A curved waveguide array and optical signal processing device

Abstract

This invention discloses a curved waveguide array, relating to the field of optical technology. The curved waveguide array includes multiple spaced curved waveguides, each comprising an input section, a middle section, and an output section. The middle section is curved in shape. The input sections of the multiple curved waveguides are located at a first end of the curved waveguide array, and the output sections of the multiple curved waveguides are located at a second end of the curved waveguide array. From the middle of the curved waveguide array to both sides, the waveguide width of the middle sections of the multiple curved waveguides gradually decreases, so that the effective refractive index variation of the multiple curved waveguides is consistent with the width variation of the middle sections of the multiple curved waveguides. The curved waveguide array provided by this invention has the advantages of simple structure, high integration, and support for Fourier transforms over a wide wavelength range.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically to a curved waveguide array and an optical signal processing device. Background Technology

[0002] The Fourier transform is a mathematical tool that can convert a signal from the time domain to the frequency domain, or from the spatial domain to the frequency domain. In optics, the Fourier transform can be used to perform spectral analysis of optical signals.

[0003] Currently, there are various technical solutions for achieving Fourier transform using optical methods. These include relying on the optical properties of lenses or microlenses to complete the frequency domain transformation of the signal; using a cascaded network of Mach-Zehnder interferometers to achieve Fourier transform by constructing a specific network structure; directly constructing photonic devices with diffraction structures on the optoelectronic device integrated substrate to achieve Fourier transform directly using the diffraction principle; or constructing AWG units (Arrayed Waveguide Gratings) on the optoelectronic device integrated substrate and using the optical path difference modulation of the waveguides in the AWG units to obtain optical signals with different frequency components at different positions at the output end, achieving an effect similar to Fourier transform.

[0004] However, the aforementioned optical methods for achieving Fourier transform have several drawbacks. Lens- or microlens-based schemes suffer from large optical device size, increasing system size and complexity. Schemes using cascaded Mach-Zehnder interferometer networks have complex network structures, resulting in high design and manufacturing costs and significant system losses. Schemes involving constructing diffractive photonic devices on optoelectronic integrated substrates suffer from significant optical signal loss and are technically challenging. Schemes based on AWG units constructed from optoelectronic integrated substrates have stringent manufacturing precision requirements and poor robustness to multi-wavelength signals.

[0005] This invention proposes a method for implementing Fourier transform using a curved waveguide array. Summary of the Invention

[0006] This invention aims to address, to a certain extent, one of the technical problems in related technologies. To this end, this invention provides a curved waveguide array and an optical signal processing device, which has the advantages of simple structure, high integration, and support for Fourier transforms over a wide wavelength range.

[0007] To achieve the above objectives, as a first aspect of the present invention, a curved waveguide array is provided, wherein the curved waveguide array includes a plurality of spaced curved waveguides, each curved waveguide including an input portion, a middle portion, and an output portion; the middle portion is curved; the input portions of the plurality of curved waveguides are located at a first end of the curved waveguide array, and the output portions of the plurality of curved waveguides are located at a second end of the curved waveguide array;

[0008] From the middle of the curved waveguide array to both sides, the waveguide width of the middle portion of the multiple curved waveguides gradually decreases, so that the effective refractive index variation law of the multiple curved waveguides is consistent with the waveguide width variation law of the middle portion of the multiple curved waveguides; wherein, the effective refractive index of the curved waveguide array satisfies the following formula (1):

[0009] N = -kn × P 2 +bn (1)

[0010] Where N is the effective refractive index of the bent waveguide to be calculated;

[0011] P is the distance between the middle part of the curved waveguide to be calculated and the middle part of the curved waveguide at the middle position.

[0012] kn is the effective refractive index variation coefficient, and 0 < kn < 1;

[0013] bn is the effective refractive index compensation coefficient, and 1 < bn < 3.

[0014] Optionally, from the middle of the curved waveguide array to both sides of the curved waveguide array, the waveguide width of the middle portion of the curved waveguide at the middle position is greater than the waveguide width of the middle portions of the curved waveguides on both sides; the waveguide width of the middle portions of the curved waveguides on both sides that are equidistant from the middle portion of the curved waveguide at the middle position is the same.

[0015] Optionally, the first and second ends of the curved waveguide array have the same width, and the waveguide width is in the range of 380–540 nm.

[0016] Optionally, the input portions of the multiple curved waveguides are not equally spaced; the output portions of the multiple curved waveguides are not equally spaced; and the middle portions of the multiple curved waveguides are equally spaced.

[0017] Optionally, the input portions of the plurality of curved waveguides are not equally spaced; the output portions of the plurality of curved waveguides are not equally spaced, including:

[0018] From the middle of the curved waveguide array to both sides of the curved waveguide array, the spacing between the input portions of each pair of adjacent curved waveguides gradually increases, and the spacing between the output portions of each pair of adjacent curved waveguides also gradually increases.

[0019] Optionally, the spacing between the input portions of two adjacent curved waveguides is greater than or equal to the spacing between the middle portions of two adjacent curved waveguides.

[0020] Optionally, the spacing between the output portions of two adjacent curved waveguides is greater than or equal to the spacing between the middle portions of two adjacent curved waveguides.

[0021] As a second aspect of the present invention, an optical signal processing device is provided, wherein the optical signal processing device includes the curved waveguide array, the signal modulation module, and the signal processing module described in the first aspect of the present invention; the input end of the curved waveguide array is connected to the signal modulation module, the output end of the curved waveguide array is connected to the signal processing module, and the signal modulation module and the signal processing module store unique identification information for each curved waveguide of the curved waveguide array, for identifying and distinguishing optical signals corresponding to different waveguides.

[0022] Optionally, the signal modulation module includes a modulation unit for modulating the amplitude and phase of the input optical signal, and the signal processing module includes a measurement unit for measuring the amplitude and phase information of the optical signal after transmission through the curved waveguide array.

[0023] The curved waveguide array described in this invention achieves Fourier transform of optical signals by designing waveguide spacing and widths with different trends in the input, middle, and output sections of multiple curved waveguides. From the middle of the curved waveguide array to both sides, the spacing between the input sections of adjacent curved waveguides gradually increases. This design facilitates the input of multiple discrete optical signals and reduces interference between them. When the optical signal is transmitted from the input section to the middle section of the curved waveguide, the waveguide spacing in the middle section of adjacent curved waveguides is much smaller than the waveguide spacing in the input section. Furthermore, the waveguide width of the middle sections of multiple curved waveguides gradually decreases from the center waveguide to both sides. This tight coupling and gradual decrease from the center waveguide to both sides... The design of gradually decreasing waveguide width alters the optical field distribution: when the waveguide width is wider, the optical field distribution is broader, and more energy is distributed in the core region of the waveguide; while when the waveguide width is narrower, the optical field is compressed, and more energy is extended to the cladding or outer region of the waveguide. This change in optical field distribution directly affects the effective refractive index of the waveguide: when the waveguide width increases, more optical field energy is concentrated in the high-refractive-index core region of the waveguide, resulting in an increase in the effective refractive index; conversely, when the waveguide width decreases, more optical field energy is extended to the low-refractive-index cladding region, resulting in a decrease in the effective refractive index. Therefore, the waveguide width of the middle section of the multiple curved waveguides gradually decreases from the center to both sides, causing the effective refractive index of the waveguides to also satisfy a quadratic function distribution in the propagation direction. This directly affects the propagation path and phase of the optical signal. By guiding the optical signal to propagate along a predetermined path in the waveguide, beam focusing can be achieved. When the waveguide length of the middle section reaches the focal length of the equivalent lens, the Fourier transform is completed. When light passes through the output section of the multiple curved waveguides, the waveguide spacing of the output section gradually increases from the center to both sides of the curved waveguide array, which helps to reduce interference between optical signals after the Fourier transform. Finally, an optical signal processing device connected to the output end of the curved waveguide array identifies and distinguishes the optical signals transmitted by the curved waveguides with different numbers, and obtains the amplitude and phase information after the Fourier transform.

[0024] The curved waveguide array described in this invention not only solves the problems of large size of optical devices, complex system, high design and manufacturing cost, high process difficulty, and stringent manufacturing precision in other optical methods for realizing Fourier transform, but also has the characteristics and advantages of simple structure, high integration and high bandwidth.

[0025] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of the present invention will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. In addition, each of these features, elements and components appearing in the following text and drawings is a plurality of, and different symbols or numbers are used for convenience of representation, but all represent parts with the same or similar construction or function. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Figure 1 This is a structural diagram of a curved waveguide array provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the waveguide width of the middle portion of the multiple curved waveguides provided by the present invention;

[0029] Figure 3 This is a graph showing the variation trend of the waveguide width in the middle portion of the multiple curved waveguides provided by the present invention.

[0030] Figure 4 This is a graph showing the variation trend of the effective refractive index of the multiple curved waveguides provided by the present invention.

[0031] Figure 5 This is a schematic diagram showing the widths at both ends of the curved waveguide array provided by the present invention, the waveguide widths of the input portions of the multiple curved waveguides, and the waveguide widths of the output portions of the multiple curved waveguides.

[0032] Figure 6 This is a schematic diagram of the waveguide spacing between adjacent waveguides in the input, middle, and output sections of the multiple curved waveguides provided by the present invention.

[0033] Figure 7 This is an embodiment of the present invention that implements Fourier transform using a curved waveguide array;

[0034] Figure 8 This is a simulation result of a curved waveguide array performing Fourier transform on optical signals of different wavelengths, provided by the present invention.

[0035] Figure 9 This is a schematic diagram of an optical signal processing device provided by the present invention;

[0036] Figure 10 (a) is a schematic diagram of the connection between the input end of the curved waveguide array and the signal modulation module provided by the present invention;

[0037] Figure 10(b) is a schematic diagram showing the connection between the output end of the curved waveguide array provided by the present invention and the signal processing module.

[0038] Figure 11 (a) is a schematic diagram of the signal modulation module and modulation unit provided by the present invention;

[0039] Figure 11 (b) is a schematic diagram of the signal processing module and measurement unit provided by the present invention.

[0040] Explanation of reference numerals in the attached figures

[0041] Among them, 100 is a bent waveguide; 101 is the input section; 102 is the intermediate section; 103 is the output section; 200 is a bent waveguide array; 201 is the first end of the bent waveguide array; 202 is the second end of the bent waveguide array; 300 is an optical signal processing device; 301 is a signal modulation module; 302 is a signal processing module; 3011 is a modulation unit; 3021 is a measurement unit; 400 is an amplitude and phase modulation structure; 500 is a beam splitter; 600 is a reference light; and 700 is a port. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain the present invention and should not be construed as limiting the invention.

[0043] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this invention. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0044] Currently, various optical Fourier transform technologies face challenges in structural design, manufacturing processes, system losses, and cost control. For example, schemes relying on the optical properties of lenses or microlenses to complete the frequency domain transformation of signals require a large space to arrange optical components, leading to increased system size and complexity due to the large volume of optical devices. Mach-Zehnder interferometer cascade networks require precise design and manufacturing of multiple interferometer units, with high requirements for coupling and alignment between each unit, increasing design and manufacturing difficulty and cost, and also resulting in high system losses. Schemes that directly construct photonic devices with diffraction structures on optoelectronic integrated substrates to directly achieve Fourier transforms using diffraction principles suffer from low efficiency of diffraction structures, with the optical signal undergoing multiple reflections and refractions in the transition structure, leading to significant energy loss. Schemes that construct AWG units based on optoelectronic integrated substrates have extremely stringent manufacturing precision requirements; even slight deviations in the optical waveguide spacing and refractive index control within the AWG structure can lead to optical signal distortion or performance degradation.

[0045] Furthermore, all of the above solutions are highly sensitive to wavelength changes and lack robustness to broadband multi-wavelength signals. This is because the optical characteristics of optical components (such as lenses, AWGs, etc.) are usually closely related to wavelength. Changes in wavelength can cause changes in the focusing, diffraction, or interference effects of the optical signal, thereby affecting the overall performance of the system.

[0046] In view of this, a first aspect of the present invention provides a curved waveguide array 200, comprising: the curved waveguide array 200 including a plurality of spaced curved waveguides 100, each curved waveguide 100 including an input portion 101, a middle portion 102, and an output portion 103; the middle portion 102 having a curved shape; the input portions 101 of the plurality of curved waveguides 100 being located at a first end 201 of the curved waveguide array, and the output portions 103 of the plurality of curved waveguides 100 being located at a second end 200 of the curved waveguide array;

[0047] From the middle of the curved waveguide array 200 to both sides of the curved waveguide array 200, the waveguide width of the middle portion 102 of the multiple curved waveguides 100 gradually decreases, so that the effective refractive index variation law of the multiple curved waveguides 100 is consistent with the waveguide width variation law of the middle portion 102 of the multiple curved waveguides 100.

[0048] like Figure 1 The curved waveguide array 200 shown includes multiple curved waveguides 100 arranged at intervals. Each curved waveguide 100 includes an input section 101, a middle section 102, and an output section 103. Figure 1The first end 201 of the curved waveguide array shown is the left end, and the second end 200 of the curved waveguide array is the right end. Figure 1 The diagram shows a curved waveguide array 200 composed of multiple spaced curved waveguides 100. The middle portions 102 of each of the curved waveguides 100 are curved, and each waveguide has a specific and identical curvature. The curvature of the middle portions 102 of the curved waveguides 100 is not specifically limited, as long as it achieves a shape that reduces optical signal transmission loss. The curvature can be circular, elliptical, or other smooth curves that enable low-loss transmission. The transition zone between the input and middle portions is a smooth circular arc, and the transition between the middle and output portions also uses a smooth circular arc to avoid significant scattering and bending loss. The specific curvature design can be optimized based on actual application requirements, waveguide material properties, and optical signal wavelength.

[0049] In a curved waveguide array 200 consisting of five spaced curved waveguides 100, the waveguide width variation pattern of the middle portion 102 of the five curved waveguides 100 is as follows: Figure 2 As shown. The waveguide widths from left to right are w2, w1, w0, w1, and w2. The waveguide widths exhibit a symmetrical distribution, with the widest width w0 in the middle and the widths gradually decreasing on both sides (w1>w2). In the SOI (Silicon on Insulator) photonic integrated circuit platform, the waveguide width along the direction of change approximately satisfies the following formula (2):

[0050] W = -kw × P 2 +bw (2)

[0051] Where W is the waveguide width of the middle part (102) of the curved waveguide (100) to be calculated;

[0052] P is the distance between the middle part (102) of the curved waveguide (100) to be calculated and the middle part (102) of the curved waveguide (100) at the middle position;

[0053] kw is the waveguide width variation coefficient, and 0 < kw < 1;

[0054] bw is the waveguide width compensation coefficient, and 500 < bw < 600.

[0055] As an optional implementation, when the waveguide width variation coefficient kw = 0.5926 and the waveguide width compensation coefficient bw = 540 in the above formula (2), the waveguide width variation trend of the middle portion 102 of the multiple curved waveguides 100 is as follows: Figure 3As shown, the horizontal axis "Position" represents distance information in μm; specifically, the distance information is the distance between the middle portion 102 of the curved waveguide 100 to be calculated and the middle portion 102 of the curved waveguide 100 at the middle position, with a distance range of -15 to 15 μm; the vertical axis "width" represents the waveguide width in nm; the waveguide width of the middle portion 102 of the curved waveguide 100 to be calculated is between 380 and 540 nm. Specifically, the waveguide width of the middle portions 102 of the multiple curved waveguides 100 gradually decreases from the center waveguide towards both sides. The waveguide width of the middle portion 102 of the curved waveguide 100 located at the center position (i.e., Position = 0 μm) of the multiple curved waveguides 100 is the largest, approximately 540 nm. As the distance between the curved waveguide 100 to be calculated and the curved waveguide 100 at the middle position gradually increases, the waveguide width of the middle portion 102 of the curved waveguide 100 to be calculated gradually decreases, with a minimum value of approximately 380 nm. The waveguide widths of the middle portions 102 of the curved waveguides 100 on both sides of the curved waveguide 100 at the center position are symmetrically distributed.

[0056] The change in waveguide width of the middle portion 102 of the multiple curved waveguides 100 affects the optical field distribution in the waveguide, and thus directly affects the effective refractive index of the waveguide. For Figure 3 The effective refractive index of the waveguides corresponding to the changing trend of the waveguide width of the middle portion 102 of the multiple curved waveguides 100 shown still satisfies formula (1). It should be specifically noted that in the SOI (Silicon on Insulator) photonic integrated circuit platform, the effective refractive index variation coefficient ranges from 0 to kn, and the effective refractive index compensation coefficient ranges from 1 to bn, which is 3. As an optional implementation, with... Figure 3 In the corresponding formula (1), the effective refractive index variation coefficient kn = 0.001422 and the effective refractive index compensation coefficient bn = 2.5. The effective refractive index variation trend of the 100-degree curved waveguide is as follows: Figure 4As shown, the effective refractive index of the waveguide follows a quadratic distribution function along the direction of waveguide width variation. The horizontal axis, Position, represents distance information in μm. This distance is the distance between the middle portion 102 of the curved waveguide 100 to be calculated and the middle portion 102 of the curved waveguide 100 at the middle position, ranging from -15 to 15 μm. The vertical axis, n, represents the effective refractive index, which is between 2.1 and 2.6. Specifically, the middle portion 102 of the curved waveguide 100 at the center position (i.e., Position = 0 μm) of the multiple curved waveguides 100 has the highest effective refractive index, approximately 2.5. As the distance between the curved waveguide 100 to be calculated and the middle portion of the curved waveguide 100 gradually increases, the effective refractive index of the curved waveguide 100 to be calculated gradually decreases, reaching a minimum of approximately 2.18. The effective refractive index of the middle portions 102 of the curved waveguides 100 on both sides of the center curved waveguide 100 exhibits a symmetrical distribution.

[0057] For the overall structure of the curved waveguide array 200, the waveguide width of the middle portion 102 of the multiple curved waveguides 100 gradually decreases from the middle to both sides, while the two ends of the curved waveguide array 200 have the same width value. As an optional implementation, such as... Figure 5The curved waveguide array 200 shown has a width of wleft at the first end 201 and a width of wright at the second end 202. The widths of the first end 201 and the second end 202 of the curved waveguide array are the same, i.e., wleft = wright. The five curved waveguides 100 are named wl1, wl2, wl3, wl4, and wl5 at the first end 201 and wr1, wr2, wr3, wr4, and wr5 at the second end 202. The waveguide widths of the five curved waveguides 100 at the first end 201 and the second end 202 are the same, which is wd. The value of wd is in the range of 380 ≤ wd ≤ 540 nm. It should be noted that the value of wd depends on the technology used. For example, in silicon photonics, the waveguide width wd of the multiple curved waveguides 100 at the first end 201 and the second end 202 of the curved waveguide array is the standard waveguide width of silicon photonics, wd = 450 nm. Therefore, the input portion 101 of the multiple curved waveguides 100 has a fixed waveguide width at the first end 201 of the curved waveguide array, gradually transitioning to a gradient waveguide width in the middle portion 102 of the multiple curved waveguides 100. Specifically, the gradient waveguide width is widest in the middle, gradually decreasing on both sides, and finally transitioning again to a fixed width at the second end 202 of the multiple curved waveguides 100, where the waveguide width at the second end 202 is the same as the waveguide width at the first end 201 of the curved waveguide array. As the waveguide widths of the multiple curved waveguides 100 change, the effective refractive index of the waveguides follows a law consistent with the change in waveguide width along the propagation direction. Specifically, when the waveguide width of the middle portion 102 of the multiple curved waveguides 100 gradually decreases from the center to both sides, the effective refractive index of the waveguide exhibits a quadratic function distribution. The change in the effective refractive index of the waveguide directly affects the propagation path and phase of the optical signal. By guiding the optical signal to propagate along a predetermined path in the waveguide, beam focusing can be achieved. When the waveguide length of the middle portion 102 of the multiple curved waveguides 100 is the same as the focal length of the equivalent lens, optical Fourier transform is achieved.

[0058] The waveguide widths of the input portions 101, intermediate portions 102, and output portions 103 of the multiple curved waveguides 100 exhibit the variation trend described above. The waveguide spacing between adjacent input portions 101, intermediate portions 102, and output portions 103 of the curved waveguides 100 is set according to the corresponding waveguide spacing. As an optional embodiment, the input portions 101 of the multiple curved waveguides 100 are not equally spaced; the output portions 103 of the multiple curved waveguides 100 are not equally spaced; and the intermediate portions 102 of the multiple curved waveguides 100 are equally spaced. Specifically, the spacing is as follows:

[0059] From the middle of the curved waveguide array 200 to both sides of the curved waveguide array 200, the spacing between the input portions 101 of each pair of adjacent curved waveguides 100 gradually increases, and the spacing between the output portions 103 of each pair of adjacent curved waveguides 100 also gradually increases.

[0060] The gradually increasing waveguide spacing in the input section 101 facilitates the input of multiple discrete optical signals and reduces interference between optical signals; the gradually increasing waveguide spacing in the output section 103 helps to reduce interference between transmitted optical signals.

[0061] Figure 6 The waveguide spacing between each pair of adjacent curved waveguides 100, including their input portions 101, intermediate portions 102, and output portions 103, is described in detail. Specifically, the spacing between the intermediate portions 102 of each pair of adjacent curved waveguides 100 is a fixed waveguide spacing d0; the spacing between the input portions 101 of each pair of adjacent curved waveguides 100 gradually increases, specifically from the middle of the curved waveguide array 200 to both sides, the spacing between the input portions 101 of each pair of adjacent curved waveguides 100 increases from d1 to d2; the spacing between the output portions 103 of each pair of adjacent curved waveguides 100 also gradually increases, specifically from the middle of the curved waveguide array 200 to both sides, the spacing between the output portions 103 of each pair of adjacent curved waveguides 100 increases from d1 to d2.

[0062] Because the spacing between any two adjacent members of the multiple curved waveguides 100 gradually increases from the middle towards both sides of the curved waveguide 100, the spacing between adjacent waveguides in the middle portion 102 of the curved waveguide 100 is a fixed value d0. Combined with... Figure 6 It can be known that:

[0063] The spacing between the input portions 101 of two adjacent curved waveguides 100 is greater than or equal to the spacing between the middle portions 102 of two adjacent curved waveguides 100.

[0064] The interval between the output portions 103 of two adjacent curved waveguides 100 is greater than or equal to the interval between the middle portions 102 of two adjacent curved waveguides 100.

[0065] The gradually increasing waveguide spacing between the input portion 101 and the output portion 103 of the multiple curved waveguides 100 improves the optical coupling efficiency, and the method of setting equal waveguide spacing in the middle wave portion for tight coupling improves the discrete diffraction effect of multiple optical signals.

[0066] Example:

[0067] The specific structure and implementation process of realizing Fourier transform using the curved waveguide array 200 proposed in this invention are as follows: Figure 7 As shown.

[0068] The input light is split into multiple signals by the beam splitter 500. Due to manufacturing errors in the beam splitter 500 and other components, the signals may be split into multiple signals with inconsistent amplitudes and phases. These multiple optical signals are first modulated by the amplitude and phase modulation structure 400 to convert the inconsistent signals into signals with the required Fourier transform amplitude and consistent phase. The modulated optical signals are then input to the curved waveguide array 200. Each curved waveguide 100's input portion 101 receives a modulated optical signal and transmits it to the intermediate portions 102 of the multiple curved waveguides 100. The curved shape of the intermediate portions 102, the fixed waveguide spacing, and the aforementioned... Figure 3 The waveguide width of the transformed waveguides is such that the optical signals couple with each other and undergo discrete diffraction during propagation. Since the effective refractive index of the multiple curved waveguides 100 exhibits a consistent trend with the waveguide width of the middle section 102 (gradually decreasing from the center to both sides), it directly affects the propagation path and phase of the optical signal, especially the phase, as shown above. Figure 3 The quadratic function distribution trend shown is used to focus the light beam, making the multiple curved waveguides 100 equivalent to a wave lens. When the waveguide length of the middle part 102 of the multiple curved waveguides 100 is the same as the focal length of the equivalent lens, an optical Fourier transform is achieved. When the Fourier-transformed optical signal passes through the output part 103 of the multiple curved waveguides 100, the amplitude and phase information after Fourier transform are obtained at port 700 by means of coherent detection (interference between the reference light 600 and the light output from the output part 103 of the curved waveguide 100). The number of ports 700 corresponds to the number of multiple curved waveguides 100, and each port 700 receives the Fourier-transformed optical signal transmitted by the output part 103 of the corresponding curved waveguide 100. Figure 7Five Fourier transforms can be obtained from the given five ports 700. It should be noted again that the waveguide lengths of the middle portions 102 of the multiple curved waveguides 100 are the same. In this embodiment of the invention, the specific value of N is not specifically limited; for example, N can be 5, 16, or 30. The type of beam splitter 500 is also not specifically limited, as long as it can uniformly split the incident beam into multiple beams. For example, it can be a multi-faceted beam splitter 500, a diffractive optical element, a microlens array, an optical fiber beam splitter 500, etc.

[0069] In this embodiment, performing relevant operations on the middle portions 102 of the multiple curved waveguides 100 can not only change the focal length or other optical parameters of their equivalent lenses, but also endow the curved waveguide array 200 with adjustment capabilities, enabling it to reconfigure the lens function. This allows for not only calibration but also the design of multifunctional optical lenses. The operation of the middle portions 102 of the multiple curved waveguides 100 can be achieved by adding hot metal (phase modulator) above the waveguide, adjusting the effective refractive index of the waveguide using the thermo-optic effect, injecting charge carriers to change the effective refractive index distribution of the waveguide, or using a waveguide array made of materials with electro-optic effects to achieve dynamic adjustment.

[0070] The simulation results of Fourier transform of optical signals of different wavelengths using the curved waveguide array 200 described in this invention are as follows: Figure 8 . Figure 8 The input wavelengths corresponding to (a)-(f) are 1.4μm, 1.5μm, 1.525μm, 1.575μm, 1.6μm, and 1.714μm, respectively. The horizontal and vertical axes represent the position coordinates of the curved waveguide array in the horizontal and vertical directions, respectively. Figure 8 Simulation results show that light of different wavelengths can converge to a single point after passing through the curved waveguide array 200 proposed in this invention. This experimental result demonstrates that the curved waveguide array 200 can effectively function as a lens, achieving the convergence of incident light. It features Fourier transform functionality supporting multiple wavelengths (1400-1700nm) and wavelength division multiplexing functionality with bandwidths exceeding 200nm.

[0071] The curved waveguide array 200 described in this invention has a simple structure design and is easy to integrate into a system-on-a-chip. Its low-complexity design significantly reduces manufacturing costs and process difficulty. Experimental results show that this structure performs well in the 1400-1700nm wavelength range, is insensitive to wavelength changes, has multi-wavelength Fourier transform capabilities, high-bandwidth wavelength division multiplexing capabilities exceeding 200nm, and higher optical signal transmission efficiency.

[0072] As a second aspect of the present invention, an optical signal processing apparatus 300 is provided, such as... Figure 9As shown. The optical signal processing device 300 includes the curved waveguide array 200, signal modulation module 301, and signal processing module 302 described in the first aspect of the present invention. The input terminal of the curved waveguide array 200 is connected to the signal modulation module 301, and the output terminal of the curved waveguide array 200 is connected to the signal processing module 302. The signal modulation module 301 and the signal processing module 302 store unique identification information for each curved waveguide 100 of the curved waveguide array 200, used to identify and distinguish optical signals corresponding to different waveguides. Figure 10 As shown in (a), the first end 201 of the curved waveguide array is the input end of the curved waveguide array 200, and the signal modulation module 301 is connected to the input end of the curved waveguide array 200; as Figure 10 As shown in (b), the second end 200 of the curved waveguide array is the output end of the curved waveguide array 200, which is connected to the signal processing module 302. The signal modulation module 301 includes a modulation unit 3011 for modulating the amplitude and phase of the input optical signal, such as... Figure 11 As shown in (a); the signal processing module 302 includes a measurement unit 3021 for measuring the amplitude and phase information of the optical signal transmitted through the curved waveguide array 200, as follows: Figure 11 As shown in (b). The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A curved waveguide array (200), characterized in that, The curved waveguide array (200) includes multiple spaced curved waveguides (100), each curved waveguide (100) including an input section (101), a middle section (102), and an output section (103); the middle section (102) is curved; the input sections (101) of the multiple curved waveguides (100) are located at the first end (201) of the curved waveguide array, and the output sections (103) of the multiple curved waveguides (100) are located at the second end (202) of the curved waveguide array; From the middle of the curved waveguide array (200) to both sides of the curved waveguide array (200), the waveguide width of the middle portion (102) of the multiple curved waveguides (100) gradually decreases, so that the effective refractive index variation law of the multiple curved waveguides (100) is consistent with the waveguide width variation law of the middle portion (102) of the multiple curved waveguides (100); wherein, the effective refractive index of the curved waveguide array (200) satisfies the following formula (1): N=-kn×P 2 +bn (1) Where N is the effective refractive index of the bent waveguide (100) to be calculated; P is the distance between the middle part (102) of the curved waveguide (100) to be calculated and the middle part (102) of the curved waveguide (100) at the middle position; kn is the effective refractive index variation coefficient, and 0 < kn < 1; bn is the effective refractive index compensation coefficient, and 1 < bn < 3.

2. The curved waveguide array (200) according to claim 1, characterized in that, From the middle of the curved waveguide array (200) to both sides of the curved waveguide array (200), the waveguide width of the middle portion (102) of the curved waveguide (100) at the middle position is greater than the waveguide width of the middle portion (102) of the curved waveguides (100) on both sides; the waveguide width of the middle portion (102) of the curved waveguide (100) on both sides is the same as that of the middle portion (102) of the curved waveguide (100) at the middle position.

3. The curved waveguide array (200) according to claim 1, characterized in that, The first end (201) and the second end (202) of the curved waveguide array have the same width, and the waveguide width is in the range of 380 to 540 nm.

4. The curved waveguide array (200) according to claim 1, characterized in that, The input portions (101) of the multiple curved waveguides (100) are not equally spaced; The output sections (103) of the multiple curved waveguides (100) are arranged at non-equal intervals; The middle portions (102) of the multiple curved waveguides (100) are arranged at equal intervals.

5. The curved waveguide array (200) according to claim 4, characterized in that, From the middle of the curved waveguide array (200) to both sides of the curved waveguide array (200), the spacing between the input portions (101) of each pair of adjacent curved waveguides (100) gradually increases, and the spacing between the output portions (103) of each pair of adjacent curved waveguides (100) also gradually increases.

6. The curved waveguide array (200) according to claim 5, characterized in that, The spacing between the input portions (101) of two adjacent curved waveguides (100) is greater than or equal to the spacing between the middle portions (102) of two adjacent curved waveguides (100).

7. The curved waveguide array (200) according to claim 5, characterized in that, The spacing between the output portions (103) of two adjacent curved waveguides (100) is greater than or equal to the spacing between the middle portions (102) of two adjacent curved waveguides (100).

8. An optical signal processing device (300), characterized in that, The optical signal processing device (300) includes a curved waveguide array (200) as described in any one of claims 1 to 7, a signal modulation module (301), and a signal processing module (302); the input end of the curved waveguide array (200) is connected to the signal modulation module (301), and the output end of the curved waveguide array (200) is connected to the signal processing module (302); the signal modulation module (301) and the signal processing module (302) store unique number information for each curved waveguide (100) of the curved waveguide array (200) for identifying and distinguishing optical signals corresponding to different waveguides.

9. The optical signal processing apparatus (300) according to claim 8, characterized in that, The signal modulation module (301) includes a modulation unit (3011) for modulating the amplitude and phase of the input optical signal, and the signal processing module (302) includes a measurement unit (3021) for measuring the amplitude and phase information of the optical signal after transmission through the curved waveguide array (200).

Images