Power beam splitter design method and power beam splitter

Abstract

The present invention provides a power beam splitter design method and a power beam splitter, wherein the power beam splitter includes a base layer and a top layer made of a phase change material and arranged on the base layer, and the power beam splitter design method includes: dividing the top layer into regions, the top layer includes an input waveguide region, an optimization region, a first output waveguide region, and a second output waveguide region; gridding the optimization region into a plurality of identical cells; scanning the cells in sequence, using a binary search algorithm to sequentially change the state of the cells, and after scanning all the cells, returning to the first cell and continuing to cycle in the original sequence until the objective function converges. The present invention achieves the effect of the power beam splitter outputting different splitting ratios, and can regulate the power beam splitter.

Description

Technical Field

[0001] The invention belongs to the technical field of power beam splitters, and in particular relates to a power beam splitter design method and a power beam splitter. Background Art

[0002] In recent years, with the development of silicon photonics and its manufacturing technology, photonic integrated circuits have attracted more and more attention. As one of the most basic power beam splitters in integrated on-chip photonic systems, power dividers have been widely used in many optical circuits. Therefore, more and more researchers have begun to study power beam splitters. As an indispensable part of optical devices, power splitters mainly realize the function of splitting the input signal energy into two or more parts. According to the implementation method, they can be divided into grating type, waveguide type and body element type. They play a very important role in interferometers, laser systems, space optical communication systems, etc.

[0003] At present, the limitations on the size of power beam splitters and the number of output ports make the beam splitting function of power beam splitters single and unable to meet various needs, and there are problems of difficulty in regulation in practical applications. Summary of the invention

[0004] The present invention provides a power beam splitter design method and a power beam splitter, which solve the problems of single power beam splitting and difficult regulation, reduce the loss of the power beam splitter and are easy to operate.

[0005] Based on the above purpose, the present invention proposes a power beam splitter design method, the power beam splitter includes a base layer and a top layer made of phase change material arranged on the base layer, the power beam splitter design method includes: dividing the top layer into regions, the top layer includes an input waveguide region, an optimization region, a first output waveguide region and a second output waveguide region; gridding the optimization region into a plurality of identical cells; scanning the cells in sequence, using a binary search algorithm to change the states of the cells in sequence, and after scanning all the cells, returning to the first cell and continuing to cycle in the original order until the objective function converges.

[0006] Optionally, the use of a binary search algorithm to sequentially change the state of the cell includes: calculating a single objective function value of the cell when the power splitter has different phase change degrees; summing the single objective function values ​​to obtain a first total objective function value, and comparing it with a second total objective function value of the cell; if the first total objective function value is greater than the second total objective function value, retaining the new state of the cell.

[0007] Optionally, the calculating of the single objective function value of the cell when the power splitter has different phase change degrees includes: calculating the average transmittance of the first output waveguide and the second output waveguide in a preset wavelength range, and obtaining the power splitting ratio of the first output waveguide and the second output waveguide when the power splitter has different phase change degrees; and calculating the single objective function value of the cell according to the power splitting ratio of the first output waveguide and the second output waveguide.

[0008] Optionally, a power splitting ratio of the first output waveguide and the second output waveguide is one of 2:1, 1:1 and 1:2.

[0009] Optionally, calculating the single objective function value of the cell according to the power splitting ratio of the first output waveguide and the second output waveguide includes: obtaining the single objective function value of each cell through an objective function, wherein the objective function is Among them, T 1 is the average transmittance of the first output waveguide region, T 2 is the average transmittance of the second output waveguide region, a i and b i is the power splitting ratio of the first output waveguide and the second output waveguide.

[0010] Optionally, the power beam splitter design method further includes: monitoring and analyzing the performance of the power beam splitter.

[0011] Optionally, the monitoring and analyzing the performance of the power beam splitter includes: obtaining the insertion loss of the power beam splitter when the phase change material has different phase change degrees.

[0012] Based on the same inventive concept, the present invention also proposes a power beam splitter obtained by applying the power beam splitter design method as described in any of the above items, characterized in that the power beam splitter includes: a base layer and a top layer made of phase change material arranged on the base layer, the top layer includes: an input waveguide area, an optimization area, a first output waveguide area and a second output waveguide area, the input signal is from the input waveguide area, passes through the optimization area to split the energy of the input signal, and finally outputs from the first output waveguide area and the second output waveguide area respectively.

[0013] Optionally, the phase change material of the top layer is indium selenide, and the refractive index changes according to the phase change degree of the indium selenide.

[0014] Optionally, the material of the base layer is silicon dioxide.

[0015] From the above, it can be seen that the beneficial effects of the technical solution provided by the present invention are: a power beam splitter design method and a power beam splitter provided by the present invention, the power beam splitter includes a base layer and a top layer made of phase change material arranged on the base layer, the power beam splitter design method includes: dividing the top layer into regions, the top layer includes an input waveguide area, an optimization area, a first output waveguide area and a second output waveguide area; gridding the optimization area into a plurality of identical cells; scanning the cells in sequence, using a binary search algorithm to change the state of the cells in sequence, and after scanning all the cells, returning to the first cell and continuing to cycle in the original order until the objective function converges. The present invention achieves the effect of the power beam splitter outputting different splitting ratios, and can regulate the power beam splitter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the process of designing a power beam splitter in an embodiment of the present invention;

[0018] Figure 2 It is a top view schematic diagram of the original state of the power beam splitter unit cell in an embodiment of the present invention;

[0019] Figure 3 It is a top view schematic diagram of the cells of the optimization area of ​​the power beam splitter after initialization in an embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of insertion loss of the top phase change material of the power beam splitter in an embodiment of the present invention at different phase change degrees;

[0021] Figure 5 is a schematic structural diagram of a power beam splitter in an embodiment of the present invention;

[0022] Figure 6 It is a schematic diagram of average transmittance of the first output waveguide T1 and the second output waveguide T2 when the top phase change material of the power beam splitter in an embodiment of the present invention is in the α state;

[0023] Figure 7 It is a schematic diagram of the average transmittance of the first output waveguide T1 and the second output waveguide T2 when the top phase change material of the power beam splitter in an embodiment of the present invention is in an intermediate state;

[0024] Figure 8 Schematic diagram of average transmittance of the first output waveguide T1 and the second output waveguide T2 when the top phase change material of the power beam splitter in an embodiment of the present invention is in the β state. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0026] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the embodiments of the present invention do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] The embodiment of the present invention provides a method for designing a power beam splitter. The power beam splitter includes a base layer and a top layer made of a phase change material disposed on the base layer. Figure 1 As shown, the power splitter design method includes:

[0028] Step S1: Divide the top layer into regions, where the top layer includes an input waveguide region, an optimization region, a first output waveguide region, and a second output waveguide region.

[0029] For example, the top layer uses an indium selenide phase change material with a thickness of 220nm, the base layer uses silicon dioxide with a thickness of 3μm, the refractive index of the substrate is preferably 1.444, and the top layer area is divided into an input waveguide area, an optimized area, a first output waveguide area, and a second output waveguide area. Specifically, the widths of the input waveguide area, the first output waveguide area, and the second output waveguide area are all 0.48μm, and the size of the optimized area is 3.6×2.4μm 2 .

[0030] Step S2: Grid the optimization area into multiple identical cells.

[0031] The optimized area is divided into multiple cells of the same size, and the size of a single cell is preferably 120nm×120nm.

[0032] Step S3: Scan the cells in order, use the binary search algorithm to change the state of the cells in turn, and after scanning all the cells, return to the first cell and continue to cycle in the original order until the objective function converges.

[0033] The cells are scanned in order from top to bottom and from left to right, and the binary search algorithm is used to change the state of the cells in turn. There are two states of the cells. One state is an air column located in the center of the cell, and the other state is no air column. The diameter of the air column is preferably 90nm. When all cells in the optimization area are scanned, continue to follow the original order to loop. If the objective function converges, stop scanning the cells.

[0034] The power beam splitter design method provided by the embodiment of the present invention divides the top layer into regions, wherein the top layer includes an input waveguide region, an optimization region, a first output waveguide region, and a second output waveguide region; the optimization region is grid-divided into a plurality of identical cells; the cells are scanned in sequence, and the states of the cells are changed in sequence using a binary search algorithm. After all cells are scanned, the first cell is returned to continue to cycle in the original sequence until the objective function converges, thereby achieving the effect of the power beam splitter outputting different splitting ratios, and being able to regulate the power beam splitter.

[0035] In step S3, when the state of the cell is changed in sequence by using a binary search algorithm, the single objective function value of the cell is first calculated when the power splitter is at different phase change degrees. Optionally, the average transmittance of the first output waveguide and the second output waveguide in a preset wavelength range is calculated, and the power splitting ratio of the first output waveguide and the second output waveguide is obtained when the power splitter is at different phase change degrees; the single objective function value of the cell is calculated according to the power splitting ratio of the first output waveguide and the second output waveguide. When calculating the single objective function value of the cell, the single objective function value of each cell is obtained through the objective function, and the objective function is Among them, T 1 is the average transmittance of the first output waveguide region in the preset wavelength range, T 2 is the average transmittance of the second output waveguide region in the preset wavelength range, a i and b i is the power splitting ratio of the first output waveguide and the second output waveguide.

[0036] Taking the top layer material of the power beam splitter as an indium selenide phase change material as an example, its phase change degree can be divided into α state, β state, and an intermediate state where the α state and β state phase change are incomplete, wherein both the α state and the β state are crystalline states, and the preset wavelength range can be preferably 1540nm-1560nm. The refractive index of the power beam splitter changes due to the degree of phase change, and a single objective function value is calculated for each unit cell at different refractive indices. The power splitting ratio of the first output waveguide and the second output waveguide is one of 2:1, 1:1 and 1:2.

[0037] When the top phase change material of the power beam splitter is in the α state, the power splitting ratio between the first output waveguide and the second output waveguide is 2:1, and the objective function is: FOM i =1-|T 1 -0.66|-|T 2 -0.33|.

[0038] When the top phase change material of the power beam splitter is in the intermediate state, the power splitting ratio of the first output waveguide and the second output waveguide is 1:1, and the objective function is: FOM i =1-|T 1 -0.5|-|T 2 -0.5|.

[0039] When the top phase change material of the power beam splitter is in the β state, the power splitting ratio of the first output waveguide and the second output waveguide is 1:2, and the objective function is: FOM i =1-|T 1 -0.33|-|T 2 -0.66|.

[0040] Then, the single objective function values ​​are summed to obtain the first total objective function value, and compared with the second total objective function value of the cell. Specifically, the single objective function values ​​obtained under different refractive indices of the power beam splitter are summed to obtain the first total objective function value, and compared with the second total objective function value of the cell. The second total objective function value of the cell is the total objective function value of the cell after the cell is initialized. Figure 2 , each cell is in the original state without air column, and then the cell is processed by preset light path to obtain the following Figure 3 The cell states shown are the states with or without air columns.

[0041] Finally, if the first total objective function value is greater than the second total objective function value, the new state of the cell is retained. If the first total objective function value is less than the second total objective function value, the cell is returned to its initial state.

[0042] In the embodiment of the present invention, the performance of the power beam splitter can also be monitored and analyzed. Optionally, when the phase change material has different phase change degrees, the insertion loss of the power beam splitter is obtained. The insertion loss of the power beam splitter can be calculated according to the formula Calculate, where T 1 is the average transmittance of the first output waveguide region in the preset wavelength range, T 2 is the average transmittance of the second output waveguide region in the preset wavelength range, T 3 is the average transmittance of the input waveguide region in the preset wavelength range. Figure 4 In the preset wavelength range of 1.54μm-1.56μm, when the top material of the power beam splitter is in the α state, the insertion loss of the power beam splitter is greater than -0.44db; when the top material of the power beam splitter is in the intermediate state, the insertion loss of the power beam splitter is greater than -0.27db; when the top material of the power beam splitter is in the β state, the insertion loss of the power beam splitter is greater than -0.32db.

[0043] The power beam splitter design method of the embodiment of the present invention is to design the diffraction of the air hole in the area and In 2 Se 3 The power splitting can be regulated by the different refractive indices of the material in different phase change states, so as to realize the function of regulating any power splitting ratio.

[0044] Based on the same inventive concept, the embodiment of the present invention further proposes a power beam splitter obtained by applying the power beam splitter design method as described above, such as Figure 5 As shown, the power splitter includes: a base layer 51 and a top layer 52 made of phase change material arranged on the base layer 51, the top layer 52 includes: an input waveguide area 521, an optimization area 522, a first output waveguide area 523 and a second output waveguide area 524. The input signal is from the input waveguide area 521, and the energy of the input signal is split through the optimization area 522, and finally output from the first output waveguide area 523 and the second output waveguide area 524 respectively.

[0045] For example, the top layer 52 of the power beam splitter is made of indium selenide with a thickness of 220nm, the base layer 51 is made of silicon dioxide with a thickness of 3um, the refractive index of the base layer 51 is preferably 1.444, the widths of the input waveguide region 521, the first output waveguide region 523 and the second output waveguide region 524 are all 0.48μm, and the size of the optimized region 522 is 3.6×2.4μm 2 The power beam splitter of the embodiment of the present invention reduces loss, can be etched in one step in the process, and is easy to operate.

[0046] In the embodiment of the present invention, the phase change material of the top layer is indium selenide, and the refractive index changes according to the phase change degree of indium selenide. The power beam splitting of the power beam splitter is regulated by the phase change material of the top layer, and the phase change state of indium selenide includes α state, β state, and an intermediate state where the phase change between α state and β state is incomplete, wherein both α state and β state are crystals, so the energy required for phase change is lower than that of other materials.

[0047] Specifically, when the top phase change material of the power beam splitter is at different phase change degrees, different average transmittances of the first output waveguide and the second output waveguide can be obtained.

[0048] Reference Figure 6 When the top phase change material of the power splitter is in the α state, the power splitting ratio of the first output waveguide and the second output waveguide is 2:1, and the average transmittances of the first output waveguide T1 and the second output waveguide T2 are 51.5% and 33.0%, respectively.

[0049] Reference Figure 7 When the top phase change material of the power splitter is in the intermediate state, the power splitting ratio of the first output waveguide and the second output waveguide is 1:1, and the average transmittances of the first output waveguide T1 and the second output waveguide T2 are 46.6% and 44.0%, respectively.

[0050] Reference Figure 8 When the top phase change material of the power splitter is in the β state, the power splitting ratio of the first output waveguide and the second output waveguide is 1:2, and the average transmittances of the first output waveguide T1 and the second output waveguide T2 are 33.0% and 58.0%, respectively.

[0051] In the embodiment of the present invention, the material of the base layer is silicon dioxide.

[0052] In the embodiment of the present invention based on 2 Se 3 The adjustable power beam splitter solves the problem of single power splitting ratio and difficult regulation. It has low loss, can be etched in one step and is easy to operate.

[0053] The above describes specific embodiments of the present invention, and other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0054] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0055] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of this disclosure.

Claims

1. A power beam splitter design method, characterized in that: The power beam splitter comprises a base layer and a top layer made of a phase change material and arranged on the base layer. The power beam splitter design method comprises: Dividing the top layer into regions, wherein the top layer includes an input waveguide region, an optimization region, a first output waveguide region, and a second output waveguide region; Performing grid division on the optimization area into a plurality of identical cells; Scan the cells in order, use a binary search algorithm to change the states of the cells in order, and after scanning all the cells, return to the first cell and continue to cycle in the original order until the objective function converges; The adopting of a binary search algorithm to sequentially change the state of the cells comprises: Calculating a single objective function value of the unit cell when the power beam splitter has different phase change degrees; Summing the single objective function values ​​to obtain a first total objective function value, and comparing the sum with the second total objective function value of the cell; If the first total objective function value is greater than the second total objective function value, retaining the new state of the cell; The calculating of the single objective function value of the unit cell when the power beam splitter has different phase change degrees includes: Calculating the average transmittance of the first output waveguide and the second output waveguide in a preset wavelength range, and obtaining the power splitting ratio of the first output waveguide and the second output waveguide according to different phase change degrees of the power splitter; Calculating a single objective function value of the unit cell according to a power splitting ratio of the first output waveguide and the second output waveguide; The calculating a single objective function value of the unit cell according to the power splitting ratio of the first output waveguide and the second output waveguide comprises: The single objective function value of each cell is obtained by the objective function, and the objective function is , wherein T1 is the average transmittance of the first output waveguide region in a preset wavelength range, T2 is the average transmittance of the second output waveguide region in a preset wavelength range, a i and b i is the power splitting ratio of the first output waveguide and the second output waveguide.

2. The power beam splitter design method according to claim 1, characterized in that: A power splitting ratio of the first output waveguide and the second output waveguide is one of 2:1, 1:1 and 1:

2.

3. The power beam splitter design method according to claim 1, characterized in that: The power beam splitter design method further includes: monitoring and analyzing the performance of the power beam splitter.

4. The power beam splitter design method according to claim 3, characterized in that: The monitoring and analyzing of the performance of the power beam splitter includes: obtaining the insertion loss of the power beam splitter when the phase change material has different phase change degrees.

5. A power beam splitter obtained by applying the power beam splitter design method according to any one of claims 1 to 4, characterized in that: The power beam splitter includes: a base layer and a top layer made of phase change material arranged on the base layer, the top layer includes: an input waveguide area, an optimization area, a first output waveguide area and a second output waveguide area. The input signal is sent from the input waveguide area, passes through the optimization area, and the energy of the input signal is split and processed, and finally output from the first output waveguide area and the second output waveguide area respectively.

6. The power beam splitter according to claim 5, characterized in that: The phase change material of the top layer is indium selenide, and the refractive index changes according to the phase change degree of the indium selenide.

7. The power beam splitter according to claim 6, characterized in that: The material of the base layer is silicon dioxide.

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