The optical multiplexer 1 described above operates in the following manner.

[0064] First, the sub-unit 21 is coupled to the standard unit 100. Specifically, Figure 3 As shown, a pair of sub-emission paths 231 and 241 of the sub-unit 21 are coupled with another main injection path 121 of the first coupling portion 11 and one main injection path 112 of the second coupling portion 12 of the standard unit 100 .

[0065] Next, the first light (complete coupling length 2L) and the second light (complete coupling length L) are respectively incident on a pair of main incident paths of the sub-unit 21. Specifically, the first light is incident on the other sub-input path 221. Moreover, the second light is incident on one sub-input path 211. The first light is incident on the sub-coupler 251 (coupling length L) from the other sub-input path 221. In the sub-coupler 251, the first light is split and emitted toward the sub-emission paths 231 and 241. Thus, the first light is separated and emitted toward each of the pair of sub-emission paths 231 and 241. On the other hand, the second light is incident on the sub-coupler 251 from one sub-input path 211. In the sub-coupler 251, the second light is substantially transferred from one sub-input path 211 to the other sub-emission path 241. Thus, the second light is substantially emitted toward the other sub-emission path 241. That is, the first light having the split light amount is emitted toward one sub-emission path 231. Then, the combined light of the first light and the second light (hereinafter referred to as the first combined light) having the split light quantity is emitted to the other sub-emission path 241 .

[0066] Furthermore, the third light (complete coupling length L / 2) enters one main input path 111 of the first coupling section 11. Furthermore, the first light emitted toward one sub-emission path 231 enters the other main input path 121 of the first coupling section 11. The third light enters the main coupler 151 (coupling length L / 2) from one main input path 111. Furthermore, the first light entering the other main input path 121 enters the main coupler 151. In the main coupler 151, the third light is substantially transferred from the one main input path 111 to the other main emission path 141. As a result, the third light is substantially emitted from the other main emission path 141. Meanwhile, in the main coupler 151, the first light is hardly transferred to one main emission path 131 but is emitted toward the other main emission path 141. Consequently, the combined light of the first and third lights (hereinafter referred to as the second combined light) is emitted toward the other main emission path 141.

[0067] Furthermore, the fourth light (complete coupling length L / 3) enters the other main input path 122 of the second coupling section 12. Furthermore, the first multiplexed light (first light and second light) emitted toward the other sub-emission path 241 enters the one main input path 112. The fourth light enters the main coupler 152 (coupling length L / 3) from the other main input path 122. Furthermore, the first multiplexed light enters the main coupler 152 from the one main input path 112. In the main coupler 152, the fourth light is substantially transferred from the other main input path 122 to the one main emission path 132. As a result, the fourth light is substantially emitted toward the one main emission path 132. Meanwhile, the first multiplexed light enters the main coupler 152 from the one main input path 112. In the main coupler 152, the first multiplexed light is substantially not transferred to the other main emission path 142 but is emitted toward the one main emission path 132. As a result, the combined light of the fourth light and the first combined light (hereinafter referred to as the third combined light) is emitted toward the one main emission path 132 .

[0068] The second multiplexed light is incident on one main input path 113 of the third coupler 13 from the other main output path 141. Furthermore, the third multiplexed light is incident on the other main input path 123 of the third coupler 13 from the one main output path 132. The second multiplexed light is incident on the one main input path 113 of the third coupler 153 (coupling length L). The third multiplexed light is incident on the other main input path 123 of the third coupler 153.

[0069] In the main coupler 153, the second combined light and the first light included in the third combined light are combined again into a single light. Furthermore, the combined first light is emitted toward a single main emission path 133. Here, although the first light is branched into a pair of sub-emission paths 231 and 241 by the subunit 21, each is emitted with a 90° phase shift. Furthermore, when coupling is performed in the third coupling section 13, the first light enters the coupling section 13 with a 90° phase shift. As a result, when the first light propagates through the coupling section 13 and, in the case of an optical coupler, the phase difference between the even mode and the odd mode of the optical coupler shifts by 90°, the first light shifts to the side of a single main emission path 133 and is emitted from the single main emission path 133.

[0070] In the main coupler 153 , the second light included in the third combiner is substantially transferred from the other main input path 123 to the one main output path 133 .

[0071] In the main coupler 153 , the third light included in the second multiplexed light hardly transfers from one main input path 113 to the other main output path 143 . Even if it transfers in the main coupler 153 , it eventually returns to its original position and is output to one main output path 133 .

[0072] In main coupler 153, the fourth light included in the third multiplexer is substantially transferred from the other main input path 123 to the one main output path 133. As a result, the second light is emitted from the one main output path 133. As described above, the first light, the second light, the third light, and the fourth light are multiplexed and emitted from the one main output path 133 as the fourth multiplexed light.

[0073] Next, the photosynthesis method will be described.

[0074] The optical multiplexing method includes a first multiplexing optical output step, a second multiplexing optical output step, a third multiplexing optical output step, and a fourth multiplexing optical output step.

[0075] The first multiplexed light output step multiplexes a portion of the first light with the second light to output as the first multiplexed light. Specifically, the first multiplexed light is emitted toward another sub-emission path 241 of the subunit 21. Furthermore, in this embodiment, in addition to the first multiplexed light, the first multiplexed light output step emits another portion of the first light out of one of the sub-emission paths 231.

[0076] The second combined light output step combines another portion of the first light with the third light to output as the second combined light. Specifically, the second combined light output step combines the first light emitted along one sub-emission path 231 with the third light to output as the second combined light. The second combined light becomes the light emitted along the other main emission path 141 of the first coupling unit 11.

[0077] The third multiplexed light output step multiplexes the first multiplexed light and the fourth light to output the third multiplexed light. The third multiplexed light becomes light emitted toward one main emission path 132 of the second coupling unit 12.

[0078] In the fourth multiplexed light output step, the output second multiplexed light is multiplexed with the third multiplexed light to output as the fourth multiplexed light. Specifically, the fourth multiplexed light is emitted from one main emission path 133 of the third coupling unit 13. The fourth multiplexed light is a light obtained by multiplexing four lights.

[0079] [Example 1]

[0080] Next, Example 1 of this embodiment will be described.

[0081] like Figure 5 As shown, λ1 = 450 nm, λ2 = 520 nm, λ3 = 635 nm, and λ4 = 720 nm. As a result, the multiplexing efficiency of the multiplexed light emitted from one main emission path 133 of the third coupling unit 13 is 96.1% for λ1, 92.8% for λ2, 98.0% for λ3, and 99.9% for λ4.

[0082] Results, such as Figure 6 As shown, in the subunit 21, the first light enters from the other sub-input path 221 and exits from each of the pair of sub-output paths 231 and 241. Then, in the first coupling section 11, the first light enters from the other main input path 121 and exits from the other main output path 141. Furthermore, in the second coupling section 12, the first light enters from one main input path 112 and exits from one main output path 132. Furthermore, in the third coupling section 13, the first light enters from the pair of main input paths 113 and 123 and exits from one main output path 133.

[0083] like Figure 7 As shown, in the subunit 21, the second light is incident from a sub-input path 211 and is emitted from another sub-emission path 241. In the second coupling portion 12, the second light is incident from a main input path 112 and is emitted from a main emission path 132. In the third coupling portion 13, the second light is incident from another main input path 123 and is emitted from a main emission path 133.

[0084] like Figure 8 As shown, in the first coupling portion 11, the third light enters from a main incident path 111 and exits from another main exit path 141. In the third coupling portion 13, the third light enters from a main incident path 113 and exits from a main exit path 133.

[0085] like Figure 9As shown, in the second coupling portion 12 , the fourth light enters from another main incident path 122 and exits from a sub-emission path 132 . In the third coupling portion 13 , the fourth light enters from another main incident path 123 and exits from a main emission path 133 .

[0086] As can be seen from this, the first light, the second light, the third light, and the fourth light are emitted from one main emission path 133 of the third coupling unit 13 .

[0087] As described above, according to the optical multiplexer 1 and the optical multiplexing method according to the present embodiment, the following effects can be achieved.

[0088] (1) An optical combiner 1 capable of combining light of multiple wavelengths has a plurality of coupling sections 10. The coupling sections 10 have a pair of main input paths 110, 120, a pair of main output paths 130, 140, and a main coupler 150. The main coupler 150 is disposed between the main input paths 110, 120 and the pair of main output paths 130, 140, and couples light incident on the main input paths 110, 120 and outputs the light to the main output paths 130, 140. One main input path 110, 120 of the coupling section 10 is connected to the main output paths 130, 140 of the other coupling sections 10. Each main coupler 150 has a coupling characteristic different from that of at least one other coupler 150. Thus, light combined by the plurality of coupling sections 10 can be collectively output from any main output path 130, 140 of any coupling section 10. Therefore, it is possible to easily combine four or more types of light. In particular, by changing the coupling relationship among the plurality of coupling portions 10 , it is possible to provide an optical multiplexer 1 that can flexibly cope with input wavelengths.

[0089] (2) The optical combiner 1 includes a standard cell 100 comprising a plurality of coupling units 10; a sub-cell 21 connectable to the standard cell 100, the sub-cell 21 including a pair of sub-input paths 211 and 221; a pair of sub-emission paths 231 and 241; and a sub-coupler 251 that couples light incident on the sub-input paths 211 and 221 and emits the light to the sub-emission paths 231 and 241, the sub-emission paths 231 and 241 being configured to be connectable to the main input paths 110 and 120. Thus, by freely reconfiguring the connection between the sub-cell 21 and the standard cell 100, the emission positions of the incident light and the combined light can be appropriately controlled. This improves the flexibility of the optical combiner 1.

[0090] (3) The standard unit 100 is composed of three coupling units 10. The other main emission paths 131 and 141 of the first coupling unit 11 are connected to the main input paths 113 and 123 of the third coupling unit 13. The main emission paths 132 and 142 of the second coupling unit 12 are connected to the other main input paths 113 and 123 of the third coupling unit 13. The main coupler 151 of the first coupling unit 11, the main coupler 152 of the second coupling unit 12, and the main coupler 153 of the third coupling unit 13 have different coupling characteristics. This allows the emission positions of each coupling unit 10 to be limited to a certain extent for multiple lights of different wavelengths. Therefore, by connecting and adjusting multiple subunits 21 based on the standard unit 100, it is possible to combine lights of various wavelengths.

[0091] (4) The main coupler 151 of the first coupling section 11 has a coupling characteristic for directing light incident on any of the main input paths 111 and 121 of the first coupling section 11 toward the other main output path 131 or 141. The main coupler 152 of the second coupling section 12 has a coupling characteristic for directing light incident on any of the main input paths 112 and 122 of the second coupling section 12 toward one of the main output paths 132 or 142. The main coupler 153 of the third coupling section 13 has a coupling characteristic for directing light incident on any of the main input paths 113 and 123 of the third coupling section 13 toward any of the main output paths 133 or 143. Thus, light emitted from the standard cell 100 can be concentrated and emitted along any of the main output paths 133 or 143 of the third coupling section 13.

[0092] (5) One sub-emission path 231, 241 of the subunit 21 is connected to the other main incident path 121 of the first coupling section 11, and the other sub-emission path 241 of the subunit 21 is connected to the one main incident path 112 of the second coupling section 12. This allows the four incident lights to be appropriately multiplexed.

[0093] (6) The subcoupler 251 of the subcell 21 has a coupling characteristic that outputs light incident on the pair of sub-incident paths 211 and 221 to at least one sub-output path 231 or 241. This allows light incident on the subcell to be converted into a desired state before entering the standard cell 100.

[0094] (7) The sub-coupler 251 of the sub-unit 21 has a coupling characteristic of splitting at least one of the lights incident on the pair of sub-incident paths 211 and 221 and outputting the light to the pair of sub-output paths 231 and 241 .

[0095] (8) An optical multiplexing method for multiplexing light of multiple wavelengths, comprising: a first multiplexed light output step of multiplexing a portion of a first light with a second light to output as a first multiplexed light; a second multiplexed light output step of multiplexing another portion of the first light with a third light to output as a second multiplexed light; a third multiplexed light output step of multiplexing the first multiplexed light with a fourth light to output as a third multiplexed light; and a fourth multiplexed light output step of multiplexing the second multiplexed light with the third multiplexed light to output as a fourth multiplexed light. Thus, it is possible to easily multiplex light of four or more wavelengths.

[0096] (9) Let the wavelength of the first light be λ1, the wavelength of the second light be λ2, the wavelength of the third light be λ3, and the wavelength of the fourth light be λ4, and λ1 < λ2 < λ3 < λ4. This allows light of four or more wavelengths to be appropriately multiplexed.

[0097] [Second embodiment]

[0098] Next, refer to Figures 10 to 12 An optical multiplexer 1 and an optical multiplexing method according to a second embodiment of the present invention will be described. In the description of the second embodiment, the same reference numerals are used for the same components as those in the above embodiment, and their descriptions will be omitted or simplified.

[0099] The optical combiner 1 and the optical combining method according to the second embodiment differ from those of the first embodiment in that five lights are combined. Figure 10 As shown, the optical multiplexer 1 and the optical multiplexing method according to the second embodiment are different from those of the first embodiment in that a sub-unit 22 is further connected to one standard unit 100 and one sub-unit 21 .

[0100] In addition, if Figure 11 As shown, the optical combiner 1 and optical combining method involved in the second embodiment are different from those of the first embodiment in that the wavelength of the first light is λ1, the wavelength of the second light is λ2, the wavelength of the third light is λ3, the wavelength of the fourth light is λ4, and the wavelength of the fifth light is λ5.

[0101] The optical combiner 1 and optical combining method according to the second embodiment differ from those of the first embodiment in that the complete coupling lengths of the respective lights are 2L, L, L / 2, L / 3, and L / 4, respectively. Furthermore, the optical combiner 1 and optical combining method according to the second embodiment differ from those of the first embodiment in that λ1 < λ2 < λ3 < λ4 < λ5.

[0102] like Figure 10As shown, the optical combiner 1 has a structure in which a subunit (hereinafter referred to as the second subunit 22) is further connected to the optical combiner 1 of the first embodiment. Specifically, the optical combiner 1 has a structure in which one sub-input path 211 of the subunit (hereinafter referred to as the first subunit 21) of the first embodiment is connected to another sub-output path 242 of another subunit (the second subunit 22). In other words, the other sub-output paths 232 and 242 of the second subunit 22 are configured to be connected to one sub-input path 211 and 221 of the other subunit (the first subunit 21). In addition, in the optical combiner 1 and the optical combining method according to the second embodiment, the fifth light is incident on one main input path 111 of the first coupling section 11. In addition, the fourth light is incident on another main input path 122 of the second coupling section 12. Furthermore, the optical combiner 1 and the optical combining method according to the second embodiment differ from the first embodiment in that the full coupling length of the first coupling section 11 is L / 4, and the full coupling length of the second coupling section 12 is L / 3. That is, the first coupling section 11 and the second coupling section 12 have complete coupling lengths for the fifth light and the fourth light directly input into the first coupling section 11 and the second coupling section 12 , respectively.

[0103] The second subunit 22 has a subcoupler 252 with a complete coupling length L. That is, the second subunit 22 has the same structure as the first subunit 21. The second light is incident on one sub-incident path 212 of the second subunit 22. The third light is incident on the other sub-incident path 222 of the second subunit 22.

[0104] Next, the operation of the optical multiplexer 1 of this embodiment will be described.

[0105] The first light is incident and emitted in the same manner as in the first embodiment.

[0106] In the second subunit 22, the second light is emitted from another sub-emission path 242. The subsequent process related to the second light is the same as that in the first embodiment.

[0107] In the second subunit 22, the third light is emitted from another sub-emission path 242. Next, in the first subunit 21, the third light is emitted from one sub-input path 211 and emitted from one sub-emission path 231. The third light is emitted from another main input path 121 of the first coupling unit 11 and emitted from another main emission path 141. The third light is emitted from one main input path 113 of the third coupling unit 13 and emitted from one main emission path 133.

[0108] The fourth light enters from the other main incident path 122 of the second coupling unit 12 and exits from the one main exit path 132. The fourth light enters from the other main incident path 123 of the third coupling unit 13 and exits from the one main exit path 133.

[0109] The fifth light enters from one main incident path 111 of the first coupling unit 11 and exits from the other main exit path 141. The fifth light enters from one main incident path 113 of the third coupling unit 13 and exits from one main exit path 133.

[0110] [Example 2]

[0111] like Figure 12 As shown, λ1 = 450 nm, λ2 = 520 nm, λ3 = 635 nm, λ4 = 720 nm, and λ5 = 840 nm. The results show that the combining efficiencies are 97.7%, 91.6%, 87.3%, 99.8%, and 96.8%, respectively, indicating that good combining is possible.

[0112] As described above, the optical multiplexer 1 and the optical multiplexing method according to the present embodiment can achieve the following effects.

[0113] (10) One sub-incident path 211 or 221 is configured to be connectable to another sub-emission path 232 or 242 of another sub-unit 22. Thus, by combining a plurality of sub-units 21, light of multiple wavelengths can be flexibly multiplexed.

[0114] [Third embodiment]

[0115] Next, refer to Figures 13 to 15 An optical multiplexer 1 and an optical multiplexing method according to a third embodiment of the present invention will be described. In the description of the third embodiment, the same reference numerals are used for the same components as those in the above embodiments, and their descriptions will be omitted or simplified.

[0116] The optical combiner 1 and the optical combining method according to the third embodiment differ from those of the first embodiment in that five lights are combined. Figure 13 As shown, the optical combiner 1 and the optical combining method according to the third embodiment are different from those of the first embodiment in that: there is one standard unit 100 and one sub-unit 21 , and a sub-unit 23 is further connected.

[0117] In addition, if Figure 14 As shown, the optical combiner 1 and optical combining method involved in the third embodiment are different from those of the first embodiment in that the wavelength of the first light is λ1, the wavelength of the second light is λ2, the wavelength of the third light is λ3, the wavelength of the fourth light is λ4, and the wavelength of the fifth light is λ5.

[0118] Furthermore, the optical combiner 1 and optical combining method according to the third embodiment differ from the first and second embodiments in that the fully coupled lengths of the respective lights are 2L, L, L / 2, L / 3, and L / 6, respectively. The optical combiner 1 and optical combining method according to the third embodiment differ from the first embodiment in that λ1 < λ2 < λ3 < λ4 < λ5. The optical combiner 1 and optical combining method according to the third embodiment differ from the first and second embodiments in that another sub-injection path 223 of the third subunit 23 is connected to one of the main output paths 133 and 134 of the third coupling portion 13. Furthermore, unlike the first embodiment, the fifth light is incident on one of the sub-injection paths 213 of the third subunit 23. The fully coupled length of the third subunit 23 is L / 6.

[0119] The third subunit 23 has a subcoupler with a complete coupling length of L / 6. The fifth light is incident on a sub-incident path 213 of the third subunit 23. In addition, a main emission path 133 of the third coupling portion 13 is connected to another main injection path 223 of the third subunit 23.

[0120] Next, the operation of the optical multiplexer 1 according to this embodiment will be described.

[0121] The relationship between the input and output of the first to fourth lights is the same as that of the first embodiment until they are emitted from one main emission path 133 of the third coupling unit 13. The first to fourth lights are incident on another sub-incident path 223 of the third subunit 23 and are emitted from another sub-emission path 243.

[0122] The fifth light is incident on one sub-incident path 213 of the third sub-unit and is emitted from the other sub-emission path 243. Thus, the first to fifth lights are multiplexed.

[0123] [Example 3]

[0124] like Figure 15 As shown in FIG. 1 , λ1 = 450 nm, λ2 = 520 nm, λ3 = 635 nm, λ4 = 720 nm, and λ5 = 960 nm. The results show that the combining efficiencies are 96.1%, 92.7%, 97.6%, 94.8%, and 95.9%, respectively, indicating that good combining is possible.

[0125] While preferred embodiments of the optical multiplexer and the optical multiplexing method of the present invention have been described above, the present disclosure is not limited to the above-described embodiments and can be modified as appropriate.

[0126] For example, in the above embodiment, the fully coupled length is achieved by varying the lengths of the main coupler 150 and the sub-coupler 251, but the present invention is not limited thereto. The fully coupled length can also be achieved by varying the spacing between the two optical waveguides. Furthermore, the fully coupled length can also be achieved by varying the thickness of the optical waveguides.

[0127] Furthermore, in the above embodiment, the number of subunits 21 is not limited to one or two, and more subunits 21 may be used. In this case, subunits 21 having various complete coupling lengths may be combined according to the wavelength of the input light.

[0128] Furthermore, in the above-described embodiment, the optical multiplexing method may include a step of connecting the output path of a coupling unit 10 capable of multiplexing at least two lights to the input path of another coupling unit 10. This allows for flexible light multiplexing by combining various couplers, depending on the amount of light to be multiplexed and the wavelength of the light.

[0129] Description of Reference Numerals

[0130] 1: Optical combiner;

[0131] 10: coupling part;

[0132] 11: first coupling portion;

[0133] 12: second coupling portion;

[0134] 13: third coupling portion;

[0135] 21, 22, 34: subunits;

[0136] 100: standard unit;

[0137] 110, 111, 112, 113, 120, 121, 122, 123: main injection path; 130, 131, 132, 133, 140, 141, 142, 143: main injection path; 150, 151, 152, 153: main coupler;

[0138] 211, 221, 212, 222, 213, 223: sub-injection path;

[0139] 231, 241, 232, 242, 233, 243: sub-emission paths;

[0140] 251: Sub-coupler.

Claims

1. An optical combiner that can combine multiple wavelengths of light. The optical combiner has a plurality of coupling parts. The coupling portion has a pair of main injection paths, a pair of main emission paths and a main coupler. The main coupler is disposed between the main incident path and the main emission path, and couples the light incident on the main incident path and emits the light to the main emission path. One of the main injection paths of the coupling portion is connected to the main emission paths of the other coupling portion. The optical combiner further comprises: a standard unit comprising the plurality of coupling portions as a group; and a subunit that can be connected to the standard unit, The subunit has: A pair of sub-injection paths; a pair of sub-ejection paths; and a sub-coupler that couples the light incident on the sub-input path and emits the light on the sub-output path; The standard unit is composed of three coupling parts as a group, The other main emission path of the first coupling portion is connected to the one main injection path of the third coupling portion. One of the main emission paths of the second coupling portion is connected to the other main injection path of the third coupling portion, One of the sub-emission paths of the sub-unit is connected to the other main injection path of the first coupling portion, Another sub-emission path of the sub-unit is connected to one main injection path of the second coupling portion, The main coupler of the first coupling portion has a coupling characteristic of emitting light incident on any one of the main incident paths of the first coupling portion to the other main outgoing path. The main coupler of the second coupling portion has a coupling characteristic of emitting light incident on any one of the main incident paths of the second coupling portion to one of the main outgoing paths. The main coupler of the third coupling unit has a coupling characteristic of emitting light incident on any of the main incident paths of the third coupling unit to any of the main outgoing paths. The sub-coupler of the sub-unit has coupling characteristics of emitting light incident on the pair of the sub-input paths toward at least one of the sub-output paths, and splitting at least one of the lights incident on the pair of the sub-input paths and emitting the light toward the pair of the sub-output paths.

2. The optical combiner according to claim 1, wherein: The sub-injection path is configured to be connectable to the sub-emission path of the other sub-unit.

3. The optical combiner according to claim 1 or 2, wherein: The sub-emission path is configured to be connectable to the sub-injection path of the other sub-unit.

4. The optical combiner according to claim 1 or 2, wherein: Among the light of multiple wavelengths incident on the standard cell, either the light with the longest wavelength or the light with the second longest wavelength is incident on one of the main incident paths of the first coupling portion. The remaining one of the light with the longest wavelength and the light with the second longest wavelength among the plurality of wavelengths of light incident on the standard cell is incident on the other main incident path of the second coupling portion. The sub-coupler of the sub-unit has a coupling characteristic of emitting light incident on a pair of the sub-incidence paths toward at least one of the sub-emission paths.

5. The optical combiner according to claim 1 or 2, wherein: Another of the sub-injection paths of the sub-unit is connected to one of the sub-emission paths of the other sub-unit.

6. The optical combiner according to claim 1 or 2, wherein: One main outgoing path of the third coupling portion is connected to another sub-incoming path of the other sub-unit.

7. A method for combining multiple wavelengths of light, comprising: a first combined light output step of combining a portion of the first light with the second light to output the combined light as the first combined light; a second combined light output step of combining another portion of the first light with the third light to output the second combined light; a third combined light output step of combining the first combined light and the fourth light to output a third combined light; as well as The fourth multiplexed light outputting step is to multiplex the second multiplexed light with the third multiplexed light to output as a fourth multiplexed light.

8. The optical wave combining method according to claim 7, wherein: Assuming that the wavelength of the first light is λ1, the wavelength of the second light is λ2, the wavelength of the third light is λ3, and the wavelength of the fourth light is λ4, then λ1<λ2<λ3<λ4.

9. A method for combining multiple wavelengths of light using a light combiner. The optical combiner has a plurality of coupling parts. The coupling portion has a pair of main injection paths, a pair of main emission paths and a main coupler. The main coupler is disposed between the main incident path and the main emission path, and couples the light incident on the main incident path and emits the light to the main emission path. One of the main injection paths of the coupling portion is connected to the main emission paths of the other coupling portion. The optical combiner further comprises a subunit, wherein the subunit comprises: A pair of sub-injection paths; a pair of sub-ejection paths; and a sub-coupler that couples the light incident on the sub-input path and emits the light on the sub-output path; The other main emission path of the first coupling portion is connected to the one main injection path of the third coupling portion. One of the main emission paths of the second coupling portion is connected to the other main injection path of the third coupling portion, One of the sub-emission paths of the sub-unit is connected to the other main injection path of the first coupling portion, Another sub-emission path of the sub-unit is connected to one main injection path of the second coupling portion, The main coupler of the first coupling portion, the main coupler of the second coupling portion, and the main coupler of the third coupling portion have different coupling characteristics. The photosynthesis method comprises: a step of injecting a second light into one of the sub-injection paths of the sub-unit; a step of injecting the first light into another said sub-injection path of said sub-unit; a step of emitting a first light toward one of the sub-emission paths of the sub-unit; a step of emitting the first combined light of the first light and the second light toward another sub-emission path of the sub-unit; a step of incident third light into one of the main incident paths of the first coupling portion; a step of incidenting the first light into the other main incident path of the first coupling portion; a step of emitting a second combined light obtained by combining the first light and the third light toward the other main emission path of the first coupling portion; a step of injecting the first combined light into one of the main injection paths of the second coupling portion; a step of injecting the fourth light into another main injection path of the second coupling portion; a step of emitting a third combined light obtained by combining the fourth light with the first light toward one of the main emission paths of the second coupling portion; a step of injecting the second combined light into one of the main injection paths of the third coupling portion; a step of injecting the third combined light into another main injection path of the third coupling portion; The step of emitting fourth multiplexed light obtained by combining the second multiplexed light and the third multiplexed light toward one of the main emission paths of the third coupling unit.

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