Phase-controllable grating, preparation method and application thereof

Abstract

The invention provides a phase-controllable grating which comprises a waveguide layer and a Bragg reflection layer which are arranged in a stacked mode, the Bragg reflection layer forms a periodic Bragg grating, the period of the periodic Bragg grating is lambda, the Bragg reflection layer comprises a removing part, and the removing part is arranged between the waveguide layer and the Bragg reflection layer. The removal part is a part formed after the Bragg reflection layer with the total length of d is removed from the Bragg reflection layer. By adjusting the length of the removal part, the phase difference of the periodic Bragg grating can be adjusted at will. Meanwhile, the invention further provides a corrosion method for preparing the grating with the controllable phase, the preparation cost of the grating with the controllable phase is reduced, and industrial popularization is facilitated.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical devices, and in particular to a phase-controllable grating, a preparation method and applications thereof. Background Art

[0002] Bragg grating is a key component widely used in optical communications and optical devices, mainly used to achieve light reflection and filtering functions. Traditional Bragg gratings are composed of periodically arranged high-refractive index and low-refractive index materials, and reflect light of a specific wavelength through the interference effect of light. The technologies for adjusting the phase of Bragg gratings in the prior art mainly include holographic exposure technology, electron beam exposure technology and nanoprinting. Although holographic exposure technology can achieve high-precision grating structure, it requires precise control of light source and exposure conditions, and has high requirements for experimental equipment and operating technology. Although electron beam exposure technology can achieve high-precision nanostructures, it is slow and not suitable for large-scale production. Nanoprinting technology uses nanoscale templates or molds to copy periodic structures onto grating materials to adjust the phase, but it requires high-quality nano templates, the preparation and maintenance costs of the templates are high, and the compatibility requirements for materials are also high.

[0003] Although holographic exposure, electron beam exposure and nano-printing technology each have their own advantages in the manufacture of Bragg gratings, these technologies also have obvious limitations. The low diffraction efficiency and applicability to specific wavelengths of holographic exposure technology limit its performance in certain applications. The high cost and low production efficiency of electron beam exposure technology make it difficult to apply on a large scale. Although nano-printing technology has the characteristics of high resolution and high efficiency, the preparation and maintenance costs of the template are high, and the compatibility requirements of the materials are strict. In addition, the performance comparison analysis of these technologies in terms of phase adjustment accuracy, manufacturing cost and production efficiency shows that it is difficult for existing technologies to simultaneously meet the requirements of high precision, low cost and high efficiency. Therefore, it is particularly urgent to develop a low-cost, high-precision, large-scale production-suitable Bragg grating phase controllable technology. Summary of the invention

[0004] The purpose of the present disclosure is to provide a low-cost, high-precision Bragg grating phase controllable technology suitable for large-scale production.

[0005] To achieve the above object, the present disclosure provides a phase-controllable grating, comprising a waveguide layer and a Bragg reflection layer stacked, wherein the Bragg reflection layer forms a periodic Bragg grating, wherein the period of the periodic Bragg grating is Λ, and the Bragg reflection layer comprises a removal portion, wherein the removal portion is a portion formed after removing a Bragg reflection layer having a total length of d from the Bragg reflection layer, and the removal portion is used to adjust the phase difference of the periodic Bragg grating. Preferably, d=mΛ, and m is a positive integer.

[0006] As a further improvement of the present application, the removed portion is located at any position of the Bragg reflection layer.

[0007] As a further improvement of the present application, the removing portion includes one or more removing units.

[0008] As a further improvement of the present application, the material of the waveguide layer is silicon-based, optical fiber, or at least two elements in the III main group and the V main group; the material of the Bragg reflection layer is silicon-based, optical fiber, or at least two elements in the III main group and the V main group.

[0009] As a further improvement of the present application, the material of the Bragg reflection layer is different from the material of the waveguide layer.

[0010] As a further improvement of the present application, the Bragg reflection layer includes a first Bragg reflection layer and a second Bragg reflection layer which are stacked, and the first Bragg reflection layer is arranged adjacent to the waveguide layer.

[0011] As a further improvement of the present application, the material of the first Bragg reflection layer is different from the materials of the waveguide layer and the second Bragg reflection layer.

[0012] To achieve the above object, the present application also provides a method for preparing the phase-controllable grating according to the above, comprising the following steps:

[0013] S1, preparing a waveguide layer and a Bragg reflection layer, and etching grating grooves on the Bragg reflection layer to form a periodic Bragg grating;

[0014] S2. Removing a Bragg reflection layer having a total length d from the Bragg reflection layer to form a removed portion.

[0015] As a further improvement of the present application, step S2 is specifically as follows:

[0016] First, coating a photoresist on the periodic Bragg grating;

[0017] Secondly, on the periodic Bragg grating, photoresist is removed at a preset position by photolithography, and then the Bragg reflection layer corresponding to the preset position is removed by etching, and the total length of the removed Bragg reflection layer is d;

[0018] Finally, the photoresist coated on the periodic Bragg grating that has not been etched is removed by photolithography.

[0019] As a further improvement of the present application, the Bragg reflection layer includes a first Bragg reflection layer and a second Bragg reflection layer which are stacked, and the material of the first Bragg reflection layer is different from the materials of the waveguide layer and the second Bragg reflection layer, step S2 is specifically as follows:

[0020] First, coating a photoresist on the periodic Bragg grating;

[0021] Secondly, on the periodic Bragg grating, photolithography is used to remove the photoresist at a preset position, and then the first Bragg reflection layer corresponding to the preset position is removed by a selective etching method, the total length of the removed first Bragg reflection layer is d, and the second Bragg reflection layer is peeled off, and the total length of the peeled second Bragg reflection layer is also d;

[0022] Finally, the photoresist coated on the periodic Bragg grating that has not been etched is removed by photolithography.

[0023] To achieve the above objectives, the present application also provides an application of the above-mentioned phase-controllable grating in an optical device.

[0024] The beneficial effect of the present application is that the present application designs a periodic Bragg grating structure, and by setting a removal portion on the Bragg reflection layer, the phase difference of the periodic Bragg grating can be arbitrarily adjusted. A preparation method of the removal portion is also provided, and the method does not need to change the original preparation process of the periodic Bragg grating. On the basis of the original process, one more process is added to remove the Bragg reflection layer at a preset position and a total length of d, thereby obtaining a periodic Bragg grating with a preset phase difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the structure of the periodic Bragg grating before the removal portion is provided;

[0026] Figure 2 is a schematic diagram of the structure of a periodic Bragg grating with a removed portion;

[0027] Figure 3 is a comparative schematic diagram of a periodic Bragg grating before and after a removal portion is provided;

[0028] Figure 4 is a schematic diagram of the structure of a periodic Bragg grating having a plurality of removal units;

[0029] Figure 5 is a schematic structural diagram of a periodic Bragg grating having a multi-layer Bragg grating;

[0030] Figure 6 is a schematic diagram of a method for preparing a phase-controllable grating of Example 3;

[0031] Figure 7 is a schematic diagram of a method for preparing a phase-controllable grating of Example 5;

[0032] Figure 8 It is a schematic diagram of the method for preparing the phase-controllable grating of Example 10.

[0033] In the figure: 1, waveguide layer; 2, Bragg reflection layer; 3, removal portion; 31, first removal unit; 32, second removal unit; 21, first Bragg reflection layer; 22, second Bragg reflection layer. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present disclosure to clearly and completely describe the technical solutions of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0035] In order to make the above-mentioned objects, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure is further described in detail below in conjunction with specific implementation methods.

[0036] In view of the limitations of the prior art, the present application discloses a phase-controllable grating, such as Figures 1 to 3 As shown, it comprises a waveguide layer 1 and a Bragg reflection layer 2 which are stacked, the Bragg reflection layer 2 forming a periodic Bragg grating, the period of the periodic Bragg grating is Λ, the Bragg reflection layer 2 comprises a removal portion 3, the removal portion 3 is a portion formed by removing a Bragg reflection layer having a total length d from the Bragg reflection layer 2, and the removal portion is used to adjust the phase difference of the periodic Bragg grating. Generally speaking, d=mΛ, m is a positive integer, but when the removal portion is located at the end of the periodic Bragg grating, the removal portion will include a distance less than one grating period Λ.

[0037] The periodic Bragg grating includes a gate portion and a groove portion, the groove portion may be filled with semiconductor material or not, the length of a gate portion and a groove portion is Λ, the refractive index of the gate portion is n1, the refractive index of the groove portion is n2, n1≠n2. The laser condition of the periodic Bragg grating is λ0=2n eff ·Λ, λ0 is the wavelength of light in vacuum, n eff The effective refractive index of the periodic Bragg grating, Λ is the period of the periodic Bragg grating.

[0038] The present application adjusts the phase difference of the periodic Bragg grating according to the following formula I:

[0039]

[0040] Where Δφ is the phase difference of the periodic Bragg grating, λ0 is the wavelength of light in vacuum, and Δn eff is the difference in effective refractive index of the periodic Bragg grating, Δn eff =n eff1 -n eff2 , n eff2 is the effective refractive index of the periodic Bragg grating corresponding to the removed portion, n eff1 is the effective refractive index of the periodic Bragg grating before the removed portion is removed.

[0041] Based on the above scheme, by designing a removal portion on the Bragg reflection layer and adjusting the length of the removal portion, the phase difference of the periodic Bragg grating can be arbitrarily adjusted, for example, the phase difference of the periodic Bragg grating can be between 0 and 180°. At the same time, by optimizing the length of the removal portion, the phase shift error caused by inaccurate processing during the production of the periodic Bragg grating can also be solved, ensuring that the phase shift error is effectively controlled within the range of 5° to 10°. For example, during the processing of the periodic Bragg grating for the distributed feedback laser, the period of the periodic Bragg grating at the end of the grating will be greater than or less than the period of the preset periodic Bragg grating due to the accuracy of the cutting equipment, thereby generating a phase shift error. By optimizing the length of the removal portion, the phase shift generated at the end of the grating can be offset at the same time. Therefore, the design of the removal portion enhances the phase control capability of the grating and improves the overall performance of the grating, making it have a wider application prospect in the fields of optical fiber communication, silicon optoelectronic devices, lasers, optical sensing, VR, MR, etc.

[0042] In an optional embodiment, the removal portion 3 is located at any position of the Bragg reflector layer 2. For example, the removal portion 3 can be located at the end, the middle position, and so on of the Bragg reflector layer 2. The position of the removal portion 3 can be optimized to be located at any position of the Bragg reflector layer 2, providing greater design flexibility. This flexibility allows the grating to adjust the position of the phase shift according to specific application requirements, thereby optimizing the reflection characteristics and filtering effect of the grating. At the same time, a grating with a specific reflection spectrum can be designed according to different application scenarios. For example, in some applications, it may be necessary to open a transmission window at a specific position, and this design can achieve such customization. In addition, by setting removal portions at different positions, the performance of the grating can be optimized, such as improving reflection efficiency, reducing sidelobe effects, etc.

[0043] In an optional embodiment, the removal section 3 includes one or more removal units. The removal section 3 can be optimized to include one or more removal units, which enables the grating to achieve multiple functions. For example, by providing multiple removal units, multiple transmission windows can be opened in the reflection spectrum of the grating to form a comb filter. At the same time, multiple removal units can further optimize the performance of the grating. For example, by symmetrically distributing multiple phase shift points at the center of the grating, the transmission window line width at the center of the stopband can be significantly widened. In addition, this design can adjust the number and position of the removal units according to different application requirements, thereby achieving higher adaptability and performance optimization. For example: Figure 4 As shown, the removal portion 3 includes a first removal unit 31 and a second removal unit 32, and the total length of the first removal unit 31 and the second removal unit 32 is d, where d=mΛ. Δn eff =n eff1 -n eff2 , n eff2 is the effective refractive index of the periodic Bragg grating corresponding to the first removal unit 31 and the second removal unit 32, n eff1 is the effective refractive index of the periodic Bragg grating before being removed by the first removing unit 31 and the second removing unit 32 .

[0044] In an optional embodiment, the material of the waveguide layer 1 can be but not limited to silicon-based, optical fiber, or at least two elements in the III main group and the V main group; the material of the Bragg reflection layer 2 can be but not limited to silicon-based, optical fiber, or at least two elements in the III main group and the V main group. The waveguide layer 1 and the Bragg reflection layer 2 can be optimized to use different materials because the phase-controllable grating designed in the present application can be applied to different optical devices. For example, in lasers, elements in the III main group and the V main group are commonly used. Compound semiconductor materials composed of elements in the III main group and the V main group (such as gallium arsenide GaAs, indium phosphide InP, etc.) usually have a higher refractive index, which helps to achieve efficient light transmission in the waveguide layer 1 and reduce light loss. The Bragg reflection layer 2 realizes light reflection of a specific wavelength through periodically arranged high refractive index and low refractive index materials. Materials composed of group III and group V elements can provide a large refractive index difference, thereby achieving higher reflectivity and narrower reflection bandwidth, thereby optimizing the reflection characteristics and filtering effect of the grating. In addition, materials composed of group III and group V elements have mature epitaxial growth technologies, such as molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD), which can achieve high-quality thin film preparation. These materials show good process stability during the manufacturing process, which helps to achieve high-precision grating structures.

[0045] In an optional embodiment, the material of the Bragg reflector layer 2 is different from that of the waveguide layer 1. This design facilitates targeted removal of the Bragg reflector layer with a length of d. For example, the Bragg reflector layer with a length of d can be removed by etching without affecting the waveguide layer. The design with different materials facilitates the preparation of the removal portion by etching. The etching method has low cost and is easy to mass-produce and industrialize.

[0046] In an alternative embodiment, if Figure 5 As shown, the Bragg reflection layer 2 includes a first Bragg reflection layer 21 and a second Bragg reflection layer 22 which are stacked, and the first Bragg reflection layer 21 is arranged adjacent to the waveguide layer 1. This structural design is convenient for design, so that the refractive index of the first Bragg reflection layer 21 is different from the refractive index of the second Bragg reflection layer 22. When light propagates in the waveguide layer 1 and encounters the Bragg reflection layer 2, the light is scattered and reflected due to the sudden change of the refractive index. This design can significantly enhance the reflection effect of light and improve the reflection efficiency of the grating. The combination of materials with different refractive indices can achieve higher reflectivity and narrower reflection bandwidth, which is crucial for high-precision optical modulation and filtering functions in optical device applications such as optical communications, optical sensors, and lasers. For example, when applied to DFB lasers, by optimizing the structure of the Bragg reflection layer 2, mode competition can be reduced, and the feedback of the main mode can be enhanced, thereby achieving more stable single-mode oscillation.

[0047] In an optional embodiment, the material of the first Bragg reflection layer 21 is different from the material of the waveguide layer 1 and the second Bragg reflection layer 22. This design facilitates the first Bragg reflection layer 21 and the second Bragg reflection layer 22 to form different refractive indices, and facilitates the targeted removal of the Bragg reflection layer 2 with a length of d. For example, the first Bragg reflection layer 21 with a length of d can be removed by a targeted etching method, and then the second Bragg reflection layer 22 corresponding to the first Bragg reflection layer 21 can be removed by a peeling method.

[0048] The present application also discloses a method for preparing the above-mentioned phase-controllable grating, comprising the following steps:

[0049] S1, preparing a waveguide layer 1 and a Bragg reflection layer 2, and etching grating grooves on the Bragg reflection layer 2 to form a periodic Bragg grating;

[0050] S2 . Removing a portion of the Bragg reflection layer 2 having a total length d from the Bragg reflection layer 2 to form a removed portion 3 .

[0051] Based on the existing method for preparing a phase-controllable grating, there is no need to change the original preparation process of the periodic Bragg grating. By adding another step on the basis of the original process, the Bragg reflection layer 2 at the preset position and with a total length of d can be removed, thereby obtaining a periodic Bragg grating with a preset phase difference, and the error of the phase difference can be controlled within the range of 5° to 10°.

[0052] In an optional embodiment, the specific removal process may be: first, coating the periodic Bragg grating with photoresist; second, photolithographically removing the photoresist at a preset position on the periodic Bragg grating, and then removing the Bragg reflection layer 2 corresponding to the preset position by etching, wherein the total length of the removed Bragg reflection layer 2 is d; finally, photolithographically removing the photoresist coated on the periodic Bragg grating that has not been corroded. It should be noted that the etching method of the present application may be, but is not limited to, any one of selective etching and non-selective etching. In addition, the total length d of the Bragg reflection layer may be greater than the length of the photoresist at the preset position. This is because the photoresist at the preset position may cover the local grating, such as Figure 8 As shown, when the photoresist at the preset position is removed, the local grating covered by the photoresist at the preset position will also contact the etching solution and be completely corroded, so that the total length d of the Bragg reflection layer may be greater than the length of the photoresist at the preset position.

[0053] Based on the preparation method of the phase-controllable grating, there is no need to change the original preparation process of the periodic Bragg grating. On the basis of the original process, the steps of coating photoresist, removing part of the photoresist at a preset position and a preset length, selectively etching and removing the Bragg reflection layer 2 corresponding to the photoresist part, and removing the remaining photoresist are added, so that the periodic Bragg grating can achieve a preset phase difference and control the phase shift error within the range of 5° to 10°, which significantly improves the reflection characteristics of the grating and the stability of the filtering effect.

[0054] In an optional embodiment, the Bragg reflection layer 2 includes a first Bragg reflection layer 21 and a second Bragg reflection layer 22 which are stacked, and the material of the first Bragg reflection layer 21 is different from the material of the waveguide layer 1 and the second Bragg reflection layer 22. Figure 6As shown, step S2 is specifically as follows: first, coating the periodic Bragg grating with photoresist; second, removing the photoresist at a preset position on the periodic Bragg grating by photolithography, and then removing the first Bragg reflection layer 21 corresponding to the preset position by a selective etching method, wherein the total length of the removed first Bragg reflection layer 21 is d, and peeling off the second Bragg reflection layer 22, wherein the total length of the peeled second Bragg reflection layer is also d; finally, removing the photoresist coated on the periodic Bragg grating that has not been corroded by photolithography.

[0055] By making the material of the first Bragg reflection layer 21 different from that of the waveguide layer 1 and the second Bragg reflection layer 22, more precise phase control can be achieved. This design allows the introduction of different refractive index modulations in the Bragg reflection layer 2, thereby optimizing the phase difference of the grating and ensuring that the phase error is effectively controlled within the range of 5° to 10°. The combination of different materials can provide a greater refractive index difference, thereby enhancing the reflection efficiency of light in the Bragg reflection layer 2. This design helps to improve the reflection characteristics of the grating and the stability of the filtering effect, especially in distributed feedback lasers (DFB lasers), which can significantly improve the performance of single-mode oscillation. The first Bragg reflection layer 21 is removed by etching, and the corresponding second Bragg reflection layer 22 is peeled off. This process step can achieve a preset phase difference for the periodic Bragg grating without changing the original periodic Bragg grating preparation process. This method improves the flexibility and compatibility of the manufacturing process.

[0056] The present application also discloses that the above-mentioned phase-controllable grating can be applied to optical devices such as optical fiber communications, silicon optoelectronic devices, lasers, optical sensors, VR, MR, etc. The difference is that in different devices, the materials and preparation methods of the phase-controllable grating are slightly different.

[0057] In order to verify that the technical solution of the present application has feasibility and excellent effect, the following examples are also provided.

[0058] Example 1

[0059] The present embodiment provides a phase-controllable grating, comprising a waveguide layer and a Bragg reflection layer which are stacked, wherein the Bragg reflection layer forms a periodic Bragg grating, wherein the period of the periodic Bragg grating is Λ, wherein the material of the waveguide layer is InP, and the material of the Bragg reflection layer is GaAs. The periodic Bragg grating comprises a gate portion and a groove portion, wherein the length of a gate portion and a groove portion is Λ, the refractive index of the gate portion is n1, the refractive index of the groove portion is n2, n1≠n2, and the Bragg reflection layer comprises a removal portion, wherein the removal portion is a Bragg reflection layer removed from the Bragg reflection layer with a total length of d.

[0060] A method for preparing the above-mentioned phase-controllable grating is also provided, comprising the following steps:

[0061] S1, preparing a waveguide layer and a Bragg reflection layer, and etching grating grooves on the Bragg reflection layer to form a periodic Bragg grating;

[0062] S2. First, a photoresist is coated on the periodic Bragg grating; secondly, the photoresist at a preset position is removed by photolithography on the periodic Bragg grating, and then the Ga element in the Bragg reflective layer corresponding to the preset position is removed by etching with a phosphoric acid (H3PO4)-based solution, thereby removing the Bragg reflective layer with a total length of d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography; wherein the phosphoric acid-based solution is a mixed solution of H3PO4, H2O2, and H2O, and the volume ratio of H3PO4, H2O2, and H2O is 1:1:1.

[0063] Example 2

[0064] The difference between this embodiment and embodiment 1 is that, in step S2, a sulfuric acid (H2SO4)-based solution is used to corrode the As element in the Bragg reflection layer not covered by the photoresist, thereby removing the Bragg reflection layer with a total length d; wherein the sulfuric acid-based solution is a mixed solution of H2SO4, H2O2, and H2O, and the volume ratio of H2SO4, H2O2, and H2O is 1:1:1.

[0065] Example 3

[0066] This embodiment provides a phase-controllable grating, comprising a waveguide layer and a Bragg reflection layer which are stacked, wherein the Bragg reflection layer forms a periodic Bragg grating, wherein the period of the periodic Bragg grating is Λ, wherein the material of the waveguide layer is InP, the Bragg reflection layer comprises a first Bragg reflection layer and a second Bragg reflection layer, wherein the material of the first Bragg reflection layer is GaAs, and the material of the second Bragg reflection layer is InP. The periodic Bragg grating comprises a gate portion and a groove portion, wherein the length of a gate portion and a groove portion is Λ, the refractive index of the gate portion is n1, the refractive index of the portion of the groove portion formed by the first Bragg grating is n2, n1≠n2, and the refractive index of the portion of the groove portion formed by the second Bragg grating is n3, n3≠n2. The Bragg reflection layer comprises a removal portion, wherein the removal portion is a Bragg reflection layer removed from the Bragg reflection layer with a total length of d.

[0067] A method for preparing the phase-controllable grating is also provided, such as Figure 6 As shown, the following steps are included:

[0068] S1, preparing a waveguide layer, a first Bragg reflection layer and a second Bragg reflection layer, and etching grating grooves on the first Bragg reflection layer and the second Bragg reflection layer to form a periodic Bragg grating;

[0069] S2. First, a photoresist is coated on the periodic Bragg grating; second, the photoresist at a preset position on the periodic Bragg grating is removed by photolithography, and then the Ga element in the first Bragg reflection layer corresponding to the preset position is removed by etching with a phosphoric acid (H3PO4)-based solution, thereby removing the first Bragg reflection layer with a total length of d, and peeling off the second Bragg reflection layer with a total length of d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography; wherein the phosphoric acid-based solution is a mixed solution of H3PO4, H2O2, and H2O, and the volume ratio of H3PO4, H2O2, and H2O is 1:1:1. Attachment Figure 6 The case where the distance covered by the photoresist at the preset position is a complete grating period is taken as an example.

[0070] Example 4

[0071] The difference between this embodiment and Embodiment 3 is that, in step S2, a sulfuric acid (H2SO4)-based solution is used to corrode the As element in the first Bragg reflection layer corresponding to the preset position, and the first Bragg reflection layer and the second Bragg reflection layer with a total length d are removed; wherein the sulfuric acid-based solution is a mixed solution of H2SO4, H2O2, and H2O, and the volume ratio of H2SO4, H2O2, and H2O is 1:1:1.

[0072] Example 5

[0073] The difference between this embodiment and embodiment 3 is that the removed portion is a Bragg reflection layer with a total length of d removed from the end of the Bragg reflection layer. Since the last grating period is incomplete, d includes the last incomplete grating period Λ. This embodiment can solve the phase shift error caused by the end of the periodic Bragg grating being limited by the cutting process during the production process, and ensure that the phase shift error is effectively controlled within the range of 5° to 10°.

[0074] A method for preparing the phase-controllable grating is also provided, such as Figure 7 As shown, the following steps are included:

[0075] S1, preparing a waveguide layer, a first Bragg reflection layer and a second Bragg reflection layer, and etching grating grooves on the first Bragg reflection layer and the second Bragg reflection layer to form a periodic Bragg grating;

[0076] S2. First, a photoresist is coated on the periodic Bragg grating; second, on the periodic Bragg grating, a preset length of the photoresist is removed by photolithography, and then the Ga element in the first Bragg reflection layer with a total length d of the end is removed by etching with a phosphoric acid (H3PO4)-based solution, thereby removing the first Bragg reflection layer with a total length d, and peeling off the corresponding second Bragg reflection layer with a total length d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography; wherein the phosphoric acid-based solution is a mixed solution of H3PO4, H2O2, and H2O, and the volume ratio of H3PO4, H2O2, and H2O is 1:1:1. The schematic diagram of the preparation process of the phase-controllable grating of this embodiment is shown in Figure 7 .

[0077] Example 6

[0078] The difference between this embodiment and the first embodiment is that the material of the waveguide layer is InP, and the material of the Bragg reflection layer is InGaAs.

[0079] A method for preparing the above-mentioned phase-controllable grating is also provided, comprising the following steps:

[0080] S1, preparing a waveguide layer and a Bragg reflection layer, and etching grating grooves on the Bragg reflection layer to form a periodic Bragg grating;

[0081] S2. First, a photoresist is coated on the periodic Bragg grating; secondly, the photoresist at a preset position is removed by photolithography on the periodic Bragg grating, and then the Ga element in the Bragg reflective layer corresponding to the preset position is removed by etching with a phosphoric acid (H3PO4)-based solution, thereby removing the Bragg reflective layer with a total length of d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography; wherein the phosphoric acid-based solution is a mixed solution of H3PO4, H2O2, and H2O, and the volume ratio of H3PO4, H2O2, and H2O is 1:1:1.

[0082] Example 7

[0083] The difference between this embodiment and Embodiment 6 is that, in step S2, a sulfuric acid (H2SO4)-based solution is used to corrode the As element in the Bragg reflection layer corresponding to the preset position, thereby removing the Bragg reflection layer with a total length d; wherein the sulfuric acid-based solution is a mixed solution of H2SO4, H2O2, and H2O, and the volume ratio of H2SO4, H2O2, and H2O is 1:1:1.

[0084] Example 8

[0085] The difference between this embodiment and the third embodiment is that the material of the waveguide layer is InP, the material of the first Bragg reflection layer is InGaAs, and the material of the second Bragg reflection layer is InP.

[0086] A method for preparing the above-mentioned phase-controllable grating is also provided, comprising the following steps:

[0087] S1, preparing a waveguide layer, a first Bragg reflection layer and a second Bragg reflection layer, and etching grating grooves on the first Bragg reflection layer and the second Bragg reflection layer to form a periodic Bragg grating;

[0088] S2. First, a photoresist is coated on the periodic Bragg grating; secondly, the photoresist at a preset position on the periodic Bragg grating is removed by photolithography, and then the Ga element in the first Bragg reflection layer corresponding to the preset position is removed by etching with a phosphoric acid (H3PO4)-based solution, thereby removing the first Bragg reflection layer with a total length of d, and peeling off the second Bragg reflection layer with a total length of d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography; wherein the phosphoric acid-based solution is a mixed solution of H3PO4, H2O2, and H2O, and the volume ratio of H3PO4, H2O2, and H2O is 1:1:1.

[0089] Example 9

[0090] The difference between this embodiment and Embodiment 8 is that, in step S2, a sulfuric acid (H2SO4)-based solution is used to corrode the As element in the first Bragg reflection layer corresponding to the preset position, and the first Bragg reflection layer and the second Bragg reflection layer with a total length d are removed; wherein the sulfuric acid-based solution is a mixed solution of H2SO4, H2O2, and H2O, and the volume ratio of H2SO4, H2O2, and H2O is 1:1:1.

[0091] Example 10

[0092] The difference between this embodiment and embodiment 3 is that the distance covered by the photoresist at the preset position includes the case of an incomplete grating period, such as Figure 8 shown.

[0093] Embodiment 11

[0094] This embodiment provides a phase-controllable grating, comprising a waveguide layer and a Bragg reflector layer which are stacked, wherein the Bragg reflector layer forms a periodic Bragg grating, wherein the period of the periodic Bragg grating is Λ, wherein the material of the waveguide layer is Si, and the material of the Bragg reflector layer is SiO2. The periodic Bragg grating comprises a gate portion and a groove portion, wherein the length of a gate portion and a groove portion is Λ, the refractive index of the gate portion is n1, the refractive index of the groove portion is n2, n1≠n2, and the Bragg reflector layer comprises a removal portion, wherein the removal portion is a Bragg reflector layer having a total length d removed from the Bragg reflector layer.

[0095] A method for preparing the above-mentioned phase-controllable grating is also provided, comprising the following steps:

[0096] S1, preparing a waveguide layer and a Bragg reflection layer, and etching grating grooves on the Bragg reflection layer to form a periodic Bragg grating;

[0097] S2. First, a photoresist is coated on the periodic Bragg grating; second, the photoresist at a preset position is removed by photolithography on the periodic Bragg grating, the total length of the photoresist at the preset position is d, and then the Bragg reflection layer corresponding to the preset position is removed by etching with a hydrofluoric acid solution, thereby removing the Bragg reflection layer with a total length of d; finally, the remaining photoresist coated on the unetched periodic Bragg grating is removed by photolithography. In this application, the concentration of hydrofluoric acid, the etching time and the temperature are controlled according to the specific situation to avoid affecting the Si waveguide layer.

[0098] It should be noted that the above embodiments are only further explanations of the technical solution of the present application, and the material of the waveguide layer is not limited to InP and Si, the material of the Bragg reflection layer is not limited to GaAs and InGaAs, the material of the first Bragg reflection layer is not limited to GaAs and InGaAs, and the material of the second Bragg reflection layer is not limited to InP. For example, the material of the Bragg reflection layer can also be Si3N4, etc.

[0099] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present disclosure. They are not intended to limit the scope of protection of the present disclosure. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A phase-controllable grating, characterized in that: The invention comprises a waveguide layer and a Bragg reflection layer which are stacked, wherein the Bragg reflection layer forms a periodic Bragg grating, wherein the period of the periodic Bragg grating is Λ, and the Bragg reflection layer comprises a removal portion, wherein the removal portion is a portion formed after the Bragg reflection layer having a total length of d is removed from the Bragg reflection layer, and the removal portion is used to adjust the phase difference of the periodic Bragg grating.

2. The phase-controllable grating according to claim 1, characterized in that: The removed portion is located at any position of the Bragg reflective layer.

3. The phase-controllable grating according to claim 1, characterized in that: The removing part includes one or more removing units.

4. The phase-controllable grating according to any one of claims 1 to 3, characterized in that: The material of the waveguide layer is silicon-based, optical fiber, or at least two elements in the III main group and the V main group; the material of the Bragg reflection layer is silicon-based, optical fiber, or at least two elements in the III main group and the V main group.

5. The phase-controllable grating according to claim 4, characterized in that: The material of the Bragg reflection layer is different from the material of the waveguide layer.

6. The phase-controllable grating according to claim 4, characterized in that: The Bragg reflection layer includes a first Bragg reflection layer and a second Bragg reflection layer which are stacked, and the first Bragg reflection layer is arranged adjacent to the waveguide layer.

7. The phase-controllable grating according to claim 6, characterized in that: The material of the first Bragg reflection layer is different from the materials of the waveguide layer and the second Bragg reflection layer.

8. A method for preparing a phase-controllable grating according to any one of claims 1 to 3, characterized in that: The steps include: S1, preparing a waveguide layer and a Bragg reflection layer, and etching grating grooves on the Bragg reflection layer to form a periodic Bragg grating; S2. Removing a Bragg reflection layer having a total length d from the Bragg reflection layer to form a removed portion.

9. The method for preparing a phase-controllable grating according to claim 8, characterized in that: Step S2 is specifically as follows: First, coating a photoresist on the periodic Bragg grating; Secondly, on the periodic Bragg grating, photoresist is removed at a preset position by photolithography, and then the Bragg reflection layer corresponding to the preset position is removed by etching, and the total length of the removed Bragg reflection layer is d; Finally, the photoresist coated on the periodic Bragg grating that has not been etched is removed by photolithography.

10. The method for preparing a phase-controllable grating according to claim 9, characterized in that: When the Bragg reflection layer comprises a first Bragg reflection layer and a second Bragg reflection layer which are stacked, and the material of the first Bragg reflection layer is different from the materials of the waveguide layer and the second Bragg reflection layer, step S2 is specifically as follows: First, coating a photoresist on the periodic Bragg grating; Secondly, on the periodic Bragg grating, photolithography is used to remove the photoresist at a preset position, and then the first Bragg reflection layer corresponding to the preset position is removed by a selective etching method, the total length of the removed first Bragg reflection layer is d, and the second Bragg reflection layer is peeled off, and the total length of the peeled second Bragg reflection layer is also d; Finally, the photoresist coated on the periodic Bragg grating that has not been etched is removed by photolithography.

11. Use of the phase-controllable grating according to any one of claims 1 to 7 in an optical device.

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