Waveguide connection structure and photoelectric device structure
By using two curved segments with continuous changes in curvature with opposite curve directions in the waveguide connection structure, a transition structure with gradient width is formed, which solves the problem of light transmission loss caused by sudden changes in the curvature radius in the existing waveguide connection structure, and achieves smaller losses and higher space utilization.
Patent Information
- Application Number
- CN202311235499.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-22
- Publication Date
- 2025-04-01
AI Technical Summary
The existing waveguide connection structure has a sudden change in the radius of curvature when connected, resulting in large optical transmission loss, and the traditional connection structure takes up a large space, reducing space utilization.
Two curved segments with continuous changes in curvature with opposite curve directions are used to form a side profile of the first body of the waveguide connection structure to form a transition structure with a gradient width between the connection end surfaces, so as to achieve the constant change in the transmission direction of the optical path and the transmission width.
It realizes a smaller transmission loss than a traditional connection structure, and uses smaller space under the same loss, or achieves smaller losses under the same space use, improving space utilization.
Smart Images
Figure CN119738916A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor integrated circuit technology, and in particular to a waveguide connection structure and an optoelectronic device structure designed based on a curve with continuously changing curvature. Background Art
[0002] The loss of optical waveguides on optoelectronic integrated chips mainly comes from two aspects: one is the transmission loss caused by the roughness of the waveguide sidewalls, and the other is the transmission loss caused by the curved waveguide.
[0003] There are two main ways to reduce waveguide transmission loss. One is to improve the waveguide processing technology and increase the smoothness of the sidewalls. The other is to use a wider ridge waveguide. For the TE mode, a large part of the mode field is still distributed on the two sidewalls of the waveguide. When using a ridge waveguide, its mode field overlaps less with the waveguide sidewalls, so it is less affected by the sidewalls, which can greatly reduce the transmission loss of the waveguide.
[0004] Strip waveguides and ridge waveguides each have their own advantages. The former can have a relatively small bending radius, while the latter can have a smaller loss. Therefore, in the application process, the narrow strip waveguide and the wide ridge waveguide can be used together. At this time, it is necessary to use a connection structure with a gradually changing width to transitionally connect the strip waveguide and the ridge waveguide. Therefore, optimizing the waveguide connection structure can reduce the connection loss between the two waveguides.
[0005] A coupler is a device that couples silicon photonic chips and optical fibers to each other. Couplers can generally be divided into two types according to the relative positions of the optical fiber and the silicon photonic chip. One is end-face coupling, also known as edge coupling, which means that the optical fiber and the silicon photonic chip are located in the same plane, on the side of the chip, and are coupled through tapered waveguides and other methods. The other is vertical coupling, which is grating coupling. The main advantage of the grating coupler is that its position is relatively flexible and can be located at any position in the chip, so it can be used for wafer-level online testing. In addition, its coupling alignment tolerance is large, which is convenient for packaging. The most difficult part of the coupling process is that the size of the optical mode between the silicon photonic chip and the optical fiber does not match. The optical mode in the silicon photonic chip is about a few hundred nanometers in size, while that in the optical fiber is several microns. Therefore, a width gradient connection structure or a fan-shaped coupler structure is also required between the coupler and the waveguide to connect so that the light energy can be better transferred to the waveguide.
[0006] Curves can be classified into G0, G1, G2, etc. Among them, G0 means point continuity, which means that the surface or curve is point-to-point continuous, the curve has no breakpoints, and there are no cracks at the junction of the surfaces; the mathematical interpretation is: the intersection of the curve or any plane with the surface is continuous everywhere. G1 means tangent continuity, which means that the surface or curve is point-to-point continuous, and all connected line segments and surface patches are tangent to each other; the mathematical interpretation is: the intersection of the curve or any plane with the surface is continuous everywhere, and the first-order derivative is continuous. G2 means curvature continuity, which means that the surface or curve is point-to-point continuous, and its curvature analysis result is a continuous change; the mathematical interpretation is: the intersection of the curve or any plane with the surface is continuous everywhere, and the second-order derivative is continuous. In addition, higher-order derivative continuous curves can be further classified using classification methods such as G3.
[0007] When a straight waveguide is connected to a curved waveguide, there will be a certain loss due to the sudden change of the curvature radius at the connection. This loss can be reduced by designing an Euler bend (a curve with continuously changing curvature), that is, the curvature radius of the curved waveguide is gradually changing (G2 curvature is continuous).
[0008] Traditional waveguide connection structures often adopt linear or quadratic curves, and grating couplers often adopt fan-shaped structures, both of which have sudden changes in curvature, thus causing loss in light transmission. If you want to reduce the transmission loss to an acceptable range, you need to control the change in its bending angle as small as possible, which will inevitably make its structure occupy a larger area and reduce space utilization. Summary of the invention
[0009] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a waveguide connection structure and an optoelectronic device structure.
[0010] To achieve the above object, the technical solution of the present invention is as follows:
[0011] The present invention provides a waveguide connection structure, comprising:
[0012] A first body, the first body comprising a first connecting end face and a second connecting end face which are oppositely arranged, and two opposite first side faces and a second side face which are connected between the same side of the first connecting end face and the second connecting end face, wherein the width of the first connecting end face is greater than the width of the second connecting end face;
[0013] At least one of the first side surface and the second side surface has a curve profile with a continuously changing curvature, and the curve with a continuously changing curvature is composed of at least two curve segments with continuously changing curvatures in opposite bending directions connected by overlapping end points of each.
[0014] Furthermore, the curvatures at two end points of each curve segment with continuously changing curvature are zero.
[0015] Further, both the first side surface and the second side surface have a curve profile with a continuously changing curvature, and the curves with continuously changing curvatures of the first side surface and the second side surface are symmetrical curves.
[0016] Furthermore, the curve with continuously changing curvature is a curve based on Euler bending.
[0017] Furthermore, it also includes: a second body, the second body is composed of a third connecting end face and a fourth connecting end face that are oppositely arranged and have the same width, and two opposite third side faces and a fourth side face connected between the same side of the third connecting end face and the fourth connecting end face to form a closed rectangle; wherein, the second body is stacked with the first body to form a boss structure, the second body is the table portion of the boss structure, the first body is the protrusion of the boss structure located on the surface of the table portion, the width of the third connecting end face is the same as the width of the first connecting end face, and the third connecting end face is coplanar and aligned with the first connecting end face, the width of the fourth connecting end face is greater than the width of the second connecting end face, and the fourth connecting end face is coplanar with the second connecting end face.
[0018] Furthermore, it also includes: a third body, the third body is composed of a fifth connecting end face and a sixth connecting end face that are oppositely arranged and have the same width, and two opposite fifth side faces and a sixth side face connected between the same side of the fifth connecting end face and the sixth connecting end face to form a closed rectangle; wherein the third body is stacked with the first body to form a boss structure, the first body is the table portion of the boss structure, the third body is the protrusion of the boss structure located on the surface of the table portion, the width of the fifth connecting end face is smaller than the width of the first connecting end face, and the fifth connecting end face is coplanar with the first connecting end face, the width of the sixth connecting end face is the same as the width of the second connecting end face, and the sixth connecting end face is coplanar with and aligned with the second connecting end face.
[0019] The present invention also provides an optoelectronic device structure, comprising a grating coupler and a first strip waveguide, and the above-mentioned waveguide connection structure comprising a first body, wherein the waveguide connection structure is used to connect the grating coupler with the first strip waveguide, the grating coupler has a first end face, the first strip waveguide has a second end face, the waveguide connection structure is seamlessly connected to the first end face through the first connection end face, and the waveguide connection structure is also seamlessly connected to the second end face through the second connection end face.
[0020] The present invention also provides an optoelectronic device structure, comprising a first strip waveguide and a ridge waveguide, and the above-mentioned waveguide connection structure comprising a first body and a second body, wherein the waveguide connection structure is used to connect the first strip waveguide with the ridge waveguide, the first strip waveguide has a third end face, and the ridge waveguide has a fourth end face, the waveguide connection structure is seamlessly connected to the third end face of the first strip waveguide through the first connection end face and the third connection end face that are coplanar and aligned, and the waveguide connection structure is also seamlessly connected to the fourth end face of the ridge waveguide through the second connection end face and the fourth connection end face that are coplanar.
[0021] The present invention also provides an optoelectronic device structure, comprising a ridge waveguide and a second strip waveguide, and the above-mentioned waveguide connection structure comprising a first body and a third body, wherein the waveguide connection structure is used to connect the ridge waveguide with the second strip waveguide, the ridge waveguide has a fifth end face, and the second strip waveguide has a sixth end face, and the waveguide connection structure is seamlessly connected to the fifth end face through the coplanar fifth connection end face and the first connection end face, and the waveguide connection structure is also seamlessly connected to the sixth end face through the coplanar and aligned sixth connection end face and the second connection end face.
[0022] The present invention also provides an optoelectronic device structure, comprising a grating coupler, a first strip waveguide, a ridge waveguide and a second strip waveguide arranged in sequence, and the above-mentioned waveguide connection structure including the first body, which serves as the first waveguide connection structure, the above-mentioned waveguide connection structure including the first body and the second body, which serves as the second waveguide connection structure, and the above-mentioned waveguide connection structure including the first body and the third body, which serves as the third waveguide connection structure; wherein the first waveguide connection structure is used to connect the grating coupler with the first strip waveguide, the grating coupler has a first end face, the first strip waveguide has a second end face, the first waveguide connection structure is seamlessly connected with the first end face through the first connection end face provided therein, and the first waveguide connection structure is also seamlessly connected with the second end face through the second connection end face provided therein; the second waveguide connection structure is used to connect the first strip waveguide with the ridge waveguide, The first strip waveguide also has a third end face opposite to the second end face, the ridge waveguide has a fourth end face, the second waveguide connection structure is seamlessly connected to the third end face of the first strip waveguide through the first connection end face and the third connection end face that are coplanar and aligned, and the second waveguide connection structure is also seamlessly connected to the fourth end face of the ridge waveguide through the second connection end face and the fourth connection end face that are coplanar; the third waveguide connection structure is used to connect the ridge waveguide with the second strip waveguide, the ridge waveguide also has a fifth end face opposite to the fourth end face, the second strip waveguide has a sixth end face, the third waveguide connection structure is seamlessly connected to the fifth end face through the coplanar fifth connection end face and the first connection end face that are coplanar, and the third waveguide connection structure is also seamlessly connected to the sixth end face through the sixth connection end face and the second connection end face that are coplanar and aligned.
[0023] It can be seen from the above technical solution that the present invention forms the side profile of the first body of the waveguide connection structure by using two curved segments with continuously changing curvatures in opposite bending directions, so as to form a transition structure with a gradually changing width between the first connection end face and the second connection end face of the first body, so as to achieve the effect of changing the transmission width while keeping the transmission direction of the optical path unchanged, thereby achieving a smaller transmission loss than the traditional connection structure. The waveguide connection structure of the present invention can be applied to all scenarios where the waveguide width needs to be changed, and can achieve the use of a smaller space under the same loss, or achieve a smaller loss under the use of the same space. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1-Figure 2 The figure is a schematic diagram of the planar structure of a waveguide connection structure according to a preferred embodiment of the present invention.
[0025] Figure 3 The figure is a schematic diagram of a photoelectric device structure according to a preferred embodiment of the present invention.
[0026] Figure 4-Figure 5 The figure is a schematic diagram of a partially enlarged structure of a photoelectric device structure according to a preferred embodiment of the present invention.
[0027] Figure 6-Figure 7 This is a curvature comb image of a curve with continuously changing curvature on the side surface of a waveguide connection structure according to a preferred embodiment of the present invention. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.
[0029] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.
[0030] refer to Figure 1 The present invention provides three waveguide connection structures. Figure 1 The waveguide connection structure shown is defined as a first waveguide connection structure 1. A first waveguide connection structure 1 of the present invention adopts a structure with a gradually changing width along the optical path transmission direction, and is used to perform a transitional connection with gradually changing sizes of waveguides with different widths, so as to utilize the first waveguide connection structure 1 to reduce the transmission loss along the optical path transmission direction.
[0031] For example, the first waveguide connection structure 1 of the present invention can be used to seamlessly connect a wider grating coupler 4 with a narrower first strip waveguide 5 .
[0032] The first waveguide connection structure 1 includes a solid first body 11. The first body 11 includes two first connection end faces 111 and a second connection end face 112 with different widths arranged in parallel along the optical path transmission direction, and a first side face 113 connected between the upper sides of the first connection end face 111 and the second connection end face 112 as shown in the figure, and a second side face 114 connected between the lower sides of the first connection end face 111 and the second connection end face 112 as shown in the figure. That is, the first body 11 is composed of the first connection end face 111 and the second connection end face 112 arranged opposite to each other, and two opposite first side faces 113 and second side faces 114 connected between the same sides of the first connection end face 111 and the second connection end face 112.
[0033] The width of the first connection end face 111 is greater than the width of the second connection end face 112. The first connection end face 111 is used to seamlessly connect with, for example, the first end face 41 of the grating coupler 4 with a wider width (that is, the two connected end faces completely overlap, the same below), and the second connection end face 112 is used to seamlessly connect with, for example, the second end face 51 of the first strip waveguide 5 with a narrower width.
[0034] At least one of the first side surface 113 and the second side surface 114 has a curve profile with a continuously changing curvature; and the curve with a continuously changing curvature is composed of at least two curve segments with continuously changing curvatures in opposite bending directions connected by overlapping endpoints.
[0035] In some embodiments, the first side surface 113 and the second side surface 114 both have a curve profile with a continuously changing curvature, and the curves with a continuously changing curvature of the first side surface 113 and the second side surface 114 are symmetrical curves. For example, the curves with a continuously changing curvature of the first side surface 113 and the second side surface 114 are both composed of two first curve segments 115 and second curve segments 116 with continuously changing curvatures in opposite bending directions; wherein the first curve segment 115 has a first endpoint 1151 and a second endpoint 1152, and the second curve segment 116 has a third endpoint 1161 and a fourth endpoint 1162 (the four endpoints are represented by short line segments to highlight the display), and the first curve segment 115 is connected to the third endpoint 1161 of the second curve segment 116 through the second endpoint 1152 in an overlapping manner, so that the first curve segment 115 and the second curve segment 116 form a curve with a continuously changing curvature, and form the first side surface 113 and the second side surface 114 of the first waveguide connection structure 1. When the first connecting end face 111 is seamlessly connected to the first end face 41 of the grating coupler 4, the first endpoint 1151 of the first curved segment 115 is connected to the side endpoint of the grating coupler 4 at the first end face 41 in an overlapping manner; when the second connecting end face 112 is seamlessly connected to the second end face 51 of the first strip waveguide 5, the fourth endpoint 1162 of the second curved segment 116 is connected to the side endpoint of the first strip waveguide 5 at the second end face 51 in an overlapping manner.
[0036] In some embodiments, the curve with continuously changing curvature is a curve based on Euler bend.
[0037] Furthermore, on the first side surface 113 and the second side surface 114, the curvatures at the two endpoints of each curve segment with continuously changing curvature are zero. That is, the curvatures at the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115 are zero, and the curvatures at the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 are zero, so as to realize the interconnection mode with continuously changing curvature and minimize the transmission loss caused by width change.
[0038] refer to Figure 6 , which shows an image of a curvature comb 117 of a curve with continuously changing curvatures of the first side surface 113 and the second side surface 114 of the first waveguide connection structure 1. It can be seen that the heights of the curvature comb 117 at the two endpoints of each curve segment with continuously changing curvature, i.e., the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115, and the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 are all zero, which indicates that the curvatures at the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115 are zero, and the curvatures at the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 are zero. Thus, seamless connections with consistent curvature are formed between the first endpoint 1151 of the first curved segment 115 and the side endpoint at the first end surface 41 of the grating coupler 4, between the fourth endpoint 1162 of the second curved segment 116 and the side endpoint at the second end surface 51 of the first strip waveguide 5, and between the second endpoint 1152 of the first curved segment 115 and the third endpoint 1161 of the second curved segment 116.
[0039] It should be noted that when the first waveguide connecting structure 1 is used to connect the grating coupler 4 and the first strip waveguide 5, it is necessary to gradually transition the grating bars 42 on the grating coupler 4 to the second end face 51 of the first strip waveguide 5 with the help of the surface of the first body 11, so that the light entering the grating coupler 4 can be further transmitted to the first strip waveguide 5 through the diffraction effect of the grating bars 42.
[0040] refer to Figure 2 , which shows a second waveguide connection structure 2 of the present invention that is evolved based on the above-mentioned first body 11. Figure 2As shown, the second waveguide connection structure 2 includes, in addition to the first body 11 having the above structure, a second body 21. The second body 21 includes a third connection end face 211 and a fourth connection end face 212 which are arranged opposite to each other and have the same width, and two opposite third side faces 213 and a fourth side face 214 connected between the same side of the third connection end face 211 and the fourth connection end face 212; that is, the second body 21 is formed by the third connection end face 211 and the fourth connection end face 212, and the third side face 213 and the fourth side face 214 are closed and connected to form a rectangular second body 21.
[0041] refer to Figure 4 , which shows the cross-sectional morphology of the boss of the second waveguide connection structure 2 at section A (the black part in the figure). The second body 21 and the first body 11 are stacked to form a boss structure, the second body 21 is the table portion of the boss structure, and the first body 11 is the protruding portion of the boss structure located on the surface of the table portion. Figure 2 It can be seen that the width of the third connection end face 211 of the second body 21 is the same as the width of the first connection end face 111 of the first body 11, and the third connection end face 211 is coplanar and aligned with the first connection end face 111, forming a rectangular combined end face of the third connection end face 211 and the first connection end face 111 with the same width, coplanar and aligned in the width direction); the width of the fourth connection end face 212 of the second body 21 is greater than the width of the second connection end face 112 of the first body 11, and the fourth connection end face 212 is coplanar with the second connection end face 112 to form a boss shape (reference Figure 4 The cross-sectional shape of the black boss at the end of the dotted arrow on the left of the figure; this boss shape will extend along the dotted arrow to the fourth connecting end face 212 and the second connecting end face 112 cut off by the section A, forming a boss-shaped combined end face of the fourth connecting end face 212 and the second connecting end face 112).
[0042] refer to Figure 5 The second waveguide connection structure 2 can be used to seamlessly connect the first strip waveguide 5 and the ridge waveguide 6 having a narrow ridge portion 62. The first strip waveguide 5 has a third end face 52 opposite to the second end face 51, and the ridge waveguide 6 has a fourth end face 63 opposite to the third end face 52 of the first strip waveguide 5 (see Figure 2); the second waveguide connection structure 2 is seamlessly connected to the third end face 52 of the first strip waveguide 5 through the coplanar and aligned first connection end face 111 and the third connection end face 211, and at the same time, the second waveguide connection structure 2 is seamlessly connected to the fourth end face 63 of the ridge waveguide 6 through the coplanar second connection end face 112 and the fourth connection end face 212. It should be noted that the ridge waveguide 6 has a narrow ridge portion 62 and a wide flat portion 61; the fourth end face 63 of the ridge waveguide 6 is formed by the end faces of the ridge portion 62 and the flat portion 61 located at the end face. The width of the ridge portion 62 is the same as the width of the second connection end face 112 of the first body 11, and a seamless connection is achieved; the width of the flat portion 61 is the same as the width of the second body 21, and a seamless connection is achieved.
[0043] refer to Figure 7 , which shows the curvature comb image of the curve with continuously changing curvature of the first side surface 113 and the second side surface 114 of the first body 11 of the second waveguide connection structure 2. It can be seen that the heights of the curvature comb at the two endpoints of each curve segment with continuously changing curvature, i.e., the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115, and the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 are all zero, which means that the curvature at the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115 is zero, and the curvature at the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 is zero. When the first connection end face 111 of the first body 11 is seamlessly connected to the third end face 52 of the first strip waveguide 5, the first endpoint 1151 of the first curve segment 115 is connected to the side endpoint at the third end face 52 in a coincident manner; when the second connection end face 112 is seamlessly connected to the end face (fourth end face 63) of the ridge portion 62 of the ridge waveguide 6, the fourth endpoint 1162 of the second curve segment 116 is connected to the side endpoint of the ridge portion 62 at the fourth end face 63 in a coincident manner. By utilizing the feature that the flat plate portion 61 of the ridge waveguide 6 and the first strip waveguide 5 have the same width, seamless connection can be successfully achieved through the second body 21 having the same width.
[0044] refer to Figure 2 , which shows a third waveguide connection structure 3 of the present invention evolved from the above-mentioned first body 11. Figure 2As shown, the third waveguide connection structure 3 includes, in addition to the first body 11 having the above structure, a third body 31. The third body 31 includes a fifth connection end face 311 and a sixth connection end face 312 which are arranged opposite to each other and have the same width, and two opposite fifth side faces 313 and sixth side faces 314 connected between the same side of the fifth connection end face 311 and the sixth connection end face 312; that is, the third body 31 is closed by the fifth connection end face 311 and the sixth connection end face 312, and the fifth side faces 313 and the sixth side faces 314 to form a rectangular third body 31.
[0045] refer to Figure 5 , which shows the convex cross-sectional morphology of the third waveguide connection structure 3 at section B. The third body 31 and the first body 11 are stacked to form a convex structure, the first body 11 is the table portion of the convex structure, and the third body 31 is the protruding portion of the convex structure located on the surface of the table portion. Figure 2 It can be seen that the width of the fifth connection end surface 311 of the third body 31 is smaller than the width of the first connection end surface 111 of the first body 11, and the fifth connection end surface 311 and the first connection end surface 111 are coplanar to form a boss shape (refer to Figure 5 The black boss cross-sectional shape shown at section B; this boss shape extends rightward to the fifth connection end face 311 and the first connection end face 111, forming a boss-shaped combined end face of the fifth connection end face 311 and the first connection end face 111); the width of the sixth connection end face 312 of the third body 31 is the same as the width of the second connection end face 112 of the first body 11, and the sixth connection end face 312 is coplanar and aligned with the second connection end face 112 (reference Figure 5 In the direction indicated by the dotted arrow on the left side of the figure; here the boss shape will extend along the dotted arrow to the sixth connecting end face 312 and the second connecting end face 112 cut off by section B, forming a rectangular combined end face of the sixth connecting end face 312 and the second connecting end face 112 with the same width, coplanar and aligned in the width direction).
[0046] refer to Figure 3. The third waveguide connection structure 3 can be used to seamlessly connect the above-mentioned ridge waveguide 6 with the second strip waveguide 7 with a narrower width. Among them, the width of the second strip waveguide 7 is the same as the width of the ridge portion 62 of the ridge waveguide 6; the ridge waveguide 6 has a fifth end face 64 opposite to the fourth end face 63, and the second strip waveguide 7 has a sixth end face 71 opposite to the fifth end face 64 of the ridge waveguide 6; the third waveguide connection structure 3 seamlessly connects with the fifth end face 64 of the ridge waveguide 6 through the coplanar first connection end face 111 and the fifth connection end face 311, and at the same time, the third waveguide connection structure 3 seamlessly connects with the sixth end face 71 of the second strip waveguide 7 through the coplanar and aligned second connection end face 112 and the sixth connection end face 312. It should be noted that the ridge waveguide 6 has a narrow ridge portion 62 and a wide flat plate portion 61; the fifth end face 64 of the ridge waveguide 6 is formed by the end faces of the ridge portion 62 and the flat plate portion 61 located at the end face. The width of the ridge 62 is the same as the width of the third body 31 and the second strip waveguide 7, thereby achieving a seamless connection between the three; the width of the flat plate portion 61 of the ridge waveguide 6 is the same as the width of the first connecting end surface 111 of the first body 11, and the width of the second connecting end surface 112 of the first body 11 is the same as the width of the second strip waveguide 7, thereby achieving a seamless connection between the three.
[0047] refer to Figure 7 , which shows the curvature comb image of the curve with continuously changing curvature of the first side surface 113 and the second side surface 114 of the first body 11 of the third waveguide connection structure 3. It can be seen that the heights of the curvature comb at the two endpoints of each curve segment with continuously changing curvature, i.e., the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115, and the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 are all zero, which means that the curvature at the first endpoint 1151 and the second endpoint 1152 of the first curve segment 115 is zero, and the curvature at the third endpoint 1161 and the fourth endpoint 1162 of the second curve segment 116 is zero. When the first connection end face 111 of the first body 11 is seamlessly connected to the fifth end face 64 of the ridge waveguide 6, the first endpoint 1151 of the first curve segment 115 is connected to the side endpoint of the flat plate portion 61 of the ridge waveguide 6 at the fifth end face 64 in a coincident manner; when the second connection end face 112 of the first body 11 is seamlessly connected to the sixth end face 71 of the second strip waveguide 7, the fourth endpoint 1162 of the second curve segment 116 is connected to the side endpoint of the second strip waveguide 7 at the sixth end face 71 in a coincident manner. By utilizing the feature that the ridge portion 62 of the ridge waveguide 6 and the second strip waveguide 7 have the same width, seamless connection can be successfully achieved through the third body 31 having the same width.
[0048] refer to Figure 1 , Figure 3-Figure 4. In some embodiments, an optoelectronic device structure of the present invention includes a grating coupler 4 and a first strip waveguide 5, and the above-mentioned first waveguide connection structure 1 including the first body 11. The first waveguide connection structure 1 is used to connect the grating coupler 4 with a wider width to the first strip waveguide 5 with a narrower width. Among them, the grating coupler 4 has a first end face 41, and the first strip waveguide 5 has a second end face 51; the first waveguide connection structure 1 seamlessly connects with the first end face 41 of the grating coupler 4 with the same width through the first connection end face 111 of the first body 11, and at the same time, the first waveguide connection structure 1 seamlessly connects with the second end face 51 of the first strip waveguide 5 with the same width through the second connection end face 112 of the first body 11. In this way, the width of the grating coupler 4 can be increased, so that the widest part of the grating coupler 4 can be adapted to the size of the optical fiber spot, and alignment with a larger area of the optical fiber spot can be achieved, thereby improving the coupling efficiency; at the same time, by utilizing the curved profile (side) with a continuously changing curvature of the first waveguide connection structure 1, the optical path transmission direction remains unchanged, while the transmission width can be changed to achieve gradual thinning (or gradual widening), and the curvature of the side surface is continuously and gradually changing during the entire transmission process, thereby achieving the purpose of minimizing transmission loss. Compared with the traditional fan-shaped grating coupler, the loss of the first waveguide connection structure 1 of the present invention during the transition from the grating coupler 4 to the strip waveguide will be smaller.
[0049] refer to Figure 2 , Figure 4-Figure 5In some embodiments, an optoelectronic device structure of the present invention includes a first strip waveguide 5 and a ridge waveguide 6, and the above-mentioned second waveguide connection structure 2 including the first body 11 and the second body 21. The second waveguide connection structure 2 is used to connect the first strip waveguide 5 with a wider width to the ridge waveguide 6 with a narrower width ridge 62. Among them, the first strip waveguide 5 has a third end face 52 opposite to the second end face 51, and the ridge waveguide 6 has a fourth end face 63; the second waveguide connection structure 2 seamlessly connects with the third end face 52 with the same width of the first strip waveguide 5 through the coplanar and aligned first connection end faces 111 and the third connection end faces 211 of the first body 11 and the second body 21, and at the same time, the second waveguide connection structure 2 also seamlessly connects with the fourth end face 63 (the end faces of the ridge 62 and the flat plate portion 61 on the fourth end face 63) of the ridge waveguide 6 through the coplanar second connection end faces 112 and the fourth connection end faces 212 of the first body 11 and the second body 21. The ridge waveguide 6 can usually be used as an electro-optic modulator structure, with both sides connected to the P / N poles, and the two wings can be used as carrier transmission channels. By utilizing the curve profile with continuously changing curvature of the second waveguide connection structure 2, seamless connection can be achieved between the first strip waveguide 5 with a wider width and the narrow ridge 62 and the wider flat plate 61 of the ridge waveguide 6, and then the light path is continued to be transmitted, thereby achieving the purpose of minimizing transmission loss. Compared with the traditional connection method using linear / quadratic curve / arc structures, the transmission / coupling loss of the second waveguide connection structure 2 using Euler bend (Euler bend with continuous curvature gradient) of the present invention is smaller.
[0050] refer to Figure 2-Figure 3 and Figure 5In some embodiments, an optoelectronic device structure of the present invention includes a ridge waveguide 6 and a second strip waveguide 7, and the third waveguide connection structure 3 including the first body 11 and the third body 31. The third waveguide connection structure 3 is used to connect the wider flat plate portion 61 and the narrower ridge portion 62 of the ridge waveguide 6 to the second strip waveguide 7. Among them, the second strip waveguide 7 has the same width as the ridge 62; the ridge waveguide 6 has a fifth end face 64 opposite to the fourth end face 63, and the second strip waveguide 7 has a sixth end face 71 opposite to the fifth end face 64; the third waveguide connection structure 3 is seamlessly connected to the fifth end face 64 (the end faces of the ridge 62 and the flat plate portion 61 on the fifth end face 64) of the ridge waveguide 6 through the coplanar first body 11 and the first connecting end face 111 and the fifth connecting end face 311 of the third body 31. At the same time, the third waveguide connection structure 3 is also seamlessly connected to the sixth end face 71 with the same width of the second strip waveguide 7 through the coplanar and aligned second connecting end faces 112 and the sixth connecting end faces 312 of the first body 11 and the third body 31. By utilizing the curve profile with continuously changing curvature of the third waveguide connection structure 3, seamless connection can be simultaneously achieved between the second strip waveguide 7 with a narrower width and the narrower ridge portion 62 and the wider flat plate portion 61 of the ridge waveguide 6, thereby continuing the light path, thereby achieving the purpose of minimizing transmission loss. Compared with the conventional connection method using linear / quadratic curve / arc structures, the transmission / coupling loss of the third waveguide connection structure 3 using Euler bend in the present invention is smaller.
[0051] refer to Figure 3 In some embodiments, an optoelectronic device structure of the present invention includes the above-mentioned grating coupler 4, the first strip waveguide 5, the ridge waveguide 6 and the second strip waveguide 7 arranged in sequence, and the above-mentioned first waveguide connection structure 1 including the first body 11, the above-mentioned second waveguide connection structure 2 including the first body 11 and the second body 21, and the above-mentioned third waveguide connection structure 3 including the first body 11 and the third body 31.
[0052] The first waveguide connection structure 1 is used to connect the grating coupler 4 to the first strip waveguide 5 in the transmission direction of the optical path. The grating coupler 4 has a first end face 41, and the first strip waveguide 5 has a second end face 51; the first waveguide connection structure 1 seamlessly connects with the first end face 41 of the same width as the grating coupler 4 through the first connection end face 111 provided on the first body 11 thereof, and at the same time, the first waveguide connection structure 1 also seamlessly connects with the second end face 51 of the same width as the first strip waveguide 5 through the second connection end face 112 provided on the first body 11 thereof.
[0053] The second waveguide connection structure 2 is used to further connect the first strip waveguide 5 with the ridge waveguide 6 in the optical transmission direction. The first strip waveguide 5 has a third end face 52 opposite to the second end face 51, and the ridge waveguide 6 has a fourth end face 63; the second waveguide connection structure 2 seamlessly connects with the third end face 52 of the same width of the first strip waveguide 5 through the first connection end face 111 and the third connection end face 211 coplanar and aligned with the first body 11 and the second body 21, and at the same time, the second waveguide connection structure 2 also seamlessly connects with the equal width end faces of the ridge portion 62 and the flat plate portion 61 at the fourth end face 63 of the ridge waveguide 6 through the second connection end face 112 and the fourth connection end face 212 coplanar with the first body 11 and the second body 21.
[0054] The third waveguide connection structure 3 is used to further connect the ridge waveguide 6 with the second strip waveguide 7 in the optical path transmission direction. The ridge waveguide 6 also has a fifth end face 64 opposite to the fourth end face 63, and the second strip waveguide 7 has a sixth end face 71; the third waveguide connection structure 3 seamlessly connects with the equal-width end faces of the ridge portion 62 and the flat plate portion 61 at the fifth end face 64 of the ridge waveguide 6 through the coplanar first connection end face 111 and the fifth connection end face 311 provided by the first body 11 and the third body 31, and at the same time, the third waveguide connection structure 3 also seamlessly connects with the equal-width sixth end face 71 of the second strip waveguide 7 through the coplanar and aligned second connection end faces 112 and the sixth connection end face 312 provided by the first body 11 and the third body 31.
[0055] In fact, the above-mentioned waveguide connection structure with continuous curvature gradient (the first waveguide connection structure 1 to the third waveguide connection structure 3) of the present invention can be used for the conversion of strip waveguides of all widths to ridge waveguides, or the conversion of ridge waveguides of all widths to strip waveguides (also including the conversion of grating couplers of all widths to strip waveguides), as well as any position on the device where the waveguide width needs to be changed, and can replace traditional connection structures in the form of linear / quadratic curves / arcs, etc.
[0056] In summary, the present invention forms the side profile of the first body 11 of the waveguide connection structure by using two curved segments with continuously changing curvatures in opposite bending directions, so as to form a transition structure with a gradually changing width between the first connection end face 111 and the second connection end face 112 of the first body 11, so as to achieve the effect of lower transmission loss than the traditional connection structure while the transmission direction of the optical path remains unchanged and the transmission width changes. Further, by stacking a second body 21 with the same width as the flat plate portion 61 of the ridge waveguide 6 and the first strip waveguide 5 on the first body 11, or a third body 31 with the same width as the ridge portion 62 of the ridge waveguide 6 and the second strip waveguide 7, it is possible to adapt to different connection forms between the ridge waveguide 6 and the strip waveguides at both ends, so as to achieve the transmission requirements of gradually thinning or gradually widening along the transmission direction of the optical path. The above-mentioned waveguide connection structure of the present invention is applicable to all scenarios where the waveguide width needs to be changed, and can achieve the use of a smaller space under the same loss to improve the space utilization, or achieve a smaller loss under the same space use.
[0057] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A waveguide connection structure, characterized in that: include: A first body, the first body comprising a first connecting end face and a second connecting end face which are oppositely arranged, and two opposite first side faces and a second side face which are connected between the same side of the first connecting end face and the second connecting end face, wherein the width of the first connecting end face is greater than the width of the second connecting end face; At least one of the first side surface and the second side surface has a curve profile with a continuously changing curvature, and the curve with a continuously changing curvature is composed of at least two curve segments with continuously changing curvatures in opposite bending directions connected by overlapping end points of each.
2. The waveguide connection structure according to claim 1, characterized in that: The curvatures at two end points of each curve segment with continuously changing curvature are zero.
3. The waveguide connection structure according to claim 1, characterized in that: The first side surface and the second side surface both have a curved profile with a continuously changing curvature, and the curves with continuously changing curvatures of the first side surface and the second side surface are symmetrical curves.
4. The waveguide connection structure according to claim 1, characterized in that: The curve with continuously changing curvature is a curve based on Euler bending.
5. The waveguide connection structure according to any one of claims 1 to 4, characterized in that: Also includes: A second body, the second body is composed of a third connecting end face and a fourth connecting end face that are oppositely arranged and have the same width, and two opposite third side faces and a fourth side face connected between the same side of the third connecting end face and the fourth connecting end face to form a closed rectangle; wherein, the second body is stacked with the first body to form a boss structure, the second body is the table portion of the boss structure, the first body is the protrusion of the boss structure located on the surface of the table portion, the width of the third connecting end face is the same as the width of the first connecting end face, and the third connecting end face is coplanar and aligned with the first connecting end face, the width of the fourth connecting end face is greater than the width of the second connecting end face, and the fourth connecting end face is coplanar with the second connecting end face.
6. The waveguide connection structure according to any one of claims 1 to 4, characterized in that: Also includes: A third body, wherein the third body is composed of a fifth connecting end face and a sixth connecting end face that are oppositely arranged and have the same width, and two opposite fifth side faces and a sixth side face connected between the same sides of the fifth connecting end face and the sixth connecting end face to form a closed rectangle; wherein the third body is stacked with the first body to form a boss structure, the first body is the table portion of the boss structure, the third body is the protrusion of the boss structure located on the surface of the table portion, the width of the fifth connecting end face is smaller than the width of the first connecting end face, and the fifth connecting end face is coplanar with the first connecting end face, the width of the sixth connecting end face is the same as the width of the second connecting end face, and the sixth connecting end face is coplanar with and aligned with the second connecting end face.
7. A photoelectric device structure, characterized in that: It comprises a grating coupler and a first strip waveguide, and a waveguide connection structure according to any one of claims 1 to 4, wherein the waveguide connection structure is used to connect the grating coupler with the first strip waveguide, the grating coupler has a first end face, the first strip waveguide has a second end face, the waveguide connection structure is seamlessly connected to the first end face through the first connection end face, and the waveguide connection structure is also seamlessly connected to the second end face through the second connection end face.
8. A photoelectric device structure, characterized in that: The invention comprises a first strip waveguide and a ridge waveguide, and a waveguide connection structure according to claim 5, wherein the waveguide connection structure is used to connect the first strip waveguide with the ridge waveguide, the first strip waveguide has a third end face, the ridge waveguide has a fourth end face, the waveguide connection structure is seamlessly connected with the third end face of the first strip waveguide through the first connection end face and the third connection end face that are coplanar and aligned, and the waveguide connection structure is also seamlessly connected with the fourth end face of the ridge waveguide through the second connection end face and the fourth connection end face that are coplanar.
9. A photoelectric device structure, characterized in that: The invention comprises a ridge waveguide and a second strip waveguide, and a waveguide connection structure according to claim 6, wherein the waveguide connection structure is used to connect the ridge waveguide with the second strip waveguide, the ridge waveguide has a fifth end face, the second strip waveguide has a sixth end face, the waveguide connection structure is seamlessly connected with the fifth end face through the coplanar fifth connection end face and the first connection end face, and the waveguide connection structure is also seamlessly connected with the sixth end face through the coplanar and aligned sixth connection end face and the second connection end face.
10. A photoelectric device structure, characterized in that: The invention comprises a grating coupler, a first strip waveguide, a ridge waveguide and a second strip waveguide arranged in sequence, and a waveguide connection structure according to any one of claims 1 to 4, which is used as a first waveguide connection structure, a waveguide connection structure according to claim 5, which is used as a second waveguide connection structure, and a waveguide connection structure according to claim 6, which is used as a third waveguide connection structure; wherein the first waveguide connection structure is used to connect the grating coupler with the first strip waveguide, the grating coupler has a first end face, the first strip waveguide has a second end face, the first waveguide connection structure is seamlessly connected with the first end face through the first connection end face provided therein, and the first waveguide connection structure is also seamlessly connected with the second end face through the second connection end face provided therein; the second waveguide connection structure is used to connect the first strip waveguide with the ridge waveguide, and the first strip waveguide is also The ridge waveguide has a third end face opposite to the second end face, the ridge waveguide has a fourth end face, the second waveguide connection structure is seamlessly connected to the third end face of the first strip waveguide through the first connection end face and the third connection end face that are coplanar and aligned, and the second waveguide connection structure is also seamlessly connected to the fourth end face of the ridge waveguide through the second connection end face and the fourth connection end face that are coplanar; the third waveguide connection structure is used to connect the ridge waveguide with the second strip waveguide, the ridge waveguide also has a fifth end face opposite to the fourth end face, the second strip waveguide has a sixth end face, the third waveguide connection structure is seamlessly connected to the fifth end face through the coplanar fifth connection end face and the first connection end face that are coplanar, and the third waveguide connection structure is also seamlessly connected to the sixth end face through the sixth connection end face and the second connection end face that are coplanar and aligned.