Silicon-based tunable optical attenuator and method of manufacturing the same

Abstract

The application discloses a silicon-based adjustable optical attenuator, which comprises a ridge waveguide, a non-doped area, a first P-type doped area, a first N-type doped area, a second P-type doped area and a second N-type doped area. The ridge waveguide is arranged on the surface of one side of the non-doped area. The first P-type doped area and the first N-type doped area are arranged on the two sides of the ridge waveguide respectively. The second P-type doped area and the second N-type doped area are arranged on the two sides of the ridge waveguide respectively. The second N-type doped area is arranged on the same side of the first P-type doped area. The second P-type doped area is arranged on the same side of the first N-type doped area. The first P-type doped area is electrically connected with the second N-type doped area. The first N-type doped area is electrically connected with the second P-type doped area. The application further discloses a manufacturing method of the silicon-based adjustable optical attenuator. The silicon-based adjustable optical attenuator and the manufacturing method thereof can significantly improve the anti-static grade of the silicon-based adjustable optical attenuator.

Description

Technical Field

[0001] The present invention relates to the field of silicon-based optoelectronics, and in particular to a silicon-based adjustable optical attenuator and a manufacturing method thereof. Background Art

[0002] Currently, silicon-based variable optical attenuators are a commonly used active device for optical intensity regulation, often used to balance the power of multiple optical signals. A common silicon-based variable optical attenuator design involves heavily doping the slab waveguides on either side of a ridge waveguide with P-type and N-type doping, respectively. Electrodes are placed on the surfaces of the heavily doped P-type and N-type regions for powering them. An I region is positioned between the heavily doped P-type and N-type regions to ensure zero loss of optical signals transmitted through the ridge waveguide when power is not applied.

[0003] During the production and use of silicon-based optoelectronic devices, static electricity is randomly generated when components of different materials rub against each other or when electrons flow through conductive materials. When the static current exceeds the device's tolerance, the electronic components within the silicon-based optoelectronic device will break down, causing irreversible damage. Therefore, improving the anti-static rating of silicon-based optoelectronic devices and their corresponding products plays a crucial role in improving product yield and reliability. However, in actual applications, static electricity is generated randomly, with no way to distinguish between forward and reverse directions. Testing has found that the reverse anti-static rating of silicon-based variable optical attenuators is lower than that of forward directions. Therefore, it can be considered that the anti-static rating of silicon-based variable optical attenuators is primarily determined by their reverse anti-static rating. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a silicon-based variable optical attenuator that can significantly improve the anti-static level of the silicon-based variable optical attenuator.

[0005] The present invention also provides a method for manufacturing a silicon-based adjustable optical attenuator.

[0006] In a first aspect, an embodiment of the present invention provides a silicon-based variable optical attenuator, comprising: a ridge waveguide, an undoped region, a first P-type doped region, a first N-type doped region, a second P-type doped region, and a second N-type doped region;

[0007] The ridge waveguide is arranged on a surface of one side of the non-doped region;

[0008] The non-doped region is arranged in the same layer as the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region; the first P-type doped region and the first N-type doped region are respectively arranged on both sides of the ridge waveguide;

[0009] The second P-type doping region and the second N-type doping region are respectively arranged on both sides of the ridge waveguide;

[0010] The second N-type doping region is arranged on the same side as the first P-type doping region;

[0011] The second P-type doping region is arranged on the same side as the first N-type doping region;

[0012] The first P-type doping region is electrically connected to the second N-type doping region; the first N-type doping region is electrically connected to the second P-type doping region.

[0013] The silicon-based variable optical attenuator of the embodiment of the present invention has at least the following beneficial effects: by adding a second N-type doped region and a second P-type doped region to set up a reverse-parallel PIN junction, and then constructing a reverse electrostatic transmission channel, the anti-static level of the silicon-based variable optical attenuator is improved.

[0014] According to other embodiments of the silicon-based variable optical attenuator of the present invention, the undoped region, the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region are disposed in the same slab waveguide. That is, the same slab waveguide is doped to form the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region, with the undoped region in the slab waveguide serving as the undoped region.

[0015] According to some other embodiments of the present invention, the silicon-based variable optical attenuator further includes: a third P-type doping region, a third N-type doping region;

[0016] The third P-type doping region and the third N-type doping region are respectively arranged on both sides of the ridge waveguide;

[0017] The third P-type doping region is arranged on the same side as the second P-type doping region;

[0018] The third N-type doping region is arranged on the same side as the second N-type doping region.

[0019] By adding a third N-type doping region and a third P-type doping region, a parallel PIN junction is set up to construct an electrostatic transmission channel.

[0020] According to some other embodiments of the present invention, the silicon-based variable optical attenuator further includes: an insulating layer, a plurality of metal vias, a first metal electrode, a second metal electrode, a third metal electrode, and a fourth metal electrode;

[0021] The insulating layer is arranged on a side of the ridge waveguide away from the non-doped region;

[0022] The plurality of metal vias are provided in the insulating layer, and the plurality of metal vias are respectively provided corresponding to the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region;

[0023] The first metal electrode, the second metal electrode, the third metal electrode, and the fourth metal electrode are respectively disposed on a side of the insulating layer away from the non-doped region, and correspond to the plurality of metal vias respectively;

[0024] The first metal electrode is electrically connected to the second metal electrode, and the third metal electrode is electrically connected to the fourth metal electrode.

[0025] The first, second, third, and fourth metal electrodes, as well as the metal traces, can be fabricated simultaneously by applying a metal film, depositing metal, or evaporating metal to electrically connect the corresponding doped regions. The first, second, third, and fourth metal electrodes and the metal traces are of the same size to simplify the production process.

[0026] In addition, the slab waveguide and the ridge waveguide are made of silicon (Si), and an insulating layer is provided to insulate and isolate the slab waveguide and the ridge waveguide from the outside, wherein the insulating layer may be made of silicon dioxide (SiO2).

[0027] The silicon-based variable optical attenuator according to some other embodiments of the present invention further includes:

[0028] The third P-type doping region is electrically connected to the first N-type doping region;

[0029] The third N-type doping region is electrically connected to the first P-type doping region.

[0030] By connecting the newly added PIN junctions in reverse parallel to construct a reverse electrostatic transmission channel, the anti-static level of the silicon-based adjustable optical attenuator is improved.

[0031] According to some other embodiments of the present invention, the silicon-based variable optical attenuator further includes: an input-end single-mode waveguide and an output-end single-mode waveguide, wherein the input-end single-mode waveguide and the output-end single-mode waveguide are used for single-mode transmission of optical signals.

[0032] According to some other embodiments of the present invention, the silicon-based variable optical attenuator further includes a first mode spot conversion structure and a second mode spot conversion structure;

[0033] The first mode spot conversion structure is used to couple the input end single-mode waveguide and the ridge waveguide;

[0034] The second mode spot conversion structure is used to couple the output end single-mode waveguide and the ridge waveguide.

[0035] By setting up a mode spot conversion structure, it is ensured that the optical signal is transmitted in single mode before and after attenuation.

[0036] According to some other embodiments of the silicon-based variable optical attenuator of the present invention, the doping concentration of the first P-type doping region is equal to the doping concentration of the first N-type doping region;

[0037] The doping concentration of the second P-type doping region is equal to the doping concentration of the second N-type doping region;

[0038] The doping concentration of the first P-type doping region is equal to the doping concentration of the second P-type doping region.

[0039] By setting a consistent doping concentration, the electrostatic tolerance of each doping area is guaranteed to be consistent, and multiple doping areas are produced in the same production process to shorten the production process and improve production efficiency.

[0040] In a second aspect, an embodiment of the present invention provides a method for manufacturing a silicon-based variable optical attenuator, comprising:

[0041] A ridge waveguide is provided on the surface of one side of the non-doped region;

[0042] A first P-type doping region, a first N-type doping region, and a non-doping region are respectively provided on both sides of the ridge waveguide;

[0043] A second N-type doping region is provided on the side where the first P-type doping region is provided, and a second P-type doping region is provided on the side where the first N-type doping region is provided;

[0044] The non-doped region and the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region are arranged in the same layer;

[0045] The first P-type doping region is electrically connected to the second N-type doping region; and the first N-type doping region is electrically connected to the second P-type doping region.

[0046] The method for manufacturing a silicon-based variable optical attenuator according to an embodiment of the present invention has at least the following beneficial effects: by adding a second N-type doped region and a second P-type doped region to set up a reverse-parallel PIN junction, a reverse electrostatic transmission channel is constructed, thereby improving the anti-static level of the silicon-based variable optical attenuator.

[0047] Doping the slab waveguide to form the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region;

[0048] The area of ​​the slab waveguide that is not doped is the non-doped area.

[0049] According to some other embodiments of the present invention, the method for setting a silicon-based variable optical attenuator further includes:

[0050] Disposing an insulating layer on a side of the ridge waveguide away from the non-doped region;

[0051] Disposing a plurality of metal vias in the insulating layer, wherein the plurality of metal vias are respectively disposed corresponding to the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region;

[0052] Disposing a first metal electrode, a second metal electrode, a third metal electrode, and a fourth metal electrode on a side of the insulating layer away from the non-doped region, wherein the first metal electrode, the second metal electrode, the third metal electrode, and the fourth metal electrode correspond to the plurality of metal vias respectively;

[0053] The first metal electrode is electrically connected to the second metal electrode, and the third metal electrode is electrically connected to the fourth metal electrode.

[0054] According to some other embodiments of the present invention, the method for setting up a silicon-based variable optical attenuator further includes: providing a third P-type doping region and a third N-type doping region on both sides of the ridge waveguide;

[0055] The third P-type doping region is arranged on the same side as the second P-type doping region;

[0056] The third N-type doping region is arranged on the same side as the second N-type doping region.

[0057] By adding a third N-type doping region and a third P-type doping region, a parallel PIN junction is set up to construct an electrostatic transmission channel or a new light attenuation channel.

[0058] According to some other embodiments of the present invention, the method for setting up a silicon-based variable optical attenuator further includes: providing an input-end single-mode waveguide on one side of the ridge waveguide;

[0059] An output end single-mode waveguide is arranged on the other side of the ridge waveguide.

[0060] According to some other embodiments of the present invention, the method for setting a silicon-based variable optical attenuator further includes: respectively setting a first mode spot conversion structure and a second mode spot conversion structure;

[0061] coupling the input-end single-mode waveguide with the ridge waveguide through the first mode spot conversion structure;

[0062] The output end single-mode waveguide is coupled to the ridge waveguide through the second mode spot conversion structure.

[0063] By setting up a mode spot conversion structure, it is ensured that the optical signal is transmitted in single mode before and after attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a schematic structural diagram of a silicon-based variable optical attenuator according to an embodiment of the present invention;

[0065] Figure 2 yes Figure 1 Schematic cross-section of the middle II section;

[0066] Figure 3 yes Figure 1 Schematic cross-section of section II-II;

[0067] Figure 4 1 is a cross-sectional schematic diagram of a silicon-based variable optical attenuator according to an embodiment of the present invention;

[0068] Figure 5 is a schematic structural diagram of a silicon-based variable optical attenuator according to another embodiment of the present invention;

[0069] Figure 6 yes Figure 5 Schematic cross-section of the middle III-III section;

[0070] Figure 7 yes Figure 5 Schematic cross-section of section IV-IV;

[0071] Figure 8 This is a circuit schematic diagram of a silicon-based adjustable optical attenuator according to an embodiment of the present invention.

[0072] Figure numerals: 10, planar waveguide; 11, first P-type doped region; 12, first N-type doped region; 13, non-doped region; 21, second P-type doped region; 22, second N-type doped region; 31, third P-type doped region; 32, third N-type doped region; 41, first mode spot conversion structure; 42, second mode spot conversion structure; 50, ridge waveguide; 51, insulating layer; 61, input end single-mode waveguide; 62, output end single-mode waveguide; 71, first PIN junction; 72, second PIN junction; 81, metal positive electrode; 82, metal negative electrode; 911, first metal trace; 912, second metal trace; 92, first metal electrode; 93, second metal electrode; 94, third metal electrode; 95, fourth metal electrode; 96, metal via. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0074] In the description of the present invention, if any directional description is involved, such as "upper," "lower," "front," "back," "left," "right," etc., indicating directions or positional relationships, these are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed or operate in a specific orientation. Therefore, they should not be understood as limiting the present invention. If a feature is referred to as being "disposed," "fixed," "connected," or "mounted" on another feature, it may be directly disposed, fixed, or connected to the other feature, or indirectly disposed, fixed, connected, or mounted on the other feature.

[0075] In the description of the embodiments of the present invention, if the word "several" is mentioned, it means more than one; if the word "plurality" is mentioned, it means more than two; if the word "greater than," "less than," or "exceeds," it should be understood as excluding the number itself; if the word "above," "below," or "within" is mentioned, it should be understood as including the number itself. If the word "first" or "second" is mentioned, it should be understood as distinguishing technical features and should not be understood as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0076] First embodiment

[0077] Reference Figure 1 , shows a schematic structural diagram of a silicon-based variable optical attenuator according to an embodiment of the present invention. Figure 1 As shown, a silicon-based variable optical attenuator includes: a ridge waveguide 50, a first P-type doped region 11, a first N-type doped region 12, an undoped region 13, a second P-type doped region 21, and a second N-type doped region 22; the ridge waveguide 50 is arranged on the surface of one side of the undoped region 13.

[0078] The non-doped region 13 , the first P-type doped region 11 , the first N-type doped region 12 , the second P-type doped region 21 , and the second N-type doped region 22 are disposed in the slab waveguide 10 .

[0079] The same slab waveguide 10 is doped to produce a first P-type doping region 11 , a first N-type doping region 12 , a second P-type doping region 21 , and a second N-type doping region 22 . The undoped region in the slab waveguide 10 is used as a non-doped region 13 .

[0080] The non-doped region 13 is arranged in the same layer as the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, and the second N-type doping region 22; the first P-type doping region 11 and the first N-type doping region 12 are respectively arranged on both sides of the ridge waveguide 50; the second P-type doping region 21 and the second N-type doping region 22 are respectively arranged on both sides of the ridge waveguide 50; the second N-type doping region 22 is arranged on the same side as the first P-type doping region 11; the second P-type doping region 21 is arranged on the same side as the first N-type doping region 12; the first P-type doping region 11 is electrically connected to the second N-type doping region 22; and the first N-type doping region 12 is electrically connected to the second P-type doping region 21.

[0081] The silicon-based variable optical attenuator further includes an input single-mode waveguide 61 and an output single-mode waveguide 62, which are disposed at the input and output ends of the silicon-based variable optical attenuator, respectively, for single-mode transmission of optical signals. A first mode spot conversion structure 41 couples the input single-mode waveguide 61 to the ridge waveguide 50, while a second mode spot conversion structure 42 couples the output single-mode waveguide 62 to the ridge waveguide 50. The first and second mode spot conversion structures 41 and 42 prevent mode field mismatch and single-mode transmission due to size and refractive index differences between the ridge waveguide 50 and the input and output single-mode waveguides 61 and 62.

[0082] By providing the first and second spot conversion structures 41 and 42 , the optical signal is inputted into the ridge waveguide 50 through the input single-mode waveguide 61 for attenuation modulation, and then transmitted to the output single-mode waveguide 62 , while maintaining single-mode transmission.

[0083] The first and second mode spot conversion structures 41 and 42 each include a first straight waveguide region, a second straight waveguide region, and a tapered transition region. The tapered transition region is disposed between the first and second straight waveguide regions to provide a smooth transition for optical signals transmitted between the first and second straight waveguide regions.

[0084] The first straight waveguide region of the first mode spot conversion structure 41 is coupled to the input end single-mode waveguide 61, and the second straight waveguide region of the first mode spot conversion structure 41 is coupled to the ridge waveguide 50; the first straight waveguide region of the second mode spot conversion structure 42 is coupled to the output end single-mode waveguide 62, and the second straight waveguide region of the second mode spot conversion structure 42 is coupled to the ridge waveguide 50.

[0085] In this embodiment, the slab waveguide and the ridge waveguide are made of silicon (Si), and an insulating layer is provided to insulate the slab waveguide and the ridge waveguide from the outside, wherein the insulating layer may be made of silicon dioxide (SiO2).

[0086] Please refer to Figure 1 The specific working principle of the variable optical attenuator provided by the embodiment of the present invention is further described below.

[0087] The metal positive electrode 81 is electrically connected to the first P-type doping region 11 and the second N-type doping region 22 respectively to ensure that the electric potentials of the first P-type doping region 11 and the second N-type doping region 22 are equal; the metal negative electrode 82 is electrically connected to the first N-type doping region 12 and the second P-type doping region 21 respectively to ensure that the electric potentials of the first N-type doping region 12 and the second P-type doping region 21 are equal.

[0088] When a high potential is applied to the positive metal electrode 81 and a low potential is applied to the negative power supply, the first P-type doped region 11 and the first N-type doped region 12 form a forward PIN junction. The ridge waveguide 50, through doping, forms region I within the forward PIN junction. By adjusting the potentials applied to the positive metal electrode 81 and the negative metal electrode 82, the concentration of free carriers in region I can be adjusted. Free carriers can absorb the energy of photons in the optical signal and transition between energy levels within the same energy band. When a photon in the optical signal is partially absorbed, the optical signal attenuates. By adjusting the free carrier concentration in region I, the absorption of the optical signal by region I can be adjusted, thereby regulating the attenuation of the optical signal.

[0089] In addition, the second P-type doping region 21 and the second N-type doping region 22 form an inverse PIN junction. Since the first P-type doping region 11 and the second N-type doping region 22 are at the same potential, there is no transmission channel between them; since the first N-type doping region 12 and the second P-type doping region 21 are at the same potential, there is no transmission channel between them.

[0090] When forward static electricity exists in the silicon-based variable optical attenuator, the forward static electricity can form a forward PIN junction through the first P-type doped region 11 and the first N-type doped region 12 to construct a forward static electricity transmission channel; when reverse static electricity exists in the silicon-based variable optical attenuator, the reverse static electricity can form a reverse PIN junction through the second P-type doped region 21 and the second N-type doped region 22 to construct a reverse static electricity transmission channel.

[0091] In this embodiment, the second P-type doping region 21 and the second N-type doping region 22 are provided to construct an anti-parallel PIN junction and provide an anti-static transmission channel.

[0092] In other modified embodiments, the doping concentrations of the first P-type doping region 11, the first N-type doping region 12, the second N-type doping region 22, and the second P-type doping region 21 may be unequal so that the constructed PIN junction reaches a predetermined electrostatic tolerance. Furthermore, the areas of the first P-type doping region 11, the first N-type doping region 12, the second N-type doping region 22, and the second P-type doping region 21 are adjusted so that the constructed PIN junction reaches a predetermined electrostatic tolerance.

[0093] Electrodes are provided in the first P-type doping region 11, the first N-type doping region 12, the second N-type doping region 22, and the second P-type doping region 21, and an insulating layer 51 is provided on the surface of the doping regions. Metal vias 96 are provided in the insulating layer 51, and metal traces 91 are provided on the side of the insulating layer 51 away from the doping regions, so that the first P-type doping region 11, the second N-type doping region 22, and the metal anode 81 are electrically connected, or the second P-type doping region 21, the first N-type doping region 12, and the metal cathode 82 are electrically connected.

[0094] Please refer to Figure 1 、 Figure 2 , Figure 2 Shown Figure 1 The first N-type doping region 12, the second P-type doping region 21, and the non-doping region 13 are arranged in the same layer. The second N-type doping region 22, the first P-type doping region 11, and the non-doping region 13 are arranged in the same layer.

[0095] The doping concentration of the first P-type doping region 11 is equal to the doping concentration of the first N-type doping region 12; the doping concentration of the second P-type doping region 21 is equal to the doping concentration of the second N-type doping region 22; and the doping concentration of the first P-type doping region 11 is equal to the doping concentration of the second P-type doping region 21. By setting consistent doping concentrations, the electrostatic tolerance of each doping region is guaranteed to be consistent. Furthermore, because the doping concentrations of the first N-type doping region 12, the second N-type doping region 22, the first P-type doping region 11, and the second P-type doping region 21 are consistent, the first N-type doping region 12 and the second N-type doping region 22, or the first P-type doping region 11 and the second P-type doping region 21, can be fabricated in the same fabrication step, thereby reducing the fabrication process and improving production efficiency.

[0096] Please refer to Figure 3 , Figure 3 Shown Figure 1 Schematic diagram of the cross section of the II-II section. Figure 3As shown, the second N-type doping region 22, the second P-type doping region 21, and the undoped region 13 are arranged in the same layer, and the ridge waveguide 50 is arranged on the surface of one side of the undoped region 13. The second N-type doping region 22 and the second P-type doping region 21 are respectively arranged on both sides of the ridge waveguide 50, and the second N-type doping region 22, the second P-type doping region 21, and the ridge waveguide 50 are respectively isolated and arranged by the undoped region 13.

[0097] Second embodiment

[0098] Please refer to Figure 4 , Figure 4 FIG1 shows a cross-sectional schematic diagram of a silicon-based variable optical attenuator according to an embodiment of the present invention. Figure 3 As shown, the silicon-based variable optical attenuator includes: a ridge waveguide 50, an undoped region 13, a first P-type doped region 11, a first N-type doped region 12, a second P-type doped region 21, and a second N-type doped region 22; the ridge waveguide 50 is arranged on a surface on one side of the undoped region 13; the undoped region 13 is arranged in the same layer as the first P-type doped region 11, the first N-type doped region 12, the second P-type doped region 21, and the second N-type doped region 22; the first P-type doped region 11 and the first N-type doped region 12 are arranged on both sides of the ridge waveguide 50; the second P-type doped region 21 and the second N-type doped region 22 are respectively arranged on both sides of the ridge waveguide 50; the second N-type doped region 22 is arranged on the same side as the first P-type doped region 11; and the second P-type doped region 21 is arranged on the same side as the first N-type doped region 12.

[0099] In addition, the silicon-based variable optical attenuator further includes: an insulating layer 51, a plurality of metal vias 96, a first metal electrode 92, a second metal electrode 93, a third metal electrode 94, and a fourth metal electrode 95; the insulating layer 51 is disposed on a side of the ridge waveguide 50 away from the undoped region 13; a plurality of metal vias 96 are disposed in the insulating layer 51, and the plurality of metal vias 96 are respectively disposed corresponding to the first P-type doped region 11, the first N-type doped region 12, the second P-type doped region 21, and the second N-type doped region 22; the first metal electrode 92, the second metal electrode 93, the third metal electrode 94, and the fourth metal electrode 95 are respectively disposed on a side of the insulating layer 51 away from the undoped region 13, and respectively correspond to the plurality of metal vias 96; the first metal electrode 92 is electrically connected to the second metal electrode 93, and the third metal electrode 94 is electrically connected to the fourth metal electrode 95.

[0100] The first metal trace 911 and the second metal trace 912 are provided to electrically connect the first metal electrode 92 and the second metal electrode 93 , and the third metal electrode 94 and the fourth metal electrode 95 , respectively.

[0101] The first P-type doping region 11 and the second N-type doping region 22 are electrically connected via corresponding metal vias 96, the first metal electrode 92, the first metal trace 911, and the second metal electrode 93. The second P-type doping region 21 and the first N-type doping region 12 are electrically connected via corresponding metal vias 96, the third metal electrode 94, the second metal trace 912, and the fourth metal electrode 95.

[0102] Moreover, the first metal electrode 92 , the second metal electrode 93 , the third metal electrode 94 , the fourth metal electrode 95 , the first metal trace 911 , and the second metal trace 912 can be simultaneously manufactured by coating a metal oil film, metal deposition, or metal evaporation, so that the corresponding doping regions are electrically connected to each other.

[0103] In this embodiment, the first metal electrode 92 , the second metal electrode 93 , and the first metal trace 911 are interconnected metal prisms; the third metal electrode 94 , the fourth metal electrode 95 , and the second metal trace 912 are interconnected metal prisms.

[0104] In other embodiments, the sizes of the first metal trace 911 and the second metal trace 912 may be smaller than the corresponding metal electrodes, so as to save costs and reduce the volume of the overall structure.

[0105] In addition, the slab waveguide and the ridge waveguide are made of silicon (Si), and an insulating layer is provided to insulate and isolate the slab waveguide and the ridge waveguide, wherein the insulating layer may be made of silicon dioxide (SiO2).

[0106] Third embodiment

[0107] Please refer to Figure 5 , Figure 5 A schematic diagram of the structure of a silicon-based variable optical attenuator according to another embodiment of the present invention is shown. The silicon-based variable optical attenuator comprises a ridge waveguide 50, an undoped region 13, a first P-type doped region 11, a first N-type doped region 12, a second P-type doped region 21, a second N-type doped region 22, a third P-type doped region 31, and a third N-type doped region 32. The ridge waveguide 50 is disposed on a surface on one side of the undoped region 13.

[0108] The same slab waveguide 10 is doped to produce a first P-type doping region 11, a first N-type doping region 12, a second P-type doping region 21, a second N-type doping region 22, a third P-type doping region 31, and a third N-type doping region 32. The undoped region in the slab waveguide 10 is used as the non-doped region 13.

[0109] The non-doped region 13, the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, the second N-type doping region 22, the third P-type doping region 31, and the third N-type doping region 32 are arranged in the same layer; the first P-type doping region 11 and the first N-type doping region 12 are respectively arranged on both sides of the ridge waveguide 50; the second P-type doping region 21 and the second N-type doping region 22 are respectively arranged on both sides of the ridge waveguide 50; and the third P-type doping region 31 and the third N-type doping region 32 are respectively arranged on both sides of the ridge waveguide 50.

[0110] The second N-type doping region 22 and the third N-type doping region 32 are arranged on the same side as the first P-type doping region 11; the second P-type doping region 21 and the third P-type doping region 31 are arranged on the same side as the first N-type doping region 12; the first P-type doping region 11 is electrically connected to the second N-type doping region 22 and the third N-type doping region 32; the first N-type doping region 12 is electrically connected to the second P-type doping region 21 and the third P-type doping region 31.

[0111] When a high potential is applied to the positive metal electrode 81 and a low potential is applied to the negative power supply, the first P-type doped region 11 and the first N-type doped region 12 form a forward PIN junction. The ridge waveguide 50, through doping, forms region I within the forward PIN junction. By adjusting the potentials applied to the positive metal electrode 81 and the negative metal electrode 82, the concentration of free carriers in region I can be adjusted. Free carriers can absorb the energy of photons in the optical signal and transition between energy levels within the same energy band. When a photon in the optical signal is partially absorbed, the optical signal attenuates. By adjusting the free carrier concentration in region I, the absorption of the optical signal by region I can be adjusted, thereby regulating the attenuation of the optical signal.

[0112] Furthermore, the second P-type doping region 21 and the second N-type doping region 22 form an inverted PIN junction, and the third P-type doping region 31 and the third N-type doping region 32 form another inverted PIN junction. Because the first P-type doping region 11, the second N-type doping region 22, and the third N-type doping region 32 are at the same potential, no transmission channel exists between them. Similarly, because the first N-type doping region 12, the second P-type doping region 21, and the third P-type doping region 31 are at the same potential, no transmission channel exists between them.

[0113] When forward static electricity exists in the silicon-based variable optical attenuator, the forward static electricity can form a forward PIN junction through the first P-type doped region 11 and the first N-type doped region 12 to construct a forward static electricity transmission channel; when reverse static electricity exists in the silicon-based variable optical attenuator, the reverse static electricity can form a reverse PIN junction through the second P-type doped region 21 and the second N-type doped region 22 and a reverse PIN junction through the third P-type doped region 31 and the third N-type doped region 32 to construct a reverse static electricity transmission channel.

[0114] In this embodiment, a second P-type doping region 21 , a second N-type doping region 22 , a third P-type doping region 31 , and a third N-type doping region 32 are provided to construct an anti-parallel PIN junction and provide an anti-static transmission channel.

[0115] Please refer to Figure 6 , Figure 6 Shown Figure 5 Schematic diagram of the cross section of the III-III section. Figure 6 As shown, the second P-type doping region 21, the first N-type doping region 12, the third P-type doping region 31, and the non-doped region 13 are arranged in the same layer, and the second P-type doping region 21, the first N-type doping region 12, and the third P-type doping region 31 are isolated by the non-doped region 13 as an isolation region.

[0116] Please refer to Figure 7 , Figure 7 Shown Figure 5 Schematic diagram of the cross section of the IV-IV section. Figure 7 As shown, the second N-type doping region 22, the first P-type doping region 11, the third N-type doping region 32, and the non-doped region 13 are arranged in the same layer, and the second N-type doping region 22, the first P-type doping region 11, and the third N-type doping region 32 are isolated by the non-doped region 13 as an isolation region.

[0117] That is, P-type doping or N-type doping is performed in the slab waveguide 10 to form a first P-type doping region 11 , a first N-type doping region 12 , a second P-type doping region 21 , and a second N-type doping region 22 , and the non-doped region 13 is used as a spacer.

[0118] In this embodiment, the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, the second N-type doping region 22, the third P-type doping region 31, and the third N-type doping region 32 have the same doping concentration to ensure consistent electrostatic tolerance across all doped regions. Furthermore, because the doping concentrations are equal, the first N-type doping region 12, the second N-type doping region 22, and the third N-type doping region 32, or the first P-type doping region 11, the second P-type doping region 21, and the third N-type doping region 32, can be fabricated in the same fabrication step, thereby reducing the fabrication process and improving production efficiency.

[0119] Please refer to Figure 6 、 Figure 7 The second P-type doping region 21 and the third P-type doping region 31 are respectively arranged on both sides of the first N-type doping region 12 ; the second N-type doping region 22 and the third N-type doping region 32 are respectively arranged on both sides of the first P-type doping region 11 .

[0120] In other embodiments, the second P-type doping region 21 and the third P-type doping region 31 may be disposed simultaneously on one side of the first N-type doping region 12; the second N-type doping region 22 and the third N-type doping region 32 may be disposed simultaneously on one side of the first P-type doping region 11. The first P-type doping region 11 is disposed correspondingly to the first N-type doping region 12; the second P-type doping region 21 is disposed correspondingly to the second N-type doping region 22; and the third P-type doping region 31 is disposed correspondingly to the third N-type doping region 32.

[0121] In addition, referring to the second embodiment, an insulating layer 51, a metal via 96, a metal electrode, and a wiring are provided to electrically connect the first N-type doping region 12, the second P-type doping region 21, and the third P-type doping region 31 or the first P-type doping region 11, the second N-type doping region 22, and the third N-type doping region 32.

[0122] Please refer to Figure 8 , Figure 8 FIG1 shows a circuit diagram of a silicon-based adjustable optical attenuator according to an embodiment of the present invention. Figure 8 As shown, the metal positive electrode 81 is electrically connected to the input end of the first PIN junction 71 , and the metal negative electrode 82 is electrically connected to the output end of the first PIN junction 71 ; the first PIN junction 71 and the second PIN junction 72 are connected in reverse parallel.

[0123] When a high potential is applied externally to the metal positive electrode 81 and a low potential is applied externally to the metal negative electrode 82, the first PIN junction 71 is in a forward conduction state, and the second PIN junction 72 is in a reverse cutoff state. The first PIN junction 71 is used to provide free carriers to absorb the optical signal in the ridge waveguide 50. When positive static electricity is present in the above circuit, the first PIN junction 71 is in a forward conduction state, and the second PIN junction 72 is in a reverse cutoff state. The positive static electricity is transmitted to the metal negative electrode 82 via the first PIN junction 71. This establishes a positive static electricity transmission channel through the first PIN junction 71. When negative static electricity is present in the circuit, the first PIN junction 71 is in a reverse cutoff state, and the second PIN junction 72 is in a forward conduction state. The negative static electricity is transmitted to the metal positive electrode 81 via the first PIN junction 71. This establishes a reverse static electricity transmission channel through the second PIN junction 72.

[0124] Fourth embodiment

[0125] Please refer to Figure 1 The embodiment of the present invention provides a method for manufacturing a silicon-based variable optical attenuator, which includes:

[0126] S1: A ridge waveguide 50 is provided on the surface of one side of the slab waveguide 10;

[0127] S2: Dispose a first P-type doping region 11 and a first N-type doping region 12 on both sides of the ridge waveguide 50 respectively;

[0128] S3: Disposing a second N-type doping region 22 on the side where the first P-type doping region 11 is disposed, and disposing a second P-type doping region 21 on the side where the first N-type doping region 12 is disposed;

[0129] The non-doped region 13 is provided in the same layer as the first P-type doping region 11 , the first N-type doping region 12 , the second P-type doping region 21 , and the second N-type doping region 22 ;

[0130] S4: electrically connecting the first P-type doping region 11 to the second N-type doping region 22 ; and electrically connecting the first N-type doping region 12 to the second P-type doping region 21 .

[0131] The above-mentioned non-doped region 13 is arranged in the same layer as the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, and the second N-type doping region 22. That is, by performing P-type doping or N-type doping in the slab waveguide 10 to respectively form the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, and the second N-type doping region 22, and providing the non-doped region 13 as a spacer, the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, and the second N-type doping region 22 are insulated and isolated.

[0132] The first P-type doping region 11 , the first N-type doping region 12 , the second P-type doping region 21 , and the second N-type doping region 22 have the same doping concentration to ensure that the electrostatic tolerance of each doping region is consistent.

[0133] Since the doping concentrations of the first N-type doping region 12, the second N-type doping region 22, the first P-type doping region 11, and the second P-type doping region 21 are consistent, the above-mentioned steps S2 and S3 can be completed in the same manufacturing process flow to produce the first N-type doping region 12, the second N-type doping region 22 or the first P-type doping region 11, the second P-type doping region 21, thereby shortening the manufacturing process flow and improving production efficiency.

[0134] In this embodiment, the second N-type doping region 22 and the second P-type doping region 21 are reversely arranged in the planar waveguide 10 of the silicon-based variable optical attenuator to set up anti-parallel PIN junctions, thereby constructing a reverse electrostatic transmission channel.

[0135] An embodiment of the present invention provides a method for manufacturing a silicon-based adjustable optical attenuator, further comprising:

[0136] S5: An input-end single-mode waveguide 61 is provided on one side of the ridge waveguide 50 ; an output-end single-mode waveguide 62 is provided on the other side of the ridge waveguide 50 .

[0137] S6: respectively setting the first mold spot conversion structure 41 and the second mold spot conversion structure 42;

[0138] The input end single-mode waveguide 61 is coupled to the ridge waveguide 50 through the first mode spot conversion structure 41;

[0139] The output-end single-mode waveguide 62 is coupled to the ridge waveguide 50 through the second mode spot conversion structure 42 .

[0140] The input single-mode waveguide 61 and output single-mode waveguide 62 are respectively disposed at the input and output ends of the silicon-based variable optical attenuator to provide single-mode transmission of optical signals. A first spot-modulation structure 41 couples the input single-mode waveguide 61 to the ridge waveguide 50, while a second spot-modulation structure 42 couples the output single-mode waveguide 62 to the ridge waveguide 50. These first and second spot-modulation structures 41 and 42 prevent mode field mismatch and single-mode transmission due to size and refractive index differences between the ridge waveguide 50 and the input and output single-mode waveguides 61 and 62.

[0141] The first and second spot conversion structures 41 and 42 each include a transition waveguide and a coupling waveguide. The transition waveguide includes a first straight waveguide region, a second straight waveguide region, and a tapered transition region. The tapered transition region is located between the first and second straight waveguide regions to ensure a smooth transition of optical signals transmitted between the first and second straight waveguide regions.

[0142] The first straight waveguide region of the first mode spot conversion structure 41 is coupled to the input end single-mode waveguide 61, and the second straight waveguide region of the first mode spot conversion structure 41 is coupled to the ridge waveguide 50; the first straight waveguide region of the second mode spot conversion structure 42 is coupled to the output end single-mode waveguide 62, and the second straight waveguide region of the second mode spot conversion structure 42 is coupled to the ridge waveguide 50.

[0143] Please refer to Figure 4 , by respectively providing an insulating layer 51, multiple metal vias 96, a first metal electrode 92, a second metal electrode 93, a third metal electrode 94, and a fourth metal electrode 95; providing an insulating layer 51 on the side of the ridge waveguide 50 away from the slab waveguide 10; providing multiple metal vias 96 in the insulating layer 51, and the multiple metal vias 96 are respectively provided corresponding to the first P-type doping region 11, the first N-type doping region 12, the second P-type doping region 21, and the second N-type doping region 22; providing a first metal electrode 92, a second metal electrode 93, a third metal electrode 94, and a fourth metal electrode 95 on the side of the insulating layer 51 away from the slab waveguide 10, and the first metal electrode 92, the second metal electrode 93, the third metal electrode 94, and the fourth metal electrode 95 correspond to the multiple metal vias 96 respectively; the first metal electrode 92 is electrically connected to the second metal electrode 93, and the third metal electrode 94 is electrically connected to the fourth metal electrode 95.

[0144] The first metal trace 911 and the second metal trace 912 are provided to electrically connect the first metal electrode 92 and the second metal electrode 93 , and the third metal electrode 94 and the fourth metal electrode 95 , respectively.

[0145] The first P-type doping region 11 and the second N-type doping region 22 are electrically connected via corresponding metal vias 96, the first metal electrode 92, the first metal trace 911, and the second metal electrode 93. The second P-type doping region 21 and the first N-type doping region 12 are electrically connected via corresponding metal vias 96, the third metal electrode 94, the second metal trace 912, and the fourth metal electrode 95.

[0146] like Figure 4 As shown in the figure, only a partial structure of the silicon-based variable optical attenuator is shown, and the unshown portion can be further provided with an insulating layer to insulate the entire structure from the outside, wherein the insulating layer can be made of silicon dioxide (SiO2).

[0147] Fifth embodiment

[0148] Please refer to Figure 5 Compared with the fourth embodiment, the embodiment of the present invention provides a method for manufacturing a silicon-based variable optical attenuator, further comprising: S31: forming a third P-type doping region 31 and a third N-type doping region 32 on both sides of the ridge waveguide 50;

[0149] The third P-type doping region 31 is disposed on the same side as the second P-type doping region 21 ; the third N-type doping region 32 is disposed on the same side as the second N-type doping region 22 .

[0150] When forward static electricity exists in the silicon-based variable optical attenuator, the forward static electricity can form a forward PIN junction through the first P-type doped region 11 and the first N-type doped region 12 to construct a forward static electricity transmission channel; when reverse static electricity exists in the silicon-based variable optical attenuator, the reverse static electricity can form a reverse PIN junction through the second P-type doped region 21 and the second N-type doped region 22 and a reverse PIN junction through the third P-type doped region 31 and the third N-type doped region 32 to construct a reverse static electricity transmission channel.

[0151] In this embodiment, a second P-type doping region 21 , a second N-type doping region 22 , a third P-type doping region 31 , and a third N-type doping region 32 are provided to construct an anti-parallel PIN junction and provide an anti-static transmission channel.

[0152] In addition, referring to the fourth embodiment, an insulating layer 51, a metal via 96, a metal electrode, and a wiring are provided to electrically connect the first N-type doping region 12, the second P-type doping region 21, and the third P-type doping region 31 or the first P-type doping region 11, the second N-type doping region 22, and the third N-type doping region 32.

[0153] Please refer to Figure 6 、 Figure 7 The second P-type doping region 21 and the third P-type doping region 31 are respectively arranged on both sides of the first N-type doping region 12 ; the second N-type doping region 22 and the third N-type doping region 32 are respectively arranged on both sides of the first P-type doping region 11 .

[0154] In other embodiments, the second P-type doping region 21 and the third P-type doping region 31 may be disposed simultaneously on one side of the first N-type doping region 12; the second N-type doping region 22 and the third N-type doping region 32 may be disposed simultaneously on one side of the first P-type doping region 11. The first P-type doping region 11 is disposed correspondingly to the first N-type doping region 12; the second P-type doping region 21 is disposed correspondingly to the second N-type doping region 22; and the third P-type doping region 31 is disposed correspondingly to the third N-type doping region 32.

[0155] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features within the embodiments may be combined with one another unless there is a conflict.

Claims

1. A silicon-based variable optical attenuator, characterized in that: include: a ridge waveguide, an undoped region, a first P-type doped region, a first N-type doped region, a second P-type doped region, and a second N-type doped region; The ridge waveguide is arranged on a surface of one side of the non-doped region; The non-doped region is provided in the same layer as the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region; The first P-type doping region and the first N-type doping region are respectively arranged on both sides of the ridge waveguide; The second P-type doping region and the second N-type doping region are respectively arranged on both sides of the ridge waveguide; The second N-type doping region is arranged on the same side as the first P-type doping region; The second P-type doping region is arranged on the same side as the first N-type doping region; The first P-type doping region is electrically connected to the second N-type doping region; the first N-type doping region is electrically connected to the second P-type doping region.

2. The silicon-based variable optical attenuator according to claim 1, characterized in that: The non-doped region, the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region are arranged in the same slab waveguide.

3. The silicon-based variable optical attenuator according to claim 1, characterized in that: The silicon-based adjustable optical attenuator further includes: a third P-type doping region and a third N-type doping region; The third P-type doping region and the third N-type doping region are respectively arranged on both sides of the ridge waveguide; The third P-type doping region is arranged on the same side as the second P-type doping region; The third N-type doping region is arranged on the same side as the second N-type doping region.

4. The silicon-based variable optical attenuator according to claim 3, wherein: The third P-type doping region is electrically connected to the first N-type doping region; The third N-type doping region is electrically connected to the first P-type doping region.

5. The silicon-based variable optical attenuator according to claim 1, characterized in that: The silicon-based adjustable optical attenuator further includes: an insulating layer, a plurality of metal vias, a first metal electrode, a second metal electrode, a third metal electrode, and a fourth metal electrode; The insulating layer is arranged on a side of the ridge waveguide away from the non-doped region; The plurality of metal vias are provided in the insulating layer, and the plurality of metal vias are respectively provided corresponding to the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region; The first metal electrode, the second metal electrode, the third metal electrode, and the fourth metal electrode are respectively disposed on a side of the insulating layer away from the non-doped region, and correspond to the plurality of metal vias respectively; The first metal electrode is electrically connected to the second metal electrode, and the third metal electrode is electrically connected to the fourth metal electrode.

6. The silicon-based variable optical attenuator according to claim 1, characterized in that: The silicon-based variable optical attenuator further includes: an input end single-mode waveguide and an output end single-mode waveguide, wherein the input end single-mode waveguide and the output end single-mode waveguide are used for single-mode transmission of optical signals.

7. The silicon-based variable optical attenuator according to claim 6, characterized in that: The silicon-based adjustable optical attenuator further includes a first mode spot conversion structure and a second mode spot conversion structure; The first mode spot conversion structure is used to couple the input end single-mode waveguide and the ridge waveguide; The second mode spot conversion structure is used to couple the output end single-mode waveguide and the ridge waveguide.

8. The silicon-based variable optical attenuator according to claim 1, characterized in that: The doping concentration of the first P-type doping region is equal to the doping concentration of the first N-type doping region; The doping concentration of the second P-type doping region is equal to the doping concentration of the second N-type doping region; The doping concentration of the first P-type doping region is equal to the doping concentration of the second P-type doping region.

9. A method for manufacturing a silicon-based variable optical attenuator, characterized in that: include: A ridge waveguide is provided on the surface of one side of the non-doped region; A first P-type doping region and a first N-type doping region are respectively provided on both sides of the ridge waveguide; A second N-type doping region is provided on the side where the first P-type doping region is provided, and a second P-type doping region is provided on the side where the first N-type doping region is provided; The non-doped region and the first P-type doped region, the first N-type doped region, the second P-type doped region, and the second N-type doped region are arranged in the same layer; The first P-type doping region is electrically connected to the second N-type doping region; and the first N-type doping region is electrically connected to the second P-type doping region.

10. The method for manufacturing a silicon-based variable optical attenuator according to claim 9, wherein: Doping the slab waveguide to form the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region; The area of ​​the slab waveguide that is not doped is the non-doped area.

11. The method for manufacturing a silicon-based variable optical attenuator according to claim 9, wherein: The production method further comprises: Disposing an insulating layer on a side of the ridge waveguide away from the non-doped region; Disposing a plurality of metal vias in the insulating layer, wherein the plurality of metal vias are respectively disposed corresponding to the first P-type doping region, the first N-type doping region, the second P-type doping region, and the second N-type doping region; Disposing a first metal electrode, a second metal electrode, a third metal electrode, and a fourth metal electrode on a side of the insulating layer away from the non-doped region, wherein the first metal electrode, the second metal electrode, the third metal electrode, and the fourth metal electrode correspond to the plurality of metal vias respectively; The first metal electrode is electrically connected to the second metal electrode, and the third metal electrode is electrically connected to the fourth metal electrode.

12. The method for manufacturing a silicon-based variable optical attenuator according to claim 9, wherein: The manufacturing method further includes: providing a third P-type doping region and a third N-type doping region on both sides of the ridge waveguide; The third P-type doping region is arranged on the same side as the second P-type doping region; The third N-type doping region is arranged on the same side as the second N-type doping region.

13. The method for manufacturing a silicon-based variable optical attenuator according to claim 9, wherein: The manufacturing method further includes: providing an input-end single-mode waveguide on one side of the ridge waveguide; An output end single-mode waveguide is arranged on the other side of the ridge waveguide.

14. The method for manufacturing a silicon-based variable optical attenuator according to claim 13, wherein: The manufacturing method further includes: respectively providing a first mold spot conversion structure and a second mold spot conversion structure; coupling the input-end single-mode waveguide and the ridge waveguide through the first mode spot conversion structure; The output end single-mode waveguide and the ridge waveguide are coupled through the second mode spot conversion structure.

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