Coating method for end face of optical waveguide device, optical waveguide device and mask strip

Abstract

The present invention relates to the technical field of optical waveguide devices, and discloses a coating method for the end face of an optical waveguide device, an optical waveguide device and a mask strip, the method comprising: providing an optical waveguide device and a first mask strip, the optical waveguide device having a front cavity surface and a rear cavity surface to be coated in a first preset direction, the first mask strip comprising a body and an extension portion, the extension portion being located at one end of the body in the first preset direction, extending from the body to a second preset direction, and the extension portion forming a preset micro-nano pattern, the first preset direction and the second preset direction being perpendicular to each other; placing the optical waveguide device and the first mask strip on a fixture, so that the target surface of the optical waveguide device fits with the extension portion, the target surface being the front cavity surface or the rear cavity surface; forming a thin film layer having a preset micro-nano pattern on the target surface. The present invention can modify the waveguide of the optical waveguide device, thereby regulating the performance, thereby improving the device performance or realizing a specific function.

Description

Technical Field

[0001] The present invention relates to the technical field of optical waveguide devices, and in particular to a coating method for an end face of an optical waveguide device, an optical waveguide device and a mask strip. Background Art

[0002] Optical waveguide devices based on end-face light emission are micro-nano optical devices specially designed to guide and control the transmission of light waves in specific media. Optical waveguide devices can be high-power semiconductor lasers, distributed feedback Bragg grating (DFB) lasers, distributed Bragg reflector (DBR) lasers, silicon photonic integrated optical circuits, arrayed waveguide grating devices, etc. They have important applications in process laser pumping, optical communications, gas detection, optical gyroscopes, quantum communications, etc., and have broad market application prospects and research and development value.

[0003] The end faces of optical waveguide devices are coated with high-reflectivity (HR) films or low-reflectivity (AR) films. At present, when coating HR films or AR films, the performance of the optical cavity of the optical waveguide device (such as light intensity distribution, cavity loss or electrical characteristics, etc.) is regulated by controlling the film refractive index or thickness in the deposition direction. However, the degree of regulation is limited by only regulating the film refractive index and thickness, resulting in poor final regulation effect. Among them, generally HR films refer to films with a reflectivity greater than 85%, and AR films refer to films with a reflectivity less than 25%. Summary of the invention

[0004] In view of this, the present invention provides a coating method for the end face of an optical waveguide device, an optical waveguide device and a mask strip to solve the problem that the performance is controlled by the film refractive index and thickness, and the degree of control is limited, resulting in poor final control effect, insufficient device performance or inability to achieve specific functions.

[0005] In a first aspect, the present invention provides a method for coating an end face of an optical waveguide device, the method comprising: providing an optical waveguide device and a first mask strip, wherein the optical waveguide device has a front cavity surface and a rear cavity surface to be coated in a first preset direction, the first mask strip comprises a body and an extension portion, the extension portion is located at one end of the body in the first preset direction, extends from the body to a second preset direction, and the extension portion forms a preset micro-nano pattern, the first preset direction and the second preset direction are perpendicular to each other; placing the optical waveguide device and the first mask strip on a fixture, so that the target surface of the optical waveguide device is attached to the extension portion, wherein the target surface is the front cavity surface or the rear cavity surface; and forming a thin film layer with a preset micro-nano pattern on the target surface.

[0006] The coating method for the end face of an optical waveguide device provided in this embodiment can transfer the preset micro-nano pattern to the thin film layer formed on the end face when coating the end face of the optical waveguide device by setting a first mask strip having a preset micro-nano pattern, thereby achieving regulation of the performance of the optical waveguide device, thereby improving the device performance or achieving specific functions, and at the same time has the characteristics of being simple, reliable, and capable of low-cost mass production.

[0007] In an optional embodiment, the number of the optical waveguide devices and the number of the first mask strips are both multiple, and the multiple optical waveguide devices and the multiple first mask strips correspond one to one. Placing the optical waveguide devices and the first mask strips on a fixture includes: cross-arranging the multiple optical waveguide devices and the multiple first mask strips on the fixture in sequence, so that the target surface of the optical waveguide device is in contact with the extension portion of the corresponding first mask strip.

[0008] In this embodiment, the preset micro-nano image on the first mask strip can be transferred to the end faces of multiple strips in batches, which can fully utilize the semiconductor micro-nano processing technology, has the advantages of high precision, relatively simple operation, reusable mask strips, and batch production.

[0009] In an optional embodiment, the fixture includes a first protrusion and a second protrusion, the first protrusion is used to place the optical waveguide device, the second protrusion is used to place the first mask strip, and the first protrusion and the second protrusion have a height difference in the first preset direction so that the target surface of the optical waveguide device fits with the extension portion of the first mask strip.

[0010] In this embodiment, through the above arrangement, the first mask strip can be more conveniently placed in the base with the inner and outer height difference, and the first mask strip can be fixed at the center of the optical waveguide device, thereby leaving an area not blocked by the mask strip on the end face of the optical waveguide device in the first preset direction, ensuring that the end face can be evenly covered with a film of a certain thickness and refractive index, thereby achieving the function of anti-reflection or high reflectivity.

[0011] In an optional embodiment, before placing the optical waveguide device and the first mask strip on a fixture, the method further includes: providing a plurality of second mask strips, wherein the second mask strips are in a rectangular structure; and cross-arranging the plurality of optical waveguide devices and the plurality of first mask strips in sequence on the fixture includes: cross-arranging the plurality of optical waveguide devices and the plurality of first mask strips in sequence on the fixture, and a side of the first mask strip away from the corresponding first optical waveguide device is bonded to a side of the second mask strip, and the other side of the second mask strip is bonded to a side of the second optical waveguide device away from the corresponding first mask strip, wherein the first optical waveguide device and the second optical waveguide device are any two adjacent optical waveguide devices among the plurality of optical waveguide devices arranged in sequence.

[0012] In this embodiment, the second mask strip is placed behind the first mask strip, which can prevent the top of the strip from directly contacting the extension of the first mask strip, thereby affecting the light extraction efficiency.

[0013] In an optional embodiment, forming a thin film layer having a preset micro-nano pattern on the target surface includes: when the target surface is in contact with the extension portion, performing a deposition process on the target surface to form a thin film layer having a preset micro-nano pattern on the target surface.

[0014] In a second aspect, the present invention provides an optical waveguide device, which has a front cavity surface and a rear cavity surface provided with a thin film layer in a first preset direction, and the thin film layer of the front cavity surface and the rear cavity surface is prepared by the method of the first aspect or any corresponding embodiment thereof.

[0015] In a third aspect, the present invention provides a mask strip, the mask strip comprising a main body and an extension portion; the extension portion is located at one end of the main body in a first preset direction, extends from the main body to a second preset direction, and the extension portion forms a preset micro-nano pattern, and the extension portion is used to transfer the preset micro-nano pattern to a thin film layer formed on the target surface of an optical waveguide device when the target surface is coated on the target surface of the optical waveguide device, wherein the first preset direction and the second preset direction are perpendicular to each other, the optical waveguide device has a front cavity surface and a rear cavity surface to be coated in the first preset direction, and the target surface is the front cavity surface and / or the rear cavity surface.

[0016] In an optional embodiment, the optical waveguide device is a quantum cascade laser, the thin film layer includes a metal thin film layer, the extension portion has a rectangular structure, the preset micro-nano pattern is rectangular, and the length of the extension portion in the second preset direction is less than the length of the target surface in the second preset direction.

[0017] In this embodiment, by making the length of the extension portion in the second preset direction smaller than the length of the target surface in the second preset direction, a part of the end face can be shielded, so as to achieve the effect of plating only part of the metal, thereby avoiding the situation where the P-face and N-face of the bar are interconnected due to the end face being fully plated with metal, thereby causing a short circuit in the quantum cascade laser, thereby optimizing the electrical characteristics of the end face while achieving the control of the performance of the optical waveguide device.

[0018] In an optional implementation, the length of the extension portion in the second preset direction ranges from 10 um to a first preset value, wherein the first preset value is the length of the optical waveguide device in the second preset direction - 20 um.

[0019] In an optional embodiment, the optical waveguide device is a metal grating device, and the extension portion includes a plurality of indicator grating lines, wherein the plurality of indicator grating lines are arranged at intervals along a third preset direction, the preset micro-nano pattern is a grating pattern, and the third preset direction, the first preset direction, and the second preset direction are perpendicular to each other.

[0020] In this embodiment, the end face has a grating pattern, and the interference effect of the metal grating pattern on the end face can be used to achieve a high reflectivity end face, thereby reducing the threshold of the light-emitting device, suppressing the diffraction loss of the cavity surface, and enhancing the power.

[0021] In an optional embodiment, the length of the extension portion in the second preset direction is less than or equal to the length of the target surface in the second preset direction.

[0022] In an optional implementation, the length of the extension portion in the second preset direction ranges from 10 um to the length of the target surface in the second preset direction.

[0023] In an optional embodiment, the optical waveguide device is a semiconductor laser, and the extension portion includes a plurality of preset micro-nano structures, wherein the plurality of preset micro-nano structures are arranged at intervals along a third preset direction so that the thin film layer on the target surface has a cavity area of ​​a preset shape at a preset position, and the third preset direction, the first preset direction and the second preset direction are perpendicular to each other.

[0024] In this embodiment, the end face has a hollow area formed by a preset micro-nano structure, which can increase the mirror loss of the high-order mode at this position, thereby reducing the high-order mode, lowering the far-field divergence angle, and improving the brightness of the laser.

[0025] In an optional embodiment, the preset micro-nano structure is in the shape of a match, and the length of the first preset micro-nano structure in the second preset direction is greater than the length of the second preset micro-nano structure in the second preset direction, wherein the first preset micro-nano structure is a part of the multiple preset micro-nano structures, and the second preset micro-nano structure is another part of the multiple preset micro-nano structures.

[0026] In an optional embodiment, the spacing between the first preset micro-nano structures in the first preset direction is a first value, the spacing between the second preset micro-nano structures in the first preset direction is a second value, the first value ranges from the waveguide width -10um to the waveguide width +10um, and the second value ranges from the first value -5um to the first value -1um.

[0027] In an optional implementation, the length of the extension portion in the first preset direction ranges from 1 um to 100 um.

[0028] In an optional implementation, a length of the body in the first preset direction is smaller than a length of the optical waveguide device in the first preset direction.

[0029] In an optional implementation, the length of the body in the second preset direction ranges from 100um to 500um.

[0030] In an optional embodiment, the material of the mask strip is one or more of gallium arsenide, indium phosphide, silicon or quartz. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a schematic structural diagram of an optical waveguide device according to an embodiment of the present invention;

[0033] Figure 2 is a schematic flow chart of a coating method for an end face of an optical waveguide device according to an embodiment of the present invention;

[0034] Figure 3 is a schematic structural diagram of a first mask strip according to an embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of a cleavage or cutting process according to an embodiment of the present invention;

[0036] Figure 5 is a schematic structural diagram of a bar in a zy plane according to an embodiment of the present invention;

[0037] Figure 6 is a schematic diagram of a three-dimensional structure of a bar according to an embodiment of the present invention;

[0038] Figure 7 is a schematic diagram of the positional relationship between a first mask strip and an optical waveguide device according to an embodiment of the present invention;

[0039] Figure 8 is a schematic diagram of a deposition process of a PVD device according to an embodiment of the present invention;

[0040] Fig. 9 yes Figure 8 A schematic diagram of the deposition results of the illustrated embodiment;

[0041] Fig.10 is a schematic structural diagram of a thin film layer of a quantum cascade laser according to an embodiment of the present invention;

[0042] Fig.11 is a schematic structural diagram of a first mask strip in an xy plane according to an embodiment of the present invention;

[0043] Fig.12 is a schematic diagram of a three-dimensional structure of a first mask strip according to an embodiment of the present invention;

[0044] Fig.13 is a schematic structural diagram of a target surface according to an embodiment of the present invention;

[0045] Fig.14 is a schematic structural diagram of a traditional target surface according to an embodiment of the present invention;

[0046] Fig.15 is a schematic structural diagram of a thin film layer of a conventional quantum cascade laser according to an embodiment of the present invention;

[0047] Fig.16a is a schematic structural diagram of a grating graphic according to an embodiment of the present invention;

[0048] Fig.16b is a schematic structural diagram of another grating graphic according to an embodiment of the present invention;

[0049] Fig.16cis a schematic structural diagram of another grating graphic according to an embodiment of the present invention;

[0050] Fig.17 is a schematic structural diagram of another first mask strip in the xy plane according to an embodiment of the present invention;

[0051] Fig.18 is a schematic structural diagram of an end face of a semiconductor laser according to an embodiment of the present invention;

[0052] Fig.19 is a schematic structural diagram of another first mask strip in the yz plane according to an embodiment of the present invention;

[0053] Fig. 20 is a schematic structural diagram of another first mask strip in the xy plane according to an embodiment of the present invention;

[0054] Fig.21 is a schematic diagram of an end face thin film layer of a semiconductor laser according to an embodiment of the present invention;

[0055] Fig. 22 is a schematic structural diagram of a coating fixture according to an embodiment of the present invention;

[0056] Fig.23 is a structural schematic diagram of an arrangement method in the zx plane according to an embodiment of the present invention;

[0057] Fig.24 is a schematic structural diagram of the first arrangement method in the zy plane according to an embodiment of the present invention;

[0058] Fig.25 is a schematic structural diagram of a second arrangement method on the zy plane according to an embodiment of the present invention;

[0059] Fig.26 is a schematic structural diagram of a third arrangement method in the zy plane according to an embodiment of the present invention;

[0060] Fig. 27 is a schematic structural diagram of a fourth arrangement method in the zy plane according to an embodiment of the present invention;

[0061] Fig.28 is a schematic structural diagram of another arrangement method in the zx plane according to an embodiment of the present invention;

[0062] Fig.29 is a partial structural schematic diagram of another coating fixture according to an embodiment of the present invention;

[0063] Fig.30 This is a physical picture of a match-shaped micro-nanostructure pattern prepared according to an embodiment of the present invention.

[0064] 1. Reference numerals: 100, optical waveguide device; 110, front cavity surface; 120, rear cavity surface; 130, bar; 131, first end surface; 132, second end surface; 300, first mask strip; 310, body; 320, extension portion; 321, indicator grating line; 322, preset micro-nano structure; 410, wafer; 810, semiconductor substrate; 820, mask strip; 830, source; 1011, first dielectric film; 1021, second dielectric film; 1022, metal film; 1023, third dielectric film; 1401, coating area; 1801, cavity area; 2200, fixture; 2210, first protrusion; 2220, second protrusion; 2230, microneedle adjuster; 2231, differential rod; 2310, second mask strip. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0066] For example, the HR film set on the end face of optical waveguide devices such as lasers and optical amplifiers can be used to form the necessary optical resonant cavity structure. Through the high reflectivity end face, the light wave can be reflected back and forth in the cavity to achieve cumulative amplification of light, and generate laser or enhance optical signals after reaching the threshold. At the same time, the HR film can also reduce the loss of light and ensure that the light can propagate as much as possible within the predetermined path.

[0067] Setting AR film on the end face of optical waveguide devices such as optical lenses can effectively reduce the reflection loss of light at the interface and increase the intensity of transmitted light. In addition, reducing reflection can not only improve the transmission efficiency, but also reduce the generation of stray light, thereby improving the signal-to-noise ratio of optical waveguide devices.

[0068] Specifically, HR film is designed by stacking multiple layers of materials with different refractive indices, and using the interference effect of light, so that light of a specific wavelength or band undergoes constructive interference after multiple reflections at the interface, thereby greatly enhancing the reflectivity, which can be as high as 99% or above. AR film also uses a multi-layer film system design, and by controlling the thickness and refractive index of each layer of material, the reflected light undergoes multiple reflections and interferences between the film layers, and then destructively reflects, thereby achieving extremely low reflectivity at a specific wavelength or band, which can be less than 1%.

[0069] At present, traditional optical waveguide devices, such as compound semiconductor lasers, generally use cleavage to form the cavity surface (end face) of the laser cavity, and then use physical vapor deposition (PVD) equipment to form HR film or AR film on the end face.

[0070] When preparing HR films or AR films, by controlling the deposition direction (such as Figure 1 The film refractive index and / or thickness of the optical waveguide device (in the direction shown on the z-axis) can be used to realize a film layer with a certain reflectivity at a specific wavelength, and to adjust the performance of the optical cavity of the optical waveguide device (such as light intensity distribution, cavity loss or electrical characteristics, etc.). For example, through this one-dimensional coating method in the end face direction, the light intensity distribution in the optical cavity can be adjusted to achieve high-power output of the HR-AR corresponding cavity face; or break the end face symmetry to achieve stable single-mode output of the DFB laser; or use AR film-AR film to break the resonant cavity to form a semiconductor optical amplifier or gain chip waveguide, etc. However, the degree of regulation is limited only by regulating the film refractive index and thickness, resulting in limited final regulation effect and failure to further improve the device characteristic parameters.

[0071] In addition, the end face coating can also prevent cavity surface oxidation and water vapor erosion, thereby protecting the optical waveguide cavity surface.

[0072] The present invention has been found through research that at the end surface (such as Figure 1 A micro-nano pattern (a pattern at the micrometer or nanometer level) is formed on the film layer of the front cavity surface 110 and the rear cavity surface 120 of the optical waveguide device 100 shown in the figure, and the HR film and / or the AR film are modified. While achieving the control of the end face electrical properties of the optical waveguide device, the wavelength, polarization, phase, intensity of the output light, and the cavity loss of the optical waveguide, the effect of controlling the output optical performance can be further improved.

[0073] In view of this, the present invention provides a coating method for the end face of an optical waveguide device. By setting a mask strip with a preset micro-nano pattern, the preset micro-nano pattern can be transferred to a thin film layer formed on the end face when coating the end face of the optical waveguide device, thereby achieving the regulation of the performance of the optical waveguide device while improving the regulation effect.

[0074] The coating method for the end face of an optical waveguide device provided by the present application is described in detail below with reference to the accompanying drawings.

[0075] Figure 2 FIG. 1 is a schematic flow chart of a method for coating an end face of an optical waveguide device according to an embodiment of the present invention. Figure 2 As shown, the method comprises the following steps:

[0076] Step S201: providing an optical waveguide device and a first mask strip.

[0077] The optical waveguide device has a front cavity surface and a rear cavity surface to be coated in a first preset direction. Figure 1 As shown, the first preset direction may be the direction shown by the z-axis of the three-dimensional rectangular coordinate system. At this time, Figure 1 110 in the figure represents the front cavity surface to be coated. Figure 1 Reference numeral 120 indicates the rear cavity surface to be coated.

[0078] For example, Figure 3 As shown, the first mask strip 300 includes a main body 310 and an extension portion 320. The extension portion 320 is located at one end of the main body 310 in a first preset direction, extends from the main body 310 to a second preset direction, and forms a preset micro-nano pattern. The extension portion 320 can form a shadow mask effect, and can transfer the preset micro-nano pattern to a thin film layer formed on the target surface when the target surface of the optical waveguide device is coated.

[0079] Among them, the target surface is the front cavity surface or the back cavity surface, and the preset micro-nano shape can be set by the staff according to the type of optical waveguide device. For example, when the optical waveguide device is a quantum cascade laser, the preset micro-nano shape can be rectangular; when the optical waveguide device is an end-face metal grating device, the preset micro-nano shape can be a grating pattern; when the optical waveguide device is a high-power semiconductor laser, the preset micro-nano shape can be a match shape.

[0080] The first preset direction and the second preset direction are perpendicular to each other. For example, the first preset direction is the direction indicated by the z-axis in the three-dimensional rectangular coordinate system, and the second preset direction may be the direction indicated by the y-axis in the three-dimensional rectangular coordinate system.

[0081] The optical waveguide device is prepared from a bar. For example, the present invention can obtain the bar by cleaving or cutting a wafer. Figure 4 As shown, cleaving or cutting refers to the process of separating a complete large-area semiconductor wafer 410 into a plurality of independent chip bars 130 along predetermined cutting paths by physical (eg, laser cutting, mechanical scribing, etc.) or chemical means.

[0082] Specifically, the bar refers to a long strip of semiconductor material that has been processed by a specific process, usually in a rectangular structure, with a certain thickness, width and length. The bar 130 can be as follows: Figure 5 and Figure 6 As shown. Figure 5 and Figure 6 As shown, the first end surface 131 and the second end surface 132 of the bar 130 in the direction indicated by the z-axis respectively form the front cavity surface and the back cavity surface of the optical waveguide device.

[0083] Step S202: placing the optical waveguide device and the first mask strip on a fixture so that the target surface of the optical waveguide device is aligned with the extension portion.

[0084] The target surface is the front cavity surface or the back cavity surface.

[0085] Specifically, after the fixture is arranged, the positional relationship between the first mask strip and the optical waveguide device can be as follows: Figure 7 shown.

[0086] Step S203, forming a thin film layer with a preset micro-nano pattern on the target surface.

[0087] Exemplarily, after the target surface of the optical waveguide device is bonded to the extension portion, the first mask strip and the optical waveguide device can be placed together in a PVD device, and the first mask strip cooperates with the physical vapor deposition method to form a shadow mask effect, and the preset micro-nano pattern on the extension portion of the first mask strip is transferred to the front cavity surface or the back cavity surface of the optical waveguide device, so as to form a thin film layer with the preset micro-nano pattern on the target surface after the deposition is completed.

[0088] Specifically, Figure 8 As shown, the source 830 (evaporation source or sputtering source) of the PVD device is a material supply source, which is used to convert the material to be deposited (such as metal) into a gaseous state or a plasma state, and then deposit it on the surface of the semiconductor substrate 810 to form a thin film. During deposition, a mask strip 820 is set on the semiconductor substrate 810 to block part of the area (shadow mask effect), which can avoid the formation of a thin film in the blocked area, and obtain the following Fig. 9 The structure shown.

[0089] The coating method for the end face of an optical waveguide device provided in this embodiment, by providing a first mask strip having a preset micro-nano pattern, can transfer the preset micro-nano pattern to a thin film layer formed on the end face when coating the end face of the optical waveguide device, thereby achieving regulation of the performance of the optical waveguide device while improving the regulation effect.

[0090] In order to facilitate understanding of the coating method for the end face of an optical waveguide device provided by the present invention, the structure of the first mask strip provided by the present invention is firstly described below with reference to a specific example.

[0091] First, the optical waveguide device is taken as a quantum cascade laser as an example for explanation.

[0092] Specifically, quantum cascade laser is an important optoelectronic device with a spectral range covering the mid-infrared band to the far-infrared band, and can be used in a variety of fields such as trace gas detection and free-space optical communication. After the wafer process is completed, cleavage coating will be carried out, that is, thin film layers (AR film and HR film) will be prepared on the front and back cavity surfaces of the bar to form a resonant cavity structure.

[0093] For example, the thin film layers of a quantum cascade laser can be Fig.10 As shown, the AR film can be a first dielectric film 1011, and the material of the first dielectric film 1011 can be one or more of silicon dioxide (SiO2), aluminum oxide (Al2O3), yttrium oxide (Y2O3), ytterbium oxide (Yb2O3), yttrium fluoride (YF3), zinc sulfide (ZnS) and zirconium oxide (Zr2O3).

[0094] The thickness of the AR film can be determined according to the design requirements of wavelength and reflectivity. For example, the thickness of the AR film (i.e., the length in the first preset direction) can be any value from 10nm to 3000nm. For example, the thickness of the AR film can be 10nm, 20nm, 50nm, 200nm, 500nm, 1000nm, 1800nm, 2000nm or 3000nm, etc.

[0095] The HR film may include a second dielectric film 1021 , a metal film 1022 and a third dielectric film 1023 which are stacked, wherein the second dielectric film 1021 covers the end face of the quantum cascade laser, and the materials of the second dielectric film 1021 and the third dielectric film 1023 are the same as those of the first dielectric film 1011 .

[0096] The thickness of the second dielectric film 1021 and the third dielectric film 1023 (i.e., the length in the first preset direction) can be any value between 10 nm and 1000 nm. For example, the thickness of the second dielectric film 1021 and the third dielectric film 1023 can be 10 nm, 20 nm, 50 nm, 200 nm, 500 nm, 800 nm or 1000 nm, etc., wherein the thickness of the second dielectric film 1021 and the thickness of the third dielectric film 1023 can be the same or different.

[0097] The metal film 1022 (i.e., the metal thin film layer) may be composed of at least one metal layer. For example, the metal film 1022 may be composed of titanium (Ti) gold (Au) Ti, Ti platinum (Pt) Au, TiAu or Au, that is, the metal film 1022 may be composed of a Ti metal layer, an Au metal layer and a Ti metal layer stacked in sequence, or the metal film 1022 may be composed of a Ti metal layer, a Pt metal layer and a Ti metal layer stacked in sequence, or the metal film 1022 may be composed of a Ti metal layer and an Au metal layer stacked in sequence, or the metal film 1022 may be composed of a single Au metal layer.

[0098] Among them, Ti is an adhesion layer between the dielectric film and Au, and the thickness of Ti is between 2nm and 50nm, for example, the thickness of Ti can be 2nm, 10nm, 30nm or 50nm, etc.; the thickness of Au is between 50nm and 500nm, for example, the thickness of Au can be 50nm, 100nm, 200nm, 350nm or 500nm, etc., which can improve the reflectivity of the thin film layer.

[0099] It should be noted that the metal film 1022 may not include an adhesion layer (ie, Ti). In this case, the dielectric film is prepared by sputtering Y2O3 to improve the adhesion of the dielectric film.

[0100] In this embodiment, the structure of the first mask strip can be as follows: Fig.11 and Fig.12 As shown, the extension portion 320 is a rectangular parallelepiped structure, the preset micro-nano pattern is a rectangle, and the length of the extension portion 320 in the second preset direction is smaller than the length of the target surface in the second preset direction.

[0101] By making the length of the extension portion in the second preset direction smaller than the length of the target surface in the second preset direction, a part of the end surface can be shielded to achieve the following: Fig.13 The effect of only partially plating metal is shown, which avoids the situation where the end face is fully plated with metal, resulting in the interconnection of the P-side and N-side of the bar, which in turn causes a short circuit in the quantum cascade laser. This optimizes the electrical characteristics of the end face while achieving regulation of the performance of the optical waveguide device.

[0102] It should be understood that the strips used in conventional coating methods are generally rectangular structures, and the end faces of the strips are not blocked, which will result in the entire end face area being fully plated with metal, such as Fig.14 As shown, the plated area 1401 of the end face is covered with metal. Fig.15 As shown, the metal plated on the end face will diffract to the P-side and N-side of the bar, causing the positive and negative poles of the quantum cascade laser to be short-circuited, thereby causing the quantum cascade laser to short-circuit.

[0103] The first dielectric film, the second dielectric film 1021 and the third dielectric film 1023 mentioned above can be formed by conventional coating methods.

[0104] For example, Figure 3 As shown, the length h1 of the extension portion in the second preset direction ranges from 10 micrometers (um) to a first preset value, wherein the first preset value is the length of the optical waveguide device in the second preset direction - 20um. That is, the length of the extension portion in the second preset direction can be 10um, the first preset value, or any value between 10um and the first preset value.

[0105] For example, Figure 3As shown, the length b1 of the extension portion in the first preset direction ranges from 1um to 100um, and the length h2 of the main body in the second preset direction ranges from 100um to 500um, that is, the length b1 of the extension portion in the first preset direction can be any value from 1um to 100um, for example, the length b1 of the extension portion in the first preset direction can be 1um, 10um, 40um, 60um or 100um, etc., and the length h2 of the main body in the second preset direction can be any value from 50um to 500um, for example, the length h2 of the main body in the second preset direction can be 50um, 150um, 300um, 400um or 500um, etc.

[0106] In this embodiment, the length of the extension portion in the first preset direction is limited to between 1um and 100um, and the length of the body in the second preset direction is limited to between 50um and 500um, which can ensure that the first mask strip has a certain mechanical strength and facilitate cutting and processing into corresponding shapes.

[0107] Exemplarily, the material of the first mask strip may be one or more of the common substrate materials used in the semiconductor or micro-nano processing fields, such as gallium arsenide (GaAs), indium phosphide (InP), silicon (Si) or quartz.

[0108] Secondly, an optical waveguide device with an end-face metal grating device is taken as an example for explanation.

[0109] Specifically, the HR film or AR film of the metal grating device has a metal grating of a certain period, for example, Fig.16a , Fig.16b and Fig.16c As shown, metal grating patterns can be divided into through type, top type and bottom type. For optical devices, the interference effect of the metal grating pattern on the end surface can be used to achieve a high reflectivity end surface, thereby reducing the threshold of the light-emitting device, suppressing the diffraction loss of the cavity surface, and enhancing the power.

[0110] In addition, due to the periodicity and directionality of the grating, the frequency mode in the waveguide can be screened, such as the mode with wavelength = 2×neff×A, where neff is the effective refractive index in the optical waveguide and A is the period of the grating. Since the grating lines in the xy plane are directional, the electromagnetic wave mode parallel to the grating line direction will be enhanced, and the electromagnetic wave mode perpendicular to the grating line direction will be weakened, thereby achieving polarization selection and improving the polarization selection ratio of the output light wave.

[0111] In this embodiment, the schematic diagram of the extension portion in the yz plane is as follows: Figure 3 As shown, the schematic diagram of the extension part in the xy plane is as follows Fig.17As shown, the extension portion 320 includes a plurality of indicating grating lines 321, wherein the plurality of indicating grating lines 321 are arranged at intervals along a third preset direction, the preset micro-nano pattern is a grating pattern, and the third preset direction, the first preset direction, and the second preset direction are perpendicular to each other. When the first preset direction is the direction indicated by the z-axis and the second preset direction is the direction indicated by the y-axis, the third preset direction may be the direction indicated by the x-axis.

[0112] Exemplarily, the length h1 of the extension portion in the second preset direction is less than or equal to the length of the target surface in the second preset direction. Specifically, when the grating pattern is a top type or a bottom type, the length h1 of the extension portion in the second preset direction is less than the length of the target surface in the second preset direction; when the grating pattern is a through type, the length of the extension portion in the second preset direction is equal to the length of the target surface in the second preset direction.

[0113] Exemplarily, the length h1 of the extension portion in the second preset direction ranges from 10um to the length of the target surface in the second preset direction, that is, the length h1 of the extension portion in the second preset direction can be any value between 10um and the length of the target surface in the second preset direction. For example, the length h1 of the extension portion in the second preset direction can be any value between 10um, the length of the target surface in the second preset direction, or 10um and the length of the target surface in the second preset direction.

[0114] In this embodiment, the length b1 of the extension in the first preset direction, the length h2 of the body in the second preset direction, and the material of the first mask strip are the same as those in the embodiment where the optical waveguide device is a quantum cascade laser, and are not described again.

[0115] Again, the optical waveguide device is described by taking a high-power semiconductor laser as an example.

[0116] Specifically, for high-power semiconductor lasers, the output optical power can be increased by increasing the waveguide width and the volume of the active area. However, the increase in the waveguide width will cause the generation of high-order modes, resulting in a larger far-field divergence angle of the laser and a decrease in the brightness of the laser, which does not make full use of the device application. Reducing the reflectivity of the coating in the local area of ​​the waveguide edge on the HR end face can increase the mirror loss in the local area, thereby causing the loss of the high-order optical mode in the local area, such as Fig.18 As shown, on the outermost sides of the waveguide, a hollow region 1801 of the HR film is formed, which can increase the mirror loss of the high-order mode at this position, thereby reducing the high-order mode, lowering the far-field divergence angle, and improving the brightness of the laser.

[0117] In this embodiment, the schematic diagram of the extension portion in the yz plane is as follows: Fig.19 As shown, the schematic diagram of the extension part in the xy plane is as follows Fig. 20As shown, the extension portion 320 includes a plurality of preset micro-nano structures 322, wherein the plurality of preset micro-nano structures 322 are arranged at intervals along a third preset direction, so that the thin film layer of the target surface has a hollow region of a preset shape at a preset position, and the third preset direction, the first preset direction, and the second preset direction are perpendicular to each other. In the case where the first preset direction is the direction indicated by the z-axis and the second preset direction is the direction indicated by the y-axis, the third preset direction may be the direction indicated by the x-axis.

[0118] For example, the HR film on the end surface can be Fig.21 As shown, the mesh area is the HR coating area, and the white matchstick-shaped area is the HR coating hole area, that is, the area blocked by the preset micro-nano pattern of the first mask strip.

[0119] Exemplarily, the preset micro-nano structure is in the shape of a matchstick, and the length h4 of the first preset micro-nano structure in the second preset direction is greater than the length h3 of the second preset micro-nano structure in the second preset direction, wherein the first preset micro-nano structure is a part of the plurality of preset micro-nano structures, and the second preset micro-nano structure is another part of the plurality of preset micro-nano structures. In this embodiment, hollow regions of different heights can be formed on the waveguide.

[0120] Specifically, Fig. 20 As shown, the spacing between the first preset micro-nano structures in the first preset direction is a first value b2, the spacing between the second preset micro-nano structures in the first preset direction is a second value b3, the first value b2 ranges from the waveguide width -10um to the waveguide width +10um, and the second value b3 ranges from the first value -5um to the first value -1um.

[0121] Among them, the first value b2 includes the endpoint values ​​of the waveguide width -10um and the waveguide width +10um, and also includes any value between the waveguide width -10um and the waveguide width +10um. The value of the second value b3 includes the endpoint values ​​of the first value -5um and the first value -1um, and also includes any value between the first value -5um and the first value -1um.

[0122] In this embodiment, the length b1 of the extension in the first preset direction, the length h2 of the body in the second preset direction, the material of the first mask stripe and the optical waveguide device are the same as those in the embodiment where the quantum cascade laser is used, and are not described in detail here.

[0123] In some optional embodiments, in order to improve the coating efficiency, the end faces of multiple bar strips can be coated simultaneously through multiple first mask strips, that is, the preset micro-nano images on the first mask strips can be transferred to the end faces of multiple bar strips in batches, which can fully utilize the semiconductor micro-nano processing technology and has the advantages of high precision, relatively simple operation, reusable mask strips, and batch production.

[0124] Specifically, when the number of the optical waveguide device and the number of the first mask strip are both plural, the step of placing the optical waveguide device and the first mask strip on the fixture (i.e. Figure 2 Step S202 of the illustrated embodiment includes: placing a plurality of optical waveguide devices and a plurality of first mask strips in a cross-like manner on a fixture in sequence, so that the target surface of the optical waveguide device is fitted with the extension portion of the corresponding first mask strip.

[0125] That is, in the second preset direction of the fixture, multiple optical waveguide devices and multiple first mask strips can be placed on the fixture in sequence in the order of first mask strip, optical waveguide device, first mask strip, and optical waveguide device.

[0126] Further, in some optional embodiments, before the step of placing the optical waveguide device and the first mask strip on the fixture, the coating method for the end face of the optical waveguide device also includes: providing a plurality of second mask strips, wherein the second mask strips are in a rectangular structure; and the step of cross-arranging the plurality of optical waveguide devices and the plurality of first mask strips on the fixture in sequence, including: cross-arranging the plurality of optical waveguide devices and the plurality of first mask strips on the fixture in sequence, and a side of the first mask strip away from the corresponding first optical waveguide device is bonded to a side of the second mask strip, and the other side of the second mask strip is bonded to a side of the second optical waveguide device away from the corresponding first mask strip, wherein the first optical waveguide device and the second optical waveguide device are any two adjacent optical waveguide devices among the plurality of optical waveguide devices arranged in sequence.

[0127] It can also be said that in the second preset direction of the fixture, multiple second mask strips, multiple optical waveguide devices, and multiple first mask strips can be placed on the fixture in sequence in the order of second mask strip, optical waveguide device, first mask strip, second mask strip, optical waveguide device, and first mask strip.

[0128] In this embodiment, the second mask strip is placed behind the first mask strip, which can prevent the top of the strip from directly contacting the extension of the first mask strip, thereby affecting the light extraction efficiency.

[0129] Exemplarily, the step of forming a thin film layer having a preset micro-nano pattern on the target surface (i.e. Figure 2 Step S203 of the embodiment shown includes: when the target surface is in contact with the extension portion, a deposition process is performed on the target surface to form a thin film layer with a preset micro-nano pattern on the target surface. The deposition method may be evaporation, sputtering or laser pulse deposition.

[0130] For example, Fig. 22As shown, the fixture 2200 may include a first protrusion 2210 and a second protrusion 2220, the first protrusion 2210 is used to place the optical waveguide device and / or the second mask strip, the second protrusion 2220 is used to place the first mask strip, and the first protrusion 2210 and the second protrusion 2220 have a height difference in a first preset direction so that the target surface of the optical waveguide device fits with the extension portion of the first mask strip.

[0131] Specifically, the length of the main body of the first mask strip in the first preset direction is smaller than the length of the optical waveguide device in the first preset direction. For example, the absolute value of the difference between the length of the main body of the first mask strip and the second mask strip in the first preset direction and the length of the optical waveguide device in the first preset direction ranges from 0um to 100um.

[0132] Through the above arrangement, the first mask strip and the second mask strip can be more conveniently placed in the base with the inner and outer height difference, and the first mask strip and the second mask strip can be fixed at the center of the optical waveguide device, thereby leaving an area not blocked by the mask strip on the end face of the optical waveguide device in the first preset direction, ensuring that the end face can be evenly covered with a film of a certain thickness and refractive index, thereby achieving the function of anti-reflection or high reflectivity.

[0133] It should be noted that the lengths of the main body of the first mask strip and the second mask strip in the third preset direction are adapted to the length of the base of the fixture in the third preset direction, that is, the main body of the first mask strip and the second mask strip can be placed on the base of the fixture spaced apart along the third preset direction.

[0134] The following describes in detail the placement of the optical waveguide device, the first mask strip and / or the second mask strip on the fixture in conjunction with the accompanying drawings.

[0135] First, the optical waveguide device is taken as a quantum cascade laser as an example for explanation.

[0136] For example, Fig.23 As shown, the length of the second mask strip 2310 and the bar strip 130 in the third preset direction is x1-1, and the matching first protrusion 2210 is placed in sequence, and then the first mask strip 300 with a length of x2-1 in the third preset direction is placed on the matching second protrusion. The height difference between the first protrusion and the second protrusion is the length of the extension of the first mask strip in the first preset direction.

[0137] Then, in this order, add the other bars, the second mask strip, and the first mask strip, and finally get Fig.24 The yz plane schematic diagram after the arrangement is shown. Fig.24 It is composed of a periodic arrangement of the first mask strip, the bar and the second mask strip.

[0138] The end face of the second mask strip in the first preset direction is flush with the target surface. The above arrangement can effectively prevent the diffraction problem on the top of the P surface when evaporating or sputtering the metal layer, and can prevent poor packaging interface in the later stage due to metal short circuit. At the same time, placing the second mask strip behind the first mask strip can prevent the top of the strip from directly contacting the first mask strip with an extension, which affects the reflectivity at the light exiting the waveguide.

[0139] Specifically, the bar also includes a front surface (P waveguide side) and a bottom surface (N substrate side). After placing a plurality of bar strips, a plurality of first mask strips and a plurality of second mask strips on a fixture, the front surface of the bar strip is bonded to the second mask strip, and the bottom surface of the bar strip is bonded to the first mask strip. Fig.24 In the figure, the left side of the bar is the bottom side, and the right side of the bar is the front side.

[0140] Since the first mask strip has an extension portion, the N bottom position is blocked. Figure 8 As shown in the shadow mask effect, only the portion of the bar not blocked by the extension of the first mask strip can be deposited with metal by PVD, thereby obtaining the following Fig.13 The coating effect is shown.

[0141] Next, an optical waveguide device that is a metal grating device is taken as an example for explanation.

[0142] For example, for a through-type grating pattern, the following may be used: Fig.25 The arrangement shown in the figure, wherein the second mask strip is flush with the bar strip, which can avoid blocking the top of the optical waveguide during coating, and the first mask strip is placed on the N side and arranged periodically. The placement of the first mask strip, the second mask strip and the bar strip can be as follows Fig.23 shown.

[0143] For bottom-type raster graphics, you can use Fig.24 In the arrangement shown, the length of the extension portion of the first mask strip in the second preset direction is not equal to the length of the bar in the second preset direction.

[0144] For top-type raster graphics, you can use Fig.26 or Fig. 27 The arrangement shown, where Fig.26 The arrangement of the bars shown can reduce the coating shielding of the N side. The arrangement of the first mask strip, the second mask strip and the bar strip can be as follows: Fig.23 As shown. Fig. 27 The arrangement shown in FIG. 1 is without the second mask strip, and the arrangement of the first mask strip and the strip can be as follows: Fig.28 shown.

[0145] Again, the optical waveguide device is described by taking a high-power semiconductor laser as an example.

[0146] For example, for a high-power semiconductor laser, Fig.28 The first mask strip is placed in the manner shown, but it is necessary to accurately align the preset micro-nano pattern of the extension portion of the first mask strip with the waveguide on the strip.

[0147] It should be noted that, in this embodiment, the side of the first mask strip having the extension portion is bonded to the bottom surface (N substrate side) of the strip.

[0148] Furthermore, if Fig.29 As shown, one side of the fixture has a microneedle adjuster 2230. After the first mask strip 300 and the bar 130 are placed on the fixture, the fixture is placed under a microscope (magnification>200), and the first mask strip 300 is pushed to move in a third preset direction by adjusting the differential rod 2231 (or actuator) to align the preset micro-nano pattern and the waveguide pattern, that is, the preset micro-nano pattern is placed at a preset position on the target surface.

[0149] The present invention also provides a method for preparing a mask strip. When the mask strip is a first mask strip corresponding to a quantum cascade laser and the optical waveguide device is a quantum cascade laser, the method for preparing the mask strip comprises steps a1 to a6:

[0150] Step a1, forming a photoresist layer on the surface of the silicon wafer.

[0151] The thickness of the photoresist layer is determined according to the length of the extending portion in the first preset direction. For example, if the length of the extending portion in the first preset direction is 50 um, the thickness of the photoresist layer is 10 um.

[0152] Step a2, using conventional ultraviolet lithography technology or electron beam lithography technology, the photoresist layer is exposed to form a mask pattern corresponding to the zx plane pattern of the extension portion.

[0153] Step a3, developing the exposed photoresist layer.

[0154] In step a4, the wafer with the mask pattern after development is placed in an Inductively Coupled Plasma (ICP) etching system for etching to transfer the mask pattern to the wafer.

[0155] Among them, the etching process is a deep silicon etching process with a high selectivity ratio. The etching gas can adopt a common gas formula composed of sulfur hexafluoride (SF6), carbon tetrafluoride (CF4) and argon (Ar). The etching depth can be 50um, and the etching selectivity ratio = silicon material: mask material>5.

[0156] Step a5, removing the photoresist.

[0157] Step a6, performing grinding and polishing to reduce the wafer thickness to a preset thickness, and then cutting it according to the required length and width to obtain a plurality of first mask strips.

[0158] The cutting method may be mechanical cutting or laser cutting.

[0159] It should be noted that the above corresponding preparation steps are the same as conventional semiconductor processes and will not be described in detail here.

[0160] When the mask strip is a first mask strip corresponding to a high-power semiconductor laser whose optical waveguide device is a high-power semiconductor laser, the method for preparing the mask strip includes steps e1 to e3:

[0161] Step e1, making a first photolithography mask to protect the second preset micro-nano structure, and performing ICP etching to obtain a match pattern corresponding to the first preset micro-nano structure.

[0162] The etching process is a conventional silicon etching process (such as silicon ball etching), and the etching gas may be SF6, oxygen (O2) or trifluoromethane (CHF3) or other gases.

[0163] Step e2, making a second photolithography mask to protect the first preset micro-nano structure, exposing the pattern and non-pattern area corresponding to the second preset micro-nano structure, and etching the entire surface.

[0164] The etching depth may be a height difference (h4-h3) between the first preset micro-nano structure and the second preset micro-nano structure.

[0165] Step e3, making a third photolithography mask to protect the first preset micro-nano structure, and etching to obtain a match pattern corresponding to the second preset micro-nano structure.

[0166] The match-shaped pattern prepared can be Fig.30 shown.

[0167] It should be noted that the above corresponding preparation steps are the same as conventional semiconductor processes and will not be described in detail here.

[0168] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0169] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0170] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0171] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0172] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0173] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the present invention.

Claims

1. A coating method for an end face of an optical waveguide device, characterized in that: The method comprises: An optical waveguide device and a first mask strip are provided, wherein the optical waveguide device has a front cavity surface and a rear cavity surface to be coated in a first preset direction, the first mask strip comprises a body and an extension portion, the extension portion is located at one end of the body in the first preset direction, extends from the body to a second preset direction, and the extension portion forms a preset micro-nano pattern, and the first preset direction and the second preset direction are perpendicular to each other; Placing the optical waveguide device and the first mask strip on a fixture so that a target surface of the optical waveguide device is in contact with the extension portion, wherein the target surface is the front cavity surface or the back cavity surface; forming a thin film layer having a preset micro-nano pattern on the target surface; Wherein, the optical waveguide device is a metal grating device, the extension portion includes a plurality of indicator grating lines, the plurality of indicator grating lines are arranged at intervals along a third preset direction, the preset micro-nano pattern is a grating pattern, and the third preset direction, the first preset direction and the second preset direction are perpendicular to each other; or, The optical waveguide device is a high-power semiconductor laser, the extension portion includes a plurality of preset micro-nano structures, the preset micro-nano structures are match-shaped, and the plurality of preset micro-nano structures are arranged at intervals along the third preset direction, so that the thin film layer on the target surface has a cavity area of ​​a preset shape at a preset position.

2. The method according to claim 1, characterized in that: The number of the optical waveguide devices and the number of the first mask strips are both multiple, and the multiple optical waveguide devices correspond to the multiple first mask strips one by one. Placing the optical waveguide devices and the first mask strips on a fixture includes: The plurality of optical waveguide devices and the plurality of the first mask strips are arranged crosswise on a fixture in sequence, so that the target surface of the optical waveguide device is fitted with the extension portion of the corresponding first mask strip.

3. The method according to claim 2, characterized in that The fixture includes a first protrusion and a second protrusion, the first protrusion is used to place the optical waveguide device, and the second protrusion is used to place the first mask strip, and the first protrusion and the second protrusion have a height difference in the first preset direction so that the target surface of the optical waveguide device is fitted with the extension portion of the first mask strip.

4. The method according to claim 2 or 3, characterized in that: Before placing the optical waveguide device and the first mask strip on a fixture, the method further includes: Providing a plurality of second mask strips, wherein the second mask strips are in a rectangular parallelepiped structure; The method of cross-arranging the plurality of optical waveguide devices and the plurality of the first mask strips on a fixture in sequence comprises: A plurality of the optical waveguide devices and a plurality of the first mask strips are arranged crosswise on a fixture in sequence, and a side of the first mask strip away from the corresponding first optical waveguide device is bonded to a side of the second mask strip, and the other side of the second mask strip is bonded to a side of the second optical waveguide device away from the corresponding first mask strip, wherein the first optical waveguide device and the second optical waveguide device are any two adjacent optical waveguide devices among the plurality of the optical waveguide devices arranged in sequence.

5. The method according to any one of claims 1 to 3, characterized in that Forming a thin film layer having a preset micro-nano pattern on the target surface includes: When the target surface is in contact with the extension portion, a deposition process is performed on the target surface to form a thin film layer having a preset micro-nano pattern on the target surface.

6. An optical waveguide device, characterized in that: The optical waveguide device has a front cavity surface and a rear cavity surface provided with a thin film layer in a first preset direction, and the thin film layers of the front cavity surface and the rear cavity surface are prepared by the method according to any one of claims 1 to 5.

7. A mask strip, characterized in that: The mask strip comprises a main body and an extension portion; The extension portion is located at one end of the body in the first preset direction, extends from the body to the second preset direction, and the extension portion forms a preset micro-nano pattern, and the extension portion is used to transfer the preset micro-nano pattern to the thin film layer formed on the target surface of the optical waveguide device when the target surface is coated, wherein the first preset direction and the second preset direction are perpendicular to each other, the optical waveguide device has a front cavity surface and a rear cavity surface to be coated in the first preset direction, and the target surface is the front cavity surface and / or the rear cavity surface; The optical waveguide device is a metal grating device, the extension portion includes a plurality of indicator grating lines, wherein the plurality of indicator grating lines are arranged at intervals along a third preset direction, the preset micro-nano pattern is a grating pattern, and the third preset direction, the first preset direction and the second preset direction are perpendicular to each other; or, The optical waveguide device is a high-power semiconductor laser, the extension portion includes a plurality of preset micro-nano structures, the preset micro-nano structures are match-shaped, and the plurality of preset micro-nano structures are arranged at intervals along the third preset direction, so that the thin film layer on the target surface has a cavity area of ​​a preset shape at a preset position.

8. The mask strip according to claim 7, characterized in that: When the preset micro-nano pattern is a grating pattern, the length of the extension portion in the second preset direction is less than or equal to the length of the target surface in the second preset direction.

9. The mask strip according to claim 8, characterized in that: The length of the extension portion in the second preset direction ranges from 10 um to the length of the target surface in the second preset direction.

10. The mask strip according to claim 7, characterized in that: When the preset micro-nano structure is in the shape of a match, the length of the first preset micro-nano structure in the second preset direction is greater than the length of the second preset micro-nano structure in the second preset direction, wherein the first preset micro-nano structure is a part of the multiple preset micro-nano structures, and the second preset micro-nano structure is another part of the multiple preset micro-nano structures.

11. The mask strip according to claim 10, characterized in that: The spacing between the first preset micro-nano structures in the first preset direction is a first value, the spacing between the second preset micro-nano structures in the first preset direction is a second value, the first value ranges from waveguide width -10um to waveguide width +10um, and the second value ranges from the first value -5um to the first value -1um.

12. The mask strip according to any one of claims 7 to 11, characterized in that: The length of the extension portion in the first preset direction ranges from 1 um to 100 um.

13. The mask strip according to any one of claims 7 to 11, characterized in that: A length of the body in the first preset direction is smaller than a length of the optical waveguide device in the first preset direction.

14. The mask strip according to any one of claims 7 to 11, characterized in that: The length of the body in the second preset direction ranges from 100um to 500um.

15. The mask strip according to any one of claims 7 to 11, characterized in that: The material of the mask strip is one or more of gallium arsenide, indium phosphide, silicon or quartz.

Images