Optical element, optical integrated element, and method for manufacturing optical integrated element

Abstract

This optical element (11) is connected to a pair of optical waveguide elements through a pair of third waveguide cores, the optical element comprising a pair of first waveguide cores (111_1, 111_2), a pair of second waveguide cores, and a connection waveguide (115), wherein: the refractive index of the first waveguide cores is greater than the refractive index of the second waveguide cores; at least a modal field changing unit of each of the first waveguide cores is covered by the second waveguide cores; the connection waveguide is connected to a pair of second waveguides through optical multiplexing / demultiplexing units (114_1, 114_2); and one of the second waveguide cores (112_1) is connected to one optical waveguide element (12_1) through one third waveguide core (131_1), and the other of the second waveguide cores (112_2) is connected to the other optical waveguide element (12_2) through the other third waveguide core (131_2).　As a result, this optical element can reduce manufacturing costs and increase the number of signal optical fibers for connection.

Description

[Technical Field]

[0001] The present invention relates to an optical element for connecting optical elements, an optical integrated element, and a method for manufacturing an optical integrated element. [Background technology]

[0002] The development of optical communication networks has led to demand for more sophisticated and economical optical communication devices. Optical communication devices require electrical elements such as drivers, switches, and electrical amplifier circuits, as well as optical elements such as semiconductor lasers, optical switches, and optical fibers.

[0003] Here, in the optical connection process where each optical element is discretely connected, precise positioning between optical elements is important to achieve low-loss optical connections. For this reason, even in general-purpose optical connectors, for example, high-precision parts are used that can keep the optical axis misalignment between waveguide cores to less than 1 μm. As such, designs and precision parts that take strict tolerances into account are important when manufacturing optical communication devices.

[0004] In particular, the positioning accuracy of optical packaging is an issue for SiPh (Silicon Photonics). SiPh is an optical device with semiconductor materials at its core, which not only enables the fabrication of ultra-compact and highly economical optical circuits, but also allows for high-density integration with electrical circuit elements.

[0005] However, SiPh requires higher alignment accuracy and tighter tolerances during connection than conventional silica-core devices such as PLC (Planar Lightwave Circuit), which increases the process load of optical connections. This is because the smaller the optical mode field diameter (MFD), the stricter the tolerance requirements during optical connection become. Therefore, optical connections for SiPh, which are semiconductor-based optical circuit devices with a tiny MFD, require more precise alignment technology.

[0006] On the other hand, by enlarging the MFD, the positioning accuracy requirement can be relaxed. However, in SiPh, the thickness of each layer during manufacturing is limited, and the high refractive index inherent in semiconductor waveguides causes high loss due to the roughness of the waveguide sidewalls. Therefore, compared to conventional optical devices such as PLC, it is difficult to achieve an MFD with low loss and high yield equivalent to that of general optical fibers.

[0007] Therefore, a method of converting the MFD of the optical element (chip) and optical fiber to an MFD of about 4 μm, which is smaller than the MFD of conventional optical fibers (about 10 μm), is used for low-loss optical connections. However, when using this method, the small MFD requires high positioning accuracy on the submicron level, which means that the positioning accuracy during optical connection and the tolerances required for optical components become stricter.

[0008] As a technology that can ease the positioning accuracy required for this connection, a self-written waveguide (hereinafter referred to as "SWW") has been disclosed (Non-Patent Document 1).

[0009] This technology is an optical connection technology that uses a photocurable resin, and can connect waveguide cores together as follows: Here, light used as signal light in optical communications (hereinafter referred to as "signal light") is emitted from the end face of at least one of the waveguide cores.

[0010] In forming the SWW, first, a photocurable resin is dropped into the gap between the waveguide cores.

[0011] Next, resin curing light, which is light for curing the photocurable resin, is irradiated from both or one of the waveguide cores. At this time, due to the property of photocurable resin that it cures sequentially from the area with the highest light intensity, SWW cores (hereinafter referred to as "SWW cores") are formed sequentially from the end face of each waveguide core. As a result, SWW cores are formed at the end faces of the waveguide cores.

[0012] Furthermore, since the SWW core is formed along the propagation path of the resin curing light, even if an optical axis misalignment occurs between the waveguide cores, an S-shaped bent SWW core is formed to compensate for the optical axis misalignment, enabling low-loss optical connection.

[0013] Finally, if necessary, the uncured portions of the photocurable resin are removed by cleaning or other methods, and then cladding resin is dripped onto the removed portion (around the SWW core) and cured appropriately to form the SWW cladding (hereinafter referred to as "SWW cladding"), completing the SWW connection.

[0014] In this way, this technology has the effect of compensating for misalignment, enabling low-loss connections even when there is a gap between waveguide cores or misalignment of the optical axis, which are factors that cause connection loss between waveguide cores. Therefore, optical connection technology using SWW can relax the tolerance requirements for the components that make up optical devices, enabling simple optical integration and high-yield, low-loss packaging.

[0015] Furthermore, the SWW fabrication process enables the formation of spot-size converters (SSCs), which are essential for connecting waveguide cores with different MFDs, and are useful for optical fiber integration on SiPh chips with small MFDs.

[0016] As shown in Fig. 22, SWW is applied to optical connection between an optical element 71 such as a SiPh chip and optical waveguide elements 72_1 and 72_2 such as optical fibers. The optical element such as a SiPh chip is composed of an optical planar circuit consisting of a first waveguide core 711 and second waveguide cores 712_1 and 712_2.

[0017] An optical multiplexer / demultiplexer 714 is also formed on the SiPh chip (optical element). While FIG. 22 shows an example in which a Y-branch structure is formed using a Y-shaped waveguide structure, any known optical multiplexer / demultiplexer structure having a similar function may be used. As shown in FIG. 23, the optical multiplexer / demultiplexer 714 is composed of a first waveguide core 711, a mode field converter 713 fabricated at one end of the first waveguide core 711, and a second waveguide core 712_2 that covers it. The mode field converter 713 causes signal light 2 to transit between the first waveguide core 711 and the second waveguide core 712_2.

[0018] 24 and 25 show cross-sectional views taken along lines XXIV-XXIV' and XXV-XXV' in Fig. 23, respectively. In the optical multiplexing / demultiplexing section 714, a first waveguide core 711 is formed on a lower cladding section 710_2 by photolithography or the like. A second waveguide core 712_2 is formed so as to cover the first waveguide core 711, and an upper cladding section 710 is formed so as to cover the upper surface of the second waveguide core 712_2.

[0019] The cross section of the optical multiplexing / demultiplexing section 714 is composed of two parts: a part formed only by the second waveguide core 712_2 as shown in the XXIV-XXIV' cross section (Figure 24), and a part having the first waveguide core 711 as shown in the XXV-XXV' cross section (Figure 25).

[0020] In SiPh chips (optical devices), visible light is emitted from the waveguide end face by using a waveguide material that can be integrated with SiPh and is transparent to the visible light used in SWW. This is because the resin curing light 1 (mainly visible light) is hardly transmitted through the Si waveguide of SiPh due to the influence of material absorption, so the use of a different transparent material makes it possible to apply SWW.

[0021] In this way, the SiPh chip (optical element) is equipped with optical multiplexing / demultiplexing unit 714, which is important for optical connections using SWW, and can couple signal light (light in the wavelength band used in optical communications) 2 and resin curing light 1 into the same waveguide core. Optical multiplexing / demultiplexing unit 714 can use, for example, a Y-branch structure. By using optical multiplexing / demultiplexing unit 714, resin curing light 1 can be coupled from the outside into the same waveguide (second waveguide core 712_2) as signal light 2, and resin curing light 1 can be emitted from the SiPh chip end face.

[0022] Furthermore, second waveguide cores 712_1 and 712_2 are formed in addition to the first waveguide core 711 through which signal light 2 propagates. The second waveguide cores 712_1 and 712_2 are formed for transmitting visible light, and by inputting resin curing light 1 into the second waveguide core 712_1 using an optical fiber (optical fiber for inputting resin curing light) 72_1 or the like, light can be output from the waveguide core end face of the optical element facing the optical fiber 72_2 for inputting and outputting signal light. This allows resin curing light 1 to be output from each of the end faces of the optical fiber 72_2 for inputting and outputting signal light and the optical element 71 facing it, thereby achieving optical connection by SWW.

[0023] In the configuration shown in Fig. 22, by providing an optical fiber 72_1 for inputting resin-curing light, it becomes possible to emit resin-curing light 1 from the waveguide end face of the optical element facing the optical fiber 72_2 for inputting and outputting signal light, along the path shown in Fig. 23. This makes it possible to emit resin-curing light 1 from both waveguide end faces between the waveguides to be connected, thereby realizing optical connection by SWW. [Prior art documents] [Non-patent literature]

[0024] [Non-Patent Document 1] Hirose, N. et al., "Optical Simple Interconnection Technology Using Self-Written Waveguides," Journal of the Japan Institute of Electronics Packaging, Vol. 5, No. 5, (2002). Summary of the Invention [Problem to be solved by the invention]

[0025] However, in the above configuration, it was necessary to prepare an optical fiber for inputting and outputting the resin curing light separately from the optical fiber for inputting and outputting the signal light.Thus, while optical connections using SWW can relax the positioning accuracy requirements, there was a problem in that it was necessary to prepare a separate optical fiber that was not used for optical communication. [Means for solving the problem]

[0026] In order to solve the above-mentioned problems, an optical element according to the present invention is an optical element connected to a set of optical waveguide elements via a set of third waveguide cores, and includes a set of first waveguide cores, a set of second waveguide cores, and a connecting waveguide, wherein the refractive index of the first waveguide core is greater than the refractive index of the second waveguide core, the first waveguide core has a mode field conversion section, and at least the mode field conversion section is covered by the second waveguide core, the connecting waveguide connects the set of second waveguides via an optical multiplexing / demultiplexing section, and one of the second waveguide cores is At a predetermined end surface of the optical element, One of the optical waveguide elements is connected via one of the third waveguide cores, and the other of the second waveguide cores is At the predetermined end surface, The other optical waveguide element is connected via the other third waveguide core. the third waveguide core is a portion in a set of photocurable resins arranged in a gap between the set of optical waveguide elements and the set of second waveguide cores, where a refractive index has been changed by irradiation with a set of resin curing light, one of the resin curing lights is emitted from one of the optical waveguide elements and is irradiated onto one of the photocurable resins arranged on the predetermined end face, the other of the resin curing lights is emitted from the other of the optical waveguide elements, and propagates in order through the other of the second waveguide cores, the connection waveguide, and one of the second waveguide cores, and is emitted from an end face of one of the second waveguide cores at the predetermined end face and is irradiated onto one of the photocurable resins, and the other of the resin curing lights is emitted from the other of the optical waveguide elements and is irradiated onto the other of the photocurable resins arranged on the predetermined end face, The aforementioned One of the resin curing lights is emitted from one of the optical waveguide elements, propagates through the one of the third waveguide cores, the one of the second waveguide cores, the connecting waveguide, and the other of the second waveguide cores in order, is emitted from an end face of the other of the second waveguide cores at the predetermined end face, and is irradiated onto the other of the photocurable resins. It is characterized by the following.

[0027] Furthermore, an optical integrated element according to the present invention comprises an optical element having a set of first waveguide cores, a set of second waveguide cores, and a connecting waveguide; a set of optical waveguide elements for inputting and outputting optical communication signals; and a set of optical connecting portions having a third waveguide core, wherein one of the second waveguide cores and one of the optical waveguide elements are At a predetermined end surface of the optical element, The optical waveguide element is connected to the second waveguide core of the other optical connecting portion via the third waveguide core of the other optical connecting portion, At the predetermined end surface, The other optical connection section is connected via the third waveguide core, the first waveguide core has a mode field conversion section and is covered by the second waveguide core, and the connection waveguide connects the pair of second waveguides via an optical multiplexing / demultiplexing section. the third waveguide core is a portion in a set of photocurable resins arranged in a gap between the set of optical waveguide elements and the set of second waveguide cores, where a refractive index has been changed by irradiation with a set of resin curing light, one of the resin curing lights is emitted from one of the optical waveguide elements and is irradiated onto one of the photocurable resins arranged on the predetermined end face, the other of the resin curing lights is emitted from the other of the optical waveguide elements, and propagates in order through the other of the second waveguide cores, the connection waveguide, and one of the second waveguide cores, and is emitted from an end face of one of the second waveguide cores at the predetermined end face and is irradiated onto one of the photocurable resins, and the other of the resin curing lights is emitted from the other of the optical waveguide elements and is irradiated onto the other of the photocurable resins arranged on the predetermined end face, The aforementioned One of the resin curing lights is emitted from one of the optical waveguide elements, propagates in order through the third waveguide core of one of the optical connecting portions, the second waveguide core of one of the optical connecting portions, the connecting waveguide, and the second waveguide core of the other of the optical connecting portions, and is emitted from an end face of the second waveguide core of the other of the optical connecting portions at the predetermined end face, and is irradiated onto the photocurable resin of the other of the optical connecting portions.It is characterized by the following.

[0028] Furthermore, a method for manufacturing an optical integrated element according to the present invention includes the steps of: arranging an end face of an optical element having a set of first waveguide cores, a set of second waveguide cores, and a connecting waveguide connecting the set of second waveguide cores, and an end face of a set of optical waveguide elements so as to face each other; aligning the center of the second waveguide core with the center of the optical waveguide elements; disposing one photocurable resin in a gap between an end face of one of the second waveguide cores at the end face of the optical element and an end face of one of the optical waveguide elements; disposing the other photocurable resin in a gap between an end face of the other of the second waveguide cores at the end face of the optical element and an end face of the other of the optical waveguide elements; and irradiating one of the resin curing light beams onto the one of the optical waveguide elements to form one self-forming waveguide. At least partially a step of forming the other resin curing light incident on the other optical waveguide element, propagating the other second waveguide core, the connecting waveguide, and the one second waveguide core in order, and irradiating the one photocurable resin to form the one self-forming waveguide. At least partially forming a self-forming waveguide; and irradiating the other resin curing light onto the other optical waveguide element and the other photocurable resin; At least partially a step of forming the other self-forming waveguide by irradiating the one of the resin curing light elements with the one of the resin curing light, propagating the one of the self-forming waveguides, the one of the second waveguide cores, the connecting waveguide, and the other of the second waveguide cores, and irradiating the other of the photocurable resin to form the other of the self-forming waveguides. At least partially and forming a substrate. [Effects of the Invention]

[0029] According to the present invention, the optical fiber for inputting resin curing light, which was previously required, is no longer necessary, so that the manufacturing costs of optical elements and optical integrated elements can be reduced and the number of signal optical fibers mounted on optical elements and optical integrated elements can be increased. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic top perspective view showing the configuration of the optical element according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram for explaining a method for manufacturing an integrated optical device according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram for explaining a method for manufacturing an integrated optical device according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a diagram for explaining a method for manufacturing an integrated optical device according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a diagram for explaining a method for manufacturing an integrated optical device according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a schematic top perspective view showing an example of the configuration of the optical element and the optical integrated element according to the first embodiment of the present invention. [Figure 8] FIG. 8 is a schematic top perspective view showing an example of the configuration of the optical element and the optical integrated element according to the first embodiment of the present invention. [Figure 9] FIG. 9 is a schematic top perspective view showing an example of the configuration of the optical element according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to the second embodiment of the present invention. [Figure 11] FIG. 11 is a schematic top perspective view showing an example of the configuration of an optical element and an optical integrated element according to the second embodiment of the present invention. [Figure 12] FIG. 12 is a schematic top perspective view showing an example of the configuration of an optical element and an optical integrated element according to the second embodiment of the present invention. [Figure 13] FIG. 13 is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to the third embodiment of the present invention. [Figure 14] FIG. 14 is a schematic top perspective view showing an example of the configuration of an optical element and an optical integrated element according to the third embodiment of the present invention. [Figure 15] FIG. 15 is a schematic top perspective view showing an example of the configuration of an optical element and an optical integrated element according to the third embodiment of the present invention. [Figure 16] FIG. 16 is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to the fourth embodiment of the present invention. [Figure 17] FIG. 17 is a diagram for explaining the operation of the optical element and the optical integrated element according to the fourth embodiment of the present invention. [Figure 18A] FIG. 18A is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to a fifth embodiment of the present invention. [Figure 18B] FIG. 18B is a diagram illustrating the operation of the optical element and the optical integrated element according to the fifth embodiment of the present invention. [Figure 19] FIG. 19 is a schematic top perspective view showing the configuration of an optical element and an optical integrated element according to the sixth embodiment of the present invention. [Figure 20] FIG. 20 is a schematic top perspective view showing an example of the configuration of a portion of an optical element according to the sixth embodiment of the present invention. [Figure 21] FIG. 21 is a schematic top perspective view showing an example of the configuration of a portion of an optical element according to the sixth embodiment of the present invention. [Figure 22] FIG. 22 is a schematic top perspective view showing the configuration of a conventional optical element and an optical integrated element. [Figure 23] FIG. 23 is a schematic top perspective view showing the configuration of a portion of a conventional optical element. [Figure 24] FIG. 24 is a schematic top perspective view showing the configuration of a portion of a conventional optical element. [Figure 25] FIG. 25 is a schematic top perspective view showing the configuration of a portion of a conventional optical element. DETAILED DESCRIPTION OF THE INVENTION

[0031] First Embodiment An optical element and an optical integrated element according to a first embodiment of the present invention will be described with reference to FIGS.

[0032] <Configuration of optical integrated device> As shown in FIG. 1, an optical integrated device 10 according to this embodiment includes an optical device 11, an optical fiber 12, and an optical connection section 13.

[0033] The optical element 11 includes two waveguide sections, an upper cladding section 110, and a lower cladding section (not shown) above and below the waveguide sections. One of the waveguide sections includes a first waveguide core 111_1 and a second waveguide core 112_1, and has a mode field conversion section 113_1 at the tip of the first waveguide core 111_1. The second waveguide core 112_1 also has an optical multiplexing / demultiplexing section 114_1.

[0034] Similarly, the other waveguide section includes a first waveguide core 111_2 and a second waveguide core 112_2, and has a mode field conversion section 113_2 at the tip of the first waveguide core 111_2. Also, the second waveguide core 112_2 has an optical multiplexing / demultiplexing section 114_2.

[0035] The second waveguide core 112_1 of one waveguide section and the second waveguide core 112_2 of the other waveguide section are connected via optical multiplexing / demultiplexing sections 114_1 and 114_2, respectively, by a connecting waveguide 115. Here, the connecting waveguide 115 has the same configuration as the second waveguide cores 112_1 and 112_2.

[0036] At the input / output end face of the optical element 11, one optical fiber 12_1 and the other optical fiber 12_2 are connected to one second waveguide core 112_1 and the other second waveguide core 112_2 via optical connecting portions 13_1 and 13_2, respectively.

[0037] One optical connecting portion 13_1 and the other optical connecting portion 13_2 respectively include third waveguide cores 131_1 and 131_2 and third waveguide clads 132_1 and 132_2 therearound.

[0038] The optical element 11 has a circuit structure in which first waveguide cores 111_1 and 111_2 each having a mode field conversion section 113_1 and 113_2 are covered by a second waveguide core 112_1 and 112_2, respectively. The upper cladding section 110 and the lower cladding section of the optical element 11 are made of, for example, silicon oxide, but may be made of other materials as long as they function as cladding sections.

[0039] In the optical element 11, for example, the first waveguide cores 111_1 and 111_2 are made of Si, and the second waveguide cores 112_1 and 112_2 are made of SiON or the like, which is made by adding nitrogen to silicon oxide.

[0040] Alternatively, the first waveguide cores 111_1 and 111_2 may be made of InP, and the second waveguide cores 112_1 and 112_2 may be made of SiOx or a resin material.

[0041] Here, it is only necessary that the refractive index of the first waveguide cores 111_1 and 111_2 is higher than the refractive index of the second waveguide cores 112_1 and 112_2.

[0042] Furthermore, it is only necessary that the first waveguide cores 111_1 and 111_2 are covered with the second waveguide cores 112_1 and 112_2, and that the second waveguide cores 112_1 and 112_2 are transparent to visible light.

[0043] The structure including the first waveguide cores 111_1 and 111_2, the second waveguide cores 112_1 and 112_2, and the mode field converters 113_1 and 113_2 adiabatically transfers light to cores having different cross-sectional areas. That is, the mode field converters 113_1 and 113_2 enable low-loss coupling between waveguides having different MFDs.

[0044] In the mode field conversion sections 113_1, 113_2, as the core width gradually narrows toward the tips of the tapered portions of the first waveguide cores 111_1, 111_2, the optical confinement of the signal light confined in the first waveguide cores 111_1, 111_2 becomes weaker, and the MFD gradually expands into the second waveguide cores 112_1, 112_2.

[0045] Subsequently, the signal light transits to the optical mode propagating in the second waveguide cores 112_1 and 112_2 and propagates therethrough. As a result, the signal light transited to the second waveguide cores 112_1 and 112_2 is emitted from the output end face of the optical element 11.

[0046] Here, if at least the mode field conversion portions 113_1 and 113_2 in the first waveguide cores 111_1 and 111_2 are covered with the second waveguide cores 112_1 and 112_2, the signal light can be propagated as described above.

[0047] Furthermore, the mode field conversion portions 113_1 and 113_2 may have a structure other than the simple tapered structure in which the core width narrows toward the tip of the first waveguide cores 111_1 and 111_2 shown in FIG. 2, such as a tapered structure having a three-pronged tip.

[0048] Furthermore, the optical multiplexing / demultiplexing sections 114_1 and 114_2 are preferably disposed at positions several tens of μm or more away from the mode field conversion sections 113_1 and 113_2 toward the interior of the optical element 11 (the side opposite to the tip side of the first waveguide core, i.e., the base end side of the first waveguide core). Hereinafter, the interior side of the optical element 11 will be referred to as the "base end side of the first waveguide core (or second waveguide core)."

[0049] This allows the optical multiplexing / demultiplexing units 114_1 and 114_2 to couple the resin curing light while suppressing the effect on the mode field conversion function that expands the MFD of the signal light. Details will be described below.

[0050] If the optical multiplexing / demultiplexing section is placed in the mode field conversion section, the signal light propagating through the first waveguide core gradually seeps into the second waveguide core, causing the signal light to be affected by the Y-branch of the optical multiplexing / demultiplexing section, resulting in loss during signal light propagation (signal transmission) and affecting mode field conversion.

[0051] On the other hand, when the optical multiplexing / demultiplexing sections 114_1 and 114_2 are located at positions away from the mode field conversion sections 113_1 and 113_2, the signal light is sufficiently confined on the proximal end side of the mode field conversion sections 113_1 and 113_2 of the first waveguide cores 111_1 and 111_2.

[0052] Here, the side surfaces of the first waveguide cores 111_1 and 111_2 and the side surfaces of the second waveguide cores 112_1 and 112_2 are separated in the width direction of the cores to an extent that they do not have an optical effect. For example, the width of the first waveguide cores 111_1 and 111_2 is about 400 nm, while the width of the second waveguide cores 112_1 and 112_2 is about 3 μm.

[0053] In this way, the Y-shaped optical multiplexing / demultiplexing units 114_1 and 114_2 are 1 μm or more away from the region where the signal light is confined. As a result, due to the above-mentioned arrangement of the optical multiplexing / demultiplexing units 114_1 and 114_2, the signal light is not optically affected by the Y branching of the optical multiplexing / demultiplexing units 114_1 and 114_2.

[0054] Therefore, it is preferable to place the optical multiplexing / demultiplexing sections 114_1 and 114_2 at positions away from the mode field converting sections 113_1 and 113_2 on the base end side of the second waveguide core.

[0055] 2, the structure of the optical element 11 has the same configuration as the second waveguide cores 112_1 and 112_2, and differs from the conventional structure in that adjacent optical multiplexing / demultiplexing sections 114_1 and 114_2 are connected by a connecting waveguide 115 having a curved waveguide. This structure allows the optical fiber for inputting and outputting signal light to be used as the optical fiber for inputting resin curing light, thereby reducing the number of fiber cores required for connection.

[0056] <Method of manufacturing an optical integrated device> A method for manufacturing the integrated optical device 10 according to this embodiment will be described with reference to FIGS.

[0057] First, the optical element 11 and the two optical fibers 12_1 and 12_2 for inputting and outputting signal light are arranged, and the centers of the optical fibers 12_1 and 12_2 for inputting and outputting signal light are aligned with the centers of the second waveguide cores 112_1 and 112_2 of the optical element 11 (FIG. 3).

[0058] Here, the alignment process can be performed using a known alignment method. For example, active alignment can be performed using signal light, or image alignment can be performed using the outer diameter of the chip or fiber as a reference. Furthermore, when a SiON core is used, image alignment can also be performed using visible light. For example, image alignment can be performed while emitting resin curing light, and rough alignment can be performed using as a marker the coordinates where the resin curing light is strongly scattered in the SiON core.

[0059] 4, a photocurable resin 14_1 is dropped into the gap between one of the signal light input / output optical fibers 12_1 and the second waveguide core 112_1 of the optical element 11. This step can be achieved by using, for example, a dispenser.

[0060] Here, the absorption loss of the photocurable resin with respect to the resin curing light depends on the material, but it can be as large as 10 dB or more. Therefore, since dripping the photocurable resin into both gaps results in a large loss of the resin curing light, it is preferable to drip the photocurable resin into only one of the gaps. Details will be described later.

[0061] Next, resin curing lights 1_1 and 1_2 are made incident on the respective optical fibers 12_1 and 12_2 for inputting and outputting signal light, and the resin curing lights 1_1 and 1_2 are emitted from the end faces of the respective optical fibers 12_1 and 12_2. This can be realized, for example, by preparing an external semiconductor laser attached to a pigtail fiber and connecting the optical fiber attached to the light source and the optical fibers 12_1 and 12_2 for inputting and outputting signal light with an optical connector.

[0062] As a result, resin curing light 1_1 is emitted from the end face of one optical fiber 12_1, and resin curing light 1_2 is emitted from the end face of the second waveguide core 112_1 of the optical element 11, and is irradiated onto the photocurable resin 14_1 (FIG. 4).

[0063] 5, the refractive index of the photocurable resin changes in the portions irradiated with the resin curing light 1_1 and 1_2, causing the resin to harden, thereby forming a third waveguide core (SWW core) 131_1. As a result, the core of the optical fiber 12_1 and the second waveguide core 112_1 of the optical element 11 are connected to each other.

[0064] Here, resin curing light 1_1 is emitted from one optical fiber 12_1 for inputting and outputting signal light.

[0065] Furthermore, the resin curing light 1_2 emitted from the other signal light input / output optical fiber 12_2 is coupled from the end face of the other second waveguide core 112_2 and is emitted from the end face of one second waveguide core 112_1 of the optical element 11.

[0066] In this way, it is possible to realize the emission of resin curing light 1_1, 1_2 from both end faces of the waveguide core to be connected using only optical fibers 12_1, 12_2 for inputting and outputting signal light, without using an optical fiber for inputting and outputting resin curing light, thereby realizing optical connection using SWW.

[0067] Furthermore, a gap exists between the end face of the other optical fiber 12_2 for inputting and outputting signal light and the second waveguide core 112_2. As a result, the light emitted from the other optical fiber 12_2 for inputting and outputting signal light is subjected to diffraction loss when coupled to the second waveguide core 112_2.

[0068] However, (1) the intensity of the resin curing light required for SWW can be low (for example, a few μW for a core diameter of approximately 3 μm thick and 3 μm wide, such as that used in this connection), (2) the diffraction loss is a few dB when assuming a gap of 100 μm used as the gap to form SWW, and (3) the output of commercially available LDs is a few mW, which is more than an order of magnitude higher than the intensity (power) of the resin curing light required for SWW, so it is possible to form SWW even with the above-mentioned gap.

[0069] Next, photocurable resin is dropped into the gap between the other signal light input / output optical fiber 12_2 and the second waveguide core 112_2 of the optical element 11, and resin curing light 1_1 and 1_2 are irradiated to form a third waveguide core (SWW core) 131_2 (FIG. 6).

[0070] At this time, a third waveguide core (SWW core) 131_1 made of a photocurable resin that absorbs light of a curing wavelength is formed in the gap between one of the optical fibers 12_1 for inputting and outputting signal light and the second waveguide core 112_1 of the optical element 11, and sufficient resin curing light 1_1 can be coupled into the other gap to form a third waveguide core (SWW core) 131_2.

[0071] This is because the SWW core of the cured photocurable resin has reduced absorption loss at the curing wavelength compared to the uncured state. This reduction in absorption loss is due to the reduction in the amount of polymerization initiator, which is the cause of absorption loss at the curing wavelength, as the resin cures. Polymerization initiators are contained in the curable resin and are activated by external factors such as light, causing the resin curing reaction.

[0072] Furthermore, since the diffraction loss is reduced in the gap between one of the optical fibers 12_1 for inputting and outputting signal light and the second waveguide core 112_1 of the optical element 11 by forming the third waveguide core (SWW core) 131_1, it is possible to couple sufficient resin curing light 1_1 into the other gap to form the third waveguide core (SWW core) 131_2.

[0073] Finally, after the third waveguide cores 131_1 and 131_2 are formed, third waveguide clads (SWW clads) 132_1 and 132_2 are formed around the third waveguide cores 131_1 and 131_2, thereby manufacturing the optical integrated device 10 shown in FIG.

[0074] For example, the uncured resin 142 around the third waveguide cores 131_1 and 131_2 is washed with an organic solvent such as ethanol, and then adhesive resin is dropped onto the resin and cured by light irradiation, thereby forming the third waveguide clads 132_1 and 132_2 and fixing the optical element 11 and the optical fibers 12_1 and 12_2.

[0075] Here, an example has been shown in which adhesive resin is used to form the third waveguide clads 132_1 and 132_2, but the present invention is not limited to this and any material that has a lower refractive index than the third waveguide cores (SWW cores) 131_1 and 131_2 and can be hardened may be used.

[0076] In this way, in the third waveguide, after the third waveguide cores 131_1 and 131_2 are formed, the third waveguide clads 132_1 and 132_2 are formed by a method of removing the uncured portions 142 around the third waveguide cores 131_1 and 131_2 and replacing them with other materials such as resin (resin replacement method).

[0077] The third waveguide clads 132_1 and 132_2 may be formed by using two types of resin, as will be described below, instead of the resin substitution method.

[0078] In this case, first, a resin that hardens at a first wavelength (λ1) and a resin that hardens at a second wavelength (λ2) are mixed, and the mixed resin is dripped into the gap between one of the optical fibers 12_1 for inputting and outputting signal light and the second waveguide core 112_1 of the optical element 11.

[0079] Next, a resin that hardens at a wavelength of λ1 is hardened by first resin hardening light (wavelength λ1) emitted from the waveguide core end face, to form third waveguide cores (SWW cores) 131_1 and 131_2.

[0080] Finally, the uncured portions, i.e., the portions of the resin that are cured at a wavelength of λ2, are cured by irradiating them with a second resin curing light (wavelength λ2) from the outside (around the SWW), thereby forming third waveguide clads 132_1 and 132_2.

[0081] In this way, the third waveguide clads 132_1 and 132_2 can be formed by using two types of resin.

[0082] Here, an example in which a third waveguide clad is formed has been shown, but the present invention is not limited to this, and the optical integrated device can be operated even if the third waveguide is formed of only a third waveguide core.

[0083] Furthermore, the shape of the connecting waveguide 115 is not limited. For example, two adjacent optical multiplexing / demultiplexing units 114_1 and 114_2 may be connected by combining a curved waveguide core and a straight waveguide core as shown in Fig. 7. Furthermore, the width of the waveguide cores connecting the optical multiplexing / demultiplexing units 114_1 and 114_2 need only be such that they function as waveguides in the resin curing light.

[0084] Furthermore, as shown in FIG. 8, the structure of the optical integrated element 10_3 according to this embodiment can be multi-cored by connecting any number (N sets) of second waveguide cores 112_1, 112_2 of the optical element 11 connected to two optical fibers 12_1, 12_2, respectively, using optical connecting portions 13_1 to 13_N made of SWW.

[0085] In this embodiment, the resin curing light for forming the SWW may have a wavelength of, for example, 405 nm, but is not limited to this and may have a wavelength of 350 nm or more, as long as it has a wavelength that can change the refractive index of the SWW material and cure it.

[0086] The medium used for the SWW is not limited to photocurable resins, but can be any material that causes a photoinduced change in refractive index. For example, the waveguide core can be formed using solid resins or crystalline materials that have the property of increasing their refractive index when photoreacted.

[0087] In addition, the waveguide structure (circuit structure) including the upper cladding portion and the lower cladding portion of the optical element is formed on a substrate. However, the waveguide structure is not limited to this and may be embedded in a material such as glass without being formed on a substrate.

[0088] In addition, in the present embodiment, an example has been shown in which the optical element is configured with a waveguide structure in which the first waveguide core is covered by the second waveguide core, but the present invention is not limited to this. As shown in Fig. 9, the second waveguide core may not have a waveguide structure on the base end side of the first waveguide core, and a layer structure 116 may be laminated on the first waveguide core.

[0089] <First Example> A method for manufacturing the optical device 11 and the integrated optical device 10 according to the first embodiment of the present invention will be described.

[0090] First, the optical element 11 according to this embodiment is manufactured. First, a material for the lower cladding is deposited on a substrate, and then a material for the first waveguide cores 111_1 and 111_2 is deposited thereon. At this time, the material for the substrate is Si, the material for the lower cladding is SiO2, and the material for the first waveguide cores 111_1 and 111_2 is Si, etc.

[0091] Next, the Si is processed into first waveguide cores 111_1 and 111_2 using photolithography.

[0092] Next, the material of the second waveguide cores 112_1 and 112_2, for example, SiON, is laminated on the first waveguide cores 111_1 and 111_2. Here, SiON can be formed by adding nitrogen when forming a silicon oxide film.

[0093] Next, the SiON is processed into second waveguide cores 112_1 and 112_2 using ordinary photolithography.

[0094] Finally, the upper cladding portion 110 is formed using, for example, silicon oxide so as to cover the second waveguide cores 112_1 and 112_2. In this way, the optical element 11 according to the embodiment of the present invention is manufactured.

[0095] Next, an optical integrated device 10 is manufactured using the optical device 11 according to the embodiment of the present invention.

[0096] First, a material for SWW, for example, a photocurable resin, is dropped (placed) on the end face of the second waveguide core 112_1 of the optical connecting element described above.

[0097] Next, in the process described above, resin curing light 1_1, 1_2 is propagated through the second waveguide cores 112_1, 112_2, and the resin curing light 1_1, 1_2 is irradiated onto the photocurable resin to photo-cure it, thereby forming third waveguide cores (SWW cores) 131_1, 131_2.

[0098] Next, for example, the portions 142 of the photocurable resin that have not been irradiated with the resin curing light 1_1 and 1_2 and have not been cured are removed by cleaning or the like.

[0099] Finally, the photocured photocurable resin, that is, the resin is dropped (placed) around the third waveguide cores (SWW cores) 131_1 and 131_2 to form the third waveguide clads 132_1 and 132_2.

[0100] <Second embodiment> An optical element and an optical integrated element according to a second embodiment of the present invention will be described with reference to FIGS.

[0101] <Configuration of optical integrated device> 10, an optical integrated device 20 according to this embodiment includes an optical device 21, optical fibers 12_1 and 12_2, and optical connecting portions 13_1 and 13_2. In the optical integrated device 20, the optical fibers 12_1 and 12_2 for inputting and outputting signal light are arranged in V-grooves 211_1 and 211_2.

[0102] The optical element 21 has a configuration similar to that of the first embodiment on a substrate 210. V-grooves 211_1 and 211_2 are formed in the substrate 210 so that the end faces of the optical fibers 12_1 and 12_2 for inputting and outputting signal light can be arranged opposite the end faces of the second waveguide cores 112_1 and 112_2.

[0103] Here, for example, the V-grooves 211_1 and 211_2 are formed by anisotropic etching using a Si substrate on the substrate 210. Since the V-grooves 211_1 and 211_2 are formed by a semiconductor wafer process, they can be positioned with high precision relative to the optical fibers for inputting and outputting signal light.

[0104] <Method of manufacturing an optical integrated device> A method for manufacturing the integrated optical device 20 according to this embodiment will be described.

[0105] First, a photocurable resin for adhesively fixing the optical fibers 12_1 and 12_2 is dropped into the V-grooves 211_1 and 211_2.

[0106] Subsequently, the two optical fibers 12_1 and 12_2 for inputting and outputting signal light are placed in the V-grooves 211_1 and 211_2, respectively. As a result, the photocurable resin penetrates and fills the gaps between the optical fibers 12_1 and 12_2 and the V-grooves 211_1 and 211_2.

[0107] Here, it is preferable to press the signal light input / output optical fibers 12_1, 12_2 from above with a glass lid 22 or the like so that the signal light input / output optical fibers 12_1, 12_2 are positioned in the V-grooves 211_1, 211_2 with high precision.

[0108] Next, the resin for adhesively fixing the optical fibers is hardened by irradiation with UV lamp light, and the V-grooves 211_1 and 211_2 and the optical fibers 12_1 and 12_2 are adhesively fixed. At this time, the glass lid 22 may also be fixed with an adhesive in the same manner.

[0109] Next, a photocurable resin is dripped into the gap between one of the signal light input / output optical fibers 12_1, 12_2 and the second waveguide core 112_1 of the optical element 21. At this time, similar to the first embodiment, it is preferable to drip the photocurable resin into only one of the gaps.

[0110] Next, resin curing light 1_1, 1_2 is made incident on the respective signal light input / output optical fibers 12_1, 12_2, and the resin curing light 1_1, 1_2 is emitted from the end faces of the respective optical fibers 12_1, 12_2. As a result, similarly to the first embodiment, a third waveguide core (SWW core) 131_1 is formed in the gap between one signal light input / output optical fiber 12_1 and the second waveguide core 112_1 of the optical element 21.

[0111] Next, resin is dripped into the gap between the other signal light input / output optical fiber 12_2 and the second waveguide core 112_2 of the optical element 21, and resin curing lights 1_1 and 1_2 are emitted from the end faces of the signal light input / output optical fibers 12_1 and 12_2, respectively. As a result, a third waveguide core (SWW core) 131_2 is formed in the gap between the other signal light input / output optical fiber 12_2 and the second waveguide core 112_2 of the optical element 21.

[0112] Finally, in the same manner as in the first embodiment, the uncured resin is appropriately replaced with another adhesive resin and cured, thereby forming the third waveguide clads 132_1 and 132_2.

[0113] In this embodiment, an example has been shown in which the SWW is formed after the optical fiber is fixed, but this is not limiting, and the optical fiber may be fixed after the SWW is formed. Also, the resin that forms the SWW may be used directly to bond the optical fiber to the V-groove.

[0114] Although the present embodiment has been described as an example in which a glass lid is used, the same effect can be obtained regardless of the lid material. For example, a lid made of a polymer material may be used. Furthermore, although the example in which the glass lid is fixed has been described, it may be removed without being fixed. For example, the lid may be removed in the final process before replacing the resin for the SWW.

[0115] 11, a resin evacuation groove 212_1 may be formed between adjacent V-grooves 211_1 and 211_2. This has the effect of preventing resin from permeating into the gap between the optical fiber 12_2 for inputting and outputting signal light and the second waveguide core 112_2 of the optical element 21 when a third waveguide core (SWW core) 131_1 is formed in the gap between the optical fiber 12_1 for inputting and outputting signal light on one side and the second waveguide core 112_1 of the optical element 21 on the other side.

[0116] In the present embodiment, unlike the first embodiment, adjacent optical fibers 12_1 and 12_2 for inputting and outputting signal light are arranged without a space between them on the same substrate 210. Therefore, for example, when the V-grooves 211_1 and 211_2 are filled with resin, or when one optical fiber 12_1 is arranged in the V-groove 211_1 and 211_2, the resin overflowing from the V-groove 211_1 permeates into the gap between the other optical fiber 12_2 for inputting and outputting signal light and the second waveguide core 112_2 of the optical element 21.

[0117] Therefore, by forming a groove (resin evacuation groove) 212_1 for evacuating the resin between the adjacent V-grooves 211_1 and 211_2, the above-mentioned unintended resin penetration can be prevented. Here, the resin evacuation groove 212_1 can be easily formed by using anisotropic etching, similar to the V-grooves 211_1 and 211_2.

[0118] Also in this embodiment, it is possible to realize a multi-core collective connection configuration, for example, as shown in FIG.

[0119] <Third embodiment> An optical element and an optical integrated element according to a third embodiment of the present invention will be described with reference to FIGS.

[0120] <Configuration of optical integrated device> As shown in FIG. 13, an optical integrated device 30 according to this embodiment has a configuration in which an optical device 11 and an optical fiber array 31 are connected via optical connecting portions 13_1 and 13_2.

[0121] In the optical integrated device 30, the connection sides of the optical fibers 32_1 and 32_2 for inputting and outputting signal light are formed as an optical fiber array. The other configurations are the same as those in the first and second embodiments.

[0122] This optical fiber array configuration increases the bonding area between the optical element 11 and the optical fibers 32_1 and 32_2 for inputting and outputting signal light. Also, the optical fibers 32_1 and 32_2 for inputting and outputting signal light can be easily fixed to an alignment jig.

[0123] 14, in the optical integrated element 30_2, a resin evacuation groove 33_1 may be formed between adjacent optical fibers 32_1 and 32_2 in the optical fiber array 31. This has the effect of preventing resin from permeating into the gap between the other optical fiber 32_2 for inputting and outputting signal light and the second waveguide core 112_2 of the optical element 11 when connecting one optical fiber 32_1 for inputting and outputting signal light and the second waveguide core 112_1 of the optical element 11 by the optical connecting portion 13_1 using SWW.

[0124] The resin evacuation groove 33_1 in the optical fiber array 31 can be produced, for example, by mechanically processing the end face of the optical fiber array 31 for inputting and outputting signal light by dicing or the like after the optical fiber array 31 for inputting and outputting signal light is produced.

[0125] Also in this embodiment, by using multiple cores as shown in FIG. 15, it becomes possible to connect multiple cores at once.

[0126] <Fourth embodiment> An optical element and an optical integrated element according to a fourth embodiment of the present invention will be described with reference to FIGS.

[0127] <Configuration of optical integrated device> As shown in FIG. 16, an optical integrated device 40 according to this embodiment includes an optical device 41, optical fibers 12_1 and 12_2, and optical connecting portions 13_1 and 13_2.

[0128] The optical integrated device 40 includes two connection waveguides 115 and 415, and two sets of optical multiplexing / demultiplexing units (first optical multiplexing / demultiplexing units 114_1 and 114_2, and second optical multiplexing / demultiplexing units 414_1 and 414_2). The other configurations are the same as those of the first embodiment.

[0129] 17, in the first embodiment, the resin curing light 1_2 incident from the end face of the optical element 11 to the other second waveguide core 112_2 reaches the optical multiplexing / demultiplexing section 114_2, branches into the connecting waveguide 115, propagates, and is then emitted from the end face of one of the second waveguide cores 112_1. On the other hand, a portion of the incident resin curing light 1_2 is not branched into the connecting waveguide 115, but is coupled to the waveguide in the straight traveling direction of the second waveguide core 112_2.

[0130] Of the resin curing light 1_2 incident on the optical element 11, the light that couples in the straight direction does not couple to one of the second waveguide cores 112_1 and does not contribute to the formation of the third waveguide core (SWW core) 131_1. As a result, the coupling efficiency of the resin curing light 1_2 to one of the second waveguide cores 112_1 decreases, and this amount becomes a loss in the resin curing light 1_2.

[0131] If the SWW core can be formed with low light intensity, optical connection using the SWW can be performed satisfactorily even if there is loss in the resin curing light as described above. On the other hand, if the SWW core is formed using a resin that is not sensitive to the resin curing light, for example, if the longitudinal length of the SWW is limited by the material's absorption of the resin curing light, a high intensity of the resin curing light is required.

[0132] Therefore, when connecting long gaps with SWW, the SWW core is formed with a wavelength that is insensitive to the resin but can induce a resin curing reaction. In this case, the resin curing light used must have a high light intensity because it has low sensitivity to the resin curing light.

[0133] As a result, as shown in FIG. 17, if the resin curing light 1_2 is coupled in a path that does not contribute to the formation of the SWW core 131_1, i.e., in a straight direction, causing loss, the resin curing light 1_2 cannot be coupled with sufficient intensity from the desired end face.

[0134] As shown in FIG. 16, the optical integrated device 40 includes two connection waveguides 115 and 415 via two stages (two sets) of Y-branch shaped optical multiplexing / demultiplexing sections (first optical multiplexing / demultiplexing sections 114_1 and 114_2, second optical multiplexing / demultiplexing sections 414_1 and 414_2).

[0135] As a result, for example, of the resin curing light 1_2 incident on the other second waveguide core 112_2, the light that is coupled in a straight direction by the other first optical multiplexing / demultiplexing section 114_2 can be propagated through the connecting waveguide 415 via the other second optical multiplexing / demultiplexing section 414_2 and coupled to one second waveguide core 112_1 via one second optical multiplexing / demultiplexing section 414_1.

[0136] Therefore, it is possible to reduce the loss in the resin curing light 1_2 described above, and to improve the substantial coupling efficiency of the resin curing light in forming the third waveguide core (SWW core) 131_1.

[0137] Although the present embodiment shows an example in which two stages of optical multiplexing / demultiplexing sections and two connecting waveguides are provided, it is also possible to provide multiple stages of optical multiplexing / demultiplexing sections and multiple connecting waveguides. This improves the coupling efficiency to the second waveguide core that contributes to the formation of the SWW core, although it depends on the absorption loss due to the material that constitutes the waveguide and the scattering loss due to the waveguide.

[0138] <Fifth embodiment> An optical element and an optical integrated element according to a fifth embodiment of the present invention will be described with reference to FIGS. 18A and 18B.

[0139] <Configuration of optical integrated device> As shown in FIG. 18A, an optical integrated device 50 according to this embodiment includes an optical device 51, optical fibers 12_1 and 12_2, and optical connecting portions 13_1 and 13_2.

[0140] 18A , in the vicinity of the optical multiplexing / demultiplexing units 514_1 and 514_2, heaters 52_1 and 52_2 made of metal thin film electrodes are integrated in the vicinity of the second waveguide cores 112_1 and 112_2 in the straight direction on the base end side of the optical multiplexing / demultiplexing units 514_1 and 514_2.

[0141] Heating the heaters 52_1 and 52_2 changes the refractive index due to the thermo-optic effect, thereby changing the coupling efficiency for each of the waveguides branched in the optical multiplexing and demultiplexing units 514_1 and 514_2. As a result, it is possible to improve the coupling efficiency of the resin curing light for a path (for example, one of the second waveguide cores 112_1) that contributes to the formation of a third waveguide core (for example, the SWW core 131_1).

[0142] 18B, a heater 52_2 is disposed near the waveguide in the linear direction of the second waveguide core 112_2 in the optical multiplexing / demultiplexing unit 514_2 (hereinafter referred to as the "second waveguide core in the linear direction"), and heating with the heater 52_2 decreases the refractive index of the second waveguide core in the linear direction.

[0143] As a result, the amount of resin curing light 1_2 coupled to the second waveguide core in the straight direction is reduced, and resin curing light 1_2 branches to connecting waveguide 115, propagates through connecting waveguide 115, and is then emitted from the end face of one of second waveguide cores 112_1, contributing to the formation of third waveguide core (SWW core) 131_1. This improves the coupling efficiency of resin curing light to the path contributing to SWW (one of second waveguide cores 112_1).

[0144] Although the present embodiment shows an example in which an optical switch having a heater is used, any structure that functions as an optical switch may be used. For example, a Mach-Zehnder optical switch or an optical switch having a MEMS mirror may be used.

[0145] In this way, by configuring the optical multiplexing / demultiplexing sections 514_1 and 514_2 in the optical element 51 with optical switches, the propagation direction of light can be switched, and the coupling efficiency of the resin curing light to the path contributing to the formation of the SWW core can be improved.

[0146] Sixth Embodiment An optical element and an optical integrated element according to a fifth embodiment of the present invention will be described with reference to FIGS.

[0147] <Configuration of optical integrated device> As shown in FIG. 19, an optical integrated device 60 according to this embodiment includes an optical device 61, optical fibers 12_1 and 12_2, and optical connecting portions 13_1 and 13_2.

[0148] The optical element 61 includes a connection waveguide 115 that connects adjacent waveguides and an optical function block 62. The other configuration of the optical integrated element 60 is the same as that of the first embodiment.

[0149] When the SWW core is formed, the SWW core can be formed with a constant diameter when the resin curing light is irradiated with an appropriate intensity. On the other hand, when the intensity of the resin curing light is higher or lower than the appropriate intensity, the SWW core becomes tapered.

[0150] Therefore, when forming the third waveguide cores (SWW cores) 131_1 and 131_2 with a constant diameter, the intensity of the resin curing light can be adjusted to an appropriate intensity by using the optical function block 62. Also, by changing the intensity of the resin curing light with the optical function block 62, the third waveguide cores (SWW cores) 131_1 and 131_2 can be formed into various shapes such as a tapered shape.

[0151] 20 shows an example of the optical function block 62 in which a Mazzenburger modulator having a modulator electrode 63 is integrated as an optical switch in the connection waveguide 115. The optical switch can control, for example, the intensity of the resin curing light from one second waveguide core 112_1 to the other second waveguide core 112_2.

[0152] The shapes of the third waveguide cores (SWW cores) 131_1 and 131_2 change depending on the intensity of the resin curing light. Therefore, the intensity of the resin curing light can be changed using an optical switch, allowing for precise control of the SWW formation conditions. Note that the optical switch may be any device other than a Mazzender modulator as long as it functions as an optical switch.

[0153] 21 shows an example of an optical function block 62 in which a groove 64 is provided in the connection waveguide 115. The resin curing light can be controlled by inserting a predetermined optical function element into this groove 64. For example, by filling the groove 64 with a resin that absorbs the resin curing light, the coupling strength of the resin curing light from one waveguide core to the other waveguide core can be controlled.

[0154] This makes it possible to control the shapes of the third waveguide cores (SWW cores) 131_1 and 131_2 according to the intensity of the resin curing light.

[0155] The optical function block using the groove 64 can be applied even when it is difficult to integrate switches. Furthermore, if filling with a resin that has absorption loss is not necessary, the influence of diffraction loss in the groove 64 can be reduced by introducing a refractive index matching agent.

[0156] In the embodiment of the present invention, an example of a method for manufacturing an optical integrated device is shown in which an SWW material is placed in the gap between one second waveguide core and one optical fiber, a resin curing light is irradiated to form one SWW core, and then an SWW material is placed in the gap between the other second waveguide core and the other optical fiber, a resin curing light is irradiated to form the other SWW core, but the present invention is not limited to this. One SWW core and the other SWW core may be formed simultaneously by placing an SWW material in the gap between one second waveguide core and the optical fiber and in the gap between the other second waveguide core and the optical fiber, and then irradiating a resin curing light.

[0157] In the embodiment of the present invention, an example has been shown in which an optical fiber is used as an element to be connected to an optical element, but the present invention is not limited to this, and any element having an optical waveguide (optical waveguide element) may be used.

[0158] In the embodiments of the present invention, examples of the structure, dimensions, materials, etc. of each component in the configuration and manufacturing method of the optical element and optical integrated element are shown, but the present invention is not limited to these. Anything that can exhibit the functions and effects of the optical element and optical integrated element may be used. [Industrial Applicability]

[0159] The present invention relates to an optical element for connecting optical elements, an optical integrated element, and a method for manufacturing an optical integrated element, and can be applied to optical communication devices and optical communication network systems. [Explanation of symbols]

[0160] 11 Optical elements 111_1, 111_2 First waveguide core 112_1, 112_2 Second waveguide core 115 Connecting Waveguide 113_1, 113_2 Mode field conversion section 114_1, 1114_2 Optical multiplexing / demultiplexing section 12 Optical waveguide elements (optical fibers) 131_1, 131_2 Third waveguide core

Claims

1. An optical element connected to a set of optical waveguide elements via a set of third waveguide cores, a set of first waveguide cores; a set of second waveguide cores; A connecting waveguide and Equipped with the refractive index of the first waveguide core is greater than the refractive index of the second waveguide core; the first waveguide core has a mode field converting portion, and at least the mode field converting portion is covered by the second waveguide core; the connecting waveguide connects the set of second waveguides via an optical multiplexing / demultiplexing section; one of the second waveguide cores is connected to one of the optical waveguide elements at a predetermined end face of the optical element via one of the third waveguide cores; the other second waveguide core is connected to the other optical waveguide element at the predetermined end face via the other third waveguide core, the third waveguide core is a portion in which a refractive index is changed by irradiation of a set of resin curing light in a set of photocurable resin disposed in a gap between the set of optical waveguide elements and the set of second waveguide cores, one of the resin curing lights is emitted from one of the optical waveguide elements and irradiated onto one of the photocurable resins arranged on the predetermined end face; the other resin curing light is emitted from the other optical waveguide element, propagates through the other second waveguide core, the connecting waveguide, and the one of the second waveguide cores in order, is emitted from an end face of the one of the second waveguide cores at the predetermined end face, and is irradiated onto the one of the photocurable resins, the other resin curing light is emitted from the other optical waveguide element and irradiated onto the other photocurable resin arranged on the predetermined end face, The one of the resin curing lights is emitted from the one of the optical waveguide elements, propagates in order through the one of the third waveguide cores, the one of the second waveguide cores, the connecting waveguide, and the other of the second waveguide cores, is emitted from an end face of the other of the second waveguide cores at the predetermined end face, and is irradiated onto the other of the photocurable resins. An optical element characterized by:

2. 2. The optical element according to claim 1, wherein the optical multiplexing / demultiplexing section is provided closer to the base end of the second waveguide core than the mode field conversion section.

3. A plurality of said connecting waveguides are provided.

3. The optical element according to claim 1 or 2.

4. The optical multiplexing / demultiplexing unit is configured by an optical switch.

4. The optical element according to claim 1, wherein the first and second electrodes are electrically connected to each other.

5. The connecting waveguide is provided with an optical function block.

5. The optical element according to claim 1, wherein the first and second electrodes are electrically connected to each other.

6. an optical element having a set of first waveguide cores, a set of second waveguide cores, and a connecting waveguide; a pair of optical waveguide elements for inputting and outputting optical communication signals; a set of optical connections having a third waveguide core; Equipped with one of the second waveguide cores and one of the optical waveguide elements are connected at a predetermined end face of the optical element via the third waveguide core of one of the optical connection parts; the other second waveguide core and the other optical waveguide element are connected at the predetermined end face via the third waveguide core of the other optical connecting portion, the first waveguide core has a mode field conversion portion and is covered by the second waveguide core; the connecting waveguide connects the set of second waveguides via an optical multiplexing / demultiplexing section; the third waveguide core is a portion in which a refractive index is changed by irradiation of a set of resin curing light in a set of photocurable resin disposed in a gap between the set of optical waveguide elements and the set of second waveguide cores, one of the resin curing lights is emitted from one of the optical waveguide elements and irradiated onto one of the photocurable resins arranged on the predetermined end face; the other resin curing light is emitted from the other optical waveguide element, propagates through the other second waveguide core, the connecting waveguide, and the one of the second waveguide cores in order, is emitted from an end face of the one of the second waveguide cores at the predetermined end face, and is irradiated onto the one of the photocurable resins, the other resin curing light is emitted from the other optical waveguide element and irradiated onto the other photocurable resin arranged on the predetermined end face, The resin curing light is emitted from the one of the optical waveguide elements, propagates in order through the third waveguide core of the one of the optical connecting portions, the second waveguide core of the one of the optical connecting portions, the connecting waveguide, and the second waveguide core of the other of the optical connecting portions, and is emitted from an end face of the second waveguide core of the other of the optical connecting portions at the predetermined end face, and is irradiated onto the photocurable resin of the other of the optical connecting portions. An optical integrated device characterized by:

7. the optical element comprises a substrate; The set of optical waveguide elements is disposed in a V-groove in the substrate.

7. The optical integrated device according to claim 6.

8. A resin evacuation groove is provided between the pair of optical waveguide elements.

8. The optical integrated device according to claim 6 or 7.

9. a step of arranging an end face of an optical element having a set of first waveguide cores, a set of second waveguide cores, and a connecting waveguide connecting the set of second waveguide cores, so as to face an end face of the set of optical waveguide elements; a step of aligning a center of the second waveguide core with a center of the optical waveguide element; a step of disposing one photocurable resin in a gap between an end face of one of the second waveguide cores at the end face of the optical element and an end face of one of the optical waveguide elements; a step of disposing another photocurable resin in a gap between an end face of the other second waveguide core at the end face of the optical element and an end face of the other optical waveguide element; a step of irradiating one of the resin curing lights onto the one of the optical waveguide elements and irradiating the one of the photocurable resins to at least partially form one of the self-forming waveguides; a step of making the other resin curing light incident on the other optical waveguide element, propagating sequentially through the other second waveguide core, the connecting waveguide, and the one second waveguide core, and outputting the light from an end face of the one second waveguide core to irradiate the one photocurable resin, thereby at least partially forming the one self-forming waveguide; a step of irradiating the other resin curing light onto the other optical waveguide element and the other photocurable resin, thereby at least partially forming the other self-forming waveguide; a step of making the one of the resin curing lights incident on the one of the optical waveguide elements, propagating the one of the self-forming waveguides, the one of the second waveguide cores, the connecting waveguide, and the other of the second waveguide cores in this order, and outputting the light from an end face of the other of the second waveguide cores to irradiate the other of the photocurable resins, thereby at least partially forming the other of the self-forming waveguides; A method for manufacturing an optical integrated device comprising:

Images