Broadband ring resonator and design system for broadband ring resonator

Abstract

To provide a broadband ring resonator that exhibits high and stable optical output performance over a wide frequency band and has low optical loss.SOLUTION: In a broadband ring resonator comprising a first waveguide and a second waveguide, the first waveguide is a closed ring. The closed ring comprises a first coupling part. The first coupling part has a first width and a first radius. The second waveguide comprises a first portion, a second coupling part, and a second portion connected to each other in this order, where the second coupling portion has a second width and a second radius, the coupling efficiency of the second waveguide coupled to the first waveguide is substantially close in a broadband part, the second radius is greater than the first radius, and the condition of 1.3≤W1 / W2≤1.7 is satisfied, here, W1 is the first width, and W2 is the second width.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a ring resonator, and more particularly to a ring resonator having high uniformity in performance for outputting light in a broadband or broad wavelength band. The present invention also relates to a design system for a broadband ring resonator, and more particularly to a design system capable of obtaining layout parameters of the ring resonator. [Background technology]

[0002] Ring resonators (also called micro-ring resonators, MRRs) are very important and fundamental elements in high-density integrated optical systems. In general, ring resonators consist of a closed waveguide (closed ring) and a long straight waveguide, which are placed close to each other to allow optical coupling, coupling photons from the long straight waveguide into the closed ring. Summary of the Invention [Problem to be solved by the invention]

[0003] However, the size of such closed waveguides is often integrated with integrated circuits and requires fabrication as small as micron-scale dimensions to achieve high density optoelectronic integrated circuits on the same wafer. [Means for solving the problem]

[0004] In view of the above problems, the present invention has the following configuration. A wideband ring resonator including a first waveguide and a second waveguide, the first waveguide is a closed ring, the closed ring having a first coupling portion, the first coupling portion having a first width and a first radius; the second waveguide includes a first portion, a second coupling portion, and a second portion connected to each other in order, the second coupling portion has a second width and a second radius, and a coupling efficiency of the second waveguide coupled to the first waveguide in a broadband portion is substantially close; The second radius is greater than the first radius and satisfies the condition 1.3≦W1 / W2≦1.7, W1 being the first width and W2 being the second width.

[0005] Further, the second radius is determined based on the relationship between the radius and the effective refractive index in Equation 1 as follows:

[0006]

number

[0007] is obtained, In the above formula 1, n eff1 is the first effective refractive index, n eff2 is a second effective refractive index, R1 is the first radius, R2 is the second radius, d is an error threshold, and the error threshold is not greater than 10%.

[0008] In addition, the second coupling portion and the first coupling portion have a coupling angle, a coupling gap distance is open, and the first width is 470 nanometers to 600 nanometers; The second width is between 300 nanometers and 400 nanometers, the coupling gap is between 150 nanometers and 250 nanometers, and the wavelength of incident light to which the broadband portion of the coupling efficiency corresponds is substantially close to 1280 nanometers and 1330 nanometers.

[0009] Also, a system for designing a wideband ring resonator is provided, the system obtaining configuration parameters of a wideband ring resonator based on a simulated resonator, the simulated resonator having a first waveguide and a second waveguide, the first waveguide having a first coupling section, the second waveguide having a second coupling section, the second coupling section and the first coupling section having a coupling angle, and a coupling gap distance, a user interface that receives the coupling gap, the widths of the plurality of waveguides, and the radii of the plurality of waveguides; a processor communicatively coupled to the user interface; The processor, Obtaining a relationship between a radius and an effective refractive index, and obtaining a width and a radius of the second coupling portion in addition to a width and a radius of the first coupling portion based on the relationship between the radius and the effective refractive index; Adjusting the coupling angle to make the coupling efficiency of the second waveguide coupled to the first waveguide substantially close to each other in a broadband portion; Adjusting one of the width and radius of the first coupling section, the width and radius of the second coupling section, the coupling gap and the coupling angle to make the coupling efficiency of the wideband section from 0% to 100%; The configuration parameters of the width and the radius of the first coupling portion, the width and the radius of the second coupling portion, the coupling gap and the coupling angle are output.

[0010] The processor is further used to readjust one of the configuration parameters by increasing or decreasing the coupling efficiency located between 0% and 100% to between 1% and 20%, and outputting the increased or decreased coupling efficiency and the corresponding configuration parameter.

[0011] Furthermore, according to this embodiment, the wavelength of the incident light corresponding to the broadband portion is from 1250 nanometers (nm) to 1370 nanometers (nm).

[0012] In addition, the first effective refractive index means first effective index, and the second effective refractive index means second effective index.

[0013] In this embodiment, the substantially close coupling efficiency is in the range of 0% to 85%. The substantially close coupling efficiency can be obtained by adjusting either the coupling angle or the first width. Effect of the Invention

[0014] As described above, according to the embodiments of the present invention, it is possible to provide a wideband ring resonator and a design system for the wideband ring resonator. Also, according to the present invention, the layout parameters of the first and second waveguides of the wideband ring resonator can be made to substantially match (approach) each other by the above-mentioned design system.

[0015] As a result, the first waveguide and the second waveguide can have approximately the same coupling efficiency (hereinafter also referred to as coupling efficiency, coupling ratio, or coupling coefficient) over a wide frequency band (broadband), so that multiple highly uniform light beams can be output over a wide frequency band.

[0016] Therefore, by using the same wideband ring resonator designed by simulation, the wideband ring resonator of this embodiment can provide suitable coupling for incident light of various wavelengths, and these incident light of different wavelengths can obtain multiple and highly uniform optical output performances.

[0017] Therefore, this embodiment can provide a wideband ring resonator that exhibits high and stable optical output performance over a wide frequency band with extremely small device manufacturing dimensions on the micron scale and has low optical loss. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing a top view structure of a wideband ring resonator according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view along the line AA of the wideband ring resonator of FIG. 1. [Diagram 3] FIG. 2 is a diagram showing a top view structure of a resonator simulated according to the present embodiment. [Figure 4] FIG. 1 is a schematic diagram of a design system for a wideband ring resonator according to an embodiment of the present invention. [Diagram 5] 13A-13C illustrate operations for modeling the relationship between radius and effective refractive index of a broadband ring resonator according to the present embodiments. [Figure 6A] FIG. 13 illustrates a simulated relationship between different coupling angles and coupling efficiency for a simulated resonator according to the present embodiment. [Figure 6B] FIG. 6B shows a simulation of the first embodiment of the overall coupling efficiency versus different coupling angles in FIG. 6A. [Figure 6C] FIG. 6B shows a simulation of the second embodiment of the overall coupling efficiency versus different coupling angles of FIG. 6A. [Figure 7A] FIG. 13 shows a simulated relationship of coupling efficiency in a wide frequency band for different coupling angles of a simulated resonator with a fixed first width (W1=500 nm) according to the present embodiment. [Figure 7B] FIG. 7B shows the relationship between the geometry parameters of FIG. 7A and the simulated coupling efficiency over a wide frequency range for a simulated resonator with a particular coupling angle (θ=23°) geometry. [Figure 8A] FIG. 13 shows a simulated relationship of coupling efficiency in a wide frequency band for different coupling angles of a simulated resonator with a fixed first width (W1=525 nm) according to the present embodiment. [Figure 8B]FIG. 8B shows the relationship between the geometry parameters of FIG. 8A and the simulated coupling efficiency over a wide frequency range for a simulated resonator with a particular coupling angle (θ=20°) geometry. [Figure 9A] FIG. 13 shows a simulated relationship of coupling efficiency in a wide frequency band for different coupling angles of a simulated resonator with a fixed first width (W1=550 nm) according to the present embodiment. [Figure 9B] FIG. 9B shows the relationship between the geometry parameters of FIG. 9A and the simulated coupling efficiency over a wide frequency range for a simulated resonator with a particular coupling angle (θ=16.5°) geometry. [Figure 10] FIG. 13 shows the present embodiment, and is a diagram showing a relationship between the optical coupling portion of the simulated resonator and the optical coupling efficiency in the wideband portion and different first widths of the resonator optical coupling portion of the long second waveguide that travels straight. [Figure 11] FIG. 9C is a diagram showing the relationship between the optical transmittance (transmission coefficient) of the optical coupling portion of the ring resonator and the optical coupling portion of the resonator of the long second waveguide that travels in a straight line, based on a simulation, for the arrangement parameters shown in FIG. 9B. [Figure 12A] FIG. 7C is a simulation versus coupling efficiency diagram of the broadband section of the simulated resonator arranged to adjust the configuration parameters shown in FIG. 7B and different coupling gaps, first widths, and second widths. [Figure 12B] FIG. 8C is a simulation versus coupling efficiency diagram of the broadband section of the simulated resonator arranged to adjust the configuration parameters shown in FIG. 8B and different coupling gaps, first widths, and second widths. [Figure 12C] FIG. 9C is a simulation versus coupling efficiency diagram of the broadband section of the simulated resonator arranged to adjust the configuration parameters shown in FIG. 9B and different coupling gaps, first widths, and second widths. [Figure 13A]FIG. 9C shows the geometry parameters of FIG. 9B and illustrates a simulated relationship to the coupling efficiency of the broadband section for different coupling gaps, first widths, and second widths of the simulated resonator at a particular coupling angle (θ=16.5°). [Figure 13B] FIG. 13B is a diagram showing the relationship between the coupling efficiency of the wideband section having different coupling gaps, first widths, and second widths of the simulation resonator having the arrangement parameters of FIG. 13A and actual measurement quantities. [Figure 13C] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the first arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13D] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the second arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13E] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the third arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13F] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the fourth arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13G] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the fifth arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13H] FIG. 14 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the sixth arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. [Figure 13I] FIG. 16 is a diagram showing the relationship between the coupling efficiency of the wideband section of the simulated resonator arranged with the seventh arrangement parameters of FIGS. 13A and 13B and the actual measurement quantity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 shows the top structure of a wideband ring resonator 10a according to this embodiment, and Fig. 2 is a cross-sectional view of the wideband ring resonator 10a taken along line AA' in Fig. 1.

[0020] 1 and 2, the broadband ring resonator 10a includes a first waveguide 12a and a second waveguide 14. The first waveguide 12a is a closed ring 120a having a center C, for example, the first waveguide 12a can be a ring waveguide.

[0021] The closed ring 120a has a first coupling portion 122, and the width and radius of the first coupling portion 122 are a first width W1 and a first radius R1, respectively. The first radius R1 is the distance from the center C of the closed ring 120a to the center of the first coupling portion 122, that is, the inner diameter of the first coupling portion 122 plus half the width of the first width W1.

[0022] The second waveguide 14 includes a first portion 140, a second coupling portion 143, and a second portion 144 connected in sequence, and the second waveguide 14 may be, for example, a curved directional coupler (CDC; or bus waveguide).

[0023] The second coupling portion 143 is parallel to the first coupling portion 122, and the distance therebetween is a coupling gap W0, so that the center of the second coupling portion 143 is the center C of the closed ring 120a. The width and radius of the second coupling portion 143 are a second width W2 and a second radius R2, respectively.

[0024] The second radius R2 is the distance from the center C to the center of the second coupling part 143, i.e., the inner diameter of the second coupling part 143 plus half the second width W2. Here, the second radius R2 is longer than the first radius R1.

[0025] The ratio of the first width W1 to the second width W2 is, for example, but not limited to, between 1.3 and 1.7, ie, 1.3≦W1 / W2≦1.7.

[0026] The second coupling portion 143 and the first coupling portion 122 have a coupling angle θ, that is, the included angle between both ends of the first coupling portion 122 and both ends of the second coupling portion 143 and a straight line connecting the center C is defined as the coupling angle θ, and the coupling angle θ of the first coupling portion 122 and the coupling angle θ of the second coupling portion 143 are substantially the same.

[0027] Therefore, the following dimensional relationship exists between the coupling gap W0, the first width W1, the first radius R1, the second width W2, and the second radius R2:

[0028]

number

[0029] Furthermore, simulation matching of each configuration parameter is performed according to the Coupled-Mode Theory and the Phase Matching Condition.

[0030] Therefore, the coupling gap W0, the first width W1, the first radius R1, the second width W2, the second radius R2, and the coupling angle θ between the first coupling portion 122 and the second coupling portion 143 can be made substantially equal (details will be described later), and the wideband ring resonator 10a can maintain high uniformity in its light output performance (e.g., highly uniform resonant dips and optical loss; details will be described later) over a wide frequency band.

[0031] The wide frequency band may be, for example, but is not limited to, O band (wavelength range 1260 nm to 1360 nm), E band (wavelength range 1360 nm to 1460 nm), S band (wavelength range 1460 nm to 1530 nm), C band (wavelength range 1530 nm to 1565 nm), L band (wavelength range 1565 nm to 1625 nm), or U band (wavelength range 1625 nm to 1675 nm).

[0032] Therefore, by using the same design of the wideband ring resonator 10a, the wideband ring resonator 10a of the present embodiment can input multiple incident light beams with different wavelengths from one end of the second waveguide 14 and couple them into the optical coupling portion of the first waveguide 12a, so that the coupling of the incident light beams with different wavelengths can have substantially similar coupling efficiency, and after adjusting the configuration parameters, the wideband ring resonator 10a can obtain multiple optical outputs with high uniformity within a wide band.

[0033] Referring to FIG. 2, in this embodiment, the above-mentioned broadband ring resonator 10a is applied to a silicon photonics platform, so that it can have functions such as high-speed optical connection, chemical and biomedical sensing, temperature sensing, optical computing, and optical spectrum filtering.

[0034] 2, the broadband ring resonator 10a further includes a base layer 40, a first protective layer 30, a waveguide layer 16, and a second protective layer 20. The first protective layer 30 is located on the base layer 40. The waveguide layer 16 is located on the first protective layer 30. The first waveguide 12a and the second waveguide 14 are located on the waveguide layer 16.

[0035] The second protective layer 20 is located on the waveguide layer 16 (including the first waveguide 12a and the second waveguide 14). The material of the base layer 40 is, for example, silicon (SiO2), but is not limited thereto, and the thickness is also not particularly limited. The material of the first protective layer 30 is, for example, silicon dioxide (SiO2), and the thickness H5 of the first protective layer 30 is, for example, 1 μm to 10 μm.

[0036] The material of the waveguide layer 16 is, for example, silicon, and the thickness H4 of the waveguide layer 16 is, for example, 150 nm or less, but is not limited to this. The material of the first waveguide 12a and the second waveguide 14 is, for example, silicon, but is not limited to this.

[0037] The first waveguide 12a and the second waveguide 14 each protrude from the surface of the waveguide layer 16. The distances between the upper surfaces of the first waveguide 12a and the surface of the waveguide layer 16 and the upper surfaces of the second waveguide 14 are the protrusion height H1 of the first waveguide 12a and the protrusion height H2 of the second waveguide 14, respectively, where H1 and H2 are, for example, 70 nm to 220 nm, but are not limited thereto.

[0038] The material of the second protective layer 20 is, for example, but not limited to, SiO2. The distance between the upper surface of the second protective layer 20 and the surface of the waveguide layer 16 is the thickness H3 of the second protective layer 20, and the thickness H3 of the second protective layer 20 is, for example, but not limited to, 1 μm to 10 μm.

[0039] Therefore, the obvious difference in refractive index between the first and second waveguides 12a and 14 made of silicon (respectively serving as the optical guiding layers of the silicon optical waveguide) and the first and second protective layers 30 and 20 made of SiO2 (respectively serving as the cladding layers) can provide a silicon optical waveguide with a relatively small dimension and strong confinement force, which can be applied to a large-scale integrated optical system.

[0040] Furthermore, through a relatively wide allowable working window (described in detail later) between the substantially coincident first coupling portion 122 and second coupling portion 143, in this embodiment, the design size can be relaxed, thereby relaxing the allowable error limit in the manufacturing process; at the same time, under the relaxed error limit, the wideband ring resonator 10a can be manufactured to have the ability to output multiple light beams with high uniformity in a wide frequency band.

[0041] This embodiment overcomes the difficult challenge of more precisely controlling process errors at micron-scale dimensions, such as in optical lithography in the manufacture of complementary metal-oxide-semiconductor (CMOS) wafers.

[0042] In order to more clearly describe the embodiments of the present invention, a wideband ring resonator 10a applied to a silicon photonic platform will be described, however, these descriptions are merely exemplary and the technical scope of the present invention is not limited to these specific embodiments.

[0043] Continuing to refer to Fig. 1, in this embodiment, the first portion 140 includes a first front portion 141 and a first middle portion 142. The second portion 144 includes a second middle portion 145 and a second rear portion 146. The first front portion 141 and the second rear portion 146 are sequentially connected via the first middle portion 142, the second coupling portion 143, and the second middle portion 145.

[0044] Both ends of the first middle portion 142 are connected to the first front portion 141 and the second coupling portion 143, which extend long and linearly. The first middle portion 142 has a radius of curvature, and its center is located on the opposite side to the center C.

[0045] Both ends of the second middle portion 145 are connected to the second coupling portion 143 and to a long, linearly extending second rear portion 146. Similarly, the second middle portion 145 has a radius of curvature, and its center is located on the opposite side to the center C.

[0046] The shapes and radii of curvature of the first middle portion 142 and the second middle portion 145 may be the same as each other (for example, mirror symmetry) or may be different from each other.

[0047] Therefore, by disposing the first middle portion 142 and the second middle portion 145, the degree of coupling between the first coupling portion 122 and the second coupling portion 143 can be adjusted more accurately in this embodiment. For example, the coupling angle θ and the coupling length (for example, the second radius R2 multiplied by the coupling angle θ) can be adjusted. This allows the first coupling portion 122 and the second coupling portion 143 to be substantially matched more accurately, as will be described in detail later.

[0048] The following description will be given with reference to Fig. 1 and Fig. 3. Fig. 3 is a diagram showing the top structure of a simulated resonator 10b according to this embodiment. In this embodiment, the arrangement parameters of the wideband ring resonator 10a as shown in Fig. 1 are obtained by simulating and adjusting in advance using the simulated resonator 10b shown in Fig. 3, which will be described in detail later.

[0049] In comparison with the wideband ring resonator 10a in FIG. 1, the configuration and the arrangement of the simulated resonator 10b in FIG. 3 are the same as those of the wideband ring resonator 10a in FIG. 1 except for the following points.

[0050] 3 includes a non-closed ring 120b, such as, but not limited to, a semicircular ring having an opening angle of 180° or an arc-shaped ring having other opening angles.

[0051] It should be noted that the semicircular first waveguide of FIG. 3 is illustrated for illustrative purposes only, and is not intended to limit the scope of the present invention to the embodiment of FIG.

[0052] 3, the second waveguide 14 has an input port P0 (input port) and an output port P2 (through port or bar port) at both ends. Incident light is input from the input port P0, and a part or all of the incident light is output from the output port P2.

[0053] The first waveguide 12b is a semicircular waveguide, and one end thereof remote from the input port P0 of the second waveguide 14 is a coupling port P1 (coupled port or cross port).

[0054] Another portion of the incident light is coupled from the second waveguide 14 to the first waveguide 12b because the second waveguide 14 is sufficiently close to the first waveguide 12b (i.e., has a sufficiently small coupling gap W0) to satisfy the resonance condition between the first waveguide 12b and the second waveguide 14, and the incident light can be coupled from the second waveguide 14 to the first waveguide 12b, and then the other portion of the incident light is output from the coupling port P1.

[0055] Therefore, the total amount of incident light is equal to the total amount of output light from the coupling port P1 and the output port P2.

[0056] In Fig. 1, the first waveguide 12a is a closed ring, so the photons coupled into the first waveguide 12b in Fig. 3 can continue to stay in the first waveguide 12a in Fig. 1. However, the photons coupled into the first waveguide 12a will stay in the first waveguide 12a for a long time, which may cause optical loss of these photons.

[0057] In this embodiment, the above-mentioned optical loss can be defined by a quality factor obtained by actually measuring the transmission spectrum of the wideband ring resonator 10a.

[0058] The above quality factor can be obtained, for example, by dividing the wavelength of the transmitted incident light by the corresponding half-width of the transmission spectrum, and the higher the quality factor, the smaller the relative optical loss and the easier the photons are confined in the first waveguide 12a, which can be used to judge the quality of the wideband ring resonator 10a.

[0059] In this embodiment, taking the high-speed ring resonator optical modulator as an example, the quality factor of the wideband ring resonator 10a after the above simulation and adjustment is between 5000 and 10000, for example, at least about 7000. More specifically, the quality factor is at least about 8000 over a wide frequency range from 1300 nm to 1320 nm (for example, 1310 nm).

[0060] Moreover, in this embodiment, the quality factor of the above-mentioned wideband ring resonator 10a can be optimized to operate in a better coupling state, so that the quality factor can reach a million level.

[0061] 1 and 3 to 5 will be simultaneously referred to. Fig. 4 is a schematic diagram of a design system 50 for a wideband ring resonator 10a according to the present embodiment. Fig. 5 is a diagram showing an operation of simulating the relationship between the radius and the effective refractive index of a simulated resonator 10b according to the present embodiment.

[0062] In this embodiment, the configuration parameters of the wideband ring resonator 10a shown in FIG. 1 are obtained by previously simulating and adjusting a design system 50 (see FIG. 4) of the wideband ring resonator 10a based on the simulated resonator 10b shown in FIG. 3.

[0063] In this embodiment, the design system 50 for the wideband ring resonator 10a described above includes a user interface 52 and a processor 54 (see FIG. 4). The user interface 52 described above includes an input element 520 and a display element 522 (see FIG. 4).

[0064] The above-mentioned input element 520 is used to receive the coupling gap W0, the widths W of the multiple waveguides (e.g., at least one of the first width W1 of the first waveguide 12b and the second width W2 of the second waveguide 14), and the radii R of the multiple waveguides (e.g., at least one of the first radius R1 of the waveguide 12b and the second radius R2 of the second waveguide 14).

[0065] The user interface 52 and the processor 54 are communicatively coupled to each other, and the user interface 52 is also communicatively coupled to an input element 520 and a display element 522 .

[0066] In step 1, processor 54 determines a radius-guidwave effective index (n) based on the coupling gap W0, the waveguide width W, and the waveguide radius R. eff R) is used to obtain the relationship between the radius and the effective refractive index. The radius and the effective refractive index are, for example, at least one of the relationship diagram between the radius and the effective refractive index in FIG. 5 and the relationship formula between the radius and the effective refractive index in the following formula 1.

[0067] The relationship between the radius and the effective refractive index in Equation 1 can be derived, for example, from the relationship between the radius and the effective refractive index in Equation 3 below.

[0068] In Equation 1 and Equation 3, n eff1 is the first effective index, and n eff2 is the second effective index, R1 is the first radius, R2 is the second radius, and d is an error threshold (see Equation 1), where the error threshold d is not greater than 10%.

[0069]

number

[0070]

number

[0071] Next, in step 2, the processor 54 is used to obtain the width and radius of the second coupling portion 143 of the second waveguide 14 (i.e., the second radius R2 and second width W2 described above, respectively) using the relationship between the radius and effective refractive index in Equation 1 and the relationship between the width and radius of the first coupling portion 122 of the first waveguide 12b (i.e., the first radius R1 and the first radius R1 and first width W1).

[0072] The following description will be given with reference to FIG. 5. The relationship between the radius and the effective refractive index in FIG. 5 is a graph showing the relationship between the radius and the effective refractive index (n eff R (i.e., the vertical axis in FIG. 5) and, as the radius R of the waveguide increases, the radius R of the waveguide of width W in each waveguide is calculated as radius-effective refractive index n eff It has an approximately positive linear relationship with R.

[0073] In this embodiment, in step 2-1, the processor 54 fixes the coupling gap W0 and selects a specific radius-effective refractive index n eff Select R and draw a dotted line parallel to the horizontal axis to represent the radius-effective refractive index n eff Draw on R to obtain a first radius R1 that corresponds to a particular first width W1 on the dotted line.

[0074] Next, the above-mentioned processor 54 obtains a specific second width W2 and a corresponding second radius R2 on the same dotted line in step 2-2.

[0075] Specifically, in step 2-1, the processor 54 described above in FIG. 5 calculates the first radius minus the first effective refractive index n eff R1 (approximately 30.75) is selected and fixed, and a dashed line parallel to the horizontal axis is drawn at a position corresponding to 30.75 on the vertical axis in FIG.

[0076] Next, using the processor 54, the width W of the waveguide is selected as a first width W1, and the intersection point between the dotted line and the curve of the first width W1 and the value corresponding to the horizontal axis of FIG. 5 (i.e., the first radius R1 shown in FIG. 5) is determined.

[0077] Next, using the processor 54, select the width W of the waveguide as the second width W2 in step 2-2, and obtain the intersection point between the dotted line and the curve of the second width W2 and its value corresponding to the horizontal axis in FIG. 5 (i.e., the second radius R2 shown in FIG. 5).

[0078] Next, in step 2-3, the processor 54 is used to back-push the obtained second radius R2 based on the above equation 3 to obtain the second effective refractive index n eff2 and calculate the second effective refractive index n eff2 and the above equation 2, the second radius R2 (also referred to here as the second pushback radius R2') located on the left side of the above equation 2 is obtained.

[0079] Next, the above processor 54 is used in step 2-4 to obtain the error rate DV of the second radius R2 and the second pushback radius R2' based on the following equation 4. Next, if the error rate DV of equation 4 is greater than the error threshold d of equation 1, the processor 54 is used to execute steps 2-2 to 2-4 again, and the width W of the other waveguide is selected as the second width W2.

[0080] Alternatively, if the error rate DV of Equation 4 is not greater than (i.e., is less than or equal to) the error threshold d of Equation 1, the processor 54 uses steps 2-5 to output the corresponding coupling gap W0, first width W1, first radius R1, second width W2, and second radius R2.

[0081] In this embodiment, the ratio of the first width W1 to the second width W2 is between 1.3 and 1.7, i.e., 1.3≦W1 / W2≦1.7. The error threshold d in the above Equation 1 can be further adjusted based on process requirements and process constraints, for example, 10%, preferably 5%, more preferably 3%, more preferably 1%, more preferably 0.5%.

[0082]

number

[0083] For example, in steps 2-4 to 2-5 above, the error threshold d in the above formula 1 is 1% or 0.5%, and the arrangement parameters of the error threshold d that matches the above formula 1 obtained by the processing of the processor 54 are shown in Table 1 below.

[0084] In Table 1, the processor 54 can obtain a range of error rate DV that is processed by the processor 54 based on Equation 4 and conforms to the error threshold d in Equation 1 above, for example, −0.033% to 0.431% (taking the absolute value, the range of the error rate DV is 0.033% to 0.431%), and all of them are lower than the error threshold d in Equation 1 above (i.e., 1% or 0.5%).

[0085] [Table 1]

[0086] Next, in step 3, the processor 54 is used to adjust the coupling angle θ between the first waveguide 12b and the second waveguide 14 (i.e., the coupling length is indirectly adjusted. For example, the coupling length is the second radius R2 multiplied by the coupling angle). As a result, the coupling efficiency of the simulated resonator 10b including the first waveguide 12b and the second waveguide 14 becomes approximately 100% in a wide frequency band.

[0087] In this embodiment, the above-mentioned processor 54 simulates the spectrum of the directional coupler by using a 3D Finite-difference time-domain (FDTD) method or by using a 3D Eigen Mode Expansion (EME) method to adjust the coupling angle θ between the first waveguide 12b and the second waveguide 14.

[0088] The following description will be given with reference to Fig. 6A. Fig. 6A is a diagram showing the relationship between different coupling angles θ and the simulation of coupling efficiency of the simulated resonator 10b according to this embodiment. In Fig. 6A, by changing different coupling angles θ, the processor 54 can obtain the coupling efficiency of each coupling port P1 in a specific frequency band (for example, the wavelength of the incident light in Fig. 6A is 1250 nm to 1350 nm) of the simulated resonator 10b configured based on each arrangement parameter (for example, the arrangement parameters in Table 2 below).

[0089] The coupling efficiency of the coupling port P1 varies from 0% to 100% at different coupling angles θ based on the trend of a sinusoid. Therefore, better coupling efficiency of the coupling port P1 occurs in certain frequency bands corresponding to the peak parts of these sine waves.

[0090] Therefore, by simulating and adjusting the coupling angle θ, configuration parameters can be obtained that can improve the coupling efficiency of the coupling port P1 (e.g., substantially close to 100%. For example, the coupling efficiency shown in FIG. 6A is in the range of 0% to 90%, or in the range of 0% to 85%).

[0091] Then, simulation and adjustment are performed based on the configuration parameters, and the coupling efficiency of the coupling port P1 can be adjusted to any range or value within the range of 0% to 100%.

[0092] [Table 2]

[0093] 6A to 6C will be described at the same time. Here, Fig. 6B is a diagram showing a relationship between different coupling angles θ in Fig. 6A and the overall coupling efficiency in a simulation of the first embodiment. Also, Fig. 6C is a diagram showing a relationship between different coupling angles θ in Fig. 6A and the overall coupling efficiency in a simulation of the second embodiment.

[0094] 6B and 6C respectively show the coupling efficiency of each coupling port P1 obtained by the processor 54 of FIG. 6A and the coupling efficiency of each output port P2 corresponding to each coupling port P1.

[0095] Moreover, the overall coupling efficiency corresponding to each coupling port P1 (i.e., P1+P2) is obtained by simulation and drawing using 10 lattice points per wavelength (relatively few) and 18 lattice points per wavelength (relatively many), respectively.

[0096] In Figures 6B and 6C, the simulation of Figure 6B, which has fewer lattice points, results in a slightly lower coupling efficiency of the coupling port P1 compared to the coupling efficiency of the coupling port P1 of Figure 6C, which is simulated with more lattice points.

[0097] The reason for this is that by performing the simulation with a larger number of lattice points, subtle changes in the waveguide structure (including the first waveguide 12b and the second waveguide 14) can be fully represented, and a coupling efficiency close to the theoretical value can be obtained.

[0098] For example, taking the data of the coupling angle θ=41° in FIGS. 6A to 6C as an example, the coupling angle θ=41° coincides with the configuration parameters in Table 2.

[0099] That is, as shown in FIG. 6C, when the wide frequency band is 1300 nm to 1320 nm (e.g., 1310 nm), a simulated resonator 10b is obtained in which the coupling efficiency of the coupling port P1 is nearly 100% (e.g., the coupling efficiency of the coupling port P1 shown in FIG. 6B is in the range of 0% to 90%, or in the range of 0% to 85%. Or, for example, the coupling efficiency of the coupling port P1 shown in FIG. 6C is in the range of 80% to 100%, or in the range of 85% to 100%).

[0100] Next, in step 4, the processor 54 is used to adjust at least one of the configuration parameters (including the first radius R1, the first width W1, the second radius R2, the second width W2, the coupling gap W0, and the coupling angle θ) based on the configuration parameters obtained in step 3 (including the first radius R1, the first width W1, the second radius R2, the second width W2, the coupling gap W0, and the coupling angle θ).

[0101] The coupling efficiency of the tuned simulated resonator 10b in a portion of a wide frequency band ranges from 0% to 100%.In this embodiment, the ratio of the first width W1 to the second width W2 is 1.3 to 1.7.

[0102] Next, in step 5, the processor 54 is used to output the adjusted coupling efficiency and corresponding configuration parameters (including the first radius R1, the first width W1, the second radius R2, the second width W2, the coupling gap W0, and the coupling angle θ).

[0103] Each of the output configuration parameters may be in a tolerance range. For example, the tolerance range for outputting the first width W1 is 470 nm to 600 nm. Or, for example, the tolerance range for outputting the coupling gap W0 is 150 nm to 250 nm.

[0104] Here, the resulting configuration parameters are the above-mentioned approximately matching configuration parameters, for example, the coupling gap W0 is sufficiently small but not too small to make its manufacture difficult, or, for example, the coupling angle θ is sufficiently large and the corresponding coupling length (e.g., the second radius R2 multiplied by the coupling angle θ) is sufficiently long so that the simulated resonator 10b can have substantially similar coupling efficiency in a wide frequency band.

[0105] Therefore, the first coupling portion 122 of the first waveguide 12b and the second coupling portion 143 of the second waveguide 14 arranged with approximately matched arrangement parameters are the above-mentioned substantially matched first coupling portion 122 and second coupling portion 143.

[0106] 7A, 8A, and 9A, which respectively show the simulated relationships of coupling efficiency in a wide frequency band with a fixed first width (W1=500 nm / 525 nm / 550 nm) and different coupling angles θ of the simulated resonator 10b.

[0107] 7A, 8A and 9A, the above-mentioned processor 54 is used in step 4 to adjust only the different first width W1 (other arrangement parameters are fixed at the same time. Taking FIG. 7A as an example, specific arrangement parameters are shown in Table 3 below) based on the arrangement parameters obtained in step 3. The coupling efficiency of a part of a wide frequency band of a specific frequency band (for example, the wavelength of the incident light in FIG. 7A is 1250 nm to 1370 nm) of the adjusted simulated resonator 10b is set to a range of 0% to 85%.

[0108] [Table 3]

[0109] In the above configuration parameters, since the coupling gap W0 here is a fixed value, the first width W1 is increased by a width adjustment amount (for example, the first width W1 is increased from 450 nm to 500 nm).

[0110] That is, for example, this means that the width adjustment amount is halved in the direction approaching the center C (see FIG. 3) of the first waveguide 12b, and is obtained by adjusting the width adjustment amount to halve in the direction moving away from the center C (see FIG. 3) of the first waveguide 12b.

[0111] Therefore, to fix the coupling gap W0 and the second width W2, the second radius R2 of the second waveguide 14 also needs to be increased by half the width adjustment amount in the direction away from the center C of the first waveguide 12b, and vice versa.

[0112] Specifically, taking the configuration parameters of Tables 2 and 3 as an example, compared with the first width W1 (W1=450 nm) of Table 2, the first width W1 of Table 3 is increased to 500 nm.

[0113] Therefore, the second radius R2 in Table 3 is also increased by half (i.e., 25 nm; 0.025 μm) of the width adjustment amount (i.e., 50 nm) in a corresponding direction away from the center C (see FIG. 3) to obtain the second radius R2 in Table 3 (i.e., 11.925 μm).

[0114] Continuing with the description, referring to FIG. 7A, in FIG. 7A, the above-mentioned processor 54 is used in step 4 to adjust only the first width W1 and the coupling angle θ (at the same time, other arrangement parameters are fixed. For specific arrangement parameters, see Table 3 above) which are different based on the arrangement parameters obtained in step 3. The coupling efficiency of the adjusted simulated resonator 10b in a wide frequency band (for example, the wavelength of the incident light in FIG. 7A is 1250 nm to 1370 nm) is in the range of 25% to 30%.

[0115] Since processor 54 first selects each of the configuration parameters of FIG. 7A (including first width W1) and only further adjusts coupling angle θ, processor 54 effectively adjusts at least two configuration parameters (including first width W1 and coupling angle θ).

[0116] 6C and 7A will be described at the same time. Taking the coupling efficiency (about 80% to 100%) of the coupling port P1 of the first width W1 in FIG. 6C as an example, in comparison with FIG. 6C, the coupling efficiency (about 25% to 30%) of the coupling port P1 in FIG. 7A is reduced to about 50% to 75% by the processor 54, and can be any range or value within the range of 0% to 100%.

[0117] Referring to Figure 7B, a graph showing a simulated relationship between the broadband coupling efficiency and a specific coupling angle (θ=23°) of a simulated resonator 10b arranged with the arrangement parameters of Figure 7A is shown.

[0118] More specifically, Fig. 7B shows the coupling efficiency of the coupling port P1 obtained based on the coupling angle θ=23° in Fig. 7A and the coupling efficiency of the output port P2 corresponding to the coupling port P1. Also, the overall coupling efficiency (P1+P2) corresponding to the coupling port P1 is obtained by simulation and drawing.

[0119] In Fig. 7B, the simulated resonator 10b has a coupling efficiency of the coupling port P1 in the range of 25% to 30% in a part of a specific frequency band (for example, the wavelength of the incident light in Fig. 7B is 1250 nm to 1370 nm). More precisely, the coupling efficiency of the coupling port P1 is in the range of 28% ± 1%.

[0120] Referring to Fig. 8A, Fig. 8A is a diagram showing the relationship of simulation of different coupling angles θ of the simulation resonator 10b in a wide frequency band with a fixed first width (W1=525 nm) according to the present embodiment. In Fig. 8A, the above-mentioned processor 54 is used in step 4 to adjust only the different first width W1 and coupling angle θ (when other configuration parameters are fixed at the same time, specific configuration parameters are referred to Table 4 below) based on the configuration parameters obtained in step 3.

[0121] The coupling efficiency of the simulated resonator 10b in a wide frequency band (for example, the wavelength of the incident light in FIG. 8A is 1250 nm to 1370 nm) is within a range of 13% to 20%. Here, the processor 54 substantially adjusts at least two configuration parameters (including the first width W1 and the coupling angle θ) as described above.

[0122] 6C and 8A simultaneously, taking the coupling efficiency (approximately 80% to 100%) of the coupling port P1 of the first width W1 in FIG. 6C as an example, in comparison with FIG. 6C, the coupling efficiency (approximately 13% to 20%) of the coupling port P1 in FIG. 8A is reduced to approximately 60% to 87% by the above-mentioned processor 54, but can be any range or value within the range of 0% to 100%.

[0123] [Table 4]

[0124] Referring to FIG. 8B, FIG. 8B is a diagram showing a simulation of coupling efficiency in a wide frequency band of a simulated resonator 10b arranged with the arrangement parameters of FIG. 8A and a specific coupling angle (θ=20°).

[0125] More specifically, Fig. 8B shows the coupling efficiency of the coupling port P1 obtained based on the coupling angle θ=20° in Fig. 8A and the coupling efficiency of the output port P2 corresponding to the coupling port P1. Also, the overall coupling efficiency (P1+P2) corresponding to the coupling port P1 is obtained by simulation and drawing.

[0126] In Fig. 8B, the coupling efficiency of the coupling port P1 of the simulated resonator 10b is within a range of 13% to 20% in a part of a specific frequency band (for example, the wavelength of the incident light in Fig. 8B is 1250 nm to 1370 nm). More precisely, the coupling efficiency of the coupling port P1 is within a range of 19% ± 1%.

[0127] Referring to FIG. 9A, FIG. 9A is a diagram showing a simulation of the coupling efficiency over a wide frequency band for different coupling angles θ of a simulated resonator 10b at a fixed first width (W1=550 nm) according to this embodiment.

[0128] In FIG. 9A, the above-mentioned processor 54 is used in step 4 to adjust only the different first width W1 and coupling angle θ (see Table 5 below for specific arrangement parameters when other arrangement parameters are fixed at the same time) based on the arrangement parameters obtained in step 3, and the coupling efficiency of the adjusted simulated resonator 10b in a wide frequency band (for example, the wavelength of the incident light in FIG. 9A is 1250 nm to 1370 nm) is within the range of 7% to 14%.

[0129] Here, the processor 54 substantially adjusts at least two configuration parameters (including the first width W1 and the coupling angle θ) as described above.

[0130] 6C and 9A simultaneously, taking the coupling efficiency (about 80% to 100%) of the coupling port P1 of the first width W1 in FIG. 6C as an example, in comparison with FIG. 6C, the coupling efficiency (about 7% to 14%) of the coupling port P1 in FIG. 9A is reduced to about 66% to 93% by the above-mentioned processor 54, but can be any range or value within the range of 0% to 100%.

[0131] [Table 5]

[0132] Referring to FIG. 9B, FIG. 9B is a diagram showing a relationship between the arrangement parameters of FIG. 9A and a simulation of coupling efficiency in a wide frequency band of a simulated resonator 10b arranged at a specific coupling angle (θ=16.5°).

[0133] Specifically, Fig. 9B shows the coupling efficiency of the coupling port P1 obtained based on the coupling angle θ=16.5° in Fig. 9A and the coupling efficiency of the output port P2 corresponding to the coupling port P1. Also, the overall coupling efficiency (P1+P2) corresponding to the coupling port P1 is obtained by simulation and drawing.

[0134] In Fig. 9B, the simulated resonator 10b has a coupling efficiency of the coupling port P1 in the range of 7% to 14% in a part of a specific frequency band (for example, the wavelength of the incident light in Fig. 9B is 1250 nm to 1370 nm). More precisely, the coupling efficiency of the coupling port P1 is in the range of 10% ± 0.5%.

[0135] Next, the display element 522 receives the configuration parameters (including the first radius R1, the first width W1, the second radius R2, the second width W2, the coupling gap W0, and the coupling angle θ) output by the processor 54 in step 5, and outputs the coupling efficiency adjusted with these configuration parameters (including the first radius R1, the first width W1, the second radius R2, the second width W2, the coupling gap W0, and the coupling angle θ).

[0136] In this way, for example, to obtain a first waveguide 12a having a closed ring 120a in the wideband ring resonator 10a of FIG. 1, the semicircular first waveguide 12b in the simulated resonator 10b of FIG. 3 can be further connected based on the obtained configuration parameters.

[0137] Therefore, the wideband ring resonator 10a of this embodiment obtained in this manner has optical output performance with multiple high uniformity over a wide frequency band (e.g., high uniformity of resonant notches and low optical loss) and a relatively high quality factor.

[0138] The following description will be given with reference to Fig. 10. Fig. 10 shows this embodiment, and is a diagram showing the relationship between the first width W1 of the optical coupling portion of the resonator of the long second waveguide 14 that advances in a straight line and the coupling efficiency in the wideband portion, which are different from those of the optical coupling portion of the simulated resonator 10b.

[0139] In FIG. 10, the optical coupling section (first coupling section 122 and second coupling section 143) of the simulated resonator 10b shown in FIG. 3 is represented by a CDC (curved directional coupler), and the optical coupling section of a ring resonator in which the curved second waveguide 14 in the simulated resonator 10b in FIG. 3 is replaced with a long straight second waveguide is represented by an SDC (straight directional coupler) corresponding to the first coupling section 122 and second coupling section 143.

[0140] Each CDC and SDC is configured based on the arrangement parameters of Figures 7B, 8B, and 9B (shown in Table 6 below), and the second waveguide of each SDC is a long, straight second waveguide, so that the second radius R2 of the SDC is the shortest distance from the second coupling portion 143 (see Figure 3) to the center C.

[0141] In Fig. 10, for the first group of CDC and SDC arranged with the arrangement parameters (W1 = 500 nm) of Fig. 7B, the coupling efficiency of the coupling port P1 of the CDC is about 25% to 30%, and the coupling efficiency of the coupling port P1 of the SDC is about 2.5% to 5%. Also, the coupling efficiency of the coupling port P1 of the CDC is obviously higher than that of the coupling port P1 of the SDC.

[0142] A similar situation is found for the CDC and SDC arranged with the arrangement parameters of the second and third groups, respectively, as shown in Figures 8B and 9B. The coupling efficiency of the coupling port P1 of the CDC is about 17.5% to 20% and 10% to 12.5%, respectively, and the coupling efficiency of the coupling port P1 of the SDC is about 1% to 4% and 1% to 3%, respectively.

[0143] It can be seen that the CDC (curved second waveguide 14) has a higher coupling efficiency at the coupling port P1 than the SDC (long straight second waveguide). The second waveguide 14 is coupled to the first waveguide 12b.

[0144] [Table 6]

[0145] FIG. 11 is a simulation diagram showing the relationship between the optical transmittance (optical transmission coefficient) of the optical coupling portion 10a of the ring resonator having the arrangement parameters shown in FIG. 9B and the optical coupling portion of the resonator of the long second waveguide that advances in a straight line.

[0146] In FIG. 11, the waveguide losses of the ring resonators of the CDC and SDC are both set to 65 dB / cm, and the multi-wavelength resonance condition is satisfied over a wide frequency band (for example, the wavelength of the incident light in FIG. 11 is 1250 nm to 1370 nm). Therefore, the incident light in the second waveguide 14 of the CDC and SDC can be coupled and confined in the corresponding first waveguide 12a, and multiple signal troughs (i.e., valleys, resonant grooves) of the optical output appear in FIG. 11.

[0147] In FIG. 11, the trough depths of these signals in the CDC are very uniform (extinction ratio is about 14±2 dB). Therefore, the CDC shown in FIG. 11 (i.e., wideband ring resonator 10a) has high uniformity of optical output performance in wideband operation (e.g., the wavelength of the incident light in FIG. 11 is 1250 nm to 1370 nm).

[0148] In contrast, in Figure 11, there is a relatively obvious and large difference in the depth of the troughs of these signals in the SDC. For example, the difference in the optical transmission coefficient between wavelengths of 1250 nm and 1365 nm is about 10%. This means that it is difficult for the SDC to operate in a wide frequency band (for example, the wavelength of the incident light in Figure 11 is 1250 nm to 1370 nm) and to provide a high level of uniform light output performance.

[0149] Therefore, the wideband ring resonator 10a of this embodiment can stably output a plurality of highly uniform light beams (e.g., high uniformity of the resonant notches and low optical loss / extinction ratio) in a wide frequency band (e.g., 1250 nm to 1370 nm).

[0150] In this embodiment, the above-mentioned processor 54 is used in step 4 to adjust four configuration parameters, such as different coupling angles θ, coupling gap W0, first width W1 and second width W2 (while simultaneously fixing other configuration parameters), based on the configuration parameters obtained in step 3, so that the coupling efficiency in a wide frequency band of the already-adjusted simulated resonator 10b is within the range of 0% to 100%.

[0151] In this embodiment, the ratio of the first width W1 to the second width W2 is 1.3 to 1.7 In this embodiment, the first width W1 is 470 nm to 600 nm.

[0152] In this embodiment, the coupling gap W0 is 150 nm to 250 nm. In this embodiment, the second width W2 is 300 nm to 400 nm.

[0153] Thereby, due to the above-mentioned limitation of the ratio of the first width W1 to the second width W2 and / or the limitation of the first width W1 and / or the limitation of the coupling gap W0 and / or the first waveguide 12b of this embodiment can be optically coupled with the second waveguide 14 at least within the range of 1250 nm to 1370 nm and has a coupling efficiency substantially close to 100% (alternatively, the coupling efficiency can be adjusted up or down to a range of 0% to 85% or 85% to 100%).

[0154] Referring to Fig. 12A, Fig. 12A is a diagram showing the relationship between the arrangement parameters shown in Fig. 7B and the coupling efficiency of the wideband part of the simulated resonator 10b arranged to adjust different coupling gaps W0, first widths W1, and second widths W2.

[0155] In FIG. 12A, as shown in FIG. 7B, the coupling gap W0 (200 nm), the first width W1 (500 nm), and the second width W2 (350 nm) are selected for tuning, and other configuration parameters are shown in FIG. 12B, but will not be described in detail here.

[0156] In FIG. 12A, the processor 54 further adjusts placement parameters such as the coupling gap W0 (+20 nm, +10 nm, -10 nm and -20 nm (i.e., 220 nm, 210 nm, 190 nm and 180 nm)), the first width W1 (-20 nm, -10 nm, +10 nm and +20 nm (i.e., 480 nm, 490 nm, 510 nm and 520 nm)) and the second width W2 (-20 nm, -10 nm, +10 nm and +20 nm (i.e., 330 nm, 340 nm, 360 nm and 370 nm)).

[0157] The coupling efficiency (about 28%±1%, ie, about 27% to 29%) of the coupling port P1 having a coupling gap W0 (200 nm), a first width W1 (500 nm) and a second width W2 (350 nm) in FIG. 12A is a reference value.

[0158] Via the processor 54, the coupling gap W0 is increased slightly by approximately 10 nm / 20 nm (and simultaneously the first width W1 and the second width W2 are decreased slightly by approximately 10 nm / 20 nm).

[0159] That is, the coupling efficiency of that coupling port P1 can be reduced to about 2% to 17%, which is about 10% to 25% (ie, any range or value within the range of 0% to 100%).

[0160] In response, the processor 54 slightly decreases the coupling gap W0 by approximately 10 nm / 20 nm (and simultaneously increases the first width W1 and the second width W2 slightly by approximately 10 nm / 20 nm).

[0161] That is, the coupling efficiency of the coupling port P1 can be increased from about 1% to 23%, and can be from about 30% to 50% (ie, any range or value within the range of 0% to 100%).

[0162] Referring to Fig. 12B, there is shown a simulation relationship diagram for the coupling efficiency of the wideband part of the simulated resonator 10b arranged to adjust the arrangement parameters shown in Fig. 8B and different coupling gaps W0, first width W1, and second width W2.

[0163] In Figure 12B, we select the coupling gap W0 (200 nm), the first width W1 (525 nm), and the second width W2 (350 nm) as shown in Figure 8B. Other configuration parameters are shown in Figure 8B and Table 4, and will not be described in detail here.

[0164] In FIG. 12B, the processor 54 further adjusts the placement parameters such as the coupling gap W0 (+30 nm, +20 nm, +10 nm, -10 nm, -20 nm and -30 nm (i.e., 230 nm, 220 nm, 210 nm, 190 nm, 180 nm and 170 nm)), the first width W1 (-30 nm, -20 nm, -10 nm, +10 nm, +20 nm and +30 nm (i.e., 495 nm, 505 nm, 515 nm, 535 nm, 545 nm and 555 nm)) and the second width W2 (-30 nm, -20 nm, -10 nm, +10 nm, +20 nm and +30 nm (i.e., 320 nm, 330 nm, 340 nm, 360 nm, 370 nm and 380 nm)).

[0165] The coupling efficiency (about 19%±1%, or about 18% to 20%) of the coupling port P1 having the coupling gap W0 (200 nm), the first width W1 (525 nm), and the second width W2 (350 nm) in FIG. 12B is taken as a standard (reference) value.

[0166] The processor 54 slightly increases the coupling gap W0 by about 10 nm / 20 nm / 30 nm (while slightly decreasing the first width W1 and the second width W2 by about 10 nm / 20 nm / 30 nm), i.e., the coupling efficiency of the coupling port P1 can be decreased to about 3% to 17%, which is about 3% to 15% (i.e., any range or value within the range of 0% to 100%).

[0167] In contrast, by slightly decreasing the coupling gap W0 by approximately 10 nm / 20 nm / 30 nm (while simultaneously slightly increasing the first width W1 and the second width W2 by approximately 10 nm / 20 nm / 30 nm), the processor 54 can increase the coupling efficiency of the coupling port P1 from approximately 4% to 24%, or from approximately 22% to 42% (i.e., any range or value within the range of 0% to 100%).

[0168] 12C, which is a graph showing the relationship between the arrangement parameters shown in FIG. 9B and the coupling efficiency of the wideband portion of the simulated resonator 10b arranged to adjust different coupling gaps W0, first widths W1, and second widths W2.

[0169] In FIG. 12C, the coupling gap W0 (200 nm), the first width W1 (550 nm) and the second width W2 (350 nm) as shown in FIG. 9B are selected for tuning, while other configuration parameters are shown in FIG. 9B and Table 5 and will not be described in detail here.

[0170] In FIG. 12C, the processor 54 adjusts configuration parameters such as the coupling gap W0 (+30 nm, +20 nm, +10 nm, -10 nm, -20 nm, and -30 nm (i.e., 230 nm, 220 nm, 210 nm, 190 nm, 180 nm, and 170 nm)), the first width W1 (-30 nm, -20 nm, -10 nm, +10 nm, +20 nm, and +30 nm (i.e., 520 nm, 530 nm, 540 nm, 560 nm, 570 nm, and 580 nm)), and the second width W2 (-30 nm, -20 nm, -10 nm, +10 nm, +20 nm, and +30 nm (i.e., 320 nm, 330 nm, 340 nm, 360 nm, 370 nm, and 380 nm)).

[0171] The coupling efficiency (about 10%±0.5%, i.e., about 9.5% to 10.5%) of the coupling gap W0 (200 nm), first width W1 (525 nm), and second width W2 (350 nm) of the coupling port P1 in FIG. 12C is set as a standard value (reference value).

[0172] The processor 54 slightly increases the coupling gap W0 by about 10 nm / 20 nm / 30 nm (and simultaneously slightly decreases the first width W1 and the second width W2 by about 10 nm / 20 nm / 30 nm), i.e., the coupling efficiency of that coupling port P1 can be decreased to about 1.5% to 5.5%, which is about 5% to 9% (i.e., any range or value within the range of 0% to 100%).

[0173] In contrast, if the processor 54 slightly reduces the coupling gap W0 by approximately 10 nm / 20 nm / 30 nm (while simultaneously slightly increasing the first width W1 and the second width W2 by approximately 10 nm / 20 nm / 30 nm), the coupling efficiency of the coupling port P1 can be increased from approximately 3.5% to 13.5%, to approximately 13% to 23% (i.e., any range or value within the range of 0% to 100%).

[0174] 12A-12C, it can be seen that the processor 54 can slightly adjust (increase or decrease) four configuration parameters, such as the coupling angle θ, the coupling gap W0, the first width W1, and the second width W2, i.e., the coupling efficiency of the coupling port P1 can be increased or decreased from about 1% to 20%, and the coupling efficiency of the coupling port P1 can be any range or value within the range of 0% to 100%.

[0175] Furthermore, it can be seen from FIGS. 12A-12C that only slight adjustments (it can be increased or decreased) have a relatively obvious effect on the coupling efficiency of the coupling port P1.

[0176] Therefore, the above characteristics of the simulated resonator 10b can also be used for its process monitoring, and the real-time monitoring result of the coupling efficiency of the coupling port P1 can tell whether there is any abnormality or error in a certain process related to each arrangement parameter (e.g., the first width W1 of the first coupling portion 122).

[0177] In this manner, the present embodiment can accurately control and detect whether there are any anomalies or errors in various processes, and can also adjust certain processes and their corresponding configuration parameters in real time to reduce unnecessary process losses.

[0178] 13A and 13B are now described in conjunction with each other, in which Fig. 13A shows the configuration parameters of Fig. 9B and illustrates the simulated relationship of coupling efficiency of the broadband section of the simulated resonator 10b with different coupling gaps W0, first widths W1, and second widths W2 at a specific coupling angle (θ=16.5°).

[0179] FIG. 13B is a diagram showing the relationship between the actual measurement quantity and the coupling efficiency of the wideband section of the simulation resonator 10b having the arrangement parameters of FIG. 13A with different coupling gaps W0, first widths W1, and second widths W2.

[0180] In Figures 13A and 13B, the coupling angle θ (16.5°) shown in Figure 9B is fixed, and the coupling gap W0 (200 nm), the first width W1 (550 nm), and the second width W2 (350 nm) are selected to further adjust the first arrangement parameter L1 to the seventh arrangement parameter L7 (detailed arrangement parameters can be seen in Figure 13B). Note that the other arrangement parameters are shown in Figure 9B and Table 5, and will not be described in detail here. The measurement method used here can be referred to above, and will not be described in detail here.

[0181] The coupling efficiency (about 14% to 18%) of the simulated coupling port P1 with the coupling gap W0 (200 nm), the first width W1 (550 nm), and the second width W2 (350 nm) in FIG. 13A (i.e., corresponding to the second configuration parameter L2 in FIG. 13B) is a reference value (baseline value).

[0182] In the wavelength range of incident light of 1260 nm to 1330 nm in FIG. 13B, the coupling efficiency of the coupling port P1 obtained by actual measurement of the second arrangement parameter L2 is approximately 9% to 11%, and the coupling efficiencies of the two coupling ports P1 have the same tendency, with the difference being approximately 3% to 9%.

[0183] From Figures 13A and 13B, it can be seen that the simulations of the other first arrangement parameter L1, the third arrangement parameter L3 to the seventh arrangement parameter L7 and the actually measured coupling efficiencies of the coupling port P1 also have similar trends, and will not be described in detail here.

[0184] Therefore, the configuration parameters obtained by simulating the design system 50 for the wideband ring resonator 10a can actually be used to actually manufacture a wideband ring resonator 10a for a specific frequency band (at least within the range of 1280 nm to 1330 nm) and achieve the performance of outputting multiple highly uniform lights.

[0185] The difference between the coupling efficiency of the coupling port P1 of the actual measurement quantity on both sides of FIG. 13A (ie, the wavelengths of the incident light are 1250 nm to 1260 nm and 1330 nm to 1350 nm, respectively) and the coupling efficiency of the coupling port P1 of the simulation of FIG. 13A is large.

[0186] The reason is that the above measurements are not the performance of a true curved directional coupler (CDC), but are limited by the bandwidth of the optical input and output interfaces (grating couplers).

[0187] Therefore, if the operator uses other optical output and input interfaces to measure the coupling efficiency of the components of the broadband edge emission coupler, the effect of the above bandwidth limitation can be solved.

[0188] Based on this, in this embodiment, the configuration parameters simulated by the design system 50 for the wideband ring resonator 10a can actually be used to actually manufacture the wideband ring resonator 10a for a specific frequency band (at least in the range of 1260 nm to 1330 nm).

[0189] The following description will be given with reference to Fig. 9B and Fig. 13C to Fig. 13I. Fig. 13C to Fig. 13I are diagrams showing the relationship between the coupling efficiency of the wideband part of the simulated resonator 10b arranged with the first to seventh arrangement parameters in Fig. 13A and Fig. 13B and the actual measurement quantity.

[0190] In Figures 13C to 13I, the coupling angle θ (16.5°) shown in Figure 9B is fixed, and the coupling gap W0 (200 nm), the first width W1 (550 nm), and the second width W2 (350 nm) are selected to adjust the first configuration parameter L1 to the seventh configuration parameter L7 (see Figure 13B for detailed configuration parameters), while the other configuration parameters are shown in Figure 9B and Table 5 and will not be described in detail here.

[0191] Taking the simulated coupling efficiency of output port P2 in FIG. 9B (about 89% to 91%) as the reference value, in FIG. 13C, in the wavelength range of incident light from 1260 nm to 1330 nm, the actually measured coupling efficiency of output port P2 is about 83% to 87%, and the trend of the coupling efficiency of the two output ports P2 is the same, with the difference being only about 6% to 8%.

[0192] Therefore, according to the trend of the difference in coupling efficiency between the coupling port P1 and the output port P2, it can be seen that the coupling efficiency simulated by the design system 50 of the wideband ring resonator 10a is actually close to the coupling efficiency actually measured, which can be said to be suitable for actually manufacturing the wideband ring resonator 10a for a specific frequency band (at least in the range of 1260 nm to 1330 nm).

[0193] Therefore, when the wideband ring resonator 10a is actually manufactured, the arrangement parameters obtained by the simulation can be directly used in this embodiment, or only slight adjustments are required, which means that the wideband ring resonator 10a can exhibit the performance of outputting light with high uniformity in multiple frequency bands within at least the wide frequency band of 1260 nm to 1330 nm.

[0194] Similarly, in Figures 13D to 13I, the coupling gap W0 (200 nm), the first width W1 (550 nm), and the second width W2 (350 nm) can be adjusted up or down to obtain the first placement parameter L1 and the third placement parameters L3 to L7 of Figure 13B.

[0195] It can be seen from FIGS. 13D to 13I that the coupling efficiencies of the coupling port P1 and the output port P2 in each figure have a stable and similar trend at least within the wavelength range of the incident light from 1260 nm to 1330 nm.

[0196] Therefore, considering the tendency of the difference in the coupling efficiency between the coupling port P1 and the output port P2, even if the coupling gap W0, the first width W1, and the second width W2 are changed, the coupling efficiency obtained from the simulation by the design system 50 of the wideband ring resonator 10a is almost the same as the coupling efficiency actually measured.

[0197] In particular, it is beneficial to apply it to the practical manufacture of a wideband ring resonator 10a for a specific frequency band (at least within the range of 1260 nm to 1330 nm).

[0198] Therefore, when the wideband ring resonator 10a is actually manufactured, the arrangement parameters obtained by the simulation can be directly used in this embodiment, or only slight adjustments are required, which means that the wideband ring resonator 10a can exhibit the performance of outputting light with high uniformity in multiple frequency bands within at least the wide frequency band of 1260 nm to 1330 nm.

[0199] Also, from Figures 13A to 13E, when actually manufacturing the wideband ring resonator 10a, in this embodiment, the working window allowed by the coupling gap W0, the first width W1, and the second width W2 (the above-mentioned allowable working window) may be ±10 nm (corresponding to a coupling efficiency of approximately ±5% to ±7%).

[0200] Moreover, the configuration parameters obtained by the simulation can be directly transferred or only slightly adjusted to output very uniform light in multiple frequency bands within a wide frequency range of at least 1260 nm to 1330 nm.

[0201] To summarize the above, in the present embodiment, the configuration parameters between the first waveguide and the second waveguide of the wideband ring resonator are obtained by simulation design using the design system, and the above-mentioned configuration parameters are substantially consistent with each other, so that the first waveguide and the second waveguide actually have substantially similar coupling efficiency in the range of 0% to 100% over a wide frequency band.

[0202] Furthermore, the effect of adjusting the coupling efficiency can be achieved by only adjusting at least the width of the first waveguide (i.e., the aforementioned first width) without significantly changing other configuration parameters such as the radius of the second waveguide (the aforementioned second radius).

[0203] This allows the broadband ring resonator to satisfy the resonance and coupling conditions for different wavelength bands over a wide frequency band, and to generate the performance of outputting multiple light beams with high uniformity.

[0204] Therefore, even with micron-scale component manufacturing dimensions, this embodiment can obtain stable, high light output performance by adjusting the coupling efficiency without significantly changing the arrangement parameters, and can accurately manufacture a wideband ring resonator with low optical loss over a wide frequency band. This allows for an excellent manufacturing process and expands the fields in which the embodiment of the present invention can be applied.

[0205] Although the present invention has been described with reference to the above-mentioned embodiments, those skilled in the art may make minor changes or modifications without departing from the spirit and scope of the present invention, and the technical scope of the present invention is defined by the claims. [Explanation of symbols]

[0206] 10a Broadband ring resonator 10b Simulation resonator 12a, 12b First waveguide 120a Closed Ring 120b Non-closing ring 122 First coupling part 14 Second Waveguide 140 First Part 141 First Front 142 First Central 143 Second coupling part 144 Second Part 145 The Second Central Region 146 2nd Rear 16 Waveguide layer 20 Second layer of protection 30 First protective layer 40 Base Layer 50 Broadband ring resonator design system 52 User Interface 520 Input Elements 522 Display Elements 54 processors AA´ Section line C center H1 Height of the protrusion of the first waveguide H2 Height of the protrusion of the second waveguide H3 Thickness of the second protective layer H4 Waveguide Layer Thickness H5 Thickness of the first protective layer L1 First configuration parameter L2 Second configuration parameter L3 Third configuration parameter L4 Fourth configuration parameter L5 Fifth configuration parameter L6 6th configuration parameter L7 Seventh configuration parameter P0 input port P1 coupling port P2 output port R1 First radius R2 Second radius W0 Coupling Cap W1 First width W2 Second width θ Coupling angle

Claims

1. A wideband ring resonator including a first waveguide and a second waveguide, the first waveguide is a closed ring, the closed ring having a first coupling portion, the first coupling portion having a first width and a first radius; the second waveguide includes a first portion, a second coupling portion, and a second portion connected to each other in sequence, the second coupling portion having a second width and a second radius, and a coupling efficiency of the second waveguide coupled to the first waveguide in a broadband portion is substantially close; The second radius is greater than the first radius, and 1.3≦W １ / W ２ ≦1.7, and W １ is the first width, W ２ is the second width 1. A wideband ring resonator comprising:

2. The second radius is determined based on the relationship between radius and effective refractive index in Equation 1, [0010] is obtained, In the formula 1, n ｅｆｆ１ is the first effective refractive index, n ｅｆｆ２ is the second effective refractive index, and R １ is the first radius, R ２ is the second radius, d is an error threshold, and the error threshold is not greater than 10%.

2. The wideband ring resonator according to claim 1 .

3. the second coupling portion and the first coupling portion have a coupling angle, a coupling gap distance is spaced apart, and the first width is between 470 nanometers and 600 nanometers; The second width is between 300 nanometers and 400 nanometers, the coupling gap is between 150 nanometers and 250 nanometers, and the wavelength of the incident light corresponding to the broadband portion of the coupling efficiency is substantially close to 1280 nanometers and 1330 nanometers.

3. The wideband ring resonator according to claim 2.

4. A system for designing a wideband ring resonator, comprising: obtaining configuration parameters of a wideband ring resonator based on a simulated resonator; the simulated resonator having a first waveguide and a second waveguide, the first waveguide having a first coupling section, the second waveguide having a second coupling section, the second coupling section and the first coupling section having a coupling angle, and a coupling gap distance; a user interface that receives the coupling gap, the widths of the plurality of waveguides, and the radii of the plurality of waveguides; a processor communicatively coupled to the user interface; The processor, A relationship between a radius and an effective refractive index is obtained, and a width and a radius of the second coupling portion are obtained in addition to a width and a radius of the first coupling portion based on the relationship between the radius and the effective refractive index; Adjusting the coupling angle to make the coupling efficiency of the second waveguide coupled to the first waveguide substantially close to each other in a broadband portion; Adjusting one of the width and the radius of the first coupling section, the width and the radius of the second coupling section, the coupling gap and the coupling angle, to make the coupling efficiency of the wideband section range from 0% to 100%; outputting the configuration parameters of the width and the radius of the first coupling portion, the width and the radius of the second coupling portion, the coupling gap and the coupling angle; A system for designing a wideband ring resonator.

5. The processor is further used to readjust one of the configuration parameters, by increasing or decreasing the coupling efficiency located between 0% and 100% to between 1% and 20%, and outputting the increased or decreased coupling efficiency and the corresponding configuration parameter.

5. The system for designing a wideband ring resonator according to claim 4.

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