WO2018090593A1

WO2018090593A1 - Optical waveguide

Info

Publication number: WO2018090593A1
Application number: PCT/CN2017/085747
Authority: WO
Inventors: 费永浩; 朱以胜; 孙敏
Original assignee: 华为技术有限公司
Priority date: 2016-11-18
Filing date: 2017-05-24
Publication date: 2018-05-24
Also published as: CN106646736A; CN106646736B

Abstract

An optical waveguide, comprising: stacked in sequence, a substrate (01), a buried oxide layer (02), a waveguide layer (06), a cladding layer (03), and a moisture barrier (05). The moisture barrier (05) covers at least a part area on the surface of the cladding layer (03), the at least a part area comprises an area directly facing to the waveguide layer (06). The moisture barrier (05) is disposed on the surface of the cladding layer (03); therefore, the moisture resistance of the optical waveguide can be improved and influences of humidity change on mode field distribution and mode field size of the optical waveguide are reduced.

Description

Optical waveguide

The present application claims priority to Chinese Patent Application No. 20161101985, filed on Nov. 18, 2016, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present application relates to the field of optical communications, and in particular to an optical waveguide.

Background technique

The silicon light technology uses a silicon-on-insulator (SOI) as a base material to fabricate an optical chip using a complementary metal oxide semiconductor (CMOS) process to realize photoelectric signal conversion. As shown in FIG. 1, the SOI is composed of a substrate, a Buried Oxide (Box), and a Waveguide layer, wherein the material of the substrate is Si, and the material of the buried oxide layer is SiO ₂ , and the waveguide The material of the layer is Si. Since the refractive index of SiO ₂ is relatively small (about 1.44), and the refractive index of Si is large (about 3.47), the refractive index difference of the SOI waveguide is large, and the limitation of light is strong, and the waveguide can be small in size. A typical waveguide size is 400 nm x 220 nm.

In the existing solution, a cladding layer is usually disposed on the waveguide layer of the SOI waveguide, and the cladding layer is generally made of SiO ₂ material, and the refractive index of the SiO ₂ material may occur due to the humidity change of the environment in which the SOI waveguide is placed. The change, correspondingly, the refractive index of the cladding using the SiO ₂ material also changes, which in turn leads to a change in the mode field distribution and the mode field size of the optical waveguide.

Summary of the invention

The present application provides an optical waveguide for reducing the mode field distribution of the optical waveguide and the magnitude of the mode field change in the case of a change in the humidity of the environment in which the optical waveguide is placed, to reduce the humidity variation of the optical waveguide. The mode field distribution and the effect of the mode field size.

In a first aspect, an optical waveguide is provided, comprising:

a substrate (01), a buried oxide layer (02), a waveguide layer (06), a cladding layer (03), and a moisture barrier layer (05) stacked in sequence;

The moisture barrier layer (05) covers at least a portion of the surface of the cladding (03), the at least partial region including a region that is opposite the waveguide layer (06).

In the optical waveguide of the present application, by providing a moisture barrier layer on the surface of the cladding layer, the moisture resistance of the optical waveguide can be improved to reduce the influence of the humidity variation of the environment in which the optical waveguide is placed on the mode field distribution and the mode field size of the optical waveguide.

In some possible implementations, the buried oxide layer (02) covers at least a portion of a first surface of the substrate (01), the waveguide layer (06) covering the buried oxide layer (02) a first region of the first surface, the cladding (03) covering at least a portion of the first surface of the buried oxide layer (02) except the first region and the waveguide layer (06),

Wherein the first surface of the substrate (01) is a surface of the substrate (01) adjacent to a side of the buried oxide layer (02), and the first surface of the buried oxide layer (02) is The buried oxide layer (02) is away from the surface of one side of the substrate (01).

In some possible implementations, the buried oxide layer (02) covers a first surface of the substrate (01), and the first surface of the buried oxide layer (02) is apart from the first region The area includes the second area, the third area, and the a fourth area and a fifth area, wherein the second area is spaced apart from the third area by the fifth area, the third area and the fourth area are both adjacent to the first area, the third The area is located on one side of the first area, and the fourth area is located on the other side of the first area;

The cladding (03) includes a first cladding (031) and a second cladding (032), the first cladding (031) covers the second region, and the second cladding (032) covers The third region, the waveguide layer (06), and the fourth region;

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and the first cladding layer (031) Adjacent to a sidewall of the second cladding (032), a sidewall of the second cladding (032) adjacent to the cladding (031), and the fifth region,

The first surface of the first cladding layer (031) is a surface of the first cladding layer (031) away from the side of the buried oxide layer (02), and the second cladding layer (032) The first surface is the surface of the second cladding (032) on the side away from the buried oxide layer (02).

In this way, the moisture barrier layer (05) can also cover the sidewall of the second cladding layer (032), preventing moisture from entering from the sidewall of the cladding layer, and further improving the moisture resistance of the optical waveguide to further reduce the position of the optical waveguide. The effect of humidity changes in the environment on the mode field distribution and mode field size of the optical waveguide.

In some possible implementations, the buried oxide layer (02) covers a first surface of the substrate (01), and the first surface of the buried oxide layer (02) is apart from the first region At least a partial area includes a second area, a third area, and a fourth area, each of the third area and the fourth area being adjacent to the first area, the third area being located at one side of the first area The fourth area is located on the other side of the first area;

The buried oxide layer (02) has a groove having a notch facing away from the substrate (01), and the second region is located on a side of the first inner sidewall of the groove, The third region, the first region, and the fourth region are located on one side of the second inner sidewall of the groove, the first inner sidewall of the groove and the second sidewall of the second groove The inner side walls are opposite,

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and the first cladding layer (031) Adjacent to a sidewall of the second cladding (032), a sidewall of the second cladding (032) adjacent to the first cladding (031), and an inner surface of the recess,

The first surface of the first cladding layer (031) is a surface of the first cladding layer (031) away from the side of the buried oxide layer (02), and the second cladding layer (032) The first surface is a surface of the second cladding layer (032) away from the side of the buried oxide layer (02), and the inner surface of the recess includes the first inner sidewall and the second inner side a wall and a bottom surface of the groove.

In this way, the moisture barrier layer (05) can also cover the inner surface of the groove on the buried oxide layer (02), and can further improve the moisture resistance of the optical waveguide to further reduce the humidity variation of the environment in which the optical waveguide is located. The effect of mode field distribution and mode field size.

In some possible implementations, the first surface of the substrate (01) includes a sixth region, a seventh region, and an eighth region, and the eighth region is spaced apart from the seventh region by the eighth region;

The buried oxide layer (02) includes a first buried oxide layer (021) and a second buried oxide layer (022), the first buried oxide layer (021) covers the sixth region, and the second buried oxide layer a layer (022) covering the seventh region, the waveguide layer (06) Covering a first region of the first surface of the second buried oxide layer (02), the first surface of the second buried oxide layer (022) is away from the liner on the first buried oxide layer (022) The surface of one side of the bottom (01);

The cladding (03) includes a first cladding layer (031) and a second cladding layer (032), the first cladding layer (031) covering a first surface of the first buried oxide layer (021), The second cladding layer (032) covers a region other than the first region on the first surface of the waveguide layer (06) and the second buried oxide layer (022), the first buried oxide layer a first surface of (021) is a surface of the first buried oxide layer (021) on a side away from the substrate (01);

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and the first cladding layer (031) Adjacent to the sidewall of the second cladding (032), the sidewall of the second cladding (032) adjacent to the first cladding (031), and the first buried oxide layer (021) a sidewall of the second buried oxide layer (022), a sidewall of the second buried oxide layer (022) adjacent to the first buried oxide layer (021), and the eighth region,

In this way, the moisture barrier layer (05) can also cover both side walls of the second buried oxide layer (022) where the waveguide layer (06) is located, which can further improve the moisture resistance of the optical waveguide to further reduce the environment of the optical waveguide. The effect of humidity variation on the mode field distribution and mode field size of the optical waveguide.

In some possible embodiments, the cladding (03) covers a region other than the first region and the waveguide layer (06) on the first surface of the buried oxide layer (02).

This is advantageous for simplifying the fabrication process of the optical waveguide.

In some possible embodiments, the optical waveguide further includes an upper cladding layer (07) covering a side surface of the moisture barrier layer (05) away from the cladding layer (03).

By providing the upper cladding layer on the moisture barrier layer, the moisture resistance of the optical waveguide can be further improved.

In some possible embodiments, the moisture barrier layer (05) comprises one or more layers of a moisture barrier layer.

In some possible embodiments, the moisture barrier layer (05) comprises at least one of the following materials: Si _x N _1-x , SiON, Al, and Al _1-x O _x , where 0<x<1.

In some possible implementations, the distance between the moisture barrier layer (05) and the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm.

By spacing the moisture barrier layer from the waveguide layer by a suitable distance, the influence of the moisture barrier layer on the mode field of the optical waveguide can be reduced, and the influence of the moisture barrier layer on the performance of the optical waveguide can be reduced.

In some possible embodiments, the moisture barrier layer (05) has a thickness greater than or equal to 2 nm and less than or equal to 200 nm.

For example, the thickness of the moisture barrier layer (05) may also be greater than or equal to 3 nm and less than or equal to 100 nm.

By setting a suitable thickness for the moisture barrier layer, the influence of the moisture barrier layer on the mode field of the optical waveguide can be reduced, and the influence of the moisture barrier layer on the performance of the optical waveguide can be reduced.

In some possible implementations, the optical waveguide is a louver converter.

The scalpel converter of the present application can reduce the influence of the humidity change of the environment in which the reverse wedge embossed converter is placed on its mode field distribution and mode field size, thereby improving the relationship between the variogram converter and the optical fiber. Mode field mismatch reduces the insertion loss of the plaque converter.

In some possible implementations, the optical waveguide is a reverse wedge die spot converter.

DRAWINGS

1 is a schematic cross-sectional structural view of silicon on a insulator;

2 is a schematic cross-sectional view of an optical waveguide according to an embodiment of the present invention;

3 is a schematic view showing the overall structure of a variogram converter;

4 is a schematic cross-sectional view of an optical waveguide according to another embodiment of the present invention;

FIG. 5 is a cross-sectional structural view of an optical waveguide according to another embodiment of the present invention; FIG.

6 is a schematic cross-sectional view of an optical waveguide according to another embodiment of the present invention;

7 is a schematic cross-sectional view of an optical waveguide according to another embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of an optical waveguide according to another embodiment of the present invention.

detailed description

The technical solutions in the present application will be described below in conjunction with the drawings in the present application.

2 is a schematic illustration of an optical waveguide in accordance with the present application. As shown in FIG. 2, the optical waveguide includes a substrate (01), a buried oxide layer (02), a waveguide layer (06), a cladding layer (03), and a moisture barrier layer (05) which are sequentially stacked.

The moisture barrier layer (05) covers at least a portion of the surface of the cladding (03), at least a portion of which includes a region that faces the waveguide layer (06).

Specifically, the buried oxide layer (02) covers at least a portion of the first surface of the substrate (01), and the waveguide layer (06) covers the first region (11) of the first surface of the buried oxide layer (02), the cladding (03) covering at least a portion of the first surface (11) of the buried oxide layer (02) except the first region (11) and the waveguide layer (06).

Wherein the first surface of the substrate (01) is a surface of the substrate (01) adjacent to the side of the buried oxide layer (02), and the first surface of the buried oxide layer (02) is away from the buried oxide layer (02) The surface of one side of the substrate (01).

As shown in FIG. 2, if the substrate (01), the buried oxide layer (02), the waveguide layer (06), the cladding layer (03), and the moisture barrier layer (05) in the optical waveguide are sequentially stacked in the direction from bottom to top. Then, the first surface of the substrate (01) is the upper surface of the substrate (01), and the first surface of the buried oxide layer (02) is the upper surface of the buried oxide layer (02). For convenience of description, the upper surface of each layer in the optical waveguide shown in FIG. 2 may be collectively described as a first surface, and the lower surface of each layer is collectively described as a second surface.

It should be noted that the buried oxide layer (02) covers at least a portion of the first surface of the substrate (01), meaning that at least the second surface of the buried oxide layer (02) and the first surface of the substrate (01) Some areas are in contact. The waveguide layer (06) covers the first region (11) of the first surface of the buried oxide layer (02), meaning that the second surface of the waveguide layer (06) and the first region of the first surface of the buried oxide layer (02) (11) Contact. Similarly, the cladding (03) covers at least a portion of the first surface (11) of the buried oxide layer (02) except the first region (11) and the waveguide layer (06), meaning the second layer of the cladding (03) The surface is in contact with at least a portion of the first surface of the buried oxide layer (02) except for the first region (11), the first surface of the waveguide layer (06), and the sidewalls on both sides of the waveguide layer (06).

In some embodiments, the optical waveguide shown in FIG. 2 may be a Spot Size Converter (SSC). Figure 3 shows the overall structure of the SSC. The SSC can couple light into other optical waveguides (such as optical fibers). It should be understood that the SSC may adopt the wedge structure shown in FIG. 3, but the present application is not limited to the wedge-shaped SSC structure shown in FIG.

It should be understood that the optical waveguide shown in Fig. 2 can also be used as other optical waveguide devices.

For example, the size of the waveguide layer (06) can be designed to be 130 nm x 220 nm, where 220 nm can be the height value of the waveguide layer (06) and 130 nm can be the width value of the waveguide layer (06). It should be understood that the waveguide layer (06) can also be designed in other sizes.

It should be noted that if the variogram converter adopts the wedge structure shown in FIG. 3, 130 nm×220 nm may refer to the size of the narrowest end waveguide layer of the wedge structure.

The scalar converter of the present application can reduce the influence of the humidity change of the environment on its mode field distribution and mode field size, thereby improving the mode field mismatch between the variogram converter and the fiber. Reduce the insertion loss of the plaque converter.

The material of the substrate (01) is Si, the material of the buried oxide layer (02) is SiO ₂ , the material of the waveguide layer (06) is Si, and the material of the cladding layer (03) is SiO ₂ .

In some embodiments, the moisture barrier layer (05) can include a layer of moisture barrier. In other embodiments, as shown in FIG. 4, the moisture barrier layer (05) may further include a multilayer moisture barrier layer. The moisture-proof effect can be further enhanced by providing a multi-layer moisture barrier layer.

It should be understood that in FIG. 4, only the two layers of moisture barrier layers (051) and (052) are exemplified, and the moisture barrier layer (05) may further include other numbers of multilayer moisture barrier layers.

The material of the moisture barrier layer (05) can protect against moisture, and the refractive index of the material of the moisture barrier layer (05) can be greater than or equal to 1.4 and less than or equal to 3, which can reduce the influence of the moisture barrier layer on the mode field of the optical waveguide. For example, the material of the moisture barrier layer (05) may be Si _x N _1-x , SiON, Al or Al _1-x O _x , where 0<x<1. However, the present application is not limited thereto, and the material of the moisture barrier layer (05) may also be other moisture-proof materials.

When the moisture barrier layer (05) includes a multi-layer moisture barrier layer, the material of the multilayer moisture barrier layer may be the same or different, which is not limited in the present application.

The refractive index of the cladding layer (03) adjacent to the waveguide layer (06) is strongly correlated with the mode field size of the optical waveguide. By providing a moisture barrier layer on the surface of the cladding layer, water vapor can be prevented from entering the cladding layer (03), thereby reducing water vapor to light. The mode field distribution of the waveguide and the effect of the mode field size.

Alternatively, as shown in FIG. 5, the optical waveguide shown in FIG. 2 may further include an upper cladding layer (04). The upper cladding layer (04) covers a side surface of the moisture barrier layer (05) away from the cladding layer (03).

In some embodiments, the material of the upper cladding layer (04) may be the same as the material of the cladding layer (03), or may be different from the material of the cladding layer (03), which is not limited in this application. For example, the material of the upper cladding layer (04) may be SiO ₂ , may be Si ₃ N ₄ , or may be doped Si _1-x O _x , for example, phosphorus (P) or boron (B) may be doped.

It should be understood that when the upper cladding layer (04) is located at the outermost layer of the optical waveguide, the upper cladding layer (04) may also be referred to as a passivation layer.

By providing an upper cladding layer on the moisture barrier layer, the moisture resistance of the optical waveguide can be further improved to further reduce the influence of the humidity variation of the environment in which the optical waveguide is placed on the mode field distribution and the mode field size of the optical waveguide.

As shown in FIG. 2, by providing a flat moisture barrier layer on the optical waveguide, water vapor can be prevented from entering from the upper surface, and the structure is simple and practical. However, the water vapor can be intruded from the side wall, and therefore the present application also proposes a structure capable of achieving three-sided cladding, as shown in FIGS. 6 to 8. It should be understood that FIGS. 6 to 8 are examples of the optical waveguide shown in FIG. 2, and the corresponding contents are appropriately omitted in order to avoid redundancy.

The cladding (03) in the optical waveguide shown in FIGS. 6 to 8 includes a first cladding layer (031) and a second cladding layer (032), and the first surface of the first cladding layer (031) is a first cladding layer ( 031) a surface away from the side of the buried oxide layer (02), the first surface of the second cladding (032) being the surface of the second cladding (032) away from the side of the buried oxide layer (02).

Optionally, as shown in FIG. 6, the buried oxide layer (02) covers the first surface of the substrate (01), and the area other than the first region (11) on the first surface of the buried oxide layer (02) includes a second region (12), a third region (13), a fourth region (14), and a fifth region (15), and a fifth region (15) between the second region (12) and the third region (13) The third area (13) and the fourth area (14) are both adjacent to the first area (11), the third area (13) is located on one side of the first area (11), and the fourth area (14) is located at the The other side of an area (11);

The first cladding (031) covers the second region, and the second cladding (032) covers the third region, the waveguide layer (06) and the fourth region (14);

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and a first cladding layer (031) adjacent to the second cladding layer (032) The sidewall, the second cladding (032) is adjacent to the sidewall of the first cladding (031) and the fifth region (15).

Thus, by further increasing the area covered by the moisture barrier layer (05), the moisture barrier layer (05) can also cover the side walls of the second cladding layer (032), preventing moisture from entering from the side walls of the cladding layer, which can be further improved. The moisture resistance of the optical waveguide is to further reduce the influence of humidity variation on the mode field distribution and mode field size of the optical waveguide.

In some embodiments, the moisture barrier layer (05) may cover only the first surface of the second cladding layer (032), the sidewalls of the second cladding layer (032) adjacent to the first cladding layer (031), and the fifth region ( 15).

It should be noted that, in some embodiments, the optical waveguide cladding layer (03) may further include a first cladding layer (031) and a second cladding layer (032), and the first cladding layer (031) is located at the second layer. One side of the cladding (032).

In some embodiments, as shown in FIG. 6, the cladding (03) in the optical waveguide may further include two first cladding layers (031) and one first second cladding layer (032), and two first packages. The layers (031) are respectively located on both sides of the second cladding (032). The positional relationship of each of the first cladding layers (031) and other portions of the optical waveguides may be referred to the above description and will not be repeated here.

Optionally, as shown in FIG. 7, the buried oxide layer (02) covers the first surface of the substrate (01), and at least a portion of the first surface of the buried oxide layer (02) except the first region (11) The area includes a second area (12), a third area (13), and a fourth area (14), the third area (13) and the fourth area (14) being adjacent to the first area (11), the third area (13) is located on one side of the first area (11), and the fourth area (14) is located on the other side of the first area (11);

The buried oxide layer (02) has a groove, the groove of the groove faces away from the substrate (01), the second region (12) is located on one side of the first inner side wall of the groove, and the third region (13), The first area (11) and the fourth area (14) are located on one side of the second inner side wall of the groove, and the first inner side wall of the groove is opposite to the second inner side wall of the second groove;

The first cladding (031) covers the second region (12), and the second cladding (032) covers the third region (13), the waveguide layer (06) and the fourth region (14);

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and a first cladding layer (031) adjacent to the second cladding layer (032) The sidewall, the second cladding (032) is adjacent to the sidewall of the first cladding (031) and the inner surface of the recess.

Wherein the inner surface of the groove comprises a first inner side wall, a second inner side wall and a bottom surface of the groove.

Thus, by further increasing the area covered by the moisture barrier layer (05), the moisture barrier layer (05) can also cover the inner surface of the groove on the buried oxide layer (02), which can further improve the moisture resistance of the optical waveguide to further reduce The change in the humidity of the environment in which the optical waveguide is placed affects the mode field distribution and mode field size of the optical waveguide.

In some embodiments, the moisture barrier layer (05) may cover only the first surface of the second cladding layer (032), the sidewall of the second cladding layer (032) adjacent to the first cladding layer (031), and the recessed portion. The inner wall of the inner wall and the groove.

In some embodiments, the first cladding (031) is adjacent to the sidewalls of the second cladding (032) and the first interior of the recess The side walls can be in the same plane.

In some embodiments, the sidewalls of the first cladding layer (031) adjacent to the sidewalls of the second cladding layer (032) and the first inner sidewalls of the recesses may also be located in different planes. For example, the first inner sidewall of the recess may protrude from the sidewall of the first cladding (031) adjacent the second cladding (032).

Similarly, the sidewall of the second cladding (032) adjacent to the first cladding (031) and the second inner sidewall of the recess may be in the same plane or may be in different planes.

It should be noted that, in some embodiments, the optical waveguide cladding layer (03) may further include a first cladding layer (031) and a second cladding layer (032), and the first cladding layer (031) is located at the second layer. One side of the cladding (032). The buried oxide layer (02) has a recess on the opposite side of the region between the first cladding (031) and the second cladding (032).

In some embodiments, as shown in FIG. 7, the cladding (03) may further include two first cladding layers (031) and one first second cladding layer (032), and two first cladding layers (031). ) are located on both sides of the second cladding (032). The buried oxide layer (02) has two grooves on the opposite sides of the region between the two first cladding layers (031) and the second cladding layer (032). Positional relationship between each of the first cladding layers (031) and other layers in the optical waveguide, and each of the two recesses and other portions of the optical waveguide The positional relationship can be referred to the above description and will not be repeated here.

Optionally, as shown in FIG. 8, the first surface of the substrate (01) includes a sixth region (16), a seventh region (17), and an eighth region (18), and the sixth region (16) and the seventh region. The eighth area (18) is spaced between the areas (17);

The buried oxide layer (02) includes a first buried oxide layer (021) and a second buried oxide layer (022), the first buried oxide layer (021) covers the sixth region (16), and the second buried oxide layer (022) covers a seventh region (17), the waveguide layer (06) covers the first region (11) of the first surface of the second buried oxide layer (02), and the first surface of the second buried oxide layer (022) is the first buried oxide a surface of the layer (022) that is away from the side of the substrate (01);

The first cladding layer (031) covers the first surface of the first buried oxide layer (021), and the second cladding layer (032) covers the first surface of the waveguide layer (06) and the second buried oxide layer (022). a region outside the region, the first surface of the first buried oxide layer (021) is a surface of the first buried oxide layer (021) on a side away from the substrate (01);

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and a first cladding layer (031) adjacent to the second cladding layer (032) a side wall, a sidewall of the second cladding layer (032) adjacent to the first cladding layer (031), a sidewall of the first buried oxide layer (021) adjacent to the second buried oxide layer (022), and a second buried oxide layer The layer (022) is adjacent to the sidewall of the first buried oxide layer (021) and the eighth region (18).

In this way, the moisture barrier layer (05) can also cover the entire sidewall of the buried oxide layer (02), which can further improve the moisture resistance of the optical waveguide, thereby further reducing the mode field distribution of the humidity variation of the optical waveguide in the environment. And the effect of the mode field size.

In some embodiments, the moisture barrier layer (05) may cover only the first surface of the second cladding layer (032), the sidewall of the second cladding layer (032) adjacent to the first cladding layer (031), and the second buried oxide layer. The layer (022) is adjacent to the sidewall and the eighth region of the first buried oxide layer (021).

It should be noted that, in some embodiments, the optical waveguide cladding layer (03) may further include a first cladding layer (031) and a second cladding layer (032), and the first cladding layer (031) is located at the One side of the second cladding (032). The buried oxide layer (02) includes a first buried oxide layer (021) and a second buried oxide layer (022), the first buried oxide layer (031) being located on one side of the second buried oxide layer (032).

In some embodiments, as shown in FIG. 8, the cladding (03) in the optical waveguide may further include two first cladding layers (031). And a first second cladding layer (032), and the two first cladding layers (031) are respectively located on opposite sides of the second cladding layer (032). The buried oxide layer (02) has two first buried oxide layers (021) and two second buried oxide layers (022), and the two first buried oxide layers (021) are respectively located in the second buried oxide layer (022) ) on both sides. a positional relationship between each of the first cladding layers (031) and the other layers in the optical waveguide, and a first buried of each of the two first buried oxide layers (021) The positional relationship between the oxygen layer (021) and other portions in the optical waveguide can be referred to the above description and will not be repeated here.

A portion of the cladding (03) and/or buried oxide layer (02) may be etched away using an etching process to obtain a structure as shown in FIGS. 6-8 to increase the area covered by the moisture barrier.

Alternatively, as shown in FIGS. 6, 7, and 8, the moisture barrier layer (05) covers a partial region of the first surface of the first cladding layer (031).

This simplifies the fabrication process of the optical waveguide.

It should be understood that the moisture barrier layer (05) may also cover the entire area of the first surface of the first cladding (031).

Optionally, the distance between the moisture barrier layer (05) and the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm. As shown in FIGS. 2, 4 to 8, the longitudinal distance between the lower edge of the moisture barrier layer 05 and the upper edge of the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm. As shown in FIGS. 6 to 8, the lateral distance of the moisture barrier layer (05) near the edge of the left side of the second cladding layer (032) and the edge of the left side of the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm. Or the lateral distance of the edge of the moisture barrier layer (05) near the right side of the second cladding layer (032) and the edge of the right side of the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm.

Optionally, the moisture barrier layer (05) has a thickness greater than or equal to 3 nm and less than or equal to 100 nm.

Optionally, the moisture barrier layer (05) has a thickness greater than or equal to 2 nm and less than or equal to 200 nm.

By providing a suitable thickness for the moisture barrier layer, the influence of the moisture barrier layer on the mode field of the optical waveguide can be reduced, and the influence of the moisture barrier layer on the performance of the optical waveguide can be reduced.

It should be noted that the present application does not limit the fabrication process of the optical waveguide.

The foregoing is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application. It should be covered by the scope of protection of this application. Therefore, the scope of protection of the present application should be determined by the scope of the claims.

Claims

An optical waveguide, comprising:

a substrate (01), a buried oxide layer (02), a waveguide layer (06), a cladding layer (03), and a moisture barrier layer (05) stacked in sequence;

The moisture barrier layer (05) covers at least a portion of the surface of the cladding (03), the at least partial region including a region that is opposite the waveguide layer (06).
The optical waveguide according to claim 1, wherein

The buried oxide layer (02) covers at least a portion of a first surface of the substrate (01), the waveguide layer (06) covering a first region of the first surface of the buried oxide layer (02), The cladding layer (03) covers at least a portion of the first surface of the buried oxide layer (02) except the first region and the waveguide layer (06),

Wherein the first surface of the substrate (01) is a surface of the substrate (01) adjacent to a side of the buried oxide layer (02), and the first surface of the buried oxide layer (02) is The buried oxide layer (02) is away from the surface of one side of the substrate (01).
The optical waveguide according to claim 2, wherein

The buried oxide layer (02) covers a first surface of the substrate (01), and a region other than the first region on the first surface of the buried oxide layer (02) includes a second region, a third area, a fourth area, and a fifth area, wherein the second area is spaced apart from the third area by the fifth area, and the third area and the fourth area are both adjacent to the first area, The third area is located on one side of the first area, and the fourth area is located on the other side of the first area;

The cladding (03) includes a first cladding (031) and a second cladding (032), the first cladding (031) covers the second region, and the second cladding (032) covers The third region, the waveguide layer (06), and the fourth region;

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and the first cladding layer (031) Adjacent to the sidewall of the second cladding (032), the sidewall of the second cladding (032) adjacent to the first cladding (031), and the fifth region,

The first surface of the first cladding layer (031) is a surface of the first cladding layer (031) away from the side of the buried oxide layer (02), and the second cladding layer (032) The first surface is the surface of the second cladding (032) on the side away from the buried oxide layer (02).
The optical waveguide according to claim 2, wherein

The buried oxide layer (02) covers a first surface of the substrate (01), and at least a portion of the first surface of the buried oxide layer (02) except the first region includes a second region a third area and a fourth area, each of the third area and the fourth area being adjacent to the first area, the third area being located at one side of the first area, the fourth area being located at Said the other side of the first area;

The buried oxide layer (02) has a groove having a notch facing away from the substrate (01), and the second region is located on a side of the first inner sidewall of the groove, The third region, the first region, and the fourth region are located on one side of the second inner sidewall of the groove, the first inner sidewall of the groove and the second sidewall of the second groove The inner side walls are opposite;

The cladding (03) includes a first cladding (031) and a second cladding (032), the first cladding (031) covers the second region, and the second cladding (032) covers The third region, the waveguide layer (06), and the fourth region;

The moisture barrier layer (05) covers at least a portion of the first surface of the first cladding layer (031), the second portion a first surface of the cladding (032), a sidewall of the first cladding (031) adjacent to the second cladding (032), and a second cladding (032) adjacent to the first package The side wall of the layer (031) and the inner surface of the groove,

The first surface of the first cladding layer (031) is a surface of the first cladding layer (031) away from the side of the buried oxide layer (02), and the second cladding layer (032) The first surface is a surface of the second cladding layer (032) away from the side of the buried oxide layer (02), and the inner surface of the recess includes the first inner sidewall and the second inner side a wall and a bottom surface of the groove.
The optical waveguide according to claim 2, wherein

The first surface of the substrate (01) includes a sixth region, a seventh region, and an eighth region, and the eighth region is spaced apart from the seventh region by the eighth region;

The buried oxide layer (02) includes a first buried oxide layer (021) and a second buried oxide layer (022), the first buried oxide layer (021) covers the sixth region, and the second buried oxide layer a layer (022) covering the seventh region, the waveguide layer (06) covering a first region of the first surface of the second buried oxide layer (02), and the second buried oxide layer (022) a surface is a surface of the first buried oxide layer (022) on a side away from the substrate (01);

The cladding (03) includes a first cladding layer (031) and a second cladding layer (032), the first cladding layer (031) covering a first surface of the first buried oxide layer (021), The second cladding layer (032) covers a region other than the first region on the first surface of the waveguide layer (06) and the second buried oxide layer (022), the first buried oxide layer a first surface of (021) is a surface of the first buried oxide layer (021) on a side away from the substrate (01);

The moisture barrier layer (05) covers at least a partial region of the first surface of the first cladding layer (031), a first surface of the second cladding layer (032), and the first cladding layer (031) Adjacent to the sidewall of the second cladding (032), the sidewall of the second cladding (032) adjacent to the first cladding (031), and the first buried oxide layer (021) a sidewall of the second buried oxide layer (022), a sidewall of the second buried oxide layer (022) adjacent to the first buried oxide layer (021), and the eighth region,

The first surface of the first cladding layer (031) is a surface of the first cladding layer (031) away from the side of the buried oxide layer (02), and the second cladding layer (032) The first surface is the surface of the second cladding (032) on the side away from the buried oxide layer (02).
The optical waveguide according to claim 2, wherein said cladding layer (03) covers a region other than said first region and said waveguide layer on said first surface of said buried oxide layer (02) (06).
The optical waveguide according to any one of claims 1 to 6, further comprising:

An upper cladding layer (07) covering a side surface of the moisture barrier layer (05) away from the cladding layer (03).
The optical waveguide according to any one of claims 1 to 7, characterized in that the moisture barrier layer (05) comprises one or more sub-moisture barrier layers.
The optical waveguide according to any one of claims 1 to 8, characterized in that the moisture barrier layer (05) comprises at least one of the following materials: Si x N 1-x , SiON, Al and Al 1-x O x , where 0<x<1.
The optical waveguide according to any one of claims 1 to 9, characterized in that the distance between the moisture barrier layer (05) and the waveguide layer (06) is greater than or equal to 1 μm and less than or equal to 20 μm.
The optical waveguide according to any one of claims 1 to 10, wherein the moisture barrier layer (05) has a thickness greater than or equal to 2 nm and less than or equal to 200 nm.
The optical waveguide according to any one of claims 1 to 11, wherein the optical waveguide is a reverse wedge die spot converter.