JP2018189875A - Optical connection structure and forming method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical connection structure capable of connecting optical devices using optical waveguide of a resin on the end faces.SOLUTION: The optical connection structure comprises a first optical device 101, a second optical device 102, and an optical waveguide 103. The optical waveguide 103 optically connects a light input/output part 101a of the first optical device 101 and a light input/output part 102a of the second optical device 102 (optical interconnection). The optical waveguide 103 is constituted of a resin core 104 formed of a light transmissive resin. The resin core 104 is formed in, for example, a folded structure such as a U shape.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical connection structure for connecting two optical devices with an optical waveguide made of resin, and a method for forming the same.

  With the progress of optical communication networks, there is a strong demand for improving the degree of integration of optical communication devices and reducing the size of optical devices. 2. Description of the Related Art Conventionally, in an optical circuit used as an optical communication device, a planar lightwave circuit (PLC) made of a quartz glass system having glass as a core has been widely used. This is excellent in coupling with optical fibers and has high reliability as a material, so it is applied to a wide variety of functional elements for optical communication such as splitters, wavelength multiplexers / demultiplexers, optical switches, and polarization control elements. .

  In recent years, in order to cope with the miniaturization of the optical circuit described above, the optical circuit with a high refractive index difference has been designed to reduce the minimum bending diameter by increasing the refractive index of the core and increasing the refractive index difference with the cladding. Research is progressing. In recent years, silicon photonics technology using silicon with a strong light confinement as a core has progressed, and an optical circuit smaller than a glass system has been realized. For silicon photonics technology, a silicon process generally used in electronic parts can be applied.

A resin waveguide made of a resin such as a transparent polymer is also well known. In addition, as a light modulation element, a wavelength conversion element, and an amplification element, an optical circuit having a ferroelectric material represented by lithium niobate (LiNbO ₃ ) as a core is widely used. In addition, III-V semiconductors represented by indium phosphide (InP) and gallium arsenide (GaAs) have been put into practical use as light-emitting elements, light-receiving elements, and light modulation elements. Optical circuit integrated light emitting elements, light receiving elements, light modulation elements, and the like that have been widely applied. These ferroelectric and semiconductor optical waveguides also have a higher refractive index than glass, so that light confinement is strong and circuit miniaturization can be expected. The above is collectively referred to as an optical device.

  The demand for miniaturization of the optical input / output portion of the optical waveguide is increasing in accordance with the miniaturization of the optical device as described above. Conventionally, in the example of optical connection (optical connection) at the optical input / output part of the silica glass PLC, the connection pitch cannot be reduced below the cladding diameter of the optical fiber. Furthermore, it is common to optically connect with an optical fiber. This connection pitch is limited, and if the optical input / output unit is included, the entire optical device cannot be miniaturized. For this reason, there is a need for a technique for optical connection at a pitch or less that is limited by the cladding diameter of the optical fiber.

  In general, in the optical connection between the optical fibers, between the optical fiber and the optical device, and between the optical devices, the connection end faces orthogonal to the optical axis of the optical device are arranged so as to face each other, A bad coupling technique for positioning and optically connecting so as not to cause an axial deviation is known. On the other hand, a spatial system connection is also widely used in which a light beam emitted from a connection end face perpendicular to the optical axis of the optical device is condensed through a spatial optical system such as a lens and then connected to the optical device again. Yes.

  In the above-described bad coupling technology, the optical connection surfaces of the optical devices must always be placed facing each other, and there are significant restrictions on mounting from the viewpoint of the thermal expansion coefficient and the consistency of the mode diameter of the guided light. There is a problem. In addition, spatial optical system coupling also has restrictions due to the spread of the beam diameter and manufacturing restrictions such as minute lenses and mirrors, and there are technical limitations in reducing the connection pitch and improving mass productivity.

  As a technique for overcoming the above-described limitations, a technique for connecting the above elements with a resin waveguide has been proposed. For example, an arbitrary optical three-dimensional wiring pattern is produced by optical connection using a self-forming waveguide or nano-level optical modeling technology using two-photon absorption as described in Non-Patent Document 1, and light in a resin. There is a method of optically connecting (optical connection) between the optical fibers, between the optical fibers and the optical devices, and between the optical devices.

  This is because a resist solution or the like, which is a resin raw material, is immersed on a substrate, a light beam from a laser is condensed by a lens or the like, and two-photon absorption is induced in the light beam condensing unit. This is a technique for hardening only the resin and further moving the condensing part by scanning this laser, resulting in stereolithography, and is also known as a stereolithography type three-dimensional printer.

  In particular, as is well known, the technology of stereolithography using two-photon absorption has a very small condensing size, so nano-level stereolithography is possible by combining it with a scanning unit that drives microscopically. It is.

N. Lindenmann et al., "Photonic wire bonding: a novel concept for chipscale interconnects", Optics Express, vol. 20, no. 16, pp. 17667-17677, 2012.

  However, the optical connection by the above-described optical modeling has a limitation on the wiring pattern that can be formed due to the production characteristics. In stereolithography, a light beam once spread in a space is condensed by a lens, and a target resin is photocured. At this time, if there is an object that blocks the light beam, modeling cannot be performed. For example, if the direction from the substrate that is the modeling starting point to the modeling laser is the height, if there is a structure that blocks the laser beam on the image side or object side in the height direction, an optical modeling object cannot be formed in the vicinity There is a problem.

  For example, consider a case where an optical fiber 601a and an optical fiber 601b are optically connected as shown in FIG. In the optical modeling, a resin wiring is formed by curing the resin of the condensing unit 604 using an exposure system using a lens 602 and a modeling laser beam 603. Here, in the optical fibers 601a and 601b, the upper and lower sides of the core 611 that guides light are sandwiched between the clads 612 and 613, respectively. In this case, the position of the core 611 is deeper than the cladding 613 when viewed from the irradiation side of the modeling laser beam 603.

  For this reason, when trying to optically connect the core 611 of the optical fiber 601a and the core 611 of the optical fiber 601b that face each other, the modeling laser beam 603 is blocked by the upper cladding 613. As a result, it is not possible to form a resin wiring pattern that directly connects to the end faces of the core 611 of the optical fiber 601a and the core 611 of the optical fiber 601b.

  For example, if the upper clad has no structure such as air, such as a rib-type waveguide, that is, an optical device with an exposed core, the core 702 of the optical device 701a, as shown in FIG. In addition, a resin waveguide 703 can be formed in a direction along the optical axis of the core 702 of the optical device 701b. For example, the resin waveguide 703 can be formed by performing optical modeling in a direction along the optical axis and curing the resin so as to be stretched along the waveguide direction of the core 702. By using the resin waveguide 703, it is possible to realize a resin wiring between the adiabatic optical circuits that is optically connected by evanescent coupling by the seepage of the guided light guided through the core 702.

  However, this optical connection is applicable when the core is exposed, and cannot be applied to the embedded optical waveguide as described above. In addition, the optical connection by evanescent coupling has a problem that the optical connection loss is larger than that of the end face connection.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to enable end face connection between optical devices with an optical waveguide made of resin.

  In the method for forming an optical connection structure according to the present invention, the end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device are respectively defined as the first end face and the second end face, A first step of disposing the second end face perpendicular to the irradiation direction of the exposure light for exposure and toward the side irradiated with the exposure light; and curing the photocurable resin by irradiating the exposure light. And forming a resin core in which the photocurable resin is photocured from the first end surface to the second end surface, and optically connecting the first end surface and the second end surface with an optical waveguide formed by the resin core. The photocurable resin becomes a resin that transmits light by photocuring.

  In the method for forming the optical connection structure, in the second step, the resin core may be formed in a U shape to optically connect the first end face and the second end face.

  In the method for forming the optical connection structure, in the first step, the first end face and the second end face may be arranged on the same plane.

  In the method for forming the optical connection structure, in the first step, the distance between the center portion of the first end face and the center portion of the second end face may be 0.3 mm or less.

  The optical connection structure according to the present invention includes a first optical device, a second optical device, and a resin that optically connects the optical input / output unit of the first optical device and the optical input / output unit of the second optical device. An optical waveguide with a resin core is provided, the end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device are arranged in the same direction, and the resin transmits light. To do.

  In the optical connection structure, the resin core may be formed in a U shape.

  In the optical connection structure, the end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device may be arranged on the same plane.

  In the above optical connection structure, if the distance between the center portion of the end face of the light input / output portion of the first optical device and the center portion of the end face of the light input / output portion of the second optical device is 0.3 mm or less Good.

  As described above, according to the present invention, it is possible to obtain an excellent effect that end faces can be connected between optical devices by an optical waveguide made of resin.

FIG. 1 is a cross-sectional view showing a configuration of an optical connection structure according to Embodiment 1 of the present invention. FIG. 2A is an explanatory diagram showing a state in each step for explaining a method for forming an optical connection structure in Embodiment 1 of the present invention. FIG. 2B is an explanatory diagram showing a state in each step for explaining the method of forming the optical connection structure in the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing another configuration of the optical connection structure according to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view showing the configuration of the optical connection structure according to Embodiment 2 of the present invention. FIG. 5 is a perspective view showing the configuration of the optical connection structure according to Embodiment 3 of the present invention. FIG. 6 is a cross-sectional view showing the configuration of the optical connection structure according to Embodiment 3 of the present invention. FIG. 7 is a perspective view showing another configuration of the optical connection structure according to Embodiment 3 of the present invention. FIG. 8 is a plan view showing a configuration example of the resin core. FIG. 9 is a cross-sectional view showing the configuration of the optical connection structure according to Embodiment 4 of the present invention. FIG. 10 is a perspective view showing the configuration of the optical connection structure according to Embodiment 4 of the present invention. FIG. 11 is a cross-sectional view showing the configuration of the optical connection structure according to Embodiment 5 of the present invention. FIG. 12 is a perspective view showing the configuration of the optical connection structure according to Embodiment 5 of the present invention. FIG. 13 is a perspective view showing the configuration of the optical connection structure according to Embodiment 6 of the present invention. FIG. 14 is an explanatory diagram for explaining a method of forming an optical connection structure. FIG. 15 is a plan view (a) and a side view (b) showing the configuration of the optical connection structure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
First, the optical connection structure in Embodiment 1 of this invention is demonstrated using FIG. This optical connection structure includes a first optical device 101, a second optical device 102, and an optical waveguide 103. The first optical device 101 is an optical fiber including a core 105, for example. The second optical device 102 is an optical fiber including a core 106, for example.

  The optical waveguide 103 optically connects (optically connects) the optical input / output unit 101a of the first optical device 101 and the optical input / output unit 102a of the second optical device 102. The optical waveguide 103 includes a resin core 104 made of a resin that transmits light. The resin core 104 is formed in a folded structure such as a U-shape, for example. In the first embodiment, the air around the resin core 104 is clad.

  Here, the first end surface 121 of the light input / output unit 101a of the first optical device 101 and the second end surface 122 of the light input / output unit 102a of the second optical device 102 are arranged in the same direction. . The end face of the core 105 on the first end face 121 and the end face of the core 106 on the second end face 122 are connected by a resin core 104 that is folded back with an appropriate curvature such as a U-shape.

  For example, light propagating through the first optical device 101 is input to the optical waveguide 103 at the first end surface 121 of the light input / output unit 101a. The light input to the optical waveguide 103 at the first end surface 121 propagates through the optical waveguide 103 and is input to the second optical device 102 at the second end surface 122 of the light input / output unit 102a.

  For example, the light that has propagated through the second optical device 102 is input to the optical waveguide 103 at the second end face 122 of the light input / output unit 102a. The light input to the optical waveguide 103 at the second end face 122 propagates through the optical waveguide 103 and is input to the first optical device 101 at the first end face 121 of the light input / output unit 101a.

  Next, a method for forming an optical connection structure in Embodiment 1 of the present invention will be described with reference to FIGS. 2A and 2B.

  First, as shown in FIG. 2A, the first end surface 121 of the light input / output unit 101a of the first optical device 101 and the second end surface 122 of the light input / output unit 102a of the second optical device 102 are exposed for exposure. It arrange | positions toward the direction in which the light 151 is irradiated. The first end surface 121 and the second end surface 122 are arranged so as to be perpendicular to the direction in which the exposure light 151 is irradiated (the optical axis 152 of the exposure light 151) (first step). The exposure light 151 is emitted from a light source (not shown) such as a laser and is collected by an optical system 153 such as a lens.

  Next, as shown in FIG. 2B, the photo-curing resin is cured by irradiating the exposure light 151, thereby forming the resin core 104 in which the photo-curing resin is photo-cured from the first end surface 121 to the second end surface 122. . As the photocurable resin, a resin that becomes a resin through which light is transmitted by photocuring is used. For example, the resin core 104 is formed in a U shape. By forming the resin core 104, the first end surface 121 and the second end surface 122 are optically connected by the optical waveguide 103 formed by the resin core 104 (second step). In this step, the trajectory of the exposure optical system for forming the resin may be any technique used in a 3D printer or the like, for example, forming the resin from each of the first end surface and the second end surface. For example, the resin may be bonded near the apex.

  Conventionally, as described with reference to FIG. 14, end faces of optical devices to be optically connected are arranged to face each other. In this case, as described above, a modeling defect due to the structure that blocks the laser beam during optical modeling occurs, and it cannot be formed in a state in which an optical waveguide made of resin is appropriately connected to the core end surface.

  On the other hand, according to the above-described embodiment, the first end surface 121 of the light input / output unit 101a of the first optical device 101 and the second end surface 122 of the light input / output unit 102a of the second optical device 102 are exposed. The light 151 is arranged in the direction of irradiation and perpendicular to the optical axis 152. In this state, a step of forming the optical waveguide 103 made of resin is performed. Accordingly, it is possible to realize an optical connection structure in which two optical devices are connected by an optical waveguide made of a resin having a folded structure.

  In the formation step (second step) of the optical waveguide 103 using the resin described above, the connection end surfaces (first end surface 121 and second end surface 122) that are the starting points of optical modeling for the laser (exposure light) and the lens (optical system). Can be easily observed. In this case, there is no influence of the shielding object. From these things, it becomes possible to form the resin wiring in a micro area | region between two optical devices with high efficiency.

  In the above description, the case where the optical device is an optical fiber has been described as an example, but the present invention is not limited to this. The optical device may be any device that transmits light and inputs and outputs light. For example, in addition to an optical fiber, a light emitting element such as a laser, a light receiving element such as a photodiode, an optical modulator, or the like may be used. The optical device can naturally be applied to any optical functional device such as an isolator, polarization rotation, polarization separation element, and optical attenuator.

  Next, the stereolithography method will be described in more detail.

  As a first method, first, a photoresist film typified by ultraviolet (UV) curable resin or SU8 is applied to form an end face of the optical device. Alternatively, the end face of the optical device is immersed in a container filled with a photoresist.

  Next, UV light from a laser for forming a waveguide is condensed and irradiated through a predetermined optical system. The irradiation position is scanned to form a desired resin waveguide. Since the photoresist irradiated with UV light is photocured, the resin is cured along the scanning locus by scanning the irradiation position, and a resin waveguide can be formed. For example, the light source and the optical system may be scanned using a motor or a piezo stage.

  As a second method, there is a method of performing optical modeling using a femtosecond laser having a wavelength longer than a wavelength at which a photocuring resin is cured. In this method, two-photon absorption at a wavelength at which the resin cures is generated by a non-linear effect at a portion where the light intensity is constant by condensing. A resin waveguide is formed by scanning the condensing portion where the two-photon absorption occurs in the same manner as described above. According to this method, as is well known, it is possible to perform high-precision and nano-level stereolithography.

  As described above, a resin waveguide can be formed by removing the resin in the uncured region after modeling by photocuring. Here, the resin has a small propagation distance, but preferably has a high transmittance at the wavelength of light input to and output from the optical device.

  The resin waveguide (resin core) may be of any size (diameter) capable of propagating light. However, the resin waveguide (resin core) has a diameter capable of propagating the air layer as a single mode to the cladding layer to reduce connection loss and bending loss. It is preferable from the viewpoint of reduction. This single mode condition can be calculated from the refractive index of the resin. Furthermore, from the viewpoint of performing microbending, the smaller the diameter of the resin core, the better. From the viewpoints of the above two points, the diameter of the resin core is preferably 30 μm or less, more preferably 10 μm or less.

  In the case where confinement is impossible with air cladding, a cladding layer 107 covering the resin core 104 may be formed as shown in FIG. As described above, after forming the resin core 104 by photo-curing modeling, the resin core 104 may be embedded with a clad material to form the clad layer 107. The clad material is a material having a refractive index smaller than that of the resin core 104. By forming the cladding layer 107, the mechanical strength of the resin core 104 can be reinforced.

  By the way, on the precision of the apparatus which performs stereolithography, the distance of the center part of a 1st end surface and the center part of a 2nd end surface is good to be in the state of 0.3 mm or less. The position accuracy of the stage that performs the operation of the optical modeling apparatus is very high when driven by a commercially available high-precision piezo motor, but the movable range that guarantees the accuracy is about 0.3 mm. . For this reason, the above-described distance should be within the range of the positional accuracy of the apparatus. The curvature of the folded portion of the resin core can be arbitrarily determined by the distance between the center portion of the first end face and the center portion of the second end face determined by the movable range for ensuring accuracy.

[Embodiment 2]
Next, the optical connection structure in Embodiment 2 of this invention is demonstrated using FIG. This optical connection structure includes a first optical device 101, a second optical device 102, and an optical waveguide 103. The first optical device 101 is an optical fiber including a core 105, for example. The second optical device 102 is an optical fiber including a core 106, for example. These configurations are the same as those in the first embodiment.

  In the second embodiment, the first end surface 121 and the second end surface 122 are arranged on the same plane 123. By adopting this configuration, the first end surface 121 and the second end surface 122 that are the start / end points of the optical modeling for forming the resin core 104 can be observed more easily than in the first embodiment. Become.

  In general, the starting point / end point of stereolithography is determined by observation of the focal position of the optical system. In the first embodiment described above, the focal position is different between the first end surface 121 and the second end surface 122, and the focal position is determined respectively. On the other hand, according to the second embodiment, since the first end surface 121 and the second end surface 122 are on the same plane 123, the focal positions are substantially the same, and from each of the first end surface and the second end surface. When the resin is formed while being stacked, the resin core 104 can be more easily optically modeled.

  What is necessary is just to arrange | position about the position of the 1st end surface 121 and the 2nd end surface 122 so that it may become substantially the same height with mechanical mounting precision. Alternatively, in order to determine the positions of the first end surface 121 and the second end surface 122 with higher accuracy, after fixing (mounting) the first optical device 101 and the second optical device 102, by dicing processing or polishing processing, You may process so that the position of the 1st end surface 121 and the 2nd end surface 122 may become the same with higher precision. Thereafter, the resin core 104 can be formed more easily by performing optical modeling as described above.

[Embodiment 3]
Next, the optical connection structure in Embodiment 3 of this invention is demonstrated using FIG.5, FIG.6, FIG.7. This optical connection structure includes a first optical device 201, a second optical device 202, and an optical waveguide 103. The optical waveguide 103 optically connects (optically connects) the optical input / output unit of the first optical device 201 and the optical input / output unit of the second optical device 202. Further, as shown in FIG. 6, the optical waveguide 103 is constituted by a resin core 104 made of a resin that transmits light.

  The first optical device 201 and the second optical device 202 are devices each including an optical waveguide having a silicon fine wire as a core. This can be manufactured using a well-known SOI (Silicon on Insulator) substrate or the like. The surface silicon layer of the SOI substrate is patterned by a known photolithography technique and etching technique to form a core layer constituting an optical waveguide (optical circuit). Next, for example, silicon oxide is deposited by a well-known deposition method such as a plasma CVD method to form an upper cladding layer. As a result, an optical waveguide can be formed in which the buried insulating layer is the lower cladding layer, and the core layer made of the fine silicon wire formed thereon is covered with the upper cladding layer.

  Here, the optical device may be a planar lightwave circuit made of a quartz glass thin film formed by being deposited on a silicon substrate, for example. Moreover, if it is an optical waveguide device which has a waveguide mechanism, it will not restrict to this. For example, as a substrate or an optical waveguide, in addition to quartz glass, an organic resin, a semiconductor such as Si, silicon nitride (SiN), gallium arsenide, or indium phosphide (InP) or a compound semiconductor waveguide, lithium niobate (LN) ), A dielectric such as periodically poled lithium niobate (PPLN) may be used.

  The optical device may be integrated with various signal processing optical circuits for processing signals and various optical functional elements for light emission / light reception / modulation / control. The optical device has the characteristics in this connection part (connection end face), and does not depend on the circuit configuration or circuit function of the optical device. Therefore, hereinafter, the optical connection end face of the optical device will be described.

  As shown in FIG. 5, the optical connection structure includes a plurality of optical waveguides 103 formed by optical modeling. Each optical waveguide 103 is optically connected to each optical waveguide formed in each of the first optical device 201 and the second optical device 202.

  The first optical device 201 and the second optical device 202 will be described in more detail with reference to FIG. The first optical device 201 is an optical waveguide layer in which a plurality of optical waveguides by the core 205 is formed, and is formed on the substrate 211. The end surface of the core 205 and the resin core 104 are optically connected to each other at the end surface of the one optical input / output unit 201a of the first optical device 201. An optical fiber 212 is optically connected to the other optical input / output unit 201b of the first optical device 201. The optical fiber 212 is fixed to the substrate 211 by a fixing component 213. The fixed component 213 is bonded to one end surface of the substrate 211 with an adhesive layer 214 made of an adhesive.

  The second optical device 202 is an optical waveguide layer in which a plurality of optical waveguides are formed by the core 206, and is formed on the substrate 221. The end surface of the core 206 and the resin core 104 are optically connected to each other at the end surface of one light input / output unit 202a of the second optical device 202. An optical fiber 222 is optically connected to the other optical input / output unit 202b of the second optical device 202. The optical fiber 222 is fixed to the substrate 221 by a fixing component 223. The fixed component 223 is bonded to one end surface of the substrate 221 with an adhesive layer 224 made of an adhesive.

  The first optical device 201 and the second optical device 202 connected by the optical waveguide 103 function as an optical device for optical fiber transmission.

  The optical device described above can optically connect the optical waveguide arrays composed of the plurality of optical waveguides in the first optical device 201 and the second optical device 202 at a minute pitch by the plurality of optical waveguides 103. Furthermore, even when the end faces of the optical waveguides of the first optical device 201 and the second optical device 202 cannot be arranged facing each other due to mechanical interference with other components, optical connection is possible, and various light Connection structure restrictions can be relaxed.

  In addition, the 1st optical device 201 and the 2nd optical device 202 are good also as a structure arrange | positioned so that it may adjoin by a side part, and may be connected by the optical waveguide 103, as shown in FIG. In this configuration, the optical waveguide 103 is folded back in the planar direction of the first optical device 201 and the second optical device 202.

  Next, the folded structure of the resin core will be described with reference to FIG. For example, as shown to (a) of FIG. 8, the resin core can be comprised from the U-shaped folding | returning part 141. FIG. Further, as shown in FIG. 8B, the resin core can be composed of a U-shaped folded portion 141 and a straight portion 142. By providing the straight portion 142, the design of the resin core layout is simplified. Also, from the viewpoint of connectivity with the optical device, it is easier to align the optical axis on the optical device side and the optical axis of the resin core to be formed with the linear portion 142, and low loss. Can be connected to.

  Further, as shown in FIGS. 8C and 8D, a tapered portion 143 and a tapered portion 144 may be provided. With these tapered portions, it is possible to provide a spot size conversion function for converting a mode field in an optical waveguide formed by a resin core. By providing such a spot size conversion function, it is possible to connect with low loss in accordance with the mode diameter of each part.

[Embodiment 4]
Next, the optical connection structure in Embodiment 4 of this invention is demonstrated using FIG. This optical connection structure includes a first optical device 301, a second optical device 302, and an optical waveguide 103. The optical waveguide 103 optically connects (optically connects) the optical input / output unit of the first optical device 301 and the optical input / output unit of the second optical device 302. The optical waveguide 103 includes a resin core 104 made of a resin that transmits light.

  The first optical device 301 is an optical fiber including a core 305. For example, as illustrated in FIG. 10, the first optical device 301 including a plurality of optical fibers is fixed on the holding substrate 311. The second optical device 302 includes, for example, a well-known semiconductor laser. For example, the second optical device 302 composed of a plurality of semiconductor lasers is fixed on the substrate 321. The substrate 321 is disposed on a temperature adjustment device 322 for stabilizing the laser oscillation wavelength.

  Each optical fiber of the first optical device 301 and each laser of the second optical device 302 are optically connected by an optical waveguide 103 formed by a resin core 104. The first optical device 301 formation side and the second optical device 302 formation side may be arranged to face each other in the thickness direction of the substrate, and the first optical device 301 formation side and the substrate 321 side are You may arrange | position so that it may face. However, from the viewpoint of reducing the distance between two devices connected by the resin core 104, it is more preferable to arrange the first optical device 301 formation side and the second optical device 302 formation side to face each other.

  The semiconductor laser is, for example, a distribution in which a distributed feedback (DFB) laser including a III-V group semiconductor layer grown or bonded to an InP substrate or Si substrate is integrated, a diffraction grating structure, or the like. It is a reflection type (Distributed Bragg Reflector: DBR) laser. For example, a semiconductor laser having an active layer of an InP-based semiconductor that emits a single mode in the vicinity of 1.3 μm or 1.55 μm is preferable.

  The semiconductor laser oscillates at a current equal to or higher than a threshold value by current injection to output laser light, is emitted from the end face of the light output unit 302 a of the second optical device 302, propagates through the optical waveguide 103, and The light enters the optical fiber from the light input unit 301a and is output from the light output unit 301b. Although not shown, a power supply or a driver circuit is connected to the semiconductor laser of the second optical device 302 by wire bonding or flip chip connection.

  In general, when outputting light from a laser to an optical fiber, the output end face of the laser and the connection end face of the optical fiber are arranged to face each other, and a spatial connection is made via a bad coupling or a lens. In this optical connection, in order to couple the optical fiber array and the laser array, as described above, in either the bad coupling or the spatial system, the laser array is matched to the cladding diameter of the optical fiber, the spatial beam diameter and the lens size. There was a restriction on the connection configuration.

  On the other hand, according to this embodiment, a plurality of optical connection intervals between the laser array and the optical fiber array can be mounted at a minute pitch without arranging the end faces facing each other. For this reason, according to the above-described embodiment, even if the optical waveguides cannot be disposed facing each other due to mechanical interference with other components, optical connection is possible, and various arrangement restrictions are imposed. Can be relaxed.

  In addition, although the arrangement interval of the plurality of optical fibers depends on the cladding diameter, the semiconductor laser may have the emission end pitch narrowed at the end face regardless of the arrangement interval of the optical fibers. According to the above-described embodiment, in the plurality of optical waveguides 103, the conversion unit that converts the interval on the semiconductor laser side into the interval of the optical fiber is configured. Thereby, miniaturization and low loss of the laser circuit itself can be realized.

  Moreover, the resin core 104 can be in various forms as described with reference to FIG. A spot size conversion function can be incorporated into the optical waveguide 103 by appropriately changing the tapered shape or the like so as to match the mode diameters of the first optical device 301 and the second optical device 302, thereby reducing the loss. Connection can be realized. In the fourth embodiment as well, as described with reference to FIG. 7, the first optical device 301 and the second optical device 302 are arranged so as to be adjacent to each other on the side and connected by the optical waveguide 103. It is good.

[Embodiment 5]
Next, the optical connection structure in Embodiment 5 of this invention is demonstrated using FIG. 11, FIG. This optical connection structure includes a first optical device 401, a second optical device 302, and an optical waveguide 103. The optical waveguide 103 optically connects (optically connects) the optical input / output unit of the first optical device 401 and the optical input / output unit of the second optical device 302. The optical waveguide 103 includes a resin core 104 made of a resin that transmits light. The optical waveguide 103 and the second optical device 302 are the same as those in the fourth embodiment.

  In this embodiment, the first optical device 401 includes a plurality of optical waveguides formed by the core 405. The first optical device 401 is formed on the substrate 411. The first optical device 401 is the same as the first optical device 201 according to the second embodiment described above, and is, for example, a device including an optical waveguide having a silicon fine wire as a core. The first optical device 401 may be a planar lightwave circuit made of a quartz glass thin film deposited and formed on a silicon substrate, for example.

  The second optical device 302 is the same as that in the fourth embodiment described above. For example, the second optical device 302 includes a plurality of well-known semiconductor lasers and is fixed on the substrate 321. The substrate 321 has a laser oscillation wavelength. It arrange | positions on the temperature control apparatus 322 for stabilizing. For example, each of the plurality of resin cores 104 connects each optical waveguide of the first optical device 401 and each semiconductor laser of the second optical device 302. The semiconductor laser oscillates at a current equal to or higher than a threshold value by current injection to output laser light, is emitted from the end face of the light output unit 302 a of the second optical device 302, propagates through the optical waveguide 103, and passes through the optical waveguide 103. The light enters the optical waveguide from the light input unit 401a and is output from the light output unit 401b.

  In general, when outputting light from a laser to an optical waveguide, the output end face of the laser and the connection end face of the optical waveguide face each other and are connected in a space system via a bad coupling or a lens. In this optical connection, in order to couple the optical waveguide array and the laser array, as described above, in either the bad coupling or the spatial system, the laser array is matched to the cladding diameter of the optical waveguide, the beam diameter of the space and the size of the lens. There was a restriction on the connection configuration.

  On the other hand, according to this embodiment, a plurality of optical connection intervals between the laser array and the optical waveguide array can be mounted at a minute pitch without arranging the end faces facing each other. For this reason, according to the above-described embodiment, even if the optical waveguides cannot be disposed facing each other due to mechanical interference with other components, optical connection is possible, and various arrangement restrictions are imposed. Can be relaxed.

  Further, the arrangement interval of the plurality of optical waveguides and the pitch of the emission ends of the respective semiconductor lasers can be set to be small, and the miniaturization of the connection portion between the optical devices can be realized.

  Moreover, the resin core 104 can be in various forms as described with reference to FIG. A spot size conversion function can be incorporated into the optical waveguide 103 by appropriately changing the tapered shape or the like so as to match the mode diameters of the first optical device 401 and the second optical device 302, thereby reducing the loss. Connection can be realized. In the fourth embodiment as well, as described with reference to FIG. 7, the first optical device 401 and the second optical device 302 are arranged so as to be adjacent to each other on the side and connected by the optical waveguide 103. It is good.

  Furthermore, each semiconductor laser in the second optical device 302 is set to have a different oscillation wavelength, and by forming a wavelength multiplexing / demultiplexing element or the like in each optical waveguide of the first optical device 401 optically connected to the semiconductor laser by the optical waveguide 103, It is also possible to realize a wavelength-multiplexed light source. Alternatively, a semiconductor optical amplifying element (SOA) is disposed in each semiconductor laser in the second optical device 302, and a ring resonator is formed by the optical waveguide of the first optical device 401, thereby extending the resonator length and oscillating. It is also possible to realize a laser device having a narrow wavelength interval.

[Embodiment 6]
Next, the optical connection structure in Embodiment 6 of this invention is demonstrated using FIG. This optical connection structure includes a first optical device 501a, a second optical device 501b, a third optical device 501c, and optical waveguides 103a and 103b. The first optical device 501a is formed on the first substrate 511a. The second optical device 501b is formed on the second substrate 511b. The third optical device 501c is formed on the third substrate 511c. The optical waveguide 103a optically connects (optically connects) the optical input / output unit of the first optical device 501a and the optical input / output unit of the second optical device 501b. The optical waveguide 103b optically connects (optically connects) the optical input / output unit of the second optical device 501b and the optical input / output unit of the third optical device 501c. The optical waveguides 103a and 103b are made of a resin core made of a resin that transmits light. The optical waveguides 103a and 103b and each optical device are the same as those in the above-described embodiment.

  In the three first optical devices 501a, 501b, and 501c, the end surfaces of the respective light input / output units are perpendicular to the irradiation direction of the exposure light for exposure and the exposure light. Is arranged facing the side to be irradiated. In the first optical device 501a, the second optical device 501b, and the third optical device 501c, the end faces of the respective light input / output units are arranged on the same plane.

  As described above, even the three optical devices are the same as those in the above-described embodiment. The same applies to not only three optical devices, but also four or more optical devices. There is no restriction on the number of optical devices to be optically connected, and a plurality of optical devices are connected in series with an optical waveguide made of resin. It can be connected as a matrix wiring, and a more functional optical device can be realized.

  As described above, in the present invention, the first end surface of the light input / output unit of the first optical device and the second end surface of the light input / output unit of the second optical device are arranged in the irradiation direction of the exposure light for exposure. The first end face and the second end face are optically connected to each other by an optical waveguide formed by a resin core. As a result, according to the present invention, end faces can be connected between optical devices by an optical waveguide made of resin.

  The present invention is not limited to the embodiment described above, and many modifications and combinations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious.

  DESCRIPTION OF SYMBOLS 101 ... 1st optical device, 101a ... Optical input / output part, 102 ... 2nd optical device, 102a ... Optical input / output part, 103 ... Optical waveguide, 104 ... Resin core, 105 ... Core, 106 ... Core, 121 ... 1st End face, 122 ... second end face.

Claims (8)

The end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device are respectively the first end face and the second end face, and the first end face and the second end face are exposure light for exposure. A first step that is arranged perpendicularly to the irradiation direction and toward the side irradiated with the exposure light;
By curing the photo-curing resin by irradiating the exposure light, a photo-cured resin core is formed from the first end surface to the second end surface, and the first end surface and the second end surface are formed. A second step of optically connecting with an optical waveguide formed by the resin core,
The method for forming an optical connection structure, wherein the photo-curing resin is a resin that transmits light by photo-curing. In the formation method of the optical connection structure of Claim 1,
In the second step, the resin core is formed in a U shape, and the first end surface and the second end surface are optically connected to each other. In the formation method of the optical connection structure of Claim 1 or 2,
In the first step, the first end face and the second end face are arranged on the same plane. In the formation method of the optical connection structure of any one of Claims 1-3,
In the first step, the distance between the center portion of the first end face and the center portion of the second end face is set to a state of 0.3 mm or less. A first optical device;
A second optical device;
An optical waveguide with a resin core made of a resin that optically connects the optical input / output unit of the first optical device and the optical input / output unit of the second optical device;
The end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device are arranged in the same direction,
The optical connection structure, wherein the resin transmits light. The optical connection structure according to claim 5,
The optical connection structure, wherein the resin core is formed in a U-shape. The optical connection structure according to claim 5 or 6,
The end face of the light input / output part of the first optical device and the end face of the light input / output part of the second optical device are arranged on the same plane. In the optical connection structure according to any one of claims 5 to 7,
The distance between the center portion of the end face of the light input / output portion of the first optical device and the center portion of the end face of the light input / output portion of the second optical device is 0.3 mm or less. Connection structure.

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