Photon chip end face coupling device, manufacturing method thereof and photon chip packaging structure

Abstract

The invention discloses a photon chip end face coupling device, a manufacturing method thereof and a photon chip packaging structure. The photon chip end face coupling device comprises a photon chip and an optical fiber. The photonic chip comprises a substrate and a waveguide structure, the waveguide structure comprises a waveguide core layer and a waveguide cladding layer and is provided with a first end face exposing the waveguide core layer and the waveguide cladding layer, and the waveguide core layer extends to the first end face from an area close to an inner area of the photonic chip in the direction parallel to the main surface of the substrate. The first end face inclines towards the internal area of the photon chip along with being far away from the substrate, and a first included angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; the optical fiber is located on one side of the photonic chip in the direction parallel to the main surface of the substrate and coupled with the waveguide structure, the optical fiber is provided with a second end face, faces the first end face of the waveguide structure and is also inclined towards the inner area of the photonic chip, a second included angle is formed between the second end face and the reference plane, and the first included angle and the second included angle are acute angles.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a photonic chip end face coupling device and a manufacturing method thereof, and a photonic chip packaging structure. Background Art

[0002] Photonic integrated chips (abbreviated as photonic chips or optical chips) have the advantages of high integration and low cost, and are gradually being developed and widely used. Photonic chips can connect to external optical paths by coupling with the end face of an optical fiber (for example, a single-mode fiber). However, when coupling the optical waveguide in the photonic chip with the end face of an optical fiber (for example, a single-mode fiber), coupling losses may occur, affecting the fiber coupling efficiency. Improving the fiber coupling efficiency of photonic chips is a key research topic in this field. Summary of the Invention

[0003] According to at least one embodiment of the present disclosure, a photonic chip end-face coupling device is provided, comprising: a photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and having a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from a region close to an inner region of the photonic chip to the first end face in a direction parallel to a main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip as it moves away from the substrate, and a first angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; and an optical fiber located on one side of the photonic chip in a direction parallel to the main surface of the substrate and coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and also inclined toward the inner region of the photonic chip, a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles.

[0004] According to at least one embodiment of the present disclosure, a photonic chip packaging structure is provided, including the above-mentioned photonic chip end face coupling device.

[0005] According to at least one embodiment of the present disclosure, a method for manufacturing a photonic chip end-face coupling device is provided, comprising: providing a photonic chip, the photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and forming a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from a region adjacent to an inner region of the photonic chip to the first end face in a direction parallel to a main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip, and a first angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; and coupling an optical fiber to the photonic chip, wherein the optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and also inclined toward the inner region of the photonic chip, a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The above and other features, advantages, and aspects of the various embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the originals and elements are not necessarily drawn to scale.

[0007] Figure 1 A schematic cross-sectional view showing a coupling device between a photonic chip and an optical fiber.

[0008] Figure 2 A schematic plan view showing a coupling device between a photonic chip and an optical fiber.

[0009] Figure 3 A schematic plan view illustrating a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown.

[0010] Figure 4A A schematic cross-sectional view illustrating a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown.

[0011] Figure 4B Another schematic cross-sectional view of a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown.

[0012] Figure 5 A schematic diagram of the optical path for coupling optical signals of a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown.

[0013] Figure 6 A schematic plan view illustrating a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown.

[0014] Figure 7A Schematic plan views of photonic chip end-face coupling devices according to other embodiments of the present disclosure are shown.

[0015] Figure 7B Schematic cross-sectional views showing photonic chip end-face coupling devices according to other embodiments of the present disclosure.

[0016] Figure 8 Schematic cross-sectional views of photonic chip end-face coupling devices according to further embodiments of the present disclosure are shown.

[0017] Figure 9A Show Figure 8 A schematic plan view of the first waveguide sub-core layer in the photonic chip end-face coupling device shown; Figure 9B Show Figure 8 A schematic plan view of the second waveguide sub-core layer in the photonic chip end-face coupling device shown; Figure 9C Show Figure 8 The schematic top view of the first waveguide sub-core layer and the second waveguide sub-core layer in the photonic chip end-face coupling device is shown.

[0018] Figure 10 A schematic block diagram showing a photonic chip packaging structure according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0019] The following describes embodiments of the present disclosure in more detail with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of protection of the present disclosure.

[0020] It should be understood that the various steps described in the method embodiments of the present disclosure may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0021] It should be noted that the modifications of "one" and "multiple" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more".

[0022] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words 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, that is, "including but not limited to". "Based on" means "at least partially based on". "Connected" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0023] In a photonic chip (e.g., a silicon-based photonic integrated chip), optical signals can be transmitted through an optical waveguide; the photonic chip and the end face of the optical fiber are coupled to each other to transmit the optical signal in the optical waveguide to the optical fiber. However, due to the large difference in the end face dimensions of the optical waveguide and the optical fiber (e.g., a single-mode optical fiber), there is a mismatch between the two, resulting in mismatch loss during coupling. In some examples, a pattern spot conversion device can be used to expand the pattern spot of the optical signal in the optical waveguide, thereby reducing the mismatch loss. The pattern spot conversion device, for example, includes an inverted wedge-shaped waveguide, the horizontal dimension of which gradually decreases as it approaches the end face of the waveguide. However, this type of pattern spot conversion device is only effective in expanding the pattern spot in the horizontal direction.

[0024] In order to further increase the mode spot of the optical signal in the waveguide in the vertical direction, the thickness of the cladding in the waveguide may be increased. However, this may bring some other problems.

[0025] For example, Figure 1 A schematic cross-sectional view showing a photonic chip and optical fiber coupling device.

[0026] refer to Figure 1 The photonic chip and optical fiber coupling device includes a photonic chip C and an optical fiber 8 coupled to each other. The photonic chip C includes a silicon-based substrate 1 and a waveguide 5 located above the silicon-based substrate 1. The waveguide 5 includes a waveguide core 2 and a waveguide cladding 3 surrounding and cladding the waveguide core 2. The optical fiber 8 includes an optical fiber core 6 and an optical fiber cladding 7 surrounding and cladding the optical fiber core 6. Optical signals are coupled at the end faces of the waveguide and the optical fiber.

[0027] For example, the waveguide 5 has a waveguide end face 5a, and the optical fiber 8 has a fiber end face 8a. The waveguide end face 5a and the fiber end face 8a are arranged face to face and coupled to each other, thereby allowing optical signals to be transmitted between the waveguide core 2 and the optical fiber core 6, for example, from the waveguide core 2 to the optical fiber core 6. Generally speaking, the end face size of the waveguide core 2 is smaller than the end face size of the optical fiber core 6. Therefore, it is necessary to increase the optical signal mode spot in the waveguide core 2 to match the waveguide and optical fiber mode spots and reduce mismatch loss.

[0028] In some examples, in order to further increase the mode spot of the waveguide 5 in the vertical direction, the thickness of the waveguide cladding 3 can be increased. However, due to the relatively thick thickness of the waveguide cladding 3, it may be difficult to form an ideal vertical end face when etching the waveguide end face 5a during the manufacturing process. For example, the waveguide end face 5a may be tilted toward the inside of the chip as it moves away from the substrate 1. Generally speaking, the optical fiber end face 8a extends in the vertical direction. However, after the optical signal is transmitted from the waveguide 5 through the inclined waveguide end face 5a and the vertical optical fiber end face 8a to the optical fiber 8, the optical path refraction of the inclined end face will cause the optical signal to deviate from the main optical path, that is, the optical path of the optical signal transmitted to the optical fiber 8 deviates from the optical path of the optical signal in the waveguide 5. This will cause loss of the optical signal and affect the optical fiber coupling efficiency.

[0029] In some examples, the space 9 between the waveguide end face 5a and the optical fiber end face 8a can be filled with a refractive index matching liquid (e.g., an organic material such as epoxy resin) to improve optical path refraction and reduce optical signal loss. However, adding refractive index matching material may introduce additional reliability risks, such as the possibility of delamination of the refractive index matching material from adjacent end faces.

[0030] Figure 2 A schematic plan view of a photonic chip and optical fiber coupling device is shown.

[0031] At the end face of a waveguide or optical fiber, it is desirable that the incident light has a certain angle relative to the end face when the optical signal enters the end face, so as to prevent the reflected light at the end face from returning along the direction of the incident light. In some examples, for example, Figure 2 As shown, while the waveguide end face 5a and the optical fiber end face 8a extend vertically in a direction perpendicular to the substrate's main surface (e.g., perpendicular to the paper), the waveguide core 2 and the optical fiber 8 can be tilted relative to the end faces in a horizontal direction parallel to the substrate's main surface, that is, the horizontal extension direction of the waveguide core 2 and the optical fiber 8 is not perpendicular to the end faces, but deviates from the normal direction of the end faces. For example, the direction of the reflected light generated by the reflection of the optical signal transmitted in the waveguide core 2 at the waveguide end face 5a can be caused to deviate from the optical path direction of the optical signal in the waveguide core 2.

[0032] However, the above method requires that the waveguide core layer and the optical fiber be tilted in the horizontal direction, which is inconvenient for the packaging design of the optical fiber array and may increase the overall occupied area of the optical module.

[0033] In this regard, the embodiments of the present disclosure provide a photonic chip end face coupling device and a manufacturing method thereof, which can improve the coupling efficiency between the waveguide structure and the optical fiber, while avoiding the adverse effects of the reflection of the optical signal at the end face on the optical signal, and can be beneficial to improving the convenience of the packaging design of the photonic chip and the optical fiber.

[0034] For example, an embodiment of the present disclosure provides a photonic chip end face coupling device, comprising: a photonic chip and an optical fiber; the photonic chip comprises a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprises a waveguide core layer and a waveguide cladding surrounding the waveguide core layer, and having a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from an area close to the inner region of the photonic chip to the first end face in a direction parallel to the main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip as it moves away from the substrate, and has a first angle between the first end face and a reference plane parallel to the main surface of the substrate; the optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and is coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and is also inclined toward the inner region of the photonic chip, has a second angle between the second end face and the reference plane, and the first angle and the second angle are acute angles.

[0035] In the photonic chip end-face coupling device of the presently disclosed embodiment, by tilting the first end face of the waveguide structure and the second end face of the optical fiber, and by forming an acute angle between the first and second end faces and a reference plane parallel to the main surface of the substrate, the reflected light of the optical signal at the end face can be deviated from the main optical path direction, thereby preventing the reflected light from affecting the optical signal. Furthermore, the first and second end faces are both tilted, thereby preventing or reducing the deviation of the optical signal after passing through the coupling interface including the first and second end faces, thereby improving the coupling efficiency between the waveguide structure and the optical fiber. For example, in some embodiments, after the optical signal passes through the coupling interface twice, its optical path direction in the waveguide core layer is substantially the same as the original optical path direction of the optical signal in the optical fiber. In addition, because the end face tilting prevents the reflected light from affecting the optical signal, the waveguide core layer and the optical fiber no longer need to be tilted in the horizontal plane, thereby avoiding the inconvenience of packaging design caused by horizontal tilting of the optical fiber, thereby improving the convenience of the packaging design of the photonic chip and the optical fiber.

[0036] Figure 3 A schematic plan view showing a photonic chip end-face coupling device according to some embodiments of the present disclosure; Figure 4A A schematic cross-sectional view showing a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown. Figure 4B Another schematic cross-sectional view of a photonic chip end-face coupling device according to some embodiments of the present disclosure is shown. For example, Figure 4A and Figure 4B Along Figure 3 The cross-sectional view taken along line II' and line II-II' is shown in FIG. Figure 3 For example, along Figure 4A and Figure 4B A plan view of the plane where the waveguide core and optical fiber core are located.

[0037] It should be understood that for the sake of simplicity of the diagram, Figure 3 、 Figure 4A 、 Figure 4B Only a portion of the photonic chip's structure near the optical fiber and a portion of the optical fiber's structure near the photonic chip are shown. Furthermore, only one waveguide structure and one optical fiber are shown, rather than the complete structure of the photonic chip and the optical fiber assembly including the optical fiber. For example, ellipsis in the figure indicates that other structures are present on the side of the photonic chip's waveguide structure away from the optical fiber.

[0038] refer to Figure 3 、 Figure 4A and Figure 4B In some embodiments, the photonic chip end-face coupling device 500 includes a photonic chip 10 and an optical fiber assembly 20 coupled to each other. For example, the photonic chip 10 includes a substrate 100 and a waveguide structure 103; the waveguide structure 103 is located on one side of the substrate 100 in a direction perpendicular to the main surface of the substrate, and includes a waveguide core layer 101 and a waveguide cladding layer 102. The waveguide cladding layer 102 surrounds and covers the waveguide core layer 101, for example, Figure 3 and Figure 4B As shown, the waveguide cladding layer 102 surrounds and covers the waveguide core layer 101 on a plane perpendicular to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer 101.

[0039] The waveguide structure 103 has a first end surface S1 , where the waveguide core 101 and the waveguide cladding 102 are exposed. For example, the first end surface S1 is a surface of the waveguide structure 103 close to the chip edge and is configured to couple with the optical fiber 20 .

[0040] In some embodiments, the waveguide core layer 101 may extend from a region near the inner region CR of the photonic chip 10 to the first end surface S1 along a direction parallel to the main surface of the substrate (e.g., a first direction D1); the waveguide core layer 101 is embedded in the waveguide cladding 102, and the opposite side walls of the waveguide core layer 101 in a second direction D2 parallel to the main surface of the substrate (see Figure 3 and Figure 4B ) and the opposite surface of the waveguide core layer 101 in the third direction D3 perpendicular to the main surface of the substrate (for example, Figure 4A and Figure 4B The waveguide structure 103 is covered by the waveguide cladding 102 (the upper and lower surfaces shown in FIG). The first direction D1 and the second direction D2 are both parallel to the main surface of the substrate and intersect each other, for example, are substantially perpendicular to each other, and may be collectively referred to as horizontal directions in some examples. The third direction D3 is perpendicular to the main surface of the substrate and may be referred to as a vertical direction in some examples. For example, the waveguide structure 103 is located on one side of the substrate 100 in the third direction D3.

[0041] One of the opposite side walls of the waveguide core 101 in the first direction D1 is exposed at the first end surface S1, and the other of the opposite side walls may be exposed by the waveguide cladding 102 or may be covered by the waveguide cladding 102. The first end surface S1 includes the side surfaces of both the waveguide core 101 and the waveguide cladding 102 that are close to the optical fiber.

[0042] The photonic chip 10 has an inner region CR. For the sake of simplicity, the figure schematically shows that the inner region CR is located on the side of the waveguide structure away from the optical fiber, and does not show the specific structure of the photonic chip in this region. Figure 6 A schematic overall plan view of the photonic chip 10 is shown, as shown in FIG. Figure 6 As shown, the inner region CR of the photonic chip 10 includes an inner region of the photonic chip 10 away from an edge region thereof and includes a central region of the photonic chip 10 .

[0043] In some embodiments, as Figure 4A As shown, the first end face S1 of the waveguide structure 103 tilts toward the inner region CR of the photonic chip 10 as it moves away from the substrate 100. In this context, the tilting of the end face toward the inner region of the photonic chip means that the top of the end face tilts toward the inner region relative to the bottom of the end face, i.e., in a horizontal direction (e.g., a first direction), the horizontal distance between the top of the end face and the inner region is smaller than the horizontal distance between the bottom of the end face and the inner region. The top of the end face refers to the portion of the end face that is farther away from the substrate in a third direction perpendicular to the main surface of the substrate, and the bottom of the end face refers to the portion of the end face that is relatively closer to the substrate in the third direction.

[0044] That is, as the distance from the first end surface S1 to the inner region CR of the photonic chip 10 in the horizontal direction (e.g., the first direction D1) gradually decreases with distance from the substrate S1 (i.e., from bottom to top in the figure). In some embodiments, the first end surface S1 of the waveguide structure 103 has a first angle α with a reference plane parallel to the main surface of the substrate, and the first angle α may be an acute angle. That is, the first end surface S1 is not perpendicular to the main surface of the substrate, but is tilted (i.e., offset) relative to a direction perpendicular to the main surface of the substrate (e.g., the third direction D3) or the reference plane; that is, there is a non-zero angle (e.g., an acute angle) between the first end surface S1 and the direction perpendicular to the main surface of the substrate or the reference plane, and the sum of the non-zero angle and the first angle is approximately equal to 90 degrees. For example, in some examples, such tilting of the first end surface may also be referred to as tilting in the vertical direction.

[0045] In some embodiments, the optical fiber assembly 20 includes an optical fiber 203, which is located on one side of the photonic chip 10 in a direction parallel to the main surface of the substrate and is coupled to the waveguide structure 103. The optical fiber 203 has a second end face S2, which faces the first end face S1 of the waveguide structure 103 and is also tilted toward the inner region CR of the photonic chip 10. The above explanation regarding the end face tilting toward the inner region of the photonic chip also applies to the second end face S2.

[0046] That is, the top of the second end surface S2 is tilted relative to its bottom toward the inner region CR of the photonic chip 10. For example, from bottom to top (i.e., in a direction perpendicular to the main surface of the chip substrate and gradually away from the substrate), the horizontal distance between the second end surface S2 and the inner region of the photonic chip gradually decreases as it approaches its top surface. The top and bottom of the optical fiber 203 correspond to the top and bottom of the waveguide structure 103, respectively.

[0047] For example, the second end face S2 has a second angle β with a reference plane parallel to the main surface of the substrate, and the second angle β is an acute angle. For example, the second angle β may be the angle between the second end face S2 and the top of the optical fiber or a plane tangent to the top of the optical fiber. That is, from a cross-sectional view, the second angle β is the angle between the second end face S2 and the top surface of the optical fiber. In other words, the second end face S2 is not perpendicular to the reference plane on which the main surface of the substrate is located, but is tilted (i.e., offset) relative to a direction perpendicular to the main surface of the substrate (e.g., third direction D3) or the reference plane; that is, there is a non-zero angle (e.g., an acute angle) between the second end face S2 and the direction perpendicular to the main surface of the substrate or the reference plane, and the sum of this non-zero angle and the second angle is approximately equal to 90 degrees. For example, in some examples, this tilt of the second end face may also be referred to as tilting in the vertical direction.

[0048] In some embodiments, the first angle and the second angle are each in a range of 80 to 85 degrees. For example, the first angle is substantially equal to the second angle, and the first end surface and the second end surface are substantially parallel to each other.

[0049] In some embodiments, the first angle α and the second angle β can each be in the range of 80 to 85 degrees. For example, setting the first angle and the second angle within the aforementioned ranges can cause the reflected optical paths of the optical signal at the first and second end faces to deviate from the corresponding original optical paths (i.e., the incident optical paths), thereby preventing the reflected light from affecting the optical signal. Furthermore, this can facilitate the optical signal being refracted at appropriate angles at the two end faces. The first angle and the second angle can be appropriately set and adjusted based on the waveguide and optical fiber materials, process conditions, and other factors.

[0050] refer to Figure 4A In some embodiments, the first angle α and the second angle β may be substantially equal to each other, and the first end face S1 and the second end face S2 may be substantially parallel to each other. The first angle and the second angle being substantially equal may include the case where the first angle and the second angle are completely equal, and also include the case where the first angle and the second angle are not completely equal but close, for example, including the case where the ratio of the difference between the first angle and the second angle to the average value of the first angle and the second angle is within the range of 0 to 7%; accordingly, the first end face S1 and the second end face S2 being substantially parallel may include the case where the first angle and the second angle are completely equal, making the two end faces completely parallel, and also include the case where the first angle and the second angle are not completely equal but close (for example, the ratio of the difference between the first angle and the second angle to the average value thereof is within the above-mentioned range of 0 to 7%), making the two end faces close to parallel.

[0051] The waveguide structure 103 and the optical fiber 203 are coupled at their opposite first end faces and second end faces. In other words, the photonic chip end face coupling device includes a coupling interface between the waveguide structure 101 and the optical fiber 203, and the coupling interface includes the first end face S1 of the waveguide structure 101 and the second end face S2 of the optical fiber 203.

[0052] The waveguide structure 103 and the optical fiber 203 are configured to transmit optical signals. In the waveguide structure 103, the optical signal is primarily transmitted through the waveguide core, and the optical signal's pattern spot can diffuse into the waveguide cladding. For example, the optical signal's pattern spot can gradually increase as it approaches the first end face, thereby achieving matching coupling with the optical fiber. The optical fiber 203 may include an optical fiber core 201 and an optical fiber cladding 202. The optical signal can be primarily transmitted in the optical fiber core 201.

[0053] In some embodiments, arranging the first end face and the second end face in an inclined and substantially parallel manner can advantageously ensure that, when an optical signal is transmitted from the waveguide structure 101 through the coupling interface to the optical fiber 203, the optical signal can still be transmitted substantially along the original optical path in the optical fiber 203 after undergoing two refractions at the coupling interface, and vice versa; that is, the optical path direction of the optical signal in the optical fiber 203 can be substantially the same as the optical path direction in the waveguide structure 101, thereby improving the coupling efficiency between the photonic chip and the optical fiber. The optical path direction of the optical signal in the optical fiber and the optical path direction of the optical signal in the waveguide structure being substantially the same includes the case where the first end face and the second end face are completely parallel, such that the optical paths of the two are exactly the same, and also includes the case where the first end face and the second end face are nearly parallel, as described above, such that the optical paths of the two are similar.

[0054] In some embodiments, the substrate 100 may be a semiconductor substrate such as a silicon substrate, and the photonic chip 10 may be referred to as a silicon photonic chip. The waveguide structure 103 may also be referred to as an optical waveguide or a silicon optical waveguide. The waveguide structure 103 disposed on one side of the substrate 100 may include a situation where the waveguide structure 103 is directly formed on the substrate 100, that is, in contact with the substrate 100. It may also include a situation where other component layers (not shown) are disposed between the waveguide structure 103 and the substrate 100, so that the waveguide structure 103 and the substrate 100 are not in direct contact. This disclosure is not limited to this.

[0055] In some embodiments, the refractive index of the waveguide core 101 is higher than the refractive index of the waveguide cladding 102. For example, the waveguide core 101 comprises a high-refractive-index medium, and its refractive index may range from approximately 1.8 to 2.2; the waveguide cladding 102 comprises a low-refractive-index medium, and its refractive index may range from approximately 1.4 to 1.5. For example, the waveguide core 101 comprises silicon nitride, and the waveguide cladding 102 comprises silicon oxide.

[0056] In some embodiments, the optical fiber includes a fiber core layer and a fiber cladding, the fiber cladding surrounds and covers the fiber core layer, and the fiber core layer and the fiber cladding are exposed at the second end face; the portion of the waveguide core layer exposed by the first end face is aligned with the portion of the optical fiber core layer exposed by the second end face in a direction parallel to the main surface of the substrate.

[0057] Continue to refer Figure 3 、 Figure 4A and Figure 4BFor example, the optical fiber 203 includes an optical fiber core 201 and an optical fiber cladding 202, and the optical fiber core 201 and the optical fiber cladding 202 are exposed at the second end surface S2. The refractive index of the optical fiber core 201 can be slightly higher than the refractive index of the optical fiber cladding 202. For example, the optical fiber core 201 and the optical fiber cladding 202 can each include a silica material, and the refractive index of the core and / or cladding can be adjusted by, for example, doping in the respective silica materials, such that the refractive index of the core is higher than the refractive index of the cladding. The refractive index range of the optical fiber material can be similar to or approximately the same as the refractive index range of the waveguide cladding material. For example, the refractive index range of the optical fiber core 201 and the optical fiber cladding 202 can each be in the range of approximately 1.4 to 1.5.

[0058] In some embodiments, the cross-sectional dimensions of the waveguide core layer 101 in a plane perpendicular to the substrate's main surface and perpendicular to its horizontal extension direction are smaller than the cross-sectional dimensions of the optical fiber core layer 201 in a plane perpendicular to the substrate's main surface and perpendicular to its horizontal extension direction. The horizontal extension direction of the waveguide core layer 101 can be substantially the same as the horizontal extension direction of the optical fiber core layer 201. For example, the portion of the waveguide core layer 101 exposed at the first end surface S1 and the portion of the optical fiber core layer 201 exposed by the second end surface S2 are aligned with each other, for example, aligned in a direction parallel to the substrate's main surface (e.g., the first direction D1). For example, the orthographic projection of the portion of the waveguide core layer 101 on a reference plane perpendicular to the horizontal extension direction of the waveguide core layer or optical fiber core layer lies within the orthographic projection of the portion of the optical fiber core layer 201 on the reference plane.

[0059] In some embodiments, the width of the waveguide core layer in a width direction gradually decreases as approaching the first end face, and the width direction is parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

[0060] refer to Figure 3 In some embodiments, the waveguide core layer 101 extends along a first direction D1 from a region near the chip inner region CR to a first end surface S1. The horizontal dimension (e.g., width) of the waveguide core layer 101 gradually decreases as it approaches the first end surface S1, and may have a minimum width at the first end surface S1. For example, in some examples, the width of the waveguide core layer 101 may be set within a range of approximately 1 micron to approximately 100 nanometers (nm). For example, the width of the waveguide core layer 101 may gradually decrease from approximately 1 micron to 100 nm from a region near the chip inner region CR to the first end surface, but the present disclosure is not limited thereto.

[0061] It should be understood that the width of the waveguide core layer 101 refers to the width in its width direction, and the width direction of the waveguide core layer 101 is a direction parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer. Figure 3As shown, the waveguide core 101 extends in a first direction D1, and the width of the waveguide core 101 is in a second direction D2. That is, the width of the waveguide core 101 at the first end surface S1 is smaller than the width of the waveguide core 101 on the side away from the first end surface. For example, the waveguide core 101 can be referred to as an inverted taper waveguide. It should be understood that the extension direction of a component refers to the extension direction of the corresponding surface of the component or the extension direction of the central axis of the component. For example, if the waveguide core 101 is inverted taper, the extension direction of the waveguide core 101 is approximately the extension direction of its central axis.

[0062] By configuring the horizontal dimensions of the waveguide core 101 to taper as it approaches the first end face, the mode spot size of the optical signal transmitted by the waveguide core 101 can be increased. For example, the mode spot size of the optical signal transmitted within the waveguide core 101 gradually increases as it approaches the first end face, allowing the mode spot size at the first end face to match that of the optical fiber 203, thereby reducing optical loss. Therefore, configuring the waveguide core 101 in this manner can increase the horizontal mode spot size of the optical signal, thereby avoiding or reducing mismatch losses in the coupling between the waveguide and the optical fiber.

[0063] In some embodiments, the waveguide cladding 102 can be configured to have a greater thickness to further expand the optical signal's vertical mode spot, thereby further reducing mismatch loss in optical signal coupling. For example, the thickness of the waveguide cladding 102 can be approximately 10 micrometers (μm) or greater. For example, the tilt of the first end face of the waveguide structure is caused by the tilt generated during etching to form the end face due to the greater thickness of the waveguide cladding.

[0064] In some embodiments, an extension direction of the waveguide core layer and a normal line of the first end face have a non-zero angle.

[0065] In some embodiments, the photonic chip has a first edge and a second edge intersecting each other, and the first end face is located at the first edge; on a plane parallel to the main surface of the substrate, the extension direction of the waveguide core layer is parallel to the extension direction of the second edge and perpendicular to the extension direction of the first edge.

[0066] In some embodiments, on a plane parallel to the main surface of the substrate, an extending direction of the optical fiber is parallel to an extending direction of the second edge of the photonic chip and perpendicular to an extending direction of the first edge.

[0067] For example, because the waveguide core 101 extends in a direction parallel to the main surface of the substrate, and the first end surface S1 is inclined and has an acute angle with a reference plane parallel to the main surface of the substrate, the horizontal extension direction of the waveguide core 101 is not perpendicular to the first end surface S1. That is, the extension direction of the waveguide core 101 is different from the normal direction of the first end surface S1, and there is a non-zero angle between the extension direction of the waveguide core 101 and the normal of the first end surface S1. In this way, the reflected light of the optical signal transmitted in the waveguide core 101 at the first end surface S1 is prevented from returning to the waveguide core 101 along the original path. In other words, the reflected light of the optical signal at the first end surface S1 is deviated from the optical path direction of the optical signal in the waveguide structure, thereby preventing the reflected light from adversely affecting the optical signal.

[0068] For example, because the end faces are tilted in a plane perpendicular to the substrate's main surface (i.e., the plane shown in the cross-sectional view) to protect the optical signal from reflected light, there is no need to further tilt the waveguide core and optical fiber in a horizontal direction parallel to the substrate's main surface. For example, the waveguide core and optical fiber can be arranged parallel to the corresponding edges of the chip, thereby facilitating chip and optical fiber packaging design and optimizing space utilization.

[0069] Figure 6 A schematic plan view schematically showing a photonic chip 10 and an optical fiber assembly 20, Figure 6 The overall outline of the photonic chip 10 and at least a portion of the structure of the optical fiber assembly 20 near the photonic chip 10 are shown to schematically illustrate the extension direction of the waveguide core layer and the optical fiber in the photonic chip 10 in a plan view. For the sake of simplicity, Figure 6 The waveguide core layer and the optical fiber core layer are shown to represent the waveguide structure and the optical fiber, but the waveguide cladding and the optical fiber cladding are not shown in detail. The specific structure of the waveguide structure and the optical fiber can be referred to the above Figure 3 、 Figure 4A and Figure 4B The content of the description. For example, Figure 3 、 Figure 4A and Figure 4B for Figure 6 Schematic enlarged view of area A.

[0070] like Figure 6As shown, the photonic chip 10 includes an inner region CR and a waveguide structure 103, at least a portion of the waveguide structure 103 is disposed on one side of the inner region CR close to the edge of the chip. For example, the photonic chip 10 has a first edge E1 and a second edge E2 that intersect with each other, and the first end surface S1 of the waveguide structure 103 is located at the first edge E1, that is, the first edge E1 includes the first end surface S1, and the first end surface S1 and the first edge E1 extend in the same direction in a plan view. In some examples, the planar shape of the photonic chip 10 is square, such as a square or a rectangle, and the first edge E1 and the second edge E2 may be substantially perpendicular to each other. It should be understood that the chip edge includes the sidewalls of each material layer located at the edge.

[0071] In some embodiments, as Figure 6 As shown in a plan view, on a plane parallel to the main surface of the substrate, the first edge E1 extends along the second direction D2. That is, the first end surface S1 of the waveguide structure located at the first edge also extends along the second direction D2. The second edge E2 extends along the first direction D1. The waveguide core layer 101 is perpendicular to the first end surface S1 and extends along the first direction D1. In other words, the extension direction of the waveguide core layer 101 (e.g., the first direction D1) is parallel to the extension direction of the second edge E2 (e.g., the first direction D1) and perpendicular to the extension direction of the first edge E1 (e.g., the second direction D2).

[0072] The extension direction of the optical fiber 203 (i.e., the extension direction of the optical fiber core layer 201) is arranged to correspond to the extension direction of the waveguide core layer 101. For example, in a plane parallel to the main surface of the substrate, the extension direction of the optical fiber 203 can be perpendicular to the first end face S1, for example, it can extend along the first direction D1. In other words, the extension direction of the optical fiber 203 and the extension direction of the second edge E2 of the photonic chip 10 can both be in the first direction D1, that is, parallel to each other, and the extension direction of the optical fiber 203 is perpendicular to the extension direction of the first edge E1 of the photonic chip 10.

[0073] In some embodiments, the photonic chip 10 includes a plurality of waveguide structures 103, each waveguide structure 103 including a waveguide core layer and a corresponding waveguide cladding layer; the optical fiber assembly 20 may include an optical fiber array, that is, it may include a plurality of optical fibers 203. For example, the plurality of waveguide structures 103 of the photonic chip 10 may be arranged in a one-to-one correspondence with the plurality of optical fibers 203 of the optical fiber assembly 20 and coupled to each other, with each waveguide core layer aligned with the corresponding optical fiber core layer. Each set of coupled waveguide structures 101 and optical fibers 203 has the characteristics described above. Figures 3 to 4B The structure described is not described in detail here.

[0074] In some embodiments, a ratio of a difference between a first effective refractive index of the first end face of the waveguide structure and a second effective refractive index of the second end face of the optical fiber to an average of the first effective refractive index and the second effective refractive index ranges from 0 to 7%.

[0075] For example, returning a reference Figure 3 、 Figure 4A and Figure 4B In some embodiments, the first effective refractive index of the first end surface S1 of the waveguide structure 103 is close to the second effective refractive index of the second end surface S2 of the optical fiber 203. This facilitates the optical signal to remain along the original optical path after two refractions at the coupling interface during transmission between the waveguide structure and the optical fiber. The first effective refractive index and the second effective refractive index being close include situations where the first effective refractive index and the second effective refractive index are completely equal, and also include situations where the first effective refractive index and the second effective refractive index are not completely equal, but the difference is small. For example, the ratio of the difference between the first effective refractive index and the second effective refractive index to the average of the first effective refractive index and the second effective refractive index can be in the range of 0 to about 7%, for example, can be in the range of 0 to about 2% or 0 to 5%.

[0076] In some embodiments, the intermediate medium between the first end face of the waveguide structure and the second end face of the optical fiber comprises air. In some embodiments, no refractive index matching material is filled between the first end face of the waveguide structure and the second end face of the optical fiber.

[0077] For example, the first end face S1 of the waveguide structure 103 and the second end face S2 of the optical fiber 203 are spaced apart from each other, and the intermediate medium 15 between the first end face S1 and the second end face S2 can be or include air. The refractive index of air is lower than that of the waveguide structure and the optical fiber. A light signal undergoes two refractions when passing through the two end faces of the coupling interface. Because the first and second end faces are both inclined and have similar effective refractive indices, the light signal can continue to propagate along the original optical path after entering the optical fiber from the waveguide structure after two refractions at the coupling interface, and vice versa. Therefore, there is no need to fill the space between the first and second end faces with a refractive index-matching material, thereby avoiding reliability issues associated with such a material and improving the reliability of the chip coupling device. For example, there can be no filling material between the first end face S1 of the waveguide structure 103 and the second end face S2 of the optical fiber 203. The intermediate medium between the two end faces is air, which can include the ambient air in the environment where the photonic chip end face coupling device is located.

[0078] In other embodiments, a suitable refractive index matching material may be provided between the first end face and the second end face according to product design and requirements to adjust the refraction of the optical signal at the end face, thereby adjusting the propagation direction of the optical signal.

[0079] In some embodiments, the waveguide structure and the optical fiber are configured such that: the optical signal is transmitted in the waveguide structure along a first optical path direction to the first end face, and is incident from the first end face to the intermediate medium between the first end face and the second end face, and undergoes a first refraction at the first end face, then the optical signal is incident from the intermediate medium to the optical fiber, undergoes a second refraction at the second end face, and then is transmitted in the optical fiber along the second optical path direction. For example, the first optical path direction and the second optical path direction are the same. In some embodiments, the waveguide structure and the optical fiber are configured such that: the reflected light of the optical signal at the first end face deviates from the first optical path direction, and the reflected light of the optical signal at the second end face deviates from the optical path direction of the optical signal in the intermediate medium.

[0080] Figure 5 The figure schematically shows the propagation of optical signals in the end-face coupling device of the photonic chip. The arrows in the figure schematically show the propagation direction of the optical signals.

[0081] refer to Figure 5 For example, an optical signal propagates along a first optical path direction 60 in the waveguide structure 103 to the first end surface S1. From the first end surface S1, the optical signal is incident on the intermediate medium 15 between the first end surface S1 and the second end surface S2, undergoing a first refraction at the first end surface S1. After the first refraction at the first end surface S1, the optical signal propagates along an optical path direction 62 in the intermediate medium 15. For example, the intermediate medium 15 is air, and the refractive index of air is lower than that of the waveguide structure. Therefore, the refraction angle of the first refraction is greater than the incident angle. That is, the angle between the first optical path direction 60 of the optical signal in the waveguide structure 103 and the normal line n1 to the first end surface S1 is smaller than the angle between the optical path direction 62 of the optical signal in the intermediate medium 15 and the normal line n1 to the first end surface S1.

[0082] Next, the light signal is incident from the intermediate medium 15 onto the optical fiber 203, for example, onto the optical fiber core 201, and undergoes a second refraction at the second end surface S2. It then propagates within the optical fiber 203 along the second optical path direction 64. Because the refractive index of the intermediate medium 15 is lower than that of the optical fiber 203, the angle of refraction during the second refraction is lower than the angle of incidence; that is, the angle between the second optical path direction 64 of the light signal within the optical fiber 203 and the normal line n2 to the second end surface S2 is lower than the angle between the optical path direction 62 of the light signal within the intermediate medium 15 and the normal line n2 to the second end surface S2.

[0083] In some embodiments, because the first end surface S1 and the second end surface S2 are approximately parallel, the normal n1 to the first end surface S1 and the normal n2 to the second end surface S2 are also approximately parallel. Therefore, the angle between the optical path direction 62 of the optical signal in the intermediate medium 15 and the normal n1 is approximately equal to the angle between the optical path direction 62 and the normal n2. In other words, the angle of refraction of the optical signal during the first refraction at the first end surface S1 is approximately equal to the angle of incidence of the optical signal during the second refraction at the second end surface S2. The effective refractive index of the waveguide structure at the first end surface is similar to the effective refractive index of the optical fiber at the second end surface. Therefore, according to the law of refraction, the angle of incidence of the optical signal during the first refraction at the first end surface S1 is approximately equal to the angle of refraction of the optical signal during the second refraction at the second end surface S2. That is, the angle between the first optical path direction 60 and the normal n1 is approximately equal to the angle between the second optical path direction 64 and the normal n2. Since the normal n1 and the normal n2 are approximately parallel, i.e., in the same direction, the first optical path direction 60 and the second optical path direction 64 are approximately the same. In this way, the loss of optical signals at the coupling interface can be reduced, and the coupling efficiency between the photonic chip and the optical fiber can be improved.

[0084] Continue to refer Figure 5 In some embodiments, because the first end face S1 is tilted and there is a non-zero angle between the extension direction of the waveguide core layer 101 and the normal to the first end face S1, the reflected light of the optical signal at the end face deviates from the main optical path direction, thereby not adversely affecting the optical signal. Specifically, the optical signal is reflected at the first end face S1, and the direction of the reflected light deviates from the first optical path direction 60, but is along the optical path direction 61. When the optical signal is incident from the intermediate medium 15 to the optical fiber core layer 201, it is reflected at the second end face S2, and the direction of the reflected light deviates from the optical path direction 62 of the optical signal in the intermediate medium, but is along the optical path direction 63. Therefore, through the above-mentioned arrangement of the first end face and the second end face, the problems of refraction and reflection can be improved at the same time, the influence of refraction on the optical coupling efficiency can be avoided or reduced, and the influence of reflected light on the optical signal can be avoided. That is, while improving the coupling efficiency between the photonic chip and the optical fiber, the reflected light at the end face deviates from the main optical path, avoiding the adverse influence of reflected light on the optical signal.

[0085] This article uses the transmission of an optical signal from a waveguide structure to an optical fiber as an example to illustrate the coupling of optical signals between the waveguide structure and the optical fiber. It should be understood that the optical signal can also be transmitted from the optical fiber to the waveguide structure, and the corresponding optical path can be deduced by analogy, which will not be repeated here.

[0086] In some other embodiments of the photonic chip end face coupling device, grooves are provided in the waveguide cladding, and the grooves are located on opposite sides of the waveguide core layer in a direction parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

[0087] Figure 7AA schematic plan view showing a photonic chip end face coupling device according to some other embodiments of the present disclosure; Figure 7B Schematic cross-sectional views of photonic chip end-face coupling devices according to other embodiments of the present disclosure are shown. For example, Figure 7B It is along Figure 7A The photonic chip end face coupling device of this embodiment is a cross-sectional view taken along the line II-II'. Figure 7A The cross-sectional view taken along line II' is similar to that of the aforementioned embodiment. Figure 4A The cross-sectional views shown are the same, and the corresponding cross-sectional structures are not described again here.

[0088] refer to Figure 7A and Figure 7B In some embodiments, the waveguide cladding 102 is provided with grooves 13. The grooves 13 are located on opposite sides of the waveguide core 101 in a direction (e.g., a second direction D2) parallel to the substrate's main surface and perpendicular to the waveguide core's extension direction (e.g., a first direction D1). For example, the depth of the grooves 13 may be greater than the depth of the waveguide core 101. For example, the grooves 13 may extend from the top of the waveguide cladding 102 along a third direction D3 perpendicular to the substrate's main surface to the bottom of the waveguide cladding 102. The waveguide core 101 overlaps the grooves 13 in the second direction D2; for example, the orthographic projection of the waveguide core 101 on a reference plane perpendicular to the second direction D2 may lie within the orthographic projection of the grooves 13 on the reference plane. For example, the waveguide cladding 102 includes a main body 102a located between the two grooves 13 in the second direction D2 and surrounding and enveloping the waveguide core 101. Providing grooves in the waveguide cladding 102 helps concentrate the optical signal's mode spot in the area between the two grooves 13, thereby controlling the optical signal's mode spot size within a suitable range and reducing optical signal loss. In a plane parallel to the substrate's main surface, the horizontal extension direction of the grooves 13 can be the same as that of the waveguide core 101. For example, the grooves 13 can extend along the first direction D1 from an area near the chip's interior to the first end surface S1.

[0089] In some embodiments, the width of the groove 13 can be set to be greater than or equal to 5 microns, or greater than or equal to 10 microns, so that the groove 13 can effectively confine the optical signal. The width of the groove 13 refers to the width in a width direction (e.g., the second direction D2) perpendicular to the extension direction (e.g., the first direction D1) of the groove 13.

[0090] In some embodiments, the waveguide core layer is a single-layer structure and extends continuously in the waveguide cladding. Figure 4A In the illustrated embodiment, the waveguide core layer 101 is a single-layer structure and continuously extends from a region close to the inner region of the chip to the first end surface S1 of the waveguide structure.

[0091] In other embodiments, the waveguide core layer includes a plurality of waveguide sub-core layers coupled to each other, and the plurality of waveguide sub-core layers include: a first waveguide sub-core layer, extending from a first region near the inner area of the photonic chip toward the first end face in a direction parallel to the main surface of the substrate, and extending to a transition region between the first region and the first end face; and a second waveguide sub-core layer, located on a side of the first waveguide sub-core layer away from the substrate, partially overlapping with the first waveguide sub-core layer in a direction perpendicular to the main surface of the substrate, and extending from the transition region to the first end face in a direction parallel to the main surface of the substrate.

[0092] In some embodiments, the width of the first waveguide sub-core layer gradually decreases as it approaches the transition region; and from the transition region to the first end face, the width of the second waveguide sub-core layer first gradually increases and then gradually decreases.

[0093] In some embodiments, the first waveguide sub-core layer includes a first waveguide end located in the transition region, the second waveguide sub-core layer includes a second waveguide end located in the transition region, the first waveguide end and the second waveguide end overlap in a direction perpendicular to the main surface of the substrate, and the width of the second waveguide end gradually increases as it approaches the first end face.

[0094] For example, Figure 8 Schematic cross-sectional views showing photonic chip end-face coupling devices according to other embodiments of the present disclosure; Figure 9A Show Figure 8 A schematic plan view of the first waveguide sub-core layer in the photonic chip end-face coupling device shown; Figure 9B Show Figure 8 A schematic plan view of the second waveguide sub-core layer in the photonic chip end-face coupling device shown; Figure 9C Show Figure 8 The schematic top view of the first waveguide sub-core layer and the second waveguide sub-core layer in the photonic chip end-face coupling device is shown.

[0095] refer to Figure 8In some embodiments, the waveguide core layer 101 may have a multi-layer structure and include multiple waveguide sub-core layers coupled to each other. For example, it may include a first waveguide sub-core layer 101a and a second waveguide sub-core layer 101b embedded in the waveguide cladding layer 102. The first waveguide sub-core layer 101a extends from a first region R1 near the inner region CR of the photonic chip 10 toward the first end surface S1 of the waveguide structure in a direction parallel to the main surface of the substrate, and extends to a transition region R2 located between the first region R1 and the first end surface S1. The second waveguide sub-core layer 101b is located on a side of the first waveguide sub-core layer 101a away from the substrate 100 and partially overlaps with the first waveguide sub-core layer 101a in a third direction D3 perpendicular to the main surface of the substrate; that is, the orthographic projection of the second waveguide sub-core layer 101b on the main surface of the substrate partially overlaps with the orthographic projection of the first waveguide sub-core layer 101a on the main surface of the substrate. For example, the second waveguide sub-core layer 101b extends from the transition region R2 to the first end surface S1 in a direction parallel to the substrate main surface. For example, the multiple waveguide sub-core layers may have the same horizontal extension direction parallel to the substrate main surface, for example, they may all extend along the first direction D1.

[0096] In some embodiments, adjacent waveguide sub-core layers overlap in the transition region, while the portion of each waveguide sub-core layer located outside the transition region does not overlap with other waveguide sub-core layers. For example, the orthographic projection of the portion of the first waveguide sub-core layer 101a located on the side of the transition region R2 away from the first end face (e.g., the portion located in the first region R1) on the substrate main surface is offset from, and therefore does not overlap with, the orthographic projection of the second waveguide sub-core layer 101b on the substrate main surface. Similarly, the orthographic projection of the portion of the second waveguide sub-core layer 101b located on the side of the transition region R2 away from the first region R1 (i.e., the portion from the edge of the transition region R2 to the first end face) on the substrate main surface is offset from, and therefore does not overlap with, the orthographic projection of the first waveguide sub-core layer 101a on the substrate main surface.

[0097] In some embodiments, the first waveguide sub-core layer 101a and the second waveguide sub-core layer 101b are spaced apart in the third direction D3; for example, a portion of the waveguide cladding 102 is located between the first waveguide sub-core layer 101a and the second waveguide sub-core layer 101b in the third direction D3.

[0098] refer to Figure 8 and Figure 9AIn some embodiments, the first waveguide sub-core layer 101a is the sub-core layer horizontally farthest from the first end surface S1 among the multiple waveguide sub-core layers (i.e., the lowest waveguide sub-core layer vertically closest to the substrate). For example, the width of the first waveguide sub-core layer 101a gradually decreases as it approaches the transition region R2. For example, the multiple waveguide sub-core layers all extend along a first direction in a plane parallel to the main surface of the substrate, and the width of the waveguide sub-core layer is the width in a width direction (i.e., a second direction) perpendicular to the direction of extension (i.e., the first direction).

[0099] refer to Figure 8 and Figure 9B In some embodiments, from the transition region R2 to the first end surface S1, the width of the second waveguide sub-core layer 101b first gradually increases and then gradually decreases.

[0100] By configuring the dimensions of the first waveguide sub-core layer 101a and the second waveguide sub-core layer 101b as described above, the optical signal's mode spot gradually increases in the first waveguide sub-core layer 101a, reaching its maximum in the transition region. This allows the optical signal to be transmitted to the second waveguide sub-core layer 101b, and the optical mode spot is moved upward, away from the substrate. The optical signal's mode spot in the first waveguide sub-core layer 101b then gradually decreases to concentrate the optical signal, and then gradually increases to match the optical fiber. In other words, by configuring the dimensions of the first waveguide sub-core layer 101a and the second waveguide sub-core layer 101b as described above, the optical signal can be efficiently transmitted from the first waveguide sub-core layer 101a to the second waveguide sub-core layer 101b, thereby improving the coupling efficiency between the first and second waveguide sub-core layers. Figure 8 The arrows in illustratively show that the optical signal is transmitted from the first waveguide sub-core layer 101a to the second waveguide sub-core layer 101b.

[0101] refer to Figure 8 and Figure 9C In some embodiments, the width of at least the portion of the second waveguide sub-core layer 101b overlapping with the first waveguide sub-core layer gradually increases as approaching the first end face.

[0102] For example, the first waveguide sub-core layer 101a includes a first waveguide end portion ep1 located in the transition region R2, and the second waveguide sub-core layer 101b includes a second waveguide end portion ep2 located in the transition region R2. The first waveguide end portion ep1 and the second waveguide end portion ep2 overlap in a third direction D3 perpendicular to the substrate's main surface. That is, the orthographic projection of the first waveguide end portion ep1 on the substrate's main surface overlaps the orthographic projection of the second waveguide end portion ep2 on the substrate's main surface. The width of the second waveguide end portion ep2 gradually increases as it moves away from the chip's internal region and approaches the first end face.

[0103] In some embodiments, the position where the second waveguide sub-core layer 101b has the maximum width is located on the side of the second waveguide end ep2 away from the first waveguide sub-core layer 101a in the horizontal direction and is located between the second waveguide end ep2 and the first end surface S1.

[0104] refer to Figure 8 In some embodiments, the uppermost waveguide sub-core layer in the waveguide core layer 101 (e.g., the second waveguide sub-core layer 101b) is exposed at the first end surface S1, and the waveguide sub-core layer is aligned with the optical fiber core layer 201 in a direction parallel to the main surface of the substrate.

[0105] It should be understood that Figure 8 and Figures 9A to 9C While the waveguide core layer includes two waveguide sub-core layers as an example to illustrate an embodiment of a multi-layer waveguide core structure, the number of waveguide sub-core layers included in the waveguide core layer is not limited to this. In other examples, the waveguide core layer may include more than two waveguide sub-core layers, and the multiple waveguide sub-core layers may be coupled to each other to transmit optical signals.

[0106] When the waveguide core layer includes more than two waveguide sub-core layers, each waveguide sub-core layer partially overlaps with the adjacent waveguide sub-core layer, and the area where the adjacent waveguide sub-core layers overlap is a transition area; in this case, the optical signal can pass through multiple transition areas in the process of transmitting from the lowest waveguide sub-core layer to the uppermost waveguide sub-core layer to reach the second end face, and the optical signal is coupled between adjacent sub-core layers in each transition area, and the optical mode spot can be gradually moved upward and away from the substrate.

[0107] For example, the width of the waveguide sub-core layer located in the bottom layer gradually decreases as it approaches the first end face, while the widths of the other waveguide sub-core layers located on the side of the bottom layer waveguide sub-core layer away from the substrate first gradually increase and then gradually decrease as they approach the first end face, thereby achieving coupling of optical signals between the multiple waveguide sub-core layers and transmitting the optical signals to the first end face S1. For example, the waveguide sub-core layers located in the upper layer all extend horizontally beyond the edges of the waveguide sub-core layers in the lower layer and toward the first end face; for example, only the top layer waveguide sub-core layer farthest from the substrate in the third direction may extend to the first end face and align with the optical fiber, while the other waveguide sub-core layers located on the side of the top layer waveguide sub-core layer close to the substrate only extend to the corresponding transition region to complete the coupling of optical signals, and do not extend to the first end face.

[0108] In this embodiment, because the waveguide core layer includes multiple waveguide sub-core layers, the thickness of the waveguide cladding layer 102 can be further increased in the third direction D3 perpendicular to the substrate's main surface. For example, the thickness of the waveguide cladding layer 102 can be increased to approximately 15 microns or greater. This can advantageously increase the optical mode spot in the vertical direction while moving the optical mode spot away from the substrate, thereby reducing optical signal leakage into the substrate and, therefore, reducing optical leakage loss.

[0109] In the photonic chip end face coupling device of this embodiment, other structural features of the waveguide structure in the photonic chip 10 and the optical fiber 203 in the optical fiber assembly 20, as well as the transmission characteristics of the optical signal at the coupling interface (including the first end face and the second end face) between the photonic chip and the optical fiber are substantially the same or similar to those of the aforementioned embodiment. In this embodiment, grooves can also be provided in the waveguide cladding. These features have the same technical effects as described above and will not be repeated here.

[0110] The present disclosure provides a photonic chip packaging structure, including the photonic chip end face coupling device described in any of the above embodiments. Figure 10 As shown, the photonic chip packaging structure 600 includes a photonic chip end face coupling device 500. For example, the photonic chip packaging structure may be or include an optical module. In some embodiments, in addition to the photonic chip and optical fiber components, the photonic chip packaging structure may also include other optical devices and / or electronic devices. The photonic chip packaging structure has the same technical effects as described above with respect to the photonic chip end face coupling device. For example, in some embodiments, the above-mentioned setting of the end face coupling device of the photonic chip and the optical fiber improves the coupling efficiency of the photonic chip and the optical fiber, thereby also providing the device performance of the packaging structure; and by arranging the optical fiber in parallel to the corresponding edge of the chip in the horizontal direction, the design of the packaging structure can be facilitated, for example, the corresponding devices can be arranged and designed more regularly, and the space occupied by multiple components in the packaging structure can be optimized.

[0111] An embodiment of the present disclosure also provides a method for manufacturing a photonic chip end-face coupling device, comprising: providing a photonic chip, wherein the photonic chip comprises a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and forming a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from an area close to an inner region of the photonic chip to a first end face in a direction parallel to a main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip, and a first angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; and coupling an optical fiber to the photonic chip, wherein the optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and is coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and also inclined toward the inner region of the photonic chip, a second angle is formed between the second end face and the reference plane, and both the first angle and the second angle are acute angles.

[0112] The manufacturing method of the photonic chip end face coupling device according to the embodiment of the present disclosure has the same technical effects as described above with respect to the photonic chip end face coupling device, and will not be described in detail here.

[0113] For example, reference Figure 3 、 Figure 4A and Figure 4B In some embodiments, a method for manufacturing a photonic chip end-face coupling device includes: providing a photonic chip 10, wherein the photonic chip 10 includes a substrate 100 and a waveguide structure 103 having a first end face S1; coupling an optical fiber assembly 20 to the photonic chip 10, wherein the optical fiber assembly 20 includes an optical fiber 203 having a second end face S2, and coupling the optical fiber 203 to the waveguide structure 103 to transmit an optical signal. The features of the photonic chip 10 and the optical fiber can be found in the detailed description above and are not further elaborated here.

[0114] In some embodiments, forming a waveguide structure 103 having a first end face S1 includes: forming an initial waveguide structure (not shown) on a substrate 100, the initial waveguide structure including a waveguide cladding and a waveguide core layer embedded in the waveguide cladding, and having a first initial end face, and the first initial end face may, for example, be perpendicular to the main surface of the substrate; then, performing an etching process on the initial waveguide structure to remove a portion of the initial waveguide structure close to the first initial end face, and forming a waveguide structure 103 having an inclined first end face S1.

[0115] In some embodiments, the inclined second end face S2 of the optical fiber 203 may also be formed by an etching process or a cutting process or other suitable process.

[0116] In various embodiments of the present disclosure, by tilting the first end face of the waveguide structure in the photonic chip and the second end face of the optical fiber, it is advantageous to ensure that the optical signal can still roughly follow the direction of the original optical path after being refracted twice at the coupling interface, thereby reducing coupling loss and improving the coupling efficiency of the photonic chip and the optical fiber. At the same time, it can cause the reflected light of the optical signal at each end face to deviate from the original optical path, avoiding the adverse effect of the reflected light on the optical signal. Moreover, it is unnecessary to set a refractive index matching material between the first end face and the second end face at the coupling interface, thereby avoiding the reliability risk introduced by the refractive index matching material and improving the reliability of the coupling device and the packaging structure including it. In addition, through the above-mentioned arrangement of the waveguide structure and the optical fiber, it is unnecessary to tilt the optical fiber in the horizontal direction, thereby avoiding the inconvenience of the packaging design caused by the horizontal tilt of the optical fiber.

[0117] In some embodiments, by configuring the waveguide core layer to be a multilayer structure including a plurality of waveguide sub-core layers, the optical mode spot can be further away from the substrate, thereby reducing the light leakage loss of the optical signal to the substrate.

[0118] An embodiment of the present disclosure provides a photonic chip end-face coupling device, comprising: a photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and having a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from a region close to an inner region of the photonic chip to the first end face in a direction parallel to the main surface of the substrate, the first end face tilts toward the inner region of the photonic chip as it moves away from the substrate, and a first angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; and an optical fiber located on one side of the photonic chip in a direction parallel to the main surface of the substrate and coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and also tilted toward the inner region of the photonic chip, a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles.

[0119] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the first angle and the second angle each have an angle range of 80 degrees to 85 degrees.

[0120] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the first angle is substantially equal to the second angle, and the first end face and the second end face are substantially parallel to each other.

[0121] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, a non-zero angle is formed between the extension direction of the waveguide core layer and the normal line of the first end face.

[0122] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the photonic chip has a first edge and a second edge intersecting each other, and the first end face is located at the first edge; on a plane parallel to the main surface of the substrate, the extension direction of the waveguide core layer is parallel to the extension direction of the second edge and perpendicular to the extension direction of the first edge.

[0123] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, on a plane parallel to the main surface of the substrate, the extension direction of the optical fiber is parallel to the extension direction of the second edge of the photonic chip and perpendicular to the extension direction of the first edge.

[0124] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the width of the waveguide core layer in the width direction gradually decreases as it approaches the first end face, and the width direction is parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

[0125] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the ratio of the difference between the first effective refractive index of the first end face of the waveguide structure and the second effective refractive index of the second end face of the optical fiber to the average value of the first effective refractive index and the second effective refractive index ranges from 0 to 7%.

[0126] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the intermediate medium between the first end face of the waveguide structure and the second end face of the optical fiber includes air.

[0127] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, no refractive index matching material is filled between the first end face of the waveguide structure and the second end face of the optical fiber.

[0128] In the photonic chip end-face coupling device according to at least one embodiment of the present disclosure, the waveguide core layer is a single-layer structure and extends continuously in the waveguide cladding.

[0129] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the waveguide core layer includes a plurality of waveguide sub-core layers coupled to each other, and the plurality of waveguide sub-core layers include: a first waveguide sub-core layer, extending from a first region of the internal area close to the photonic chip toward the first end face in a direction parallel to the main surface of the substrate, and extending to a transition region between the first region and the first end face; and a second waveguide sub-core layer, located on a side of the first waveguide sub-core layer away from the substrate, partially overlapping with the first waveguide sub-core layer in a direction perpendicular to the main surface of the substrate, and extending from the transition region to the first end face in a direction parallel to the main surface of the substrate.

[0130] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the width of the first waveguide sub-core layer gradually decreases as it approaches the transition region; and from the transition region to the first end face, the width of the second waveguide sub-core layer first gradually increases and then gradually decreases.

[0131] In the photonic chip end-face coupling device according to at least one embodiment of the present disclosure, the first waveguide sub-core layer includes a first waveguide end located in the transition region, the second waveguide sub-core layer includes a second waveguide end located in the transition region, the first waveguide end and the second waveguide end overlap in a direction perpendicular to the main surface of the substrate, and the width of the second waveguide end gradually increases as it approaches the first end face.

[0132] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the waveguide structure and the optical fiber are configured as follows: the optical signal is transmitted in the waveguide structure along a first optical path direction to the first end face, and is incident from the first end face to the intermediate medium between the first end face and the second end face, and undergoes a first refraction at the first end face; then the optical signal is incident from the intermediate medium to the optical fiber, undergoes a second refraction at the second end face, and is transmitted in the optical fiber along a second optical path direction, wherein the first optical path direction and the second optical path direction are the same.

[0133] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the waveguide structure and the optical fiber are configured such that: the reflected light of the optical signal at the first end face deviates from the first optical path direction, and the reflected light of the optical signal at the second end face deviates from the optical path direction of the optical signal in the intermediate medium.

[0134] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, grooves are provided in the waveguide cladding, and the grooves are located on opposite sides of the waveguide core layer in a direction parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

[0135] In the photonic chip end face coupling device according to at least one embodiment of the present disclosure, the optical fiber includes an optical fiber core layer and an optical fiber cladding, the optical fiber cladding surrounds and covers the optical fiber core layer, and the optical fiber core layer and the optical fiber cladding are exposed at the second end face; the portion of the waveguide core layer exposed by the first end face and the portion of the optical fiber core layer exposed by the second end face are aligned in a direction parallel to the main surface of the substrate.

[0136] At least one embodiment of the present disclosure provides a photonic chip packaging structure, comprising any of the photonic chip end face coupling devices described above.

[0137] At least one embodiment of the present disclosure provides a method for manufacturing a photonic chip end-face coupling device, comprising: providing a photonic chip, the photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and forming a first end face exposing the waveguide core layer and the waveguide cladding, wherein the waveguide core layer extends from a region adjacent to an inner region of the photonic chip to the first end face in a direction parallel to a main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip, and a first angle is formed between the first end face and a reference plane parallel to the main surface of the substrate; and coupling an optical fiber to the photonic chip, wherein the optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and also inclined toward the inner region of the photonic chip, a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles.

[0138] There are a few points to note:

[0139] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to conventional designs.

[0140] (2) Unless there is any conflict, the features of the same embodiment and different embodiments of the present disclosure may be combined with each other.

[0141] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned disclosure concept, such as the technical solutions formed by replacing the above-mentioned features with the technical features with similar functions disclosed in this disclosure (but not limited to). All of them should be included in the protection scope of the present disclosure. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A photonic chip end-face coupling device, comprising: A photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and having a first end surface exposing the waveguide core layer and the waveguide cladding layer, wherein the waveguide core layer extends from a region proximate to an inner region of the photonic chip to the first end surface along a direction parallel to a main surface of the substrate, the first end surface is inclined as it moves away from the substrate toward the inner region of the photonic chip, and a first angle is formed between the first end surface and a reference plane parallel to the main surface of the substrate; and An optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and is coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and is also inclined toward the inner area of the photonic chip, and a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles. 2 . The photonic chip end face coupling device according to claim 1 , wherein the first angle and the second angle each range from 80 degrees to 85 degrees. 3 . The photonic chip end-face coupling device according to claim 1 , wherein the first angle is substantially equal to the second angle, and the first end face and the second end face are substantially parallel to each other. 4 . The photonic chip end face coupling device according to claim 1 , wherein an extension direction of the waveguide core layer and a normal line of the first end face have a non-zero angle.

5. The photonic chip end-face coupling device according to claim 1, wherein the photonic chip has a first edge and a second edge intersecting each other, and the first end face is located at the first edge; On a plane parallel to the main surface of the substrate, an extending direction of the waveguide core layer is parallel to an extending direction of the second edge and perpendicular to an extending direction of the first edge.

6. The photonic chip end face coupling device according to claim 5, wherein on a plane parallel to the main surface of the substrate, the extension direction of the optical fiber is parallel to the extension direction of the second edge of the photonic chip and perpendicular to the extension direction of the first edge.

7. The photonic chip end face coupling device according to claim 1, wherein the width of the waveguide core layer in the width direction gradually decreases as it approaches the first end face, and the width direction is parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

8. The photonic chip end-face coupling device according to claim 1, wherein a ratio of a difference between a first effective refractive index of the first end face of the waveguide structure and a second effective refractive index of the second end face of the optical fiber to an average value of the first effective refractive index and the second effective refractive index ranges from 0 to 7%. 9 . The photonic chip end-face coupling device according to claim 1 , wherein an intermediate medium between the first end face of the waveguide structure and the second end face of the optical fiber comprises air. 10 . The photonic chip end-face coupling device according to claim 1 , wherein no refractive index matching material is filled between the first end face of the waveguide structure and the second end face of the optical fiber. 11 . The photonic chip end-face coupling device according to claim 1 , wherein the waveguide core layer is a single-layer structure and extends continuously in the waveguide cladding.

12. The photonic chip end-face coupling device according to claim 1, wherein the waveguide core layer comprises a plurality of waveguide sub-core layers coupled to each other, and the plurality of waveguide sub-core layers comprise: a first waveguide sub-core layer extending in a direction parallel to the main surface of the substrate from a first region close to the inner area of the photonic chip toward the first end surface and extending to a transition region between the first region and the first end surface; as well as The second waveguide sub-core layer is located on a side of the first waveguide sub-core layer away from the substrate, partially overlaps with the first waveguide sub-core layer in a direction perpendicular to the main surface of the substrate, and extends from the transition region to the first end face in a direction parallel to the main surface of the substrate.

13. The photonic chip end face coupling device according to claim 12, wherein The width of the first waveguide sub-core layer gradually decreases as approaching the transition region; and From the transition region to the first end face, the width of the second waveguide sub-core layer first gradually increases and then gradually decreases.

14. The photonic chip end face coupling device according to claim 13, wherein The first waveguide sub-core layer includes a first waveguide end located in the transition region, and the second waveguide sub-core layer includes a second waveguide end located in the transition region. The first waveguide end and the second waveguide end overlap in a direction perpendicular to the main surface of the substrate, and the width of the second waveguide end gradually increases as it approaches the first end face.

15. A photonic chip end face coupling device according to any one of claims 1 to 14, wherein the waveguide structure and the optical fiber are configured as follows: an optical signal is transmitted in the waveguide structure along a first optical path direction to the first end face, and is incident from the first end face to an intermediate medium between the first end face and the second end face, and undergoes a first refraction at the first end face; then the optical signal is incident from the intermediate medium to the optical fiber, and undergoes a second refraction at the second end face, and is transmitted in the optical fiber along a second optical path direction, wherein the first optical path direction and the second optical path direction are the same.

16. The photonic chip end face coupling device according to claim 15, wherein the waveguide structure and the optical fiber are configured such that: the reflected light of the optical signal at the first end face deviates from the first optical path direction, and the reflected light of the optical signal at the second end face deviates from the optical path direction of the optical signal in the intermediate medium.

17. The photonic chip end-face coupling device according to any one of claims 1 to 14, wherein a groove is provided in the waveguide cladding, and the groove is located on opposite sides of the waveguide core layer in a direction parallel to the main surface of the substrate and perpendicular to the extension direction of the waveguide core layer.

18. The photonic chip end-face coupling device according to any one of claims 1 to 14, wherein the optical fiber comprises an optical fiber core layer and an optical fiber cladding, the optical fiber cladding surrounds and covers the optical fiber core layer, and the optical fiber core layer and the optical fiber cladding are exposed at the second end face; The portion of the waveguide core layer exposed by the first end face is aligned with the portion of the optical fiber core layer exposed by the second end face in a direction parallel to the main surface of the substrate.

19. A photonic chip packaging structure, comprising the photonic chip end face coupling device according to any one of claims 1 to 18.

20. A method for manufacturing a photonic chip end-face coupling device, comprising: A photonic chip is provided, the photonic chip comprising a substrate and a waveguide structure located on one side of the substrate, the waveguide structure comprising a waveguide core layer and a waveguide cladding surrounding and covering the waveguide core layer, and having a first end face exposing the waveguide core layer and the waveguide cladding layer, wherein the waveguide core layer extends from a region close to an inner region of the photonic chip to the first end face in a direction parallel to a main surface of the substrate, the first end face is inclined toward the inner region of the photonic chip, and has a first angle between the first end face and a reference plane parallel to the main surface of the substrate; and An optical fiber is coupled to the photonic chip, wherein the optical fiber is located on one side of the photonic chip in a direction parallel to the main surface of the substrate and is coupled to the waveguide structure, wherein the optical fiber has a second end face facing the first end face of the waveguide structure and is also inclined toward the inner area of the photonic chip, and a second angle is formed between the second end face and the reference plane, and the first angle and the second angle are acute angles.

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