Optical device, optical transmitter and optical receiver

Abstract

To suppress optical coupling loss between an optical waveguide and an optical fiber.SOLUTION: An optical device incudes an optical element ana an optical fiber block. The optical element has an optical waveguide, a first end face on which an end face of the optical waveguide is arranged, and a second end face protruding from the first end face. The optical fiber block has an optical fiber, a third end face on which an end face of the optical fiber is arranged, and a fourth end face concaved from the third end face. With the second end face and the fourth end face being fixed to be pressed against each other, the optical device connects the first end face and the third end face through butt coupling and optically couples the end face of the optical waveguide to the end face of the optical fiber.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical device, an optical transmitting apparatus, and an optical receiving apparatus. [Background technology]

[0002] In recent years, there has been a demand for higher optical data transmission capacity in optical devices equipped with optical waveguides. In addition, optical waveguides, which are suitable for miniaturization and integration, are widely used in optical transceivers equipped with optical transmission and reception functions.

[0003] FIG. 19 is a schematic cross-sectional view showing an example of a conventional optical device 100. The optical device 100 shown in FIG. 19 has an optical element 110 and an optical fiber block 120. The optical element 110 is an optical element created based on an SOI (Silicon On Insulator) wafer. The optical element 110 has a Si substrate 111, an insulating layer 112, an optical waveguide 113, and a passivation layer 114. The Si substrate 111 is a support substrate that constitutes the SOI wafer. The insulating layer 112 is a SiO 2 The passivation layer 114 is formed of, for example, SiO 2 Or Si 3 N 4 and functions as an upper cladding layer of the optical waveguide 113.

[0004] The optical fiber block 120 has an optical fiber 121 and a glass block 122. The optical fiber 121 has a core 121B and a cladding 121A that covers the core 121B. With the optical fiber 121 inserted into the glass block 122, the optical fiber 121 and the glass block 122 are fixed together with an optical adhesive A.

[0005] The end face 113A of the optical waveguide 113 and the core end face 121B1 of the optical fiber 121 are optical surfaces (mirror surfaces) to prevent light scattering. The end face 113A of the optical waveguide 113 and the core end face 121B1 are optically coupled to each other by butt-jointing using an optical adhesive A that is transparent in the optical communication wavelength range. At this time, in order to sufficiently reduce the optical coupling loss between the optical waveguide 113 and the core 121B of the optical fiber 121, the optical axes of the end face 113A of the optical waveguide 113 and the core end face 121B1 of the optical fiber 121 are adjusted to be approximately the same position in the vertical and horizontal directions. Furthermore, the distance between the end face 113A of the optical waveguide 113 and the core end face 121B1 of the optical fiber 121 is also sufficiently short.

[0006] Fig. 20 is a schematic cross-sectional view showing an example of a cutting process of a conventional optical element 110. As shown in Fig. 20, the optical element 110 is vertically diced using a rotating cutting blade B1. Fig. 21 is a schematic cross-sectional view showing an example of the optical element 110 after the cutting process. In the optical element 110 after dicing, as shown in Fig. 21, a cut surface 110A including an end surface 113A of the optical waveguide 13 is rough, and if this is left as it is, light scattering will increase, resulting in a large optical coupling loss between the optical waveguide 113 and the optical fiber 121.

[0007] Fig. 22 is a schematic cross-sectional view showing an example of the optical element 110 in a polishing process. In the optical element 110 after dicing, as shown in Fig. 22, the end face 113A of the optical waveguide 113 is optically polished using a polisher B2 with the cut surface 110A facing down, so that the end face 113A becomes an optical surface. Similarly, the core end face 121B1 of the optical fiber 121 also requires optical polishing. Therefore, the optical element 110 undergoes the cutting (dicing) and optical polishing processes, which increases the processing cost and lengthens the lead time.

[0008] In recent years, a method of lapping using a special blade B3 with abrasive grains attached to the side of the blade has been developed, and the cutting process and the end face polishing process can be performed continuously with one blade dicing device, thereby shortening the lead time. FIG. 23 is a schematic cross-sectional view showing an example of the lapping process of the optical element 110. For example, after dicing the optical element 110 using the blade B3, the blade B3 is inserted into the cut groove 110C in the optical element 110 cut by the blade B3, and the end face 113A of the optical waveguide 113 above the optical element 110 is polished by the blade B3 to form the end face 110B on the cut face 110A. As a result, the end face 110B including the end face 113A of the optical waveguide 113 of the optical element 110 becomes an optical surface. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2020-106678 A [Patent Document 2] JP 2003-057467 A [Patent Document 3] JP 2007-199254 A [Patent Document 4] US Patent Application Publication No. 2002 / 0154866 [Patent Document 5] Japanese Patent Application Publication No. 9-026529 Summary of the Invention [Problem to be solved by the invention]

[0010] However, even if lapping is performed to polish the entire surface of the cut surface 110A of the optical element 110, the blade B3 for lapping applied to the cut surface 110A will be warped due to a repulsive force from the end surface of the optical element 110. As a result, the distance between the end surface 113A of the optical waveguide 113 on the cut surface 110A of the optical element 110 and the core end surface 121B1 of the optical fiber 121 cannot be shortened. Therefore, it is difficult to suppress the optical coupling loss between the optical waveguide 113 and the optical fiber 121.

[0011] The disclosed technique has been made in view of the above points, and aims to provide an optical device etc. that can suppress optical coupling loss between an optical waveguide and an optical fiber. [Means for solving the problem]

[0012] In one embodiment, the optical device disclosed in the present application includes an optical element and an optical fiber block. The optical element includes an optical waveguide, a first end face on which an end face of the optical waveguide is disposed, and a second end face protruding from the first end face. The optical fiber block includes an optical fiber, a third end face on which an end face of the optical fiber is disposed, and a fourth end face recessed from the third end face. In the optical device, with the second end face and the fourth end face fixed in contact with each other, the first end face and the third end face are connected by butt coupling to optically couple the end face of the optical waveguide and the end face of the optical fiber. Effect of the Invention

[0013] According to one aspect of the optical device disclosed in the present application, it is possible to suppress optical coupling loss between an optical waveguide and an optical fiber. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of an optical device according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an example of a lapping process for an optical fiber block. [Diagram 3] FIG. 3 is an explanatory diagram of the lapping process of the optical fiber block as viewed from the Y direction. [Figure 4A] FIG. 4A is a schematic cross-sectional view showing an example of an optical fiber block after a lapping process. [Figure 4B] FIG. 4B is a schematic cross-sectional view showing an example of an optical element after the lapping process. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing an example of an optical device according to the second embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view showing an example of a first lapping process step for an optical fiber block. [Figure 7] FIG. 7 is an explanatory view of the first lapping process step of the optical fiber block as viewed from the Y direction. [Figure 8] FIG. 8 is a schematic cross-sectional view showing an example of the second lapping process step of the optical fiber block. [Figure 9] FIG. 9 is an explanatory view of the second lapping process step of the optical fiber block as viewed from the Y direction. [Figure 10] FIG. 10 is a schematic cross-sectional view showing an example of an optical device according to the third embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view showing an example of a lapping process for an optical fiber block. [Figure 12] FIG. 12 is a schematic cross-sectional view showing an example of the second glass block arranging step. [Figure 13] FIG. 13 is a schematic cross-sectional view showing an example of an optical fiber block. [Figure 14] FIG. 14 is an explanatory diagram of the optical fiber block as viewed from the Y direction. [Figure 15] FIG. 15 is an explanatory diagram showing an example of an optical transceiver that employs the optical device of this embodiment. [Figure 16] FIG. 16 is a schematic cross-sectional view showing an example of an optical device according to a first comparative example. [Figure 17] FIG. 17 is a schematic cross-sectional view showing an example of the optical element of Comparative Example 1. As shown in FIG. [Figure 18] FIG. 18 is a schematic cross-sectional view showing an example of an optical device according to the second comparative example. [Figure 19] FIG. 19 is a schematic cross-sectional view showing an example of a conventional optical device. [Figure 20] FIG. 20 is a schematic cross-sectional view showing an example of a conventional cutting process for an optical element. [Figure 21] FIG. 21 is a schematic cross-sectional view showing an example of an optical element after a cutting process. [Figure 22] FIG. 22 is a schematic cross-sectional view showing an example of an optical element in a polishing process. [Figure 23] FIG. 23 is a schematic cross-sectional view showing an example of a lapping process for an optical element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] However, as shown in FIG. 23, the blade B3 for lapping applied to the cut surface 110A of the optical element 110 is warped by the repulsive force of the cut surface 110A, so that the cut surface 110A of the optical element 110 cannot be polished entirely. Therefore, a method of lapping only the vicinity of the end surface 113A of the optical waveguide 113 of the optical element 110 can be considered. FIG. 16 is a schematic cross-sectional view showing an example of an optical device 100A of Comparative Example 1, and FIG. 17 is a schematic cross-sectional view showing an example of the optical element 110 of Comparative Example 1. For convenience of explanation, the thickness of the Si substrate 111 is set to, for example, 625 um. Therefore, the entire cut surface 110A of the optical element 110 is not lapped, but the end surface 110B is optically polished to a depth of about 10 um from the surface of the optical waveguide 113 of the optical element 110 to a depth of about 80 um. As a result, end face 110B including end face 113A of optical waveguide 113 becomes an optical surface. In this case, a step L between end face 113A of optical waveguide 113 and cut surface 110A of optical element 110 is set to, for example, about 10 um.

[0016] 16, an optical fiber block 120 in which a core end face 121B1 of an optical fiber 121 and an end face of a glass block 122 are flush with each other are connected to an optical element 110 by a butt joint. That is, in a state in which a cut face 110A of an optical element 110 and an end face of a glass block 122 are abutted against each other, an end face 113A of an optical waveguide 113 and a core end face 121B1 of an optical fiber 121 are butt-jointed with an optical adhesive A. As a result, the distance between the core end face 121B1 of an optical fiber 121 and an end face 113A of an optical waveguide 113 is 10 um, which is the step L between the end face 113A of an optical waveguide 113 and the cut face 110A.

[0017] However, even when the core end face 121B1 of the normal optical fiber 121 is butt-jointed directly to the end face 113A of the lapped optical waveguide 113, the distance between the end face 113A of the optical waveguide 113 and the core end face 121B1 is 10 um or more. As a result, the optical coupling loss between the optical waveguide 113 and the optical fiber 121 is large, for example, about 1.35 dB.

[0018] Therefore, in order to suppress the optical coupling loss, a method of providing a lens between the end face 113A of the optical waveguide 113 and the core end face 121B1 of the optical fiber 121 may be considered. FIG. 18 is a schematic cross-sectional view showing an example of an optical device 100B of Comparative Example 2. A first lens 131A having a focal length of 2 mm and a second lens 131B having a focal length of 2 mm are arranged on an optical path 130 between the end face 113A of the optical waveguide 113 and the core end face 121B1 of the optical fiber 121 with a lens distance of, for example, 1.5 mm. In the optical device 100B, the light emitted from the core end face 121B1 of the optical fiber 121 is collected by the first lens 131A and the second lens 131B, and optically coupled to the end face 113A of the optical waveguide 113. However, in the optical device 100B, it is necessary to secure a length dimension of 5.5 mm, which is the sum of the focal length of the first lens 131A and the second lens 131B and the distance between the lenses. As a result, the optical device 100B becomes larger and the cost of the lenses increases.

[0019] Therefore, the following describes an embodiment of a small optical device that can suppress the optical coupling loss between the end face of the optical waveguide of the lapped optical element and the core end face of the optical fiber. Note that the disclosed technology is not limited to the embodiment. In addition, the embodiments shown below may be appropriately combined within a range that does not cause contradictions. EXAMPLES

[0020] FIG. 1 is a schematic cross-sectional view showing an example of an optical device 1 according to a first embodiment. The optical device 1 shown in FIG. 1 includes an optical element 2 and an optical fiber block 3. The optical element 2 is an optical element fabricated based on an SOI (Silicon On Insulator) wafer. The optical element 2 includes a Si substrate 11, an insulating layer 12, an optical waveguide 13, and a passivation layer 14. The Si substrate 11 is a support substrate constituting the SOI wafer. The insulating layer 12 is a SiO 2 The passivation layer 114 is formed of, for example, SiO 2 Or Si 3 N 4 and functions as an upper cladding layer of the optical waveguide 113.

[0021] The optical fiber block 3 has an optical fiber 21 and a glass block 22. The optical fiber 21 has a core 21B and a cladding 21A that covers the core 21B. With the optical fiber 21 inserted into the glass block 22, the optical fiber 21 and the glass block 22 are fixed together with an optical adhesive A.

[0022] The optical element 2 has an optical waveguide 13, a first end face 31 including an end face 13A of the optical waveguide 13, and a second end face 32 protruding from the first end face 31. The second end face 32 is an end face protruding in the axial direction of the optical waveguide 13. The second end face 32 is formed from a cut surface 30 of the optical element 2 cut by a blade B used for lapping, and the cut surface 30 is a rough surface. Furthermore, the first end face 31 is formed by optically polishing the portion of the cut surface 30 including the end face 13A in an optical polishing process using the blade B. The cut surface 30 of the optical element 2 has a first step L1 between the first end face 31 and the second end face 32.

[0023] The optical fiber block 3 has an optical fiber 21, a third end face 41 including a core end face 21B1 of the optical fiber 21, and a fourth end face 42 recessed relative to the third end face 41. The third end face 41 of the optical fiber block 3 is configured as a cut face 40 of the optical fiber block 3 cut by a blade B used for lapping. The fourth end face 42 is an end face recessed in the axial direction of the core 21B of the optical fiber 21 by being formed in a cutting process with the blade B. The cut face 40 of the optical fiber block 3 has a second step L2 between the third end face 41 and the fourth end face 42.

[0024] The first step L1 of the optical element 2 is set to be substantially equal to the second step L2 of the optical fiber block 3. Considering the elimination of the step of 10 um that occurs in normal lapping, the dimensions of the first step L1 and the second step L2 are preferably at least 3 um or less, for example, 1 um or less. In the optical device 1, the first end face 31 and the third end face 41 are butt-coupled with the optical adhesive A in a state where the second end face 32 and the fourth end face 42 are fixed in contact with each other, thereby optically coupling the end face 13A of the optical waveguide 13 to the core end face 21B1 of the optical fiber 21.

[0025] Next, a method for manufacturing the optical device 1 of the first embodiment will be described.

[0026] FIG. 2 is a schematic cross-sectional view showing an example of the lapping process of the optical fiber block 3, and FIG. 3 is an explanatory diagram of the lapping process of the optical fiber block 3 viewed from the Y direction. A part of the cladding 21A of the core end face 21B1 of the optical fiber 21 of the optical fiber block 3 is cut to a range that does not affect the optical path. Specifically, a blade B is placed on the XZ plane and moved in the X direction to cut, thereby forming a fourth end face 42 on the third end face 41, which is the cut surface 40 of the optical fiber block 3. Then, a second step L2 is formed between the third end face 41 and the fourth end face 42. As a result, the second step L2, which is approximately equal to the first step L1, which is the distance between the first end face 31 including the end face 13A of the optical waveguide 13 of the lapped optical element 2, and the second end face 32, can be easily provided on the cut surface 40 of the optical fiber block 3.

[0027] 4A is a schematic cross-sectional view showing an example of the optical fiber block 3 after the lapping process. The fiber diameter of the optical fiber block 3 is, for example, 250 um, the cladding diameter of the optical fiber 21 is, for example, 125 um, and the core diameter (mode field diameter) of the optical fiber 21 is, for example, 4 um. The second step L2 between the third end face 41 and the fourth end face 42 is, for example, 10 um or more. Furthermore, the cladding 21A of the optical fiber 21 near the fourth end face 42 corresponds to the cladding remainder 21A1 between the core 21B and the fourth end face 42, and the dimension from the core 21B to the recessed portion 40A of the fourth end face 42 is, for example, in the range of 2 um to 50 um.

[0028] FIG. 4B is a schematic cross-sectional view showing an example of the optical element 2 after the lapping process. The thickness of the Si substrate 11 is, for example, 625 um. The optical element 2 is formed with a second end face 32, which becomes the cut surface 30, by dicing with a blade B for lapping, and the first end face 31 is formed by optically polishing the cut surface 30 near the end face 13A of the optical waveguide 13. Specifically, the entire cut surface 30 of the optical element 2 is not lapped, but is lapped to a depth of about 80 um from the surface of the optical waveguide 13 side of the optical element 2, so that the cut surface is optically polished to a depth of about 10 um from the surface of the optical waveguide 13 side of the optical element 2. As a result, the first end face 31 including the end face 13A of the optical waveguide 13 becomes an optical surface. Then, a first step L1 is formed between the first end face 31 and the second end face 32. At this time, the first step L1 between the first end face 31 and the second end face 32 is, for example, about 10 um.

[0029] Then, in the optical device 1, with the second end face 32 and the fourth end face 42 fixed in contact with each other, the first end face 31 and the third end face 41 are connected by butt coupling using optical adhesive A. The end face 13A of the optical waveguide 13 in the optical element 2 and the core end face 21B1 of the optical fiber 21 in the optical fiber block 3 are optically coupled. The remaining cladding 21A1 of the cut optical fiber 21 has the recessed portion 40A filled with optical adhesive A, thereby reducing the effect on the optical refractive index caused by cutting part of the cladding 21A.

[0030] In the optical device 1 of the first embodiment, as shown in FIG. 4A, a second step L2 having a distance substantially equal to the first step L1 formed on the cut surface 30 of the lapped optical element 2 is provided on the cut surface 40 of the optical fiber block 3. Then, in the optical device 1, the first end surface 31 and the third end surface 41 are butt-jointed to optically couple the end surface 13A of the optical waveguide 13 to the core end surface 21B1 of the optical fiber 21 in a state where the fourth end surface 42 of the optical fiber block 3 and the second end surface 32 of the optical element 2 are abutted against each other. As a result, the optical coupling loss between the optical fiber 21 and the optical waveguide 13 is 0.74 dB, which is improved by 0.62 dB compared to the optical device 100A of the first comparative example. In addition, the configuration of this embodiment makes it possible to shorten the lead time by selectively optically polishing the first end surface 31 including the end surface of the waveguide 13 of the optical element 2 using the lapping process.

[0031] In the illustrated example, the optical fiber block 3 is cut by placing the blade B on the XZ plane and moving it in the X direction to form the fourth end face 42 on the third end face 41, which is the cut surface 40 of the optical fiber block 3. However, the present invention is not limited to this and can be modified as appropriate. Therefore, the embodiment will be described below as Example 2. EXAMPLES

[0032] 5 is a schematic cross-sectional view showing an example of an optical device 1A according to the second embodiment. The same components as those in the optical device 1 according to the first embodiment are denoted by the same reference numerals, and the description of the overlapping components and operations will be omitted. The optical fiber block 3A has a third end face 41, a fourth end face 42A, and an opening 43 formed between the third end face 41 and the fourth end face 42A.

[0033] In the optical device 1A, the second end face 32 and the fourth end face 42A are fixed in contact with each other, and the first end face 31 and the third end face 41 are connected by butt coupling using the optical adhesive A. Then, the end face 13A of the optical waveguide 13 in the optical element 2 and the core end face 21B1 of the optical fiber 21 in the optical fiber block 3A are optically coupled. The opening 43 is filled with the optical adhesive A.

[0034] Next, a manufacturing method of the optical device 1A of the second embodiment will be described. The fourth end face 42A of the optical fiber block 3A is formed by two-stage cutting of a portion that does not affect the optical path of the optical fiber 21. Fig. 6 is a schematic cross-sectional view showing an example of a first lapping process of the optical fiber block 3A, and Fig. 7 is an explanatory view of the first lapping process of the optical fiber block 3A viewed from the Y direction. In the first lapping process shown in Figs. 6 and 7, a blade B is placed on the XY plane, and cutting is performed horizontally to the optical path (X direction) to form an opening 43 in the third end face 41, which is the cut surface 40.

[0035] Fig. 8 is a schematic cross-sectional view showing an example of the second lapping process of the optical fiber block 3A, and Fig. 9 is an explanatory diagram of the second lapping process of the optical fiber block 3A viewed from the Y direction. In the second lapping process shown in Fig. 8 and Fig. 9, a blade B is placed on the XZ plane and moved in the X direction to perform cutting, thereby forming a fourth end face 42A on the cut surface 40. As a result, a second step L2 that is approximately equal to the first step L1 of the optical element 2 that has been lapped with higher accuracy can be provided on the cut surface 40 of the optical fiber block 3A.

[0036] In the optical device 1A of the second embodiment, the first end face 31 and the third end face 41 are connected by butt coupling using the optical adhesive A, with the second end face 32 and the fourth end face 42A fixed in contact with each other. As a result, the end face 13A of the optical waveguide 13 in the optical element 2 and the core end face 21B1 of the optical fiber 21 in the optical fiber block 3A are optically coupled. In addition, the opening 43 of the cut cladding 21A of the optical fiber 21 is filled with the optical adhesive A, so that the effect of cutting a part of the cladding 21A on the optical refractive index can be reduced.

[0037] In the optical device 1A, the distance between the core end face 21B1 of the optical fiber 21 and the end face 13A of the optical waveguide 13 can be shortened, and therefore the optical coupling loss between the optical waveguide 13 and the optical fiber 21 can be minimized. In addition, cutting for forming the fourth end face 42A of the optical fiber block 3A can be easily performed in a short time. EXAMPLES

[0038] FIG. 10 is a schematic cross-sectional view showing an example of an optical device 1B of Example 3. The same components as those of the optical device 1 of Example 1 are given the same reference numerals, and the description of the overlapping components and operations will be omitted. The optical fiber block 3B shown in FIG. 10 has an optical fiber 21, a first glass block 22A, and a second glass block 24 that is separate from the first glass block 22A. The optical fiber 21 has an opening 44 formed by cutting the cladding 21A near the core end face 21B1. The second glass block 24 is fixed to the opening 44 of the optical fiber 21 with an optical adhesive A.

[0039] The optical fiber block 3B has a third end face 41 and a fourth end face 42B. The third end face 41 is formed by a core end face 21B1 of the optical fiber 21 and an end face of the first glass block 22A. The fourth end face 42B is formed by an end face 24A of the second glass block 24.

[0040] In the optical device 1B, the first end face 31 and the third end face 41 are connected by butt coupling using the optical adhesive A, with the second end face 32 and the fourth end face 42B being fixed in contact with each other. The end face 13A of the optical waveguide 13 in the optical element 2 and the core end face 21B1 of the optical fiber 21 are optically coupled. The opening 44 is filled with the optical adhesive A.

[0041] Next, a manufacturing method of the optical device 1B of the third embodiment will be described. FIG. 11 is a schematic cross-sectional view showing an example of a lapping process of the optical fiber block 3B. As shown in FIG. 11, the optical fiber block 3B is formed by cutting a part of the cladding 21A of the optical fiber 21 horizontally to the optical path within a range that does not affect the optical path of the optical fiber 21 to form an opening 44. The second glass block 24 is fixed to the optical fiber 21 in the opening 44 with an optical adhesive A so that a second step L2 approximately equal to the first step L1 of the optical element 2 is formed. FIG. 12 is a schematic cross-sectional view showing an example of a second glass block arrangement process. As shown in FIG. 12, a jig D1 used in forming the second step L2 is prepared. In the second glass block arrangement process, the second glass block 24 is arranged in the opening 44 in a state where the second glass block 24 is abutted against the third end face 41 of the first glass block 22A and the jig D1 is abutted against the fourth end face 42B of the second glass block 24 in the opening 44. Then, the second glass block 24 is disposed in the opening 44, and the second glass block 24 is fixed to the optical fiber 21 in the opening 44. As a result, the optical fiber block 3B has a second step L2 between the third end face 41 and the fourth end face 42B.

[0042] Fig. 13 is a schematic cross-sectional view showing an example of the optical fiber block 3B, and Fig. 14 is an explanatory diagram of the optical fiber block 3B as viewed from the Y direction. In the optical device 1B, the first end face 31 and the third end face 41 are connected by butt coupling using optical adhesive A, with the second end face 32 and the fourth end face 42B being fixed in contact with each other. The end face 13A of the optical waveguide 13 in the optical element 2 and the core end face 21B1 of the optical fiber 21 are optically coupled. Furthermore, the opening 44 of the cut cladding 21A of the optical fiber 21 is filled with optical adhesive A, so that the effect of cutting a part of the cladding 21A on the optical refractive index can be reduced.

[0043] In the embodiment, an example is given of performing cutting processing using a blade B for lapping processing, but this is not limited to a blade, and for example, cutting processing may be performed using a laser or water flow pressure, and can be modified as appropriate.

[0044] Next, an optical transceiver 50 employing the optical device 1 of this embodiment will be described. FIG. 15 is an explanatory diagram showing an example of an optical transceiver employing the optical device of this embodiment. The optical transceiver 50 shown in FIG. 15 has an optical transmitter / receiver 51 and a DSP (Digital Signal Processor) 52. The optical transmitter / receiver 51 has an optical modulator element 54, a driver circuit 55, an optical receiver element 56, and a TIA (Transimpedance Amplifier) ​​57. The DSP 52 controls the entire optical transmitter / receiver 51. The DSP 52 is an electrical component that performs digital signal processing, such as IQ modulation processing of a transmission signal and demodulation processing of a reception signal.

[0045] The DSP 52 executes processing such as encoding of transmission data, generates an electrical signal including the transmission data, and outputs the generated electrical signal to a driver circuit 55. The driver circuit 55 drives an optical modulator element 54 in response to the electrical signal from the DSP 52. The optical modulator element 54 incorporates an optical device 1 that connects an optical waveguide in an optical modulator that optically modulates signal light to an optical fiber.

[0046] The optical receiver element 56 converts the signal light into an electrical signal. The optical receiver element 56 incorporates an optical device 1 that connects an optical waveguide in a photodetector that converts the signal light into an electrical signal to an optical fiber. The TIA 57 amplifies the electrical signal after the electrical conversion, and outputs the amplified electrical signal to the DSP 52. The DSP 52 performs processing such as decoding the electrical signal obtained from the TIA 57 to obtain received data.

[0047] For ease of explanation, the optical transceiver 50 is illustrated as incorporating an optical modulator element 54 and an optical receiver element 56, but the present invention is also applicable to an optical transmitting device incorporating only an optical modulator element 54, or an optical receiving device incorporating only an optical receiver element 56.

[0048] Furthermore, each component of each unit shown in the figure does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each unit is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0049] Furthermore, the various processing functions performed by each device may be executed in whole or in part on a CPU (Central Processing Unit) (or a microcomputer such as an MPU (Micro Processing Unit) or an MCU (Micro Controller Unit)). It goes without saying that the various processing functions may be executed in whole or in part on a program analyzed and executed by a CPU (or a microcomputer such as an MPU or an MCU), or on hardware using wired logic. [Explanation of symbols]

[0050] 1. Optical Devices 2. Optical elements 3 Optical fiber block 13 Optical waveguide 13A End face 21 Optical Fiber 21B1 Core end face 31 First end face 32 Second end face 41 Third end face 42 Fourth end face

Claims

1. an optical element having an optical waveguide, a first end face on which an end face of the optical waveguide is disposed, and a second end face protruding from the first end face; an optical fiber block having an optical fiber, a third end face on which the end face of the optical fiber is disposed, and a fourth end face recessed relative to the third end face; an optical device comprising: a first end face and a third end face connected by butt coupling with each other while the second end face and the fourth end face are fixed in contact with each other; and an optical device comprising: an optical waveguide having an end face that is optically coupled to an end face of the optical fiber;

2. The optical fiber block comprises: The optical device according to claim 1 , wherein an opening is disposed between the third end face and the fourth end face.

3. The optical fiber block comprises: A first glass block and a second glass block different from the first glass block, The fourth end surface is 2. The optical device according to claim 1, wherein the optical device is formed from an end surface of the second glass block.

4. 2. The optical device according to claim 1, wherein a first step between the first end face and the second end face is approximately equal to a second step between the third end face and the fourth end face.

5. an optical modulator element having an optical waveguide, a first end face on which an end face of the optical waveguide is disposed, and a second end face protruding from the first end face; an optical fiber block having an optical fiber, a third end face on which the end face of the optical fiber is disposed, and a fourth end face recessed relative to the third end face; an optical fiber having an end face of the optical waveguide and an end face of the optical fiber, the end face of the optical waveguide being optically coupled to the end face of the optical fiber by connecting the first end face and the third end face by butt coupling while the second end face and the fourth end face are fixed in contact with each other.

6. an optical receiver element having an optical waveguide, a first end face on which an end face of the optical waveguide is disposed, and a second end face protruding from the first end face; an optical fiber block having an optical fiber, a third end face on which the end face of the optical fiber is disposed, and a fourth end face recessed relative to the third end face; an optical receiving device, characterized in that, with the second end face and the fourth end face fixed in contact with each other, the first end face and the third end face are connected by butt coupling, optically coupling the end face of the optical waveguide and the end face of the optical fiber.

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