Optical splitter, optical switch and modulator
By simplifying the optical waveguide structure and optimized processing technology of multi-mode interference polarization insensitive spectrometers, the problem of complex optical waveguide structure in the existing technology is solved, and the structure simplification and processing cost of the spectrometer are achieved, while ensuring the smooth transmission of optical signals and the polarization insensitive spectrometer function are ensured.
Patent Information
- Application Number
- CN202421016921.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-05-11
AI Technical Summary
The existing multimode interference polarization insensitive spectrometers are difficult to process due to the complex structure of the optical waveguide.
A light splitter is designed, and its optical waveguide components include a multi-mode interference part, an input waveguide and an output waveguide. By simplifying the structure and optimizing the process, the processing difficulty of optical waveguide components is reduced. Specifically, the structure of the optical waveguide component is more simplified and can be prepared by two etching, reducing the processing difficulty and cost of the optical splitter.
The structure of the spectrometer is simplified and the processing difficulty is reduced, the processing cost of the spectrometer is reduced, and the smooth transmission of optical signals and polarization insensitive spectrometers are ensured.
Smart Images
Figure CN222704756U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of optical technology, and in particular to a spectrometer, an optical switch and a modulator. Background Art
[0002] A spectrometer is a passive device, which can also be called an optical splitter, splitter or power divider. It is often used in optical devices such as optical switches and modulators. Common devices with spectrometer functions include directional couplers, multi-mode interference (MMI) spectrometers, Y-branch waveguides, adiabatic tapered waveguides, and photonic crystals. Among them, the multi-mode interference polarization-insensitive spectrometer uses the principle of self-imaging to achieve spectrometering, and has many advantages such as large tolerance and large bandwidth. However, while the existing multi-mode interference polarization-insensitive spectrometers have the above advantages, their disadvantages are also obvious. For example, the multi-mode interference polarization-insensitive spectrometer based on the sub-wavelength grating structure has a complex optical waveguide structure, which makes the optical waveguide structure difficult to process. Utility Model Content
[0003] The embodiments of the present application provide a beam splitter, an optical switch and a modulator, which simplify the structure of the beam splitter and reduce the difficulty of manufacturing the beam splitter.
[0004] In the first aspect, an embodiment of the present application provides a spectrometer, which includes a substrate, an optical waveguide component and a cladding, wherein the optical waveguide component is arranged on a side surface of the substrate, the cladding is arranged on a side surface of the substrate on which the optical waveguide component is arranged, and the cladding covers the optical waveguide component. Specifically, the optical waveguide component includes a multimode interference portion, at least one input waveguide and a plurality of output waveguides, and the multimode interference portion includes a flat plate portion arranged on the surface of the substrate and a ridge portion arranged on the side of the flat plate portion facing away from the substrate. The at least one input waveguide is arranged at the first end of the multimode interference portion, and each input waveguide is connected to the ridge portion and the flat plate portion. The plurality of output waveguides are arranged at the second end of the multimode interference portion, and each output waveguide is connected to the ridge portion and the flat plate portion. In this way, the structure of the optical waveguide component is more simplified, and the optical waveguide component can be obtained by etching twice when the optical waveguide component is prepared, and the processing difficulty of the optical waveguide component is smaller, thereby greatly reducing the processing difficulty and processing cost of the spectrometer. Furthermore, along the first direction, the cross-sectional dimension of the input waveguide perpendicular to the first direction gradually increases, and the cross-sectional dimension of the output waveguide perpendicular to the first direction gradually decreases. The first direction is the direction from the first end to the second end, so that the optical signal in the input waveguide can enter the multimode interference unit more smoothly, and the optical signal in the multimode interference unit can enter each output waveguide more smoothly.
[0005] In a possible embodiment, the ridge portion includes a first side surface and a second side surface that are arranged opposite to each other, and the first side surface and the second side surface are both connected between the first end and the second end of the multi-mode interference portion. Furthermore, the first side surface and the second side surface are respectively perpendicular to the surface of the flat plate portion for setting the ridge portion, and the first side surface and the second side surface respectively form a step with the surface of the flat plate portion for setting the ridge portion. In this solution, there is a step between the flat plate portion and the ridge portion of the optical waveguide component, which can reduce the number of etching times in the process of preparing the optical waveguide component compared to the situation where there are multiple steps between the flat plate portion and the ridge portion, which is conducive to further reducing the difficulty of processing the spectrometer.
[0006] In a possible embodiment, the ridge portion includes a central axis extending along the first direction, and the at least one input waveguide is symmetrical about the central axis. When the input waveguide adopts the above configuration, the loss when using the optical splitter is lower.
[0007] In a possible embodiment, the ridge portion includes a central axis extending along the first direction, and the plurality of output waveguides are symmetrically arranged about the central axis. When the output waveguides are arranged in the above manner, the loss when using the optical splitter is lower.
[0008] In a possible embodiment, the cross-section of the input waveguide perpendicular to the first direction is rectangular or trapezoidal, and the cross-section of the output waveguide perpendicular to the first direction is rectangular or trapezoidal, so as to simplify the manufacturing process of the input waveguide and the output waveguide.
[0009] In a possible embodiment, the cross section of the flat plate portion perpendicular to the first direction is rectangular or trapezoidal, and the cross section of the ridge portion perpendicular to the first direction is rectangular or trapezoidal. In this way, the processing of the optical waveguide component can be simplified, thereby reducing the difficulty of processing the beam splitter.
[0010] In a possible embodiment, the ridge portion includes a central axis extending along the first direction, and the multi-mode interference portion is symmetrical about the central axis. The symmetry of the multi-mode interference portion about the central axis m is beneficial to reducing the loss of the optical splitter.
[0011] In a possible embodiment, the surface of the input waveguide facing the substrate and the surface of the flat plate portion facing the substrate are located in the same plane, the surface of the input waveguide facing away from the substrate and the surface of the ridge portion facing away from the substrate are located in the same plane, and the surface of the input waveguide facing the substrate is parallel to the surface of the input waveguide facing away from the substrate. In this solution, in the third direction, the size of the multimode interference portion is the same as the size of the input waveguide, which can reduce the number of etching times during the processing of the optical waveguide component, thereby facilitating the reduction of the difficulty of processing the optical splitter.
[0012] In a possible embodiment, the surface of the output waveguide facing the substrate and the surface of the flat plate portion facing the substrate are located in the same plane, the surface of the output waveguide facing away from the substrate and the surface of the ridge portion facing away from the substrate are located in the same plane, and the surface of the output waveguide facing the substrate is parallel to the surface of the output waveguide facing away from the substrate. In this solution, in the third direction, the size of the multimode interference portion is the same as the size of the output waveguide, which can reduce the number of etching times during the processing of the optical waveguide component, thereby facilitating the reduction of the difficulty of processing the optical splitter.
[0013] In a possible embodiment, the dimension of the optical waveguide component in the third direction is greater than or equal to 0.2 micrometers, and the dimension of the optical waveguide component in the third direction is less than or equal to 2 micrometers, and the third direction is the stacking direction of the substrate and the optical waveguide component. This solution facilitates achieving equal beat lengths of the TE mode and the TM mode.
[0014] In a possible embodiment, the ridge portion includes a first side surface and a second side surface that are arranged opposite to each other in a second direction, the first side surface and the second side surface are respectively perpendicular to the surface of the flat plate portion for setting the ridge portion, and the distance between the first side surface and the second side surface is greater than or equal to 2 microns. The second direction is perpendicular to the first direction and the stacking direction of the substrate and the optical waveguide component. This solution facilitates achieving equal beat lengths of the TE mode and the TM mode.
[0015] In a possible embodiment, one end surface of the flat plate portion in the first direction is coplanar with one end surface of the ridge portion in the first direction, and another end surface of the flat plate portion in the first direction is coplanar with another end surface of the ridge portion in the first direction. In this way, the etching difficulty during the processing of the optical waveguide component can be reduced, thereby reducing the processing difficulty of the beam splitter.
[0016] In the second aspect, the embodiment of the present application provides an optical switch, which includes two optical splitters and two phase shift arms provided by the technical solution of the first aspect, wherein one optical splitter includes two output waveguides, and the other optical splitter includes two input waveguides, and the two phase shift arms are connected to one output waveguide at one end and connected to one input waveguide at the other end. The optical switch includes the above-mentioned optical splitter, and thus, at least the effect that can be achieved by the above-mentioned optical splitter can be achieved, that is, the structure of the optical splitter is more simplified, and the optical waveguide component can be obtained by etching twice when preparing the optical waveguide component, and the processing difficulty of the optical waveguide component is smaller, thereby greatly reducing the processing difficulty and processing cost of the optical splitter. In addition, along the first direction, the size of the cross section of the input waveguide perpendicular to the first direction gradually increases, so that the optical signal in the input waveguide can enter the multimode interference part more smoothly; the size of the cross section of the output waveguide perpendicular to the first direction gradually decreases, so that the optical signal in the multimode interference part can enter each output waveguide more smoothly.
[0017] In the third aspect, the embodiment of the present application provides a modulator, which includes two optical splitters provided by the technical solution of the first aspect and two modulation arms, wherein one optical splitter includes two output waveguides, and the other optical splitter includes two input waveguides, and the two modulation arms are connected to an output waveguide at one end and an input waveguide at the other end. The modulator includes the above-mentioned optical splitter, and thus, at least the effect that can be achieved by the above-mentioned optical splitter can be achieved, that is, the structure of the optical splitter is more simplified, and the optical waveguide component can be obtained by etching twice when preparing the optical waveguide component, and the processing difficulty of the optical waveguide component is smaller, thereby greatly reducing the processing difficulty and processing cost of the optical splitter. In addition, along the first direction, the dimension of the input waveguide perpendicular to the first direction gradually increases, so that the optical signal in the input waveguide can enter the multimode interference part more smoothly; the dimension of the output waveguide perpendicular to the first direction gradually decreases, so that the optical signal in the multimode interference part can enter each output waveguide more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 A schematic diagram of the structure of a spectrometer provided in an embodiment of the present application;
[0019] Figure 2 for Figure 1 An exploded view of the beam splitter shown;
[0020] Figure 3 for Figure 2 A schematic diagram of the structure from another angle;
[0021] Figure 4 for Figure 1 AA cross-sectional view of the beam splitter shown;
[0022] Figure 5 for Figure 1 BB cross-sectional view of the beam splitter shown;
[0023] Figure 6 A schematic diagram of the structure of an optical waveguide component in a spectrometer provided in an embodiment of the present application;
[0024] Figure 7a A light field transmission distribution diagram of the TE mode of a spectrometer provided in an embodiment of the present application when the incident light wavelength is 1.55 μm;
[0025] Figure 7b A light field transmission distribution diagram of the TM mode of a spectrometer provided in an embodiment of the present application when the incident light wavelength is 1.55 μm;
[0026] Figure 8 is a graph of insertion loss versus wavelength;
[0027] Fig. 9 A schematic diagram of the structure of an optical switch provided in an embodiment of the present application;
[0028] Fig.10 This is a schematic diagram of the application scenario of real-time monitoring of optical switch lines;
[0029] Fig.11 A schematic diagram of the structure of a modulator provided in an embodiment of the present application.
[0030] Figure numerals: 1-substrate; 11-first region; 12-second region; 2-optical waveguide component; 21-multimode interference portion; 211-planar portion; 2111-cladding connection region; 212-ridge portion; 22-input waveguide; 23-output waveguide; 3-cladding; 100-splitter; 200-phase shift arm; 300-modulation arm; 400-spectral analysis module; 500-optical switch. DETAILED DESCRIPTION
[0031] The embodiments of the present application provide a beam splitter, an optical switch and a modulator to simplify the structure of the beam splitter and reduce the difficulty of processing the beam splitter. In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.
[0032] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "an", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context.
[0033] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.
[0034] Figure 1 A schematic diagram of the structure of a spectrometer 100 provided in an embodiment of the present application is shown in FIG. Figure 2 for Figure 1 An exploded view of the optical splitter 100 is shown. Figure 3 for Figure 2 A schematic diagram of the structure from another angle. Figure 4 for Figure 1The AA cross-sectional view of the optical splitter 100 is shown. Figure 5 for Figure 1 BB cross-sectional view of the optical splitter 100 is shown. Figure 1 to Figure 5 As shown, a spectrometer 100 provided by the present application includes a substrate 1, an optical waveguide component 2 and a cladding 3. Specifically, the optical waveguide component 2 is arranged on one side surface of the substrate 1, and the cladding 3 is arranged on one side surface of the substrate 1 where the optical waveguide component 2 is arranged, and the cladding 3 covers the optical waveguide component 2. It should be understood that the cladding 3 covers the surfaces of the optical waveguide component 2 exposed to the substrate 1. Since the cladding 3 has a certain thickness, the cladding 3 also covers at least part of the surface of the substrate 1 facing the optical waveguide component 2 except the area where the optical waveguide component 2 is located. For example, the surface of the substrate 1 used to arrange the optical waveguide component 2 is the top surface of the substrate 1, the area on the top surface of the substrate 1 where the optical waveguide component 2 is arranged is the first area 11, and the area on the top surface of the substrate 1 where the optical waveguide component 2 is not arranged is the second area 12. While the cladding 3 covers the surfaces of the optical waveguide component 2 exposed to the substrate 1, due to the thickness of the cladding 3, the cladding 3 will at least cover the part of the second area 12 adjacent to the first area 11. That is, the cladding 3 covers the surface of the optical waveguide member 2 exposed to the substrate 1 and also covers the portion of the second region 12 adjacent to the first region 11 or covers the entire second region 12 .
[0035] Next, please refer to Figure 2 and Figure 3 , the optical waveguide component 2 includes a multimode interference portion 21, at least one input waveguide 22 and a plurality of output waveguides 23 (that is, the number of the output waveguides 23 is greater than or equal to two), wherein the multimode interference portion 21 includes a flat portion 211 and a ridge portion 212, the flat portion 211 is arranged on the substrate 1, and the ridge portion 212 is arranged on the side of the flat portion 211 facing away from the substrate 1. Specifically, the at least one input waveguide 22 is arranged at the first end of the multimode interference portion 21, and each input waveguide 22 is connected to the ridge portion 212 and the flat portion 211. The plurality of output waveguides 23 are arranged at the second end of the multimode interference portion 21, and each output waveguide 23 is connected to the ridge portion 212 and the flat portion 211. In this way, the structure of the optical waveguide component 2 is simplified, and the optical waveguide component 2 can be obtained by etching twice when preparing the optical waveguide component 2, and the processing difficulty of the optical waveguide component 2 is lower, so that the processing difficulty and processing cost of the optical splitter 100 are also greatly reduced. For example, when preparing the optical waveguide component 2 , an optical waveguide structure with a first thickness may be obtained by performing a first etching, and then a second etching may be performed on a part of the optical waveguide structure to obtain the optical waveguide component 2 .
[0036] Furthermore, with the direction from the first end of the multimode interference unit 21 to the second end as the first direction C1, along the first direction C1, the size of the cross-section of the input waveguide 22 perpendicular to the first direction C1 gradually increases, and the size of the cross-section of the output waveguide 23 perpendicular to the first direction C1 gradually decreases, so that the optical signal in the input waveguide 22 can enter the multimode interference unit 21 more smoothly, and the optical signal in the multimode interference unit 21 can enter each output waveguide 23 more smoothly.
[0037] It is worth noting that, when the optical splitter 100 is used, the output waveguide 23 and the input waveguide 22 are determined according to the incident direction of the optical signal, the waveguide that the optical signal passes through before entering the multimode interference unit 21 is the input waveguide 22, and the waveguide that the optical signal passes through after passing through the multimode interference unit 21 is the output waveguide 23. In other words, the output waveguide 23 and the input waveguide 22 can be interchanged according to the incident direction of the optical signal. Among them, when the optical splitter 100 includes multiple input waveguides 22 and one output waveguide 23, the optical splitter 100 is used for combining multiple optical signals. The input waveguide 22 and the output waveguide 23 mentioned in this embodiment are relative to the situation where the optical splitter 100 is used to split the optical signal.
[0038] The following briefly introduces the process of determining the size of the optical waveguide component 2 by taking the stacking direction of the optical waveguide component 2 and the substrate 1 as the third direction C3 and the direction perpendicular to the first direction C1 and the third direction C3 as the second direction C2, as an example:
[0039] First, the total thickness of the optical waveguide component 2 is preliminarily determined according to the constituent material of the optical waveguide component 2; for example, if the material of the optical waveguide component 2 is silicon (Si), the total thickness of the optical waveguide component 2 can be approximately 220 nanometers; it is worth noting that the thickness of the component in the spectrometer is the size of the component in the third direction C3;
[0040] Subsequently, the design size of the ridge portion 212 in the second direction C2 is determined by simulation software; specifically, the size of the ridge portion 212 in the second direction C2 when the optical waveguide component 2 supports at least the fundamental mode and the first-order mode is the design size of the ridge portion 212 in the second direction C2;
[0041] Then, in the simulation software, the design dimension of the ridge portion 212 in the second direction C2 and the total thickness of the optical waveguide component 2 are set to certain values, and the thickness of the plate portion 211 is changed until the beat lengths (L π) are equal, and the thickness of the flat plate portion 211 is determined. The beat lengths of the TE mode and the TM mode are equal, and the optical splitter 100 can achieve polarization-insensitive splitting. The so-called beat length is the length when the phase difference between the 0th order mode and the 1st order mode of the TE mode (TM mode) is π. The beat lengths are equal, that is, the difference in the propagation constants (equivalent refractive index) of the 0th order mode and the 1st order mode is equal.
[0042] In a specific implementation, the optical waveguide component 2 can be prepared on the surface of the substrate 1 in a patterned manner. Specifically, when preparing the optical waveguide component 2, an optical waveguide structure with a first thickness can be obtained by a first etching, and then the ridge portion and the flat plate portion are formed by partially etching the area where the multimode interference portion 21 is located, thereby forming the optical waveguide component 2. By partially etching the area where the multimode interference portion 21 is located, the beat lengths of the TE mode and the TM mode are equal, achieving a polarization-insensitive splitting effect, and at the same time, it has the advantages of simple structure and process.
[0043] Please continue to refer to Figure 2 and Figure 3 The ridge-shaped portion 212 includes a first side surface and a second side surface that are arranged opposite to each other in the second direction C2. Specifically, the first side surface and the second side surface are connected between the first end and the second end of the multi-mode interference portion 21, and the first side surface and the second side surface are respectively perpendicular to the surface of the flat portion 211 used to set the ridge-shaped portion 212, and the first side surface and the second side surface respectively form a step with the surface of the flat portion 211 used to set the ridge-shaped portion 212. Exemplarily, a side surface of the flat portion 211 used to set the ridge-shaped portion 212 includes a ridge-shaped portion setting area and two cladding connection areas 2111, and the two cladding connection areas 2111 are arranged at intervals in the direction from the first side surface of the ridge-shaped portion 212 to the second side surface, and the ridge-shaped portion setting area is located between the two cladding connection areas 2111, and the ridge-shaped portion 212 is set in the ridge-shaped portion setting area, and the first side surface and the second side surface respectively form a step with the cladding connection area 2111 adjacent to the side surface. In this solution, there is a single step between the flat portion 211 and the ridge portion 212 of the optical waveguide component 2. Compared with the case where there are multiple steps between the flat portion 211 and the ridge portion 212, the number of etching times in the process of preparing the optical waveguide component 2 can be reduced, which is beneficial to further reduce the processing difficulty of the splitter 100.
[0044] Next, combine Figure 2 and Figure 3 The multi-mode interference portion 21 is introduced in detail. In a specific implementation, the cross section of the flat portion 211 perpendicular to the first direction C1 may be rectangular or trapezoidal, and the cross section of the ridge portion 212 perpendicular to the first direction C1 may also be rectangular or trapezoidal. Figure 2 and Figure 3In the case shown in FIG. 1 , the cross sections of the flat plate portion 211 and the ridge portion 212 perpendicular to the first direction C1 are both rectangular. In this way, the processing of the optical waveguide component 2 can be simplified, thereby reducing the difficulty of processing the beam splitter 100 .
[0045] Please continue to refer to Figure 2 and Figure 3 In a specific implementation, the ridge portion includes a central axis m extending along the first direction C1, and the multimode interference portion is symmetrical about the central axis m. The symmetry of the multimode interference portion 21 about the central axis m is beneficial to reducing the loss of the optical splitter 100. Of course, in other implementations, the multimode interference portion 21 may also be an asymmetric structure about the central axis m of the ridge portion.
[0046] In some embodiments, the size of the optical waveguide component in the third direction C3 is greater than or equal to 0.2 microns, and the size of the optical waveguide component in the third direction C3 is less than or equal to 2 microns; in some embodiments, the first side surface and the second side surface of the ridge portion are respectively perpendicular to the surface of the flat portion for setting the ridge portion, and the distance between the first side surface and the second side surface is greater than or equal to 2 microns. This solution facilitates achieving equal beat lengths of the TE mode and the TM mode.
[0047] In a specific implementation, one end face of the flat portion 211 located in the first direction C1 is coplanar with one end face of the ridge portion 212 located in the first direction C1, and the other end face of the flat portion 211 located in the first direction C1 is coplanar with the other end face of the ridge portion 212 located in the first direction C1. In this way, the etching difficulty during the processing of the optical waveguide component 2 can be reduced, thereby reducing the processing difficulty of the splitter 100.
[0048] Next, please continue to refer to Figure 2 and Figure 3 In a specific implementation, the surface of the input waveguide 22 facing the substrate 1 and the surface of the flat plate portion 211 facing the substrate 1 are located in the same plane, the surface of the input waveguide 22 facing away from the substrate 1 and the surface of the ridge portion 212 facing away from the substrate 1 are located in the same plane, and the surface of the input waveguide 22 facing the substrate 1 is parallel to the surface of the input waveguide 22 facing away from the substrate 1. In this solution, in the third direction C3, the size of the multimode interference portion 21 is the same as the size of the input waveguide 22, which can reduce the number of etching times during the processing of the optical waveguide component 2, thereby facilitating the reduction of the processing difficulty of the optical splitter 100.
[0049] In some embodiments, the surface of the output waveguide 23 facing the substrate 1 and the surface of the flat plate portion 211 facing the substrate 1 are located in the same plane, the surface of the output waveguide 23 facing away from the substrate 1 and the surface of the ridge portion 212 facing away from the substrate 1 are located in the same plane, and the surface of the output waveguide 23 facing the substrate 1 is parallel to the surface of the output waveguide 23 facing away from the substrate 1. In this solution, in the third direction C3, the size of the multimode interference portion 21 is the same as the size of the output waveguide 23, which can reduce the number of etching times during the processing of the optical waveguide component 2, thereby facilitating the reduction of the processing difficulty of the optical splitter 100.
[0050] Of course, in some embodiments, the above two situations can also be satisfied at the same time, that is, the surface of the input waveguide 22 facing the substrate 1 and the surface of the flat plate portion 211 facing the substrate 1 are located in the same plane, the surface of the input waveguide 22 facing away from the substrate 1 and the surface of the ridge portion 212 facing away from the substrate 1 are located in the same plane, and the surface of the input waveguide 22 facing the substrate 1 is parallel to the surface of the input waveguide 22 facing away from the substrate 1. At the same time, the surface of the output waveguide 23 facing the substrate 1 and the surface of the flat plate portion 211 facing the substrate 1 are located in the same plane, the surface of the output waveguide 23 facing away from the substrate 1 and the surface of the ridge portion 212 facing away from the substrate 1 are located in the same plane, and the surface of the output waveguide 23 facing the substrate 1 is parallel to the surface of the output waveguide 23 facing away from the substrate 1. In this way, the number of etching times in the processing of the optical waveguide component 2 can be reduced to a greater extent, thereby reducing the processing difficulty of the optical splitter 100 to a greater extent.
[0051] In some possible implementations, the cross-section of the input waveguide 22 perpendicular to the first direction C1 is rectangular or trapezoidal, and the cross-section of the output waveguide 23 perpendicular to the first direction C1 is rectangular or trapezoidal, so as to simplify the manufacturing process of the input waveguide 22 and the output waveguide.
[0052] Please continue to refer to 2. When the above-mentioned input waveguides 22 are specifically arranged, each input waveguide 22 is symmetrically arranged about the central axis m of the ridge-shaped portion 212. That is, when the input waveguide 22 is one (such as Figure 6), the input waveguide 22 itself is symmetrically arranged about the central axis m of the ridge-shaped portion 212; when there are multiple input waveguides 22, the multiple input waveguides 22 are symmetrically arranged about the central axis m of the ridge-shaped portion 212. It is worth noting that when there are multiple input waveguides 22, and the number of input waveguides 22 is an odd number greater than 1, the input waveguide 22 located in the middle in the second direction C2 is symmetrically arranged about the central axis m of the ridge-shaped portion 212. Similarly, the multiple output waveguides 23 can also be symmetrically arranged about the central axis m of the ridge-shaped portion 212. That is to say, when there is one output waveguide 23, the output waveguide 23 itself is symmetrically arranged about the central axis m of the ridge-shaped portion 212; when there are multiple output waveguides 23, the multiple output waveguides 23 are symmetrically arranged about the central axis m of the ridge-shaped portion 212. When there are multiple output waveguides 23, and the number of the output waveguides 23 is an odd number greater than 1, the output waveguide 23 located in the middle in the second direction C2 is symmetrically arranged about the central axis m of the ridge portion 212. When the input waveguide 22 and the output waveguide 23 are arranged as described above, the loss when using the optical splitter 100 is lower.
[0053] Combine the following Figure 2 The structure of the optical waveguide component 2 in the optical splitter 100 provided in the embodiment of the present application is introduced. Figure 2 As shown, the optical waveguide component 2 includes two input waveguides 22 and two output waveguides 23. The cross-sections of each input waveguide 22 and each output waveguide 23 perpendicular to the first direction C1 are rectangular. Along the first direction C1, the size of the cross-section of the input waveguide 22 perpendicular to the first direction C1 gradually increases, and the size of the cross-section of the output waveguide 23 perpendicular to the first direction C1 gradually decreases. The surfaces of each input waveguide 22 and each output waveguide 23 facing the substrate 1 are located in the same surface as the surface of the flat plate portion 211 facing the substrate 1, and the surfaces of each input waveguide 22 and each output waveguide 23 facing away from the substrate 1 are located in the same surface as the surface of the ridge portion 212 facing away from the substrate 1, and the surface of the flat plate portion 211 facing the substrate 1 is parallel to the surface of the ridge portion 212 facing away from the substrate 1. The input waveguides 22 are symmetrically distributed about the central axis m of the ridge portion 212, and the output waveguides 23 are also symmetrically distributed about the central axis m of the ridge portion 212. The cross-sections of the flat plate portion 211 and the ridge portion 212 perpendicular to the first direction C1 are both rectangular. By properly designing the size of the ridge portion 212 in the second direction C2 and the size of the flat portion 211 in the third direction C3, the difference in effective refractive index between the fundamental mode and the first-order mode of the TE mode and the difference in effective refractive index between the fundamental mode and the first-order mode of the TM mode are almost equal. For example, the order of magnitude of the difference is <10 -4 , so that the beat lengths of the TE mode and the TM mode are equal, achieving polarization-insensitive spectrometry.
[0054] It should be understood that the refractive index of the material of the cladding 3 is less than the refractive index of the material of the optical waveguide component 2, the input waveguide 22 and the output waveguide 23 are both single-mode waveguides, and the multi-mode interference unit 21 is a multi-mode waveguide. Among them, the single-mode waveguide refers to a waveguide that only allows the lowest-order mode or the narrowest light beam to pass through, and the multi-mode waveguide refers to a waveguide that allows multiple different light eigenmodes to propagate simultaneously at the same polarization state and the same wavelength. Exemplarily, the material of the optical waveguide component 2 is silicon nitride (SiN), the material of the cladding 3 is silicon dioxide (SiO2), the size of the end of the input waveguide 22 opposite to the multimode interference portion 21 in the second direction C2 is 800 nanometers, the size of the end of the input waveguide 22 opposite to the multimode interference portion 21 in the third direction C3 is also 800 nanometers, the size of the end of the input waveguide 22 connected to the multimode interference portion 21 in the second direction C2 is 2.2 microns, the size of the ridge portion 212 in the second direction C2 is 5.7 microns, the size of the multimode interference portion 21 in the first direction C1 is 83 microns, and the size of the flat plate portion 211 in the third direction C3 is 340 nanometers.
[0055] Figure 7a The optical field transmission distribution diagram of the TE mode of the optical splitter 100 with the above structure and parameters when the incident light wavelength is 1.55 μm, Figure 7b The light field transmission distribution diagram of the TM mode of the optical splitter 100 with the above structure and parameters when the incident light wavelength is 1.55 μm. Figure 7a and Figure 7b It can be seen that 1:1 splitting is achieved when both TE mode and TM mode are incident, and it has polarization-insensitive splitting function. Figure 8 FIG. 4 is a graph showing the relationship between insertion loss and wavelength. The TE mode and TM mode losses are almost equal, which further proves that the optical splitter 100 has a polarization-insensitive function.
[0056] It should be understood that the optical splitter 100 mentioned in the embodiment of the present application can be used alone, or multiple optical splitters 100 can be cascaded to obtain multiple output ends.
[0057] Fig. 9 This is a schematic diagram of the structure of an optical switch provided in an embodiment of the present application. Fig. 9As shown, the optical switch includes two of the above-mentioned optical splitters 100 and two phase shift arms 200, wherein the optical splitter 100 on the left is used for splitting, and the optical splitter 100 on the right is used for combining. The optical splitter 100 on the left includes two output waveguides, and the optical splitter 100 on the right includes two input waveguides. One end of each of the two phase shift arms 200 is connected to an output waveguide, and the other end is connected to an input waveguide. Specifically, the optical splitter 100 on the left of the above-mentioned two optical splitters 100 is used to split the input optical signal to obtain a first optical signal and a second optical signal, and the phase shift arm 200 is used to adjust the phase of the first optical signal and the second optical signal, and the optical splitter 100 on the right of the above-mentioned two optical splitters 100 is used to combine the first optical signal and the second optical signal after the phase adjustment by each phase shift arm 200. The optical switch includes the above-mentioned optical splitter 100, and thus, at least the effect that can be achieved by the above-mentioned optical splitter 100 can be achieved, that is, the structure of the optical splitter 100 is more simplified, and the optical waveguide component 2 can be obtained by etching twice when preparing the optical waveguide component 2, and the processing difficulty of the optical waveguide component 2 is lower, thereby greatly reducing the processing difficulty and processing cost of the optical splitter 100. In addition, along the first direction C1, the size of the cross section of the input waveguide 22 perpendicular to the first direction C1 gradually increases, so that the optical signal in the input waveguide 22 can enter the multimode interference unit 21 more smoothly; the size of the cross section of the output waveguide 23 perpendicular to the first direction C1 gradually decreases, so that the optical signal in the multimode interference unit 21 can enter each output waveguide 23 more smoothly.
[0058] Optical switches can be used for access network protection switching, real-time line monitoring, metropolitan area routing, etc. Fig.10 This is a schematic diagram of the application scenario of real-time monitoring of optical switch lines. Fig.10 As shown, the four optical signals are respectively switched to the spectrum analysis module 400 through the optical switch 500 for spectrum analysis to monitor the health of the line. For example, the optical switch 500 may be a Mach-Zehnder interferometer (MZI) optical switch, and the optical splitter 100 may be a 3dB optical splitter.
[0059] Fig.11 A schematic diagram of the structure of a modulator provided in an embodiment of the present application. Fig.11As shown, a modulator provided in an embodiment of the present application includes two optical splitters 100 and two modulation arms 300, wherein the optical splitter 100 on the left is used for splitting, and the optical splitter 100 on the right is used for combining. The optical splitter 100 on the left includes two output waveguides, and the optical splitter 100 on the right includes two input waveguides. One end of each of the two modulation arms 300 is connected to an output waveguide, and the other end is connected to an input waveguide. Specifically, the optical splitter 100 on the left of the two optical splitters 100 is used to split the input optical signal to obtain a first optical signal and a second optical signal, and the modulation arm 300 is used to modulate the first optical signal and the second optical signal, and the optical splitter 100 on the right of the two optical splitters 100 is used to combine the first optical signal and the second optical signal modulated by each modulation arm 300. The modulator includes the above-mentioned optical splitter 100, and thus, at least the effect that can be achieved by the above-mentioned optical splitter 100 can be achieved, that is, the structure of the optical splitter 100 is more simplified, and the optical waveguide component 2 can be obtained by etching twice when preparing the optical waveguide component 2, and the processing difficulty of the optical waveguide component 2 is lower, thereby greatly reducing the processing difficulty and processing cost of the optical splitter 100. In addition, along the first direction C1, the size of the input waveguide 22 perpendicular to the first direction C1 gradually increases, so that the optical signal in the input waveguide 22 can enter the multimode interference unit 21 more smoothly; the size of the output waveguide 23 perpendicular to the first direction C1 gradually decreases, so that the optical signal in the multimode interference unit 21 can enter each output waveguide 23 more smoothly.
[0060] Exemplarily, the modulator may be an MZI modulator, and the optical splitter 100 may be a 3dB optical splitter.
[0061] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A spectrometer, characterized in that: The optical waveguide device comprises a substrate, an optical waveguide component and a cladding, wherein the optical waveguide component is arranged on one side surface of the substrate, the cladding is arranged on one side surface of the substrate on which the optical waveguide component is arranged, and the cladding covers the optical waveguide component; The optical waveguide component comprises a multimode interference portion, at least one input waveguide and a plurality of output waveguides, the multimode interference portion comprises a flat plate portion and a ridge portion, the flat plate portion is arranged on the substrate, and the ridge portion is arranged on a side of the flat plate portion facing away from the substrate; the at least one input waveguide is arranged at a first end of the multimode interference portion, and each of the input waveguides is connected to the ridge portion and the flat plate portion; the plurality of output waveguides are arranged at a second end of the multimode interference portion, and each of the output waveguides is connected to the ridge portion and the flat plate portion; Along a first direction, a cross-sectional dimension of the input waveguide perpendicular to the first direction gradually increases, and a cross-sectional dimension of the output waveguide perpendicular to the first direction gradually decreases. The first direction is a direction from the first end to the second end.
2. The optical splitter according to claim 1, wherein: The ridge-shaped portion includes a first side surface and a second side surface that are oppositely arranged, wherein the first side surface and the second side surface are both connected between the first end and the second end of the multi-mode interference portion, and the first side surface and the second side surface are respectively perpendicular to the surface of the flat plate portion used to set the ridge-shaped portion, and the first side surface and the second side surface respectively form a step with the surface of the flat plate portion used to set the ridge-shaped portion.
3. The optical splitter according to claim 1, wherein: The ridge portion includes a central axis extending along the first direction, and the at least one input waveguide is symmetrical about the central axis.
4. The optical splitter according to claim 1, wherein: The ridge portion includes a central axis extending along the first direction, and the plurality of output waveguides are symmetrically arranged about the central axis.
5. The spectrometer according to any one of claims 1 to 4, characterized in that: The cross section of the input waveguide perpendicular to the first direction is rectangular or trapezoidal, and the cross section of the output waveguide perpendicular to the first direction is rectangular or trapezoidal.
6. The spectrometer according to any one of claims 1 to 4, characterized in that: The cross section of the flat plate portion perpendicular to the first direction is rectangular or trapezoidal, and the cross section of the ridge portion perpendicular to the first direction is rectangular or trapezoidal.
7. The spectrometer according to any one of claims 1 to 4, characterized in that: The ridge portion includes a central axis extending along the first direction, and the multi-mode interference portion is symmetrical about the central axis.
8. The spectrometer according to any one of claims 1 to 4, characterized in that: The surface of the input waveguide facing the substrate and the surface of the flat portion facing the substrate are located in the same plane, the surface of the input waveguide facing away from the substrate and the surface of the ridge portion facing away from the substrate are located in the same plane, and the surface of the input waveguide facing the substrate is parallel to the surface of the input waveguide facing away from the substrate.
9. The spectrometer according to any one of claims 1 to 4, characterized in that: The surface of the output waveguide facing the substrate and the surface of the flat portion facing the substrate are located in the same plane, the surface of the output waveguide facing away from the substrate and the surface of the ridge portion facing away from the substrate are located in the same plane, and the surface of the output waveguide facing the substrate is parallel to the surface of the output waveguide facing away from the substrate.
10. The spectrometer according to any one of claims 1 to 4, characterized in that: The dimension of the optical waveguide component in a third direction is greater than or equal to 0.2 micrometers, and the dimension of the optical waveguide component in the third direction is less than or equal to 2 micrometers, and the third direction is a stacking direction of the substrate and the optical waveguide component.
11. The spectrometer according to any one of claims 1 to 4, characterized in that: The ridge portion includes a first side surface and a second side surface that are arranged opposite to each other in a second direction, the first side surface and the second side surface are respectively perpendicular to a surface of the flat plate portion for arranging the ridge portion, and a distance between the first side surface and the second side surface is greater than or equal to 2 micrometers; The second direction is perpendicular to the first direction and the stacking direction of the substrate and the optical waveguide component.
12. The spectrometer according to any one of claims 1 to 4, characterized in that: One end surface of the flat plate portion in the first direction is coplanar with one end surface of the ridge portion in the first direction, and the other end surface of the flat plate portion in the first direction is coplanar with the other end surface of the ridge portion in the first direction.
13. An optical switch, characterized in that: It comprises two optical splitters as claimed in any one of claims 1 to 12 and two phase shifting arms, wherein one of the optical splitters comprises two output waveguides, the other optical splitter comprises two input waveguides, and one end of each of the two phase shifting arms is connected to one of the output waveguides, and the other end is connected to one of the input waveguides.
14. A modulator, characterized in that: It comprises two optical splitters as described in any one of claims 1 to 12 and two modulation arms, wherein one of the optical splitters comprises two output waveguides, the other optical splitter comprises two input waveguides, and one end of each of the two modulation arms is connected to one of the output waveguides, and the other end is connected to one of the input waveguides.