Polarization beam splitter and electronic equipment

Abstract

This application provides a polarization beamsplitter and an electronic device, relating to the field of optical signal processing technology. The polarization beamsplitter includes: an input waveguide, a first output waveguide, and a second output waveguide; a portion of the input waveguide is disposed between the first and second output waveguides; in a vertical direction perpendicular to the signal transmission direction of the input waveguide, the input waveguide, the first output waveguide, and the second output waveguide have overlapping coupling regions; the input waveguide is used to transfer an input optical signal to the adjacent first and second output waveguides based on the coupling regions; the first output waveguide is used to output a first optical signal, and the second output waveguide is used to output a second optical signal; wherein the aspect ratios of the input port of the input waveguide, the first output port of the first output waveguide, and the second output port of the second output waveguide are greater than or equal to 0.8 and less than or equal to 1.2; the effective refractive indexes of the input waveguide, the first output waveguide, and the second output waveguide are the same in different polarization modes.

Description

Technical Field

[0001] This application relates to the field of optical signal processing technology, and more specifically, to a polarization beam splitter and electronic device. Background Technology

[0002] Silicon photonics technology, with its excellent compatibility with mature CMOS processes, has become the mainstream solution for realizing high-density photonic integrated circuits (PICs). At the Rx receiver, efficient coupling between the optical fiber and the silicon photonic chip is crucial for improving system performance, directly affecting core indicators such as coupling efficiency, chip signal-to-noise ratio, and bit error rate. However, the inherent polarization sensitivity of silicon photonic devices presents a fundamental contradiction with the uncertainty of polarization states in standard single-mode optical fibers.

[0003] In photonic integrated optical circuits, optical power dividers, as fundamental components for optical signal distribution, are crucial for complex systems such as optical communication networks and sensor arrays. However, when implemented on the standard 220nm silicon-on-insulator (SOI) platform, the high refractive index contrast introduces significant polarization dependence, posing a major challenge to polarization-independent applications. To achieve polarization-independent applications, the commonly used "polarization diversity reception" technique uses a polarization beam splitter to decompose arbitrary incident polarized light into two orthogonal fixed polarization states. However, this requires the introduction of additional polarization processing components, increasing chip area and structural complexity, and raising system costs due to the need for two sets of detectors and corresponding electrical signal merging circuits. Therefore, current polarization beam splitter devices are expensive and highly susceptible to polarization sensitivity, resulting in poor practicality and failing to meet current optical signal processing requirements. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a polarization beam splitter and electronic device to improve the problem of poor practicality of polarization beam splitters in the prior art.

[0005] To address the aforementioned issues, in a first aspect, embodiments of this application provide a polarization beam splitter, which includes: an input waveguide, a first output waveguide, and a second output waveguide;

[0006] The input waveguide portion is disposed between the first output waveguide and the second output waveguide; wherein, in the vertical direction perpendicular to the signal transmission direction of the input waveguide, the input waveguide, the first output waveguide, and the second output waveguide have overlapping coupling regions;

[0007] The input waveguide is used to transfer the input optical signal to the adjacent first output waveguide and second output waveguide based on the coupling region; the first output waveguide is used to output a first optical signal, and the second output waveguide is used to output a second optical signal.

[0008] The aspect ratios of the input port of the input waveguide, the first output port of the first output waveguide, and the second output port of the second output waveguide are greater than or equal to 0.8 and less than or equal to 1.2; the effective refractive indices of the input waveguide, the first output waveguide, and the second output waveguide are the same in different polarization modes.

[0009] In the above implementation, the polarization beamsplitter includes an input waveguide and two output waveguides. The input waveguide is positioned between the two output waveguides, forming a trident-shaped structure. Vertically, perpendicular to the signal transmission direction in the input waveguide, the input waveguide and the two output waveguides form an overlapping coupling region. Based on the principle of adiabatic coupling, the input waveguide can transfer the input optical signal to the two adjacent output waveguides through the coupling region. The first output waveguide outputs a first optical signal, and the second output waveguide outputs a second optical signal. Furthermore, to meet the requirements of polarization-insensitive applications, the aspect ratio of the input waveguide's input port and the output waveguide's output port is greater than or equal to 0.8 and less than or equal to 1.2. Optimizing the waveguide aspect ratio ensures that the input waveguide and the two output waveguides have the same effective refractive efficiency under different polarization modes, thereby achieving a high-performance and polarization-insensitive beamsplitter structure. This effectively reduces the required device cost and meets the optical communication processing needs of various polarization-independent applications.

[0010] Optionally, the input waveguide, the first output waveguide, and the second output waveguide are all ridge waveguides; wherein the ridge waveguide is fabricated by selective etching onto a silicon waveguide;

[0011] The input waveguide, the first output waveguide, and the second output waveguide are each provided with a constant width segment in the vertical direction of the signal transmission direction and a width-varying segment in the vertical direction of the signal transmission direction where the waveguide width changes.

[0012] In the vertical direction of the signal transmission direction, the waveguide width of the equal-width segment is the maximum width, the equal-width segment connects to the maximum width end of the width-changing segment, and the width-changing segment changes from the maximum width to the minimum width.

[0013] In the above implementation process, both the input waveguide and the two output waveguides can be ridge waveguides selectively etched onto silicon waveguides to facilitate and maintain single-mode transmission, improve coupling efficiency, and easily achieve polarization insensitivity. Furthermore, the waveguide widths of both the input and output waveguides vary in the vertical direction. Each waveguide includes a constant-width segment with a fixed width and a width-varying segment with varying widths. In the vertical direction, the constant-width segment has the maximum width, which connects to the maximum width segment of the width-varying segment. The width-varying segment can vary from its maximum width to its minimum width, forming a tapered waveguide structure through the combination of the constant-width segment and the width-varying segment. This allows signal transfer based on an inverted conical thermally adiabatic coupler formed within the coupling region.

[0014] Optionally, the maximum width is determined based on the depth length of the silicon waveguide;

[0015] The minimum width is determined based on the machining accuracy.

[0016] In the above implementation process, the maximum vertical width of the input waveguide and output waveguide is determined based on the depth of the silicon waveguide, so that the input port of the input waveguide, the first output port of the first output waveguide, and the second output port of the second output waveguide can meet the corresponding waveguide aspect ratio conditions, thereby ensuring that the input waveguide and the two output waveguides have the same effective refractive index in different polarization modes. The minimum vertical width of the input waveguide and output waveguide is determined based on the manufacturing precision, and a smaller minimum width is set as much as possible within the feasible manufacturing conditions to extend the coupling length of the coupling region in the signal transmission direction, thereby further optimizing the coupling effect of the coupling region.

[0017] Optionally, the etching depth of the ridge waveguide is determined based on single-mode transmission requirements; wherein, the single-mode transmission requirements include the fundamental mode under different polarization modes.

[0018] In the above implementation process, in order to enable the waveguide to meet the single-mode transmission requirements and reduce the adverse effects caused by other higher-order modes, the etching depth of the ridge waveguide on the silicon waveguide can be determined based on the fundamental mode under different polarization modes in the single-mode transmission requirements. This ensures that the ridge waveguide can only transmit multiple fundamental modes, cut off other higher-order modes, and reduce the severe crosstalk and performance degradation caused by optical power coupling into higher-order modes.

[0019] Optionally, the coupling region includes three width-varying segments;

[0020] In the signal transmission direction, the waveguide width of the first width-changing segment of the input waveguide changes from wide to narrow;

[0021] In the signal transmission direction, the waveguide width of the second width-changing segment of the first output waveguide changes from narrow to wide;

[0022] In the signal transmission direction, the waveguide width of the third width-changing segment of the second output waveguide changes from narrow to wide.

[0023] In the above implementation, the coupling region is formed by combining three width-varying segments of three waveguides. In the signal transmission direction, the waveguide width of the first width-varying segment in the input waveguide narrows, while the waveguide widths of the second and third width-varying segments in the first and second output waveguides both widen. This allows the first width-varying segment to be positioned within the inverted conical region formed between the parallel second and third width-varying segments, creating a corresponding thermally adiabatic coupler. Utilizing the span variation of the waveguides in the width-varying segments, the optical power of the optical signal is guided to be smoothly transferred from the input waveguide to the first and second output waveguides with extremely high efficiency, enabling the optical signal to be output from the first and second output ports, thus achieving beam splitting functionality.

[0024] Optionally, the input port of the input waveguide is a first equal-width segment;

[0025] The first output port of the first output waveguide is a second equal-width segment;

[0026] The second output port of the second output waveguide is the third equal-width segment.

[0027] In the above implementation process, the first equal-width segment of the input waveguide, the second equal-width segment of the first output waveguide, and the third equal-width segment of the second output waveguide are all parts outside the coupling region. The first equal-width segment serves as the input port of the input waveguide, the second equal-width segment serves as the first output port of the first output waveguide, and the third equal-width segment serves as the second output port of the second output waveguide, so that signal transmission can be carried out through a relatively wide waveguide segment. By precisely controlling the maximum width of the equal-width segment to compensate for the birefringence of the material, the effective refractive index of different polarization modes remains consistent during transmission, thereby ensuring that the polarization beam splitter has excellent polarization-independent characteristics, i.e., polarization-insensitive characteristics, throughout the entire operating band.

[0028] Optionally, the second equal-width segment is configured as a bent segment that bends away from the second output waveguide;

[0029] The third equal-width segment is configured as a bent segment that bends away from the first output waveguide;

[0030] The lengths of the second equal-width segment and the third equal-width segment are both the first length, and the length of the first equal-width segment is the second length;

[0031] Wherein, the second length is less than the first length.

[0032] In the above implementation process, considering that the two output ports are prone to mutual interference when they are close together, the second equal-width segment can be configured as a bent segment that bends away from the second output waveguide. Similarly, the third equal-width segment can also be configured as a bent segment that bends away from the first output waveguide, thus reducing the disadvantage of the first and second output ports being too close. Furthermore, the extension lengths of the second and third equal-width segments are equal, both being the first length. The length of the first equal-width segment is the second length. To allow the second and third equal-width segments to have the corresponding bends, the second length is greater than the first length.

[0033] Optionally, in the vertical direction, the distance between the first output port and the second output port is greater than or equal to a preset distance.

[0034] In the above implementation process, in the vertical direction, the distance between the two output ports is greater than or equal to the corresponding preset distance, so that there is sufficient distance between the two output ports, further reducing the adverse situation of mutual interference between the two output ports.

[0035] Optionally, in the vertical direction, there is a first distance between the first output waveguide and the input waveguide in the coupling region;

[0036] The second output waveguide and the input waveguide in the coupling region have a second distance;

[0037] The ratio of the first distance to the second distance is used to limit the beam splitting ratio of the first output waveguide and the second output waveguide.

[0038] In the above implementation process, in the signal transmission direction, the first output waveguide and the second output waveguide are partially disposed on both sides of the input waveguide to form a coupling region. Therefore, in the vertical direction, there is a first distance between the first output waveguide and the input waveguide in the coupling region, and a second distance between the second output waveguide and the input waveguide. The ratio of the first distance to the second distance can be used to limit the beam splitting ratio when the first output waveguide and the second output waveguide output optical signals. By adjusting the ratio of the two distances, various beam splitting ratios can be achieved, that is, arbitrary beam splitting ratios can be achieved to meet the beam splitting requirements of various application scenarios.

[0039] Optionally, in the signal transmission direction, the coupling length of the coupling region is set based on the spatial requirements and insertion loss optimization requirements of the polarization beam splitter.

[0040] In the above implementation process, the coupling length of the coupling region in the signal transmission direction will affect the device size of the polarization beam splitter and the resulting insertion loss. Therefore, a suitable coupling length can be set according to the spatial requirements of the polarization beam splitter and the corresponding insertion loss optimization requirements, so as to achieve low insertion loss signal transmission with a smaller device size.

[0041] Optionally, the coupling length is less than or equal to 500 μm.

[0042] In the above implementation process, the coupling length of the coupling region is negatively correlated with the insertion loss, that is, the longer the coupling length, the smaller the insertion loss. However, when the coupling length exceeds a certain length, the insertion loss will not change significantly. Therefore, the coupling length can be set to less than or equal to 500μm to achieve low insertion loss signal transmission with a smaller device size.

[0043] Secondly, embodiments of this application also provide an electronic device, which includes the polarization beam splitter described in any one of the first aspects above.

[0044] In summary, the embodiments of this application provide a polarization beamsplitter and electronic device. Based on the principle of thermal coupling, the input waveguide can transfer the input optical signal to two adjacent output waveguides through the coupling region. By optimizing the waveguide aspect ratio, the input waveguide and the two output waveguides have the same effective refractive efficiency in different polarization modes, thereby realizing a high-performance and polarization-insensitive beamsplitter structure, effectively reducing the required device cost, and meeting the optical communication processing needs of various polarization-independent applications. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of a polarization beam splitter provided in an embodiment of this application;

[0047] Figure 2 This is a schematic diagram of the specific structure of a polarization beam splitter provided in an embodiment of this application.

[0048] Icons: 100 - Silicon waveguide; 110 - Input waveguide; 120 - First output waveguide; 130 - Second output waveguide; 211 - Signal transmission direction; 212 - Vertical direction; 140 - Coupling region; 111 - Input port; 121 - First output port; 131 - Second output port; 112 - First equal-width segment; 113 - First width-varying segment; 122 - Second equal-width segment; 123 - Second width-varying segment; 132 - Third equal-width segment; 133 - Third width-varying segment; 221 - Maximum width; 222 - Minimum width; 231 - First distance; 232 - Second distance; 241 - Coupling length. Detailed Implementation

[0049] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0050] To achieve polarization-independent applications, existing polarization diversity reception technology uses a polarization beam splitter to decompose arbitrary incident polarized light into two orthogonal fixed polarization states. However, this requires the introduction of additional polarization processing components, which not only increases chip area and structural complexity but also raises system costs due to the need for two sets of detectors and corresponding electrical signal merging circuits. Therefore, current polarization beam splitter devices are expensive and highly susceptible to polarization sensitivity, resulting in poor practicality and failing to meet current optical signal processing requirements.

[0051] To address the aforementioned issues, this application provides a polarization beamsplitter and electronic device. Based on the principle of thermal coupling, the input waveguide can transfer the input optical signal to two adjacent output waveguides through the coupling region. By optimizing the waveguide aspect ratio, the input waveguide and the two output waveguides have the same effective refractive efficiency in different polarization modes, thereby achieving a high-performance and polarization-insensitive beamsplitter structure. This effectively reduces the required device cost and meets the optical communication processing needs of various polarization-independent applications.

[0052] Optionally, the polarization beam splitter provided in this application embodiment can be installed in various types of electronic devices, such as optical sensing and measurement devices, laser devices, optical communication and information processing devices, imaging and display devices, etc.

[0053] Please see Figure 1 , Figure 1This is a schematic diagram of a polarization beam splitter provided in an embodiment of this application. The polarization beam splitter may include: an input waveguide 110, a first output waveguide 120, and a second output waveguide 130.

[0054] The input waveguide 110 is partially disposed between the first output waveguide 120 and the second output waveguide 130, meaning that the first output waveguide 120 and the second output waveguide 130 are respectively disposed on both sides of the portion of the input waveguide 110, forming a trident-shaped structure. In the vertical direction 212, which is perpendicular to the signal transmission direction 211 of the input waveguide 110 and parallel to the waveguide plane, the input waveguide 110, the first output waveguide 120, and the second output waveguide 130 have an overlapping coupling region 140.

[0055] It should be noted that in the vertical direction 212, the three waveguides have overlapping coupling regions 140, and in the signal transmission direction 211, there are two output waveguides on both sides of the input waveguide 110. That is, the part of the input waveguide 110 adjacent to the output waveguide is the corresponding coupling region 140.

[0056] The input waveguide 110 is used to transfer the input optical signal to the adjacent first output waveguide 120 and second output waveguide 130 based on the coupling region 140. The first output waveguide 120 is used to output the first optical signal, and the second output waveguide 130 is used to output the second optical signal. Based on the principle of thermal coupling, the input waveguide 110 can transfer the input optical signal to the two adjacent output waveguides through the coupling region 140, with the first output waveguide 120 outputting the corresponding first optical signal and the second output waveguide 130 outputting the corresponding second optical signal.

[0057] Optionally, the optical signal entering the input waveguide 110 can be an optical signal from a mixed optical field with different polarization modes. The polarization beam splitter can receive optical signals from various light sources such as lasers and light-emitting diodes and perform beam splitting.

[0058] It should be noted that, to meet the requirements of polarization-insensitive applications, the waveguide aspect ratios of the input port 111 of the input waveguide 110, the first output port 121 of the first output waveguide 120, and the second output port 131 of the second output waveguide 130 are greater than or equal to 0.8 and less than or equal to 1.2; the effective refractive indices of the input waveguide 110, the first output waveguide 120, and the second output waveguide 130 are the same in different polarization modes. By optimizing the waveguide aspect ratio, the input waveguide 110 and the two output waveguides can have the same or similar effective refractive efficiencies in different polarization modes, thereby realizing a high-performance and polarization-insensitive beamsplitter structure, effectively reducing the required device costs, and meeting the optical communication processing needs of various polarization-independent applications.

[0059] Optionally, different polarization modes can include different propagation modes, such as TE mode and TM mode, i.e., Transverse Electric mode, where the electric field vector is completely perpendicular to the propagation direction of the waveguide and parallel to the plane of the waveguide (usually horizontal), while the magnetic field has a component along the propagation direction; and Transverse Magnetic mode, where the magnetic field vector is completely perpendicular to the propagation direction of the waveguide, while the electric field has a component along the propagation direction.

[0060] Optionally, please refer to Figure 2 , Figure 2 This is a schematic diagram of a polarization beam splitter provided in an embodiment of this application. The input waveguide 110, the first output waveguide 120, and the second output waveguide 130 are all ridge waveguides. The ridge waveguides are fabricated by selective etching on the silicon waveguide 100 to achieve and maintain single-mode transmission, improve coupling efficiency, and easily realize polarization insensitivity.

[0061] It should be noted that the input waveguide 110, the first output waveguide 120, and the second output waveguide 130 all have a constant-width section in the vertical direction 212, and a width-varying section in the vertical direction 212 where the waveguide width changes. The input waveguide 110 and the two output waveguides exhibit variations in waveguide width in the vertical direction 212, and all have a constant-width section in the vertical direction 212, and a width-varying section in the vertical direction 212 where the waveguide width changes.

[0062] It should be noted that a constant-width segment is a waveguide segment whose width remains consistent and unchanged along the vertical direction 212, while a width-varying segment is a waveguide segment whose width changes along the vertical direction 212. The constant-width segment and the width-varying segment are merely descriptive structures used to distinguish different shape regions of the waveguide; each waveguide is essentially a continuously arranged, integral ridge waveguide.

[0063] Optionally, in the vertical direction 212, the waveguide width of the constant-width segment is the maximum width 221. The constant-width segment connects to the maximum width end of the width-changing segment, which varies from the maximum width 221 to the minimum width 222. In the vertical direction 212, the waveguide width of the constant-width segment is the maximum width 221. The constant-width segment is connected to the maximum width end of the width-changing segment, which can vary from the maximum width 221 to the minimum width 222. By combining the constant-width segment and the width-changing segment, a conical waveguide structure is formed, thereby achieving signal transfer based on the inverted conical thermally adiabatic coupler formed within the coupling region 140.

[0064] It should be noted that although the input waveguide 110, the first output waveguide 120 and the second output waveguide 130 are all inverted conical waveguides with equal width sections and width-varying sections, the cone tip direction of the input waveguide 110 is opposite to that of the first output waveguide 120 and the second output waveguide 130 in the signal transmission direction 211, so that a portion of the input waveguide 110 can be disposed between the two output waveguides and remain parallel to the adjacent sides of the two output waveguides.

[0065] Optionally, the maximum width 221 of the waveguide is determined based on the depth length of the silicon waveguide 100, so that the input port 111 of the input waveguide 110, the first output port 121 of the first output waveguide 120, and the second output port 131 of the second output waveguide 130 can meet the corresponding waveguide aspect ratio conditions, thereby enabling the input waveguide 110 and the two output waveguides to have the same effective refractive index in different polarization modes.

[0066] Optionally, the minimum width 222 of the waveguide is determined based on the processing precision. If the minimum width 222 is too small, effective etching cannot be achieved due to the limitation of processing precision, resulting in errors in the waveguide parameters and failing to achieve the preset functional effect. If the minimum width 222 is too large, the width variation range between the minimum width 222 and the maximum width 221 is low, and the corresponding width variation segment is also short in the signal transmission direction 211, which cannot meet the actual coupling requirements. Therefore, the minimum width 222 can be determined based on the processing precision of the actual processing method. Under feasible processing conditions, the minimum width 222 can be set as small as possible, that is, the minimum value allowed under the processing precision is determined as the minimum width 222, so as to expand the variation range between the minimum width 222 and the maximum width 221, thereby extending the coupling length 241 of the coupling region 140 in the signal transmission direction 211, thereby further optimizing the coupling effect of the coupling region 140.

[0067] It should be noted that the waveguides processed in this application are micron-level waveguides, which effectively reduces the process tolerance caused by excessively small processing precision.

[0068] For example, the maximum width 221 and minimum width 222 of the three equal-width segments of the three waveguides can be set uniformly. Taking the depth of the silicon waveguide 100 as an example, the maximum width 221 can be set to a width close to the depth, such as 2μm or 4μm. Preferably, the maximum width 221 can be set to 2.6μm, and the corresponding waveguide aspect ratio is 2.6 / 3, which is approximately 0.87, satisfying the ratio range of waveguide aspect ratio being greater than or equal to 0.8 and less than or equal to 1.2. The minimum width 222 can be set to 0.7μm.

[0069] It should be noted that, in order to enable the waveguide to meet the single-mode transmission requirements and reduce the adverse effects caused by other higher-order modes, the etching depth of the ridge waveguide is determined based on the single-mode transmission requirements. The single-mode transmission requirements include the fundamental modes under different polarization modes, such as the fundamental modes of the TE mode and the TM mode, namely TE0 and TM0, so that the ridge waveguide can only transmit multiple fundamental modes and block other higher-order modes (such as TE1), thereby reducing the severe crosstalk and performance degradation caused by optical power coupling into higher-order modes.

[0070] For example, on a 3μm silicon waveguide 100, the etching depth of the ridge waveguide can be 1.2μm.

[0071] Please continue reading. Figure 2 The coupling region 140 includes three width-varying segments, meaning that the coupling region 140 is formed by combining the three width-varying segments of the three waveguides. In the signal transmission direction 211, the waveguide width of the first width-varying segment 113 of the input waveguide 110 decreases from wide to narrow. In the signal transmission direction 211, the waveguide width of the second width-varying segment 123 of the first output waveguide 120 increases from narrow to wide. In the signal transmission direction 211, the waveguide width of the third width-varying segment 133 of the second output waveguide 130 increases from narrow to wide. To make the second width variation segment 123 and the third width variation segment 133 have an asymmetrical structure, the first width variation segment 113 can be set in the inverted conical region formed between the parallel second width variation segment 123 and the third width variation segment 133 to form a corresponding thermally adiabatic coupler. By utilizing the span variation of the waveguide in the width variation segment, the optical power of the optical signal is guided to be smoothly transferred from the input waveguide 110 to the first output waveguide 120 and the second output waveguide 130 with extremely high efficiency, so that the optical signal can be output from the first output port 121 and the second output port 131, thereby realizing the beam splitting function.

[0072] It should be noted that the minimum width 222 end of the first width variation segment 113 is the cutoff position of the coupled waveguide of the input waveguide 110, and the coupling length 241 of the coupling region 140 can be the length between the starting point and the cutoff point of the region where the three width variation segments overlap in the vertical direction 212.

[0073] Optionally, the first output port 121 and the second output port 131 can simultaneously output the corresponding first optical signal and second optical signal, thereby effectively avoiding intermodal crosstalk and scattering loss.

[0074] It should be noted that the input port 111 of the input waveguide 110 is the first equal-width segment 112, the first output port 121 of the first output waveguide 120 is the second equal-width segment 122, and the second output port 131 of the second output waveguide 130 is the third equal-width segment 132, so that the signal can be transmitted through a wider waveguide segment. By precisely controlling the maximum width 221 of the equal-width segment to compensate for the birefringence of the material, the effective refractive index of different polarization modes remains consistent during transmission, thereby ensuring that the polarization beam splitter has excellent polarization-independent characteristics, i.e., polarization-insensitive characteristics, throughout the entire operating band.

[0075] Optionally, both input port 111 and the two input ports 111 are equal-width segments with a waveguide width of the maximum width 221. Correspondingly, the aspect ratio of the waveguide of both input port 111 and the two input ports 111 is greater than or equal to 0.8 and less than or equal to 1.2. For example, on a silicon waveguide 100 with a depth of 3μm, a maximum width 221 of 2.4μm-3.6μm can be set. For example, a maximum width 221 of 2.6μm can be set, which can make the effective refractive index of the input waveguide 110, the first output waveguide 120 and the second output waveguide 130 the same in different polarization modes.

[0076] Please continue reading. Figure 2 Considering that the two output ports are prone to mutual interference when they are close together, the second equal-width segment 122 can be configured as a bent segment that bends away from the second output waveguide 130, and the third equal-width segment 132 can be configured as a bent segment that bends away from the first output waveguide 120, in order to reduce the disadvantage of the first output port 121 and the second output port 131 being too close together. Furthermore, the lengths of the second equal-width segment 122 and the third equal-width segment 132 are both equal to a first length, and the length of the first equal-width segment 112 is a second length, which is less than the first length, so that the second equal-width segment 122 and the third equal-width segment 132 can have corresponding bends.

[0077] For example, a single bend can be set to increase the distance between the first output port 121 and the second output port 131.

[0078] Optionally, the first equal-width segment 112 of the input waveguide 110 is located outside the coupling region 140, that is, there is no output waveguide near the output port of the input waveguide 110, which can effectively reduce the adverse effects of other waveguides on the signal input.

[0079] It should be noted that, in the vertical direction 212, the distance between the first output port 121 and the second output port 131 is greater than or equal to a preset distance. This distance between the two output ports in the vertical direction 212 is greater than or equal to the corresponding preset distance to ensure sufficient distance between them, further reducing the adverse effects of mutual interference.

[0080] For example, the preset spacing can be set according to the actual spatial requirements of the polarization beam splitter in the vertical direction 212, for example, it can be set to 20μm-30μm.

[0081] Please continue reading. Figure 2 In the signal transmission direction 211, the first output waveguide 120 and the second output waveguide 130 are partially disposed on both sides of the input waveguide 110 to form a coupling region 140. Therefore, in the vertical direction 212, there is a first distance 231 between the first output waveguide 120 and the input waveguide 110 in the coupling region 140, and a second distance 232 between the second output waveguide 130 and the input waveguide 110 in the coupling region 140. The ratio of the first distance 231 to the second distance 232 is used to limit the beam splitting ratio of the first output waveguide 120 and the second output waveguide 130. By adjusting the ratio of the two distances, various beam splitting ratios can be achieved, i.e., arbitrary beam splitting ratios can be realized to meet the beam splitting requirements of various application scenarios.

[0082] For example, when the ratio of the first distance 231 to the second distance 232 is 1:1, the splitting ratio is 50:50; when the ratio of the first distance 231 to the second distance 232 is 1:2, the splitting ratio is 60:40; and when the ratio of the first distance 231 to the second distance 232 is 1:2.5, the splitting ratio is 80:20.

[0083] It should be noted that the first distance 231 and the second distance 232 can be the distance between the center position of the output waveguide in the signal transmission direction 211 and the center position of the input waveguide 110. Throughout the coupling region 140, the first distance 231 remains constant to ensure that the edges of the first output waveguide 120 and the input waveguide 110 are parallel, and the second distance 232 remains constant to ensure that the edges of the second output waveguide 130 and the input waveguide 110 are parallel. The first distance 231 and the second distance 232 can also be the distance between the edges of the waveguides, such as... Figure 2 As shown.

[0084] For example, when the splitting ratio is 50:50, the first distance 231 can be set to equal the second distance 232 to achieve an evenly splitting ratio, maintaining an additional loss of less than 1 dB and a polarization-dependent loss of less than 0.3 dB at each splitting ratio. After determining the ratio of the first distance 231 to the second distance 232, the specific values ​​of the first distance 231 and the second distance 232 can also be determined based on the actual spatial requirements of the polarization beam splitter in the vertical direction 212.

[0085] Please continue reading. Figure 2In the signal transmission direction 211, the coupling length 241 of the coupling region 140 can be set based on the spatial requirements and insertion loss optimization requirements of the polarization beam splitter.

[0086] Optionally, the coupling length 241 is the length of the width variation segment in the signal transmission direction 211, and can be adjusted based on the variation range of the maximum width 221 and the minimum width 222.

[0087] It should be noted that the coupling length 241 of the coupling region 140 is negatively correlated with insertion loss; that is, the longer the coupling length 241, the lower the insertion loss. However, when the coupling length 241 exceeds a certain length, the insertion loss will not change significantly. The coupling length 241 of the coupling region 140 is also limited by the spatial requirements of the polarization beamsplitter in the signal transmission direction 211. For example, the design may require a polarization beamsplitter with a length of less than 800 μm.

[0088] For example, with a silicon waveguide 100 depth of 3 μm, a ridge waveguide etching depth of 1.2 μm, a maximum width 221 of 2.6 μm, and a minimum width 222 of 0.7 μm, the coupling length 241 is less than or equal to 500 μm. For instance, the coupling length 241 can be set to 300 μm or 500 μm. When the coupling length 241 is greater than 500 μm, the insertion loss will not change significantly, thus achieving low insertion loss signal transmission within a smaller device size. In other insertion loss configurations, the coupling length 241 can also be greater than 500 μm.

[0089] In summary, the polarization beamsplitter provided in this application, through a design scheme that combines process compatibility and stable performance, offers an ideal power management solution for polarization diversity receiver modules in dense wavelength division multiplexing (DWDM) systems and coherent optical communication systems. The polarization beamsplitter can be integrated into the receiver chip of an electronic device. Based on the high polarization correlation and low insertion loss properties of the polarization beamsplitter, precise control of the aspect ratio of the transverse waveguide compensates for material birefringence, ensuring consistent TE and TM mode field distributions and maintaining a consistent effective refractive index for both polarization modes during transmission. Optimizing the minimum width of the width variation segment increases the coupling length of the coupling region, maintaining low insertion loss performance. The micron-level waveguide design increases the device's process tolerance. By adjusting the first and second distances, arbitrary beam splitting ratios can be flexibly achieved, realizing the functional effects of low loss, polarization insensitivity, and arbitrary beam splitting ratio characteristics.

[0090] In addition, the components in the various embodiments of this application can be integrated together to form an independent part, or each component can exist independently, or two or more components can be integrated to form an independent part.

[0091] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0092] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes said element.

Claims

1. A polarization beam splitter, characterized by, The polarization beam splitter comprises an input waveguide, a first output waveguide and a second output waveguide; Part of the input waveguide is arranged between the first output waveguide and the second output waveguide; wherein, in the vertical direction perpendicular to the signal transmission direction of the input waveguide, the input waveguide, the first output waveguide and the second output waveguide have an overlapping coupling area; The input waveguide is used to transfer the input optical signal to the adjacent first output waveguide and second output waveguide based on the coupling area; the first output waveguide is used to output the first optical signal, and the second output waveguide is used to output the second optical signal; Wherein, the waveguide width length ratio of the input port of the input waveguide, the first output port of the first output waveguide and the second output port of the second output waveguide is greater than or equal to 0.8 and less than or equal to 1.2; the effective refractive index of the input waveguide, the first output waveguide and the second output waveguide under different polarization modes is the same.

2. The polarizing beam splitter of claim 1, wherein, The input waveguide, the first output waveguide and the second output waveguide are all ridge waveguides; wherein, the ridge waveguide is prepared by selectively etching on the silicon waveguide; The input waveguide, the first output waveguide and the second output waveguide are all provided with an equal-width section with unchanged waveguide width in the vertical direction, and a width change section with changed waveguide width in the vertical direction; In the vertical direction, the waveguide width of the equal-width section is the maximum width, the equal-width section connects the maximum width end of the width change section, and the width change section changes from the maximum width to the minimum width.

3. The polarizing beam splitter of claim 2, wherein, Wherein, The maximum width is determined based on the longitudinal length of the silicon waveguide; The minimum width is determined based on the processing precision.

4. The polarizing beam splitter of claim 2, wherein, The etching depth of the ridge waveguide is determined based on the single-mode transmission requirement; wherein, the single-mode transmission requirement includes the fundamental mode under different polarization modes.

5. The polarizing beam splitter of claim 2, wherein, The coupling area comprises three width change sections; In the signal transmission direction, the waveguide width of the first width change section of the input waveguide changes from wide to narrow; In the signal transmission direction, the waveguide width of the second width change section of the first output waveguide changes from narrow to wide; In the signal transmission direction, the waveguide width of the third width change section of the second output waveguide changes from narrow to wide.

6. The polarizing beam splitter of claim 2, wherein, The input port of the input waveguide is a first equal-width section; The first output port of the first output waveguide is a second equal-width section; The second output port of the second output waveguide is a third equal-width section.

7. The polarizing beam splitter of claim 6, wherein, The second equal-width section is configured as a bending section that produces bending in the direction away from the second output waveguide; The third equal-width section is configured as a bending section that produces bending in the direction away from the first output waveguide; The lengths of the second equal-width section and the third equal-width section are a first length, and the length of the first equal-width section is a second length; Wherein, the second length is less than the first length.

8. The polarizing beam splitter of claim 7, wherein, In the vertical direction, the distance between the first output port and the second output port is greater than or equal to a preset distance.

9. The polarizing beam splitter according to any one of claims 1-8, wherein, In the vertical direction, the first output waveguide and the input waveguide in the coupling area have a first distance; The second output waveguide in the coupling region has a second distance from the input waveguide; The ratio of the first distance and the second distance is used to limit the splitting ratio of the first output waveguide and the second output waveguide.

10. The polarizing beam splitter according to any one of claims 1-8, wherein, In the signal transmission direction, the coupling length of the coupling region is set based on the space requirement and the insertion loss optimization requirement of the polarization beam splitter.

11. The polarizing beam splitter of claim 10, wherein, The coupling length is less than or equal to 500μm. The electronic device comprises the polarization beam splitter of any one of claims 1-11.

12. An electronic device, comprising: ​

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