Integrated grating coupler and optical system using the same

Abstract

An integrated grating coupler is provided. The integrated grating coupler includes a substrate and a reflector disposed on the substrate. The integrated grating coupler also includes a metal grating structure disposed above the reflector. The integrated grating coupler further includes a waveguide disposed above the metal grating structure, wherein the waveguide includes a main grating structure.

Description

Technical Field

[0001] This disclosure relates to an integrated grating coupler, and more particularly to an integrated grating coupler comprising a metal grating structure and an optical system using this integrated grating coupler. Prior Technology

[0002] Integrated sensing devices have recently become increasingly prevalent in the field of bioanalysis. For example, conventional integrated grating couplers can be used to measure, identify, or sequence analytes (e.g., glucose, viruses / bacteria, or DNA fragments) obtained from living (e.g., human) media (e.g., interstitial fluid, blood, saliva, or nasal mucosa) for health monitoring, disease diagnosis, or DNA sequencing. Grating couplers are often integrated into integrated sensing devices. However, conventional grating couplers require a light source with a very small beam diameter (e.g., approximately 2–10 μm) and allow for very small alignment offsets (e.g., approximately 1 μm) to achieve good optical coupling. Therefore, a novel integrated grating coupler remains needed. Summary of the Invention

[0003] In the embodiments disclosed herein, the integrated grating coupler includes a reflector and a metal grating structure disposed above the reflector, which can effectively improve the optical coupling efficiency of light sources with a large beam size diameter (e.g., about 50 μm). Therefore, when the integrated grating coupler is embedded in a disposable biochip, it can provide a larger alignment tolerance (e.g., greater than 10 μm). This feature facilitates plug-and-play rapid alignment with operating devices (providing light source, reagent processing, and signal acquisition), making it more suitable for various biosensing devices and optical systems.

[0004] This disclosure provides an embodiment of an integrated grating coupler. The integrated grating coupler includes a substrate and a reflector disposed on the substrate. The integrated grating coupler also includes a metal grating structure disposed above the reflector. The integrated grating coupler further includes a waveguide disposed above the metal grating structure, wherein the waveguide includes a main grating structure.

[0005] In some embodiments, the reflector comprises a plurality of high-refractive-index films and a plurality of low-refractive-index films stacked alternately.

[0006] In some embodiments, the width of the metal grating structure is greater than 1 μm and less than or equal to 100 μm, and the maximum thickness of the metal grating structure is greater than or equal to 0.1 μm and less than or equal to 2 μm.

[0007] In some embodiments, the metal grating structure has a plurality of recesses of the same depth, wherein the depth of the recesses is greater than 0 and less than or equal to the maximum thickness of the metal grating structure.

[0008] In some embodiments, the shortest distance between the metal grating structure and the waveguide is equal to the shortest distance between the metal grating structure and the reflector.

[0009] In some embodiments, the shortest distance between the metal grating structure and the reflector is greater than 0 and less than or equal to 3 μm.

[0010] In some embodiments, the shortest distance between the reflector and the waveguide is greater than or equal to 0.1 μm and less than or equal to 6 μm.

[0011] In some embodiments, the width of the main grating structure is greater than or equal to 10 μm and less than or equal to 300 μm.

[0012] In some embodiments, the width of the metal grating structure is less than half the width of the main grating structure.

[0013] In some embodiments, the maximum thickness of the main grating structure is greater than or equal to 0.16 μm and less than or equal to 0.6 μm.

[0014] In some embodiments, the main grating structure has a plurality of recesses of the same depth, wherein the depth of the recesses is greater than or equal to 0.04 μm and less than or equal to the maximum thickness of the main grating structure.

[0015] In some embodiments, the main grating structure has multiple recesses of different depths.

[0016] In some embodiments, the main grating structure has different grating spacings.

[0017] In some embodiments, the main grating structure is composed of irregular patterns, which include unetched patterns, lightly etched patterns, and fully etched patterns.

[0018] In some embodiments, the integrated grating coupler further includes a first cladding layer disposed between the reflector and the waveguide, wherein a metallic grating structure is disposed within the first cladding layer.

[0019] In some embodiments, the integrated grating coupler further includes a second cladding layer disposed on the waveguide.

[0020] In some embodiments, the thickness of the second cladding layer above the waveguide is greater than 0 and less than or equal to 2 μm.

[0021] This disclosure provides an embodiment of an optical system. The optical system includes an integrated grating coupler and a light source, with the light source disposed above the integrated grating coupler. The integrated grating coupler includes a substrate and a reflector, with the reflector disposed on the substrate. The integrated grating coupler also includes a metallic grating structure disposed above the reflector. The integrated grating coupler further includes a waveguide disposed above the metallic grating structure, wherein the waveguide includes a main grating structure.

[0022] In some embodiments, the extension of the optical axis of the light source is separated from the metal grating structure.

[0023] In some embodiments, the diameter of the light beam size of the light source is greater than or equal to 2 μm and less than or equal to 2000 μm. Simple Explanation of the Diagram

[0024] The embodiments disclosed herein will be described in detail below with reference to the accompanying drawings. It should be noted that, according to industry standard practice, the various feature components are not drawn to scale. In fact, the dimensions of the various feature components may be enlarged or reduced to clearly demonstrate the technical features of the embodiments disclosed herein. Figure 1 is a partial cross-sectional view illustrating an integrated grating coupler and optical system according to some embodiments of the present disclosure. Figure 2 is a partial cross-sectional view illustrating an integrated grating coupler according to some other embodiments disclosed herein. Figure 3 is a partial top view illustrating the main grating structure according to some other embodiments disclosed herein. Implementation

[0025] The following disclosure provides many different embodiments or examples to implement different features of this invention. Specific examples of the various components and their arrangements described below are provided to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. For example, if it is stated that a first feature is formed on or above a second feature, it may include embodiments where the first and second feature are in direct contact, or embodiments where other feature is formed between the first and second feature, so that the first and second feature may not be in direct contact.

[0026] It should be understood that other operational steps may be performed before, between, or after the method, and in other embodiments of the method, some operational steps may be replaced or omitted.

[0027] Furthermore, this document may use spatially related terms such as "below," "below," "down," "above," "above," "up," and similar terms to facilitate the description of the relationship between one element or feature and other elements or features in the diagram. These spatially related terms encompass different orientations of the device in use or operation, as well as the orientations described in the diagram. The device may be rotated to different orientations (rotated 90 degrees or other orientations), and the spatially related adjectives used in this document will be interpreted in accordance with the orientation after rotation.

[0028] In this disclosure, the terms "about," "approximately," and "substantially" generally mean within 20%, 10%, 5%, 3%, 2%, 1%, or even 0.5% of a given value. The given values ​​in this disclosure are approximate values. That is, even without a specific description of "about," "approximately," or "substantially," the given value may still contain the meaning of "about," "approximately," or "substantially."

[0029] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should be understood that these terms, such as those defined in commonly used dictionaries, should be interpreted in a meaning consistent with the context of the relevant art and will not be interpreted in an idealized or overly formal manner, unless specifically defined in the embodiments of this disclosure.

[0030] The same reference numerals and / or designations may be used repeatedly in the following embodiments. These repetitions are for simplicity and clarity purposes and are not intended to limit any specific relationship between the various embodiments and / or structures discussed.

[0031] Figure 1 is a partial cross-sectional view illustrating the integrated grating coupler 100 and optical system 1 according to some embodiments of the present disclosure. It should be noted that, for the sake of simplicity, some components of the integrated grating coupler 100 and optical system 1 have been omitted in Figure 1.

[0032] Referring to Figure 1, in some embodiments, the optical system 1 includes an integrated grating coupler 100 and a light source 70, with the light source 70 disposed above the integrated grating coupler 100. The integrated grating coupler 100 can be used for on-chip or on-wafer device testing. More specifically, the integrated grating coupler 100 can be used to couple light from the light source 70. For example, the light source 70 can be a visible-light laser-beam pointer, but this disclosure is not limited to this embodiment.

[0033] In some embodiments, the operating wavelength of the light source 70 (i.e., the light from the light source 70) can be in the range of about 400 nm to about 750 nm, about 300 nm to about 1800 nm, or about 250 nm to about 3500 nm, but the embodiments disclosed herein are not limited thereto. As shown in Figure 1, in some embodiments, the diameter D70 of the beam size of the light source 70 is greater than or equal to about 2 μm and less than or equal to about 2000 μm. More specifically, the diameter D70 of the beam size is greater than or equal to about 10 μm and less than or equal to about 200 μm. That is, the light source 70 can have a large mode field diameter (MFD), which can be in the range of about 50 μm, or about 10 μm to about 200 μm, about 5 μm to about 500 μm, or about 2 μm to about 2000 μm.

[0034] Referring to Figure 1, in some embodiments, the integrated grating coupler 100 includes a substrate 10, which may have a photoelectric conversion element (not shown). For example, the substrate 10 may be a glass substrate or a semiconductor substrate (e.g., a CMOS substrate), and the photoelectric conversion element may be a photodiode. The substrate 10 may contain flexible materials such as polyethylene terephthalate (PET), polystyrene (PES), polyimide (PI), polycarbonate (PC), polymethyl methacrylate (PMMA), silicone, epoxy resin, the like, or combinations thereof. The substrate 10 may also contain rigid materials such as glass, quartz, or sapphire, but this disclosure is not limiting. In some embodiments, the thickness F1 of the substrate 10 is greater than or equal to about 200 μm and less than or equal to about 850 μm. Here, the thickness F1 of the substrate 10 may be defined as the distance between the top and bottom of the substrate 10 in the Z direction (i.e., the vertical direction) in Figure 1.

[0035] Referring to Figure 1, in some embodiments, the integrated grating coupler 100 includes a reflector 20 disposed on the substrate 10. For example, the reflector 20 may be a distributed Bragg reflector (DBR), but this disclosure is not limited thereto. As shown in Figure 1, in some embodiments, the reflector includes alternately stacked high-refractive-index films 21 and low-refractive-index films 23. For example, the high-refractive-index film 21 may be titanium dioxide (TiO₂), tantalum pentoxide (Ta₂O₅), silicon nitride (Si₃N₄), silicon (Si), or niobium pentoxide (Nb₂O₅), while the low-refractive-index film 23 may be silicon dioxide (SiO₂). The high-refractive-index films 21 and 23 may be formed by a deposition process. Deposition processes include, for example, chemical vapor deposition (CVD), plasma-assisted chemical vapor deposition (PECVD), atomic layer deposition (ALD), other similar processes or combinations thereof, but the embodiments disclosed herein are not limited thereto.

[0036] In some embodiments, the thickness E1 of the monolayer high-refractive-index film 21 is λ / 4 / λH, the thickness E2 of the monolayer low-refractive-index film 23 is λ / 4 / λL, and the thickness E3 of the reflector 20 (i.e., the total thickness of the high-refractive-index film 21 and the low-refractive-index film 23) is greater than or equal to about 0.5 μm and less than or equal to 50 μm. More specifically, the thickness E3 of the reflector 20 is greater than or equal to about 1 μm and less than or equal to 5 μm. Here, the thickness E3 of the reflector 20 can be defined as the distance between the top and bottom of the reflector 20 in the Z direction (i.e., the vertical direction) in Figure 1. Furthermore, λ is the wavelength of the light emitted from the light source 70, λH is the refractive index of the high-refractive-index film 21, and λL is the refractive index of the low-refractive-index film 23.

[0037] Referring to Figure 1, in some embodiments, the integrated grating coupler 100 includes a metal grating structure 30 disposed above the reflector 20. For example, the metal grating structure 30 may comprise aluminum (Al), gold (Au), silver (Ag), other suitable materials, or combinations thereof, but this disclosure is not limited thereto. The metal grating structure 30 may be formed through deposition processes, photolithography processes, and etching processes, but this disclosure is not limited thereto. For example, photolithography processes may include photoresist coating (e.g., spin coating), soft baking, mask alignment, exposure, post-exposure baking (PEB), development, rinsing, drying (e.g., hard baking), other suitable processes, or combinations thereof, but this disclosure is not limited thereto.

[0038] In some embodiments, the width D1 of the metallic grating structure 30 (which overlaps with the main grating structure 40G on the waveguide 40) is greater than 1 μm and less than or equal to about 100 μm. Here, the width D1 of the metallic grating structure 30 can be defined as the distance between the leftmost and rightmost ends of the metallic grating structure 30 in the X direction (i.e., the horizontal direction) in Figure 1.

[0039] In some embodiments, the maximum thickness D2 of the metal grating structure 30 is greater than or equal to about 0.1 μm and less than or equal to about 2 μm. Here, the maximum thickness D2 of the metal grating structure 30 can be defined as the distance between the top and bottom of the metal grating structure 30 in the Z direction (i.e., the vertical direction) in Figure 1. Furthermore, as shown in Figure 1, in some embodiments, the metal grating structure 30 has a plurality of recesses 30R with the same depth D3, the depth D3 of the recesses 30R being greater than 0 and less than or equal to the maximum thickness D2 of the metal grating structure 30.

[0040] Referring to Figure 1, in some embodiments, the integrated grating coupler 100 includes a waveguide 40 disposed above the metallic grating structure 30, and the waveguide 40 includes a main grating structure 40G. For example, the waveguide 40 may include silicon (Si), silicon nitride (SiN), tantalum pentoxide (Ta₂O₅), titanium dioxide (TiO), aluminum oxide (AlO), other similar materials, or combinations thereof, but the embodiments disclosed herein are not limited thereto. The waveguide 40 may be formed through deposition processes, photolithography processes, and etching processes, but the embodiments disclosed herein are not limited thereto.

[0041] In some embodiments, the width B1 of the main grating structure 40G is greater than or equal to about 10 μm and less than or equal to about 300 μm. More specifically, the width B1 of the main grating structure 40G is greater than or equal to about 10 μm and less than or equal to about 100 μm. Here, the width B1 of the main grating structure 40G can be defined as the distance between the leftmost and rightmost ends of the main grating structure 40G in the X direction (i.e., the horizontal direction) in Figure 1. The width D1 of the metal grating structure 30 can be adjusted according to the width B1 of the main grating structure 40G. In some embodiments, the width D1 of the metal grating structure 30 overlapping the main grating structure 40G above the waveguide 40 is less than half the width of the main grating structure 40G.

[0042] In some embodiments, the maximum thickness B2 of the main grating structure 40G is greater than or equal to about 0.16 μm and less than or equal to about 0.6 μm. Here, the maximum thickness B2 of the main grating structure 40G can be defined as the distance between the top and bottom of the main grating structure 40G in the Z direction (i.e., the vertical direction) in Figure 1. In other words, the thickness C1 of the portion of the waveguide 40 other than the main grating structure 40G can be substantially equal to the maximum thickness B2 of the main grating structure 40G. Furthermore, as shown in Figure 1, in some embodiments, the main grating structure 40G has a plurality of recesses 40R with the same depth B3, the depth B3 of which is greater than 0 and less than or equal to the maximum thickness B2 of the main grating structure 40G.

[0043] In some embodiments, in the Z-direction (i.e., vertical direction) of Figure 1, the shortest distance D4 between the metallic grating structure 30 and the main grating structure 40G (or waveguide 40) is equal to the shortest distance D5 between the metallic grating structure 30 and the reflector 20. In some embodiments, in the Z-direction (i.e., vertical direction) of Figure 1, the shortest distance D5 between the metallic grating structure 30 and the reflector 20 is greater than 0 and less than or equal to about 3 μm. In other words, in the Z-direction (i.e., vertical direction) of Figure 1, the shortest distance C2 between the metallic grating structure 30 and the portion of the waveguide 40 other than the main grating structure 40G can be substantially equal to the shortest distance D4 between the metallic grating structure 30 and the main grating structure 40G. Furthermore, as shown in Figure 1, in some embodiments, in the Z-direction (i.e., vertical direction) of Figure 1, the shortest distance D6 between the reflector 20 and the waveguide 40 is greater than or equal to about 0.1 μm and less than or equal to about 6 μm.

[0044] As shown in Figure 1, in some embodiments, the integrated grating coupler 100 includes a first cladding layer 51 disposed between the reflector 20 and the waveguide 40, and a metallic grating structure 30 disposed within the first cladding layer 51. Furthermore, the integrated grating coupler 100 further includes a second cladding layer 53 disposed on the waveguide 40. More specifically, portions of the second cladding layer 53 are disposed within recesses 40R of the main grating structure 40G.

[0045] In some embodiments, in the Z direction (i.e., the vertical direction) of Figure 1, the thickness B4 of the second cladding layer 53 above the main grating structure 40G is greater than 0 and less than or equal to about 2 μm. In other words, in the Z direction (i.e., the vertical direction) of Figure 1, the thickness C3 of the second cladding layer 53 above the waveguide 40 is greater than 0 and less than or equal to about 2 μm.

[0046] As shown in Figure 1, in some embodiments, in the X direction (i.e., the horizontal direction) of Figure 1, the shortest distance A1 between the center of the emitting surface 70E of the light source 70 and the leftmost end of the main grating structure 40G is greater than or equal to 0 and less than or equal to half the diameter D70 of the beam size of the light source 70. Furthermore, in the Z direction (i.e., the vertical direction) of Figure 1, the shortest distance A2 between the light source 70 and the integrated grating coupler 100 (second cladding layer 53) is greater than 0 and less than or equal to approximately 10 μm.

[0047] In some embodiments, the extension of the optical axis 70A of the light source 70 is separate from the metal grating structure 30. Furthermore, in some embodiments, the angle A3 between the optical axis 70A of the light source 70 and the normal direction 40N of the main grating structure 40G is substantially between approximately -10° and approximately +10°, and the angle A3 between the optical axis 70A of the light source 70 and the normal direction 40N of the main grating structure 40G may extend between approximately -30° and approximately +30°.

[0048] According to embodiments disclosed herein, the metal grating structure 30 can effectively improve the optical coupling efficiency of the main grating structure 40G. Furthermore, to reduce substrate transmittance loss and improve the optical coupling efficiency of the main grating structure 40G, a reflector 20 (e.g., an additional distributed Bragg mirror (DBR)) is integrated beneath the main grating structure 40G to maximize constructive interference. For this purpose, the reflector 20, comprising multiple periodic thin film combinations (e.g., high-refractive-index film 21 and low-refractive-index film 23), utilizes constructive interference mechanisms during reflection to achieve phase alignment, thereby promoting constructive interference.

[0049] Taking the integrated grating coupler 100 and optical system 1 shown in Figure 1 as an example, the following parameters were used for experimental simulation: the wavelength of the light emitted from the light source 70 was set to approximately 532 nm; the diameter D70 of the beam size of the light source 70 was set to approximately 50 μm; the shortest distance A1 between the center of the emitting surface 70E of the light source 70 and the leftmost end of the main grating structure 40G was set to approximately 14 μm; the shortest distance A2 between the light source 70 and the integrated grating coupler 100 (second cladding layer 53) was set to approximately 10 μm; the angle A3 between the optical axis 70A of the light source 70 and the normal direction 40N of the main grating structure 40G was set to approximately 27.3°; the number of periods of the main grating structure 40G was set to 155; the spacing (period) of the main grating structure 40G was set to approximately 353 nm; the depth B3 of the recess 40R in the main grating structure 40G was set to approximately 48 nm; and the thickness of the second cladding layer 52 was set to approximately 2.619 nm. μm; the number of periods of the metal grating structure 30 is set to 21; the spacing (period) of the metal grating structure 30 is set to approximately 761 nm; the maximum thickness D2 of the metal grating structure 30 is set to approximately 792 nm; the horizontal distance between the first recess 40R1 in the main grating structure 40G and the first recess 30R1 in the metal grating structure 30 is set to approximately 8.551 μm; and the number of high refractive index films 21 and the number of low refractive index films 23 are set to 20.

[0050] In this example, the optimal coupling efficiency (CE) of the integrated grating coupler 100 is likely to be approximately 56.4%. In a comparative example without the metal grating structure 30, the optimal coupling efficiency of the integrated grating coupler is likely to be approximately 38.0%. In another comparative example without the reflector 20, the optimal coupling efficiency of the integrated grating coupler is likely to be approximately 3.23%. In yet another comparative example without both the reflector 20 and the metal grating structure 30, the optimal coupling efficiency of the integrated grating coupler is likely to be approximately 3.20%.

[0051] That is, the integrated grating coupler 100 (which includes a metal grating structure 30 disposed on the reflector 20) according to the embodiments of this disclosure can effectively improve optical coupling efficiency. Therefore, the light source 70 can have a larger beam size diameter D70. When the integrated grating coupler 100 is embedded in a disposable biochip, it has a larger alignment tolerance (e.g., greater than 10 μm). This characteristic facilitates plug-and-play rapid alignment with operating devices (providing light source, reagent processing, and signal acquisition), making it more suitable for various biosensing devices and optical systems.

[0052] Figure 2 is a partial cross-sectional view of the integrated grating coupler 102 according to some other embodiments of this disclosure. Similarly, for simplicity, some components of the integrated grating coupler 102 are omitted in Figure 2.

[0053] Referring to Figure 2, in this embodiment, the main grating structures 40G have different spacings. Here, the spacing of the main grating structures 40G can be defined as the distance between the leftmost end of the recess 40R and the leftmost end of the adjacent recess 40R in the X direction (i.e., the horizontal direction) in Figure 2. As shown in Figure 2, the spacing B6 of the main grating structures 40G is not equal to the spacing B7 or the spacing B8.

[0054] Furthermore, as shown in Figure 2, in this embodiment, the main grating structure 40G has multiple recesses 40R of different depths in the Z direction (i.e., the vertical direction) of Figure 2. For example, the depth B3 of the recesses 40R is different from the depth B9 of the recesses 40R.

[0055] Figure 3 is a partial top view of the main grating structure 40G according to some other embodiments disclosed herein. It should be noted that the top view shown in Figure 3 is not a direct top-down view of the main grating structure 40G.

[0056] Referring to Figure 3, in this embodiment, the main grating structure 40G is composed of irregular patterns, including an unetched pattern PN, a lightly etched pattern PS, and a fully etched pattern PF. By combining different etching depths and customized subwavelength grating spacing (and orientation), a composite beveled grating or gradient grating can be formed in the XZ (propagation height) cross-sectional view, thereby achieving higher coupling efficiency. Here, the unetched pattern (PN) represents the grating structure on the original waveguide 40, which protrudes from the original upper surface of the waveguide 40 without removing the material of the waveguide 40 through the etching process; the lightly etched pattern (PS) represents the grating structure on the original waveguide 40, which protrudes from the original upper surface of the waveguide 40, and subsequently removes part of the material of the waveguide 40 through a light etching process (incomplete etching); the fully etched pattern (PF) represents the grating structure on the original waveguide 40, which protrudes from the original upper surface of the waveguide 40, and subsequently completely removes the material of the waveguide 40 through a light etching process (complete etching).

[0057] As described above, the integrated grating coupler according to the embodiments of this disclosure includes a reflector and a metal grating structure disposed above the reflector, which can effectively improve optical coupling efficiency. Therefore, the light source can have a large beam diameter. When the integrated grating coupler is embedded in a disposable biochip, it has a large alignment tolerance (e.g., greater than 10 μm). This characteristic facilitates plug-and-play rapid alignment with operating devices (providing light source, reagent processing, and signal acquisition), making it more suitable for various biosensing devices and optical systems.

[0058] The features of several embodiments have been summarized above to enable those skilled in the art to better understand the viewpoints of the embodiments disclosed herein. Those skilled in the art should understand that they can design or modify other processes and structures based on the embodiments disclosed herein to achieve the same purpose and / or advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent structures do not depart from the spirit and scope of this disclosure, and that they can make various changes, substitutions, and replacements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the appended claims. Furthermore, although this disclosure has been presented above with reference to several embodiments, it is not intended to limit the scope of this disclosure.

[0059] References to features, advantages, or similar language throughout this specification do not imply that all features and advantages achievable using this disclosure should or may be implemented in any single embodiment of this disclosure. Rather, language relating to features and advantages is to be understood as meaning that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Thus, the discussion of features and advantages, as well as similar language, throughout this specification may, but does not necessarily, represent the same embodiments.

[0060] Furthermore, in one or more embodiments, the features, advantages, and characteristics described herein can be combined in any suitable manner. Based on the description herein, those skilled in the art will recognize that this disclosure can be implemented without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be identified in certain embodiments that may not be present in all embodiments of this disclosure.

[0061] 1: Optical System 100, 102: Integrated grating coupler 10:Substrate 20: Reflector 21: High Refractive Index Film 23: Low refractive index film 30: Metal grating structure 30R, 40R: concave part 30R1, 40R1: first concave part 40: Waveguide 40G: Main grating structure 40N: Normal direction 51: First coating layer 53: Second coating layer 70: Light source 70A: Optical Axis 70E: Luminous surface A1, A2, C2, D4, D5, D6: Shortest distance A3: Angle B1: Width B2: Maximum Thickness B3, B9: Depth B4, C1, C3, E1, E2, E3, F1: Thickness Spacing of B6, B7, B8 D1: Width D2: Maximum thickness D3: Depth D70: diameter PF: Fully Etched Pattern PN: Unetched pattern PS: Lightly etched pattern X, Z: Coordinate axes

Claims

1. An integrated grating coupler, comprising: One substrate; A reflector is disposed on the substrate; A metal grating structure is disposed above the reflector; And a waveguide disposed above the metal grating structure, wherein the waveguide includes a main grating structure.

2. The integrated grating coupler as claimed in claim 1, wherein the reflector comprises a plurality of alternating stacked high-refractive-index films and a plurality of low-refractive-index films.

3. The integrated grating coupler as described in claim 1, wherein the width of the metal grating structure is greater than 1 μm and less than or equal to 100 μm, and the maximum thickness of the metal grating structure is greater than or equal to 0.1 μm and less than or equal to 2 μm.

4. The integrated grating coupler as claimed in claim 3, wherein the metal grating structure has a plurality of recesses of the same depth, the depth of which is greater than 0 and less than or equal to the maximum thickness of the metal grating structure.

5. The integrated grating coupler as claimed in claim 1, wherein the width of the main grating structure is greater than or equal to 10 μm and less than or equal to 300 μm, and the width of the metal grating structure is less than half the width of the main grating structure.

6. The integrated grating coupler as described in claim 1, wherein the maximum thickness of the main grating structure is greater than or equal to 0.16 μm and less than or equal to 0.6 μm.

7. The integrated grating coupler as claimed in claim 6, wherein the main grating structure has a plurality of recesses of the same depth, the depth of which is greater than or equal to 0.04 μm and less than or equal to the maximum thickness of the main grating structure.

8. The integrated grating coupler as described in claim 1, wherein the main grating structure has a different grating pitch.

9. An optical system, comprising: An integrated grating coupler includes: a substrate; a reflector disposed on the substrate; a metal grating structure disposed above the reflector; a waveguide disposed above the metal grating structure, wherein the waveguide includes a main grating structure; and a light source disposed above the integrated grating coupler.

10. The optical system of claim 9, wherein an extension of one optical axis of the light source is separated from the metal grating structure, and the diameter of the beam size of the light source is greater than or equal to 2 μm and less than or equal to 2000 μm.

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