Bent waveguide array and optical signal processing device

Abstract

The invention discloses a bent waveguide array, and relates to the technical field of optics, the bent waveguide array comprises a plurality of bent waveguides arranged at intervals, and each bent waveguide comprises an input part, a middle part and an output part; the middle part is in a bent shape; the input parts of the plurality of bent waveguides are located at the first end of the bent waveguide array, and the output parts of the plurality of bent waveguides are located at the second end of the bent waveguide array; the waveguide widths of the middle parts of the plurality of bent waveguides are gradually reduced from the middle of the bent waveguide array to the two sides of the bent waveguide array, so that the refractive index change rule of the plurality of bent waveguides is consistent with the width change rule of the middle parts of the plurality of bent waveguides. The bent waveguide array provided by the invention has the advantages of being simple in structure, high in integration level and capable of supporting Fourier transform in a wide wavelength range.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a curved waveguide array and an optical signal processing device. Background Art

[0002] Fourier transform is a mathematical tool that can convert a signal from the time domain (time domain) to the frequency domain (frequency domain), or from the space domain (spatial domain) to the frequency domain. In the field of optics, the spectrum analysis of optical signals can be achieved by using Fourier transform.

[0003] At present, there are many technical solutions for realizing Fourier transform by optical means, such as relying on the optical properties of lenses or microlenses to complete the frequency domain transformation of signals; using a cascade network of Mach-Zehnder interferometers to realize Fourier transform by constructing a specific network structure; or directly constructing some photonic devices with diffraction structures on the integrated substrate of optoelectronic devices to directly realize Fourier transform by using the diffraction principle; or constructing an AWG unit (Arrayed Waveguide Grating) on ​​the integrated substrate of optoelectronic devices, and using the optical path difference modulation of the waveguide in the AWG unit to obtain optical signals with different frequency components at different positions of the output end, achieving an effect similar to Fourier transform.

[0004] However, the above-mentioned optical methods for realizing Fourier transform have many disadvantages. The solution that relies on lenses or microlenses has the problem of large optical device volume, increased system size and complexity; the solution of Mach-Zehnder interferometer cascade network has a complex network structure, which not only has high design and manufacturing costs, but also large system losses; the solution of constructing diffraction structure photonic devices on optoelectronic device integrated substrates has large optical signal losses and high process difficulty; the solution of constructing AWG units based on optoelectronic device integrated substrates has strict requirements on manufacturing precision and poor multi-wavelength signal robustness.

[0005] The invention proposes a method for realizing Fourier transform by using a curved waveguide array. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a curved waveguide array and an optical signal processing device, which have the advantages of simple structure, high integration, and support for Fourier transform in a wide wavelength range.

[0007] In order to achieve the above object, as a first aspect of the present invention, a curved waveguide array is provided, wherein the curved waveguide array comprises a plurality of curved waveguides arranged at intervals, the curved waveguides comprising an input portion, a middle portion, and an output portion; the middle portion is in a curved shape; 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 of the curved waveguide array, the waveguide width of the middle part of the plurality of curved waveguides gradually decreases, so that the refractive index variation law of the plurality of curved waveguides is consistent with the waveguide width variation law of the middle part of the plurality of curved waveguides.

[0009] Optionally, the refractive index of the curved waveguide array satisfies the following formula (1):

[0010] N=-kn×P 2 +bn (1)

[0011] Wherein, N is the refractive index of the curved waveguide to be calculated;

[0012] P is the distance between the middle portion of the curved waveguide to be calculated and the middle portion of the curved waveguide at the middle position;

[0013] kn is the refractive index variation coefficient, and 0<kn<1;

[0014] bn is a refractive index compensation coefficient, and 1<bn<3.

[0015] Optionally, from the middle of the curved waveguide array to the two sides of the curved waveguide array, the waveguide width of the middle part of the curved waveguide at the middle position is greater than the waveguide width of the middle parts of the curved waveguides on both sides; the waveguide widths of the middle parts of the curved waveguides on both sides equidistant from the middle part of the curved waveguide at the middle position are the same.

[0016] Optionally, the first end and the second end of the curved waveguide array have the same width, and the waveguide width is in the range of 380 to 540 nm.

[0017] Optionally, the input parts of the plurality of curved waveguides are arranged at unequal intervals; the output parts of the plurality of curved waveguides are arranged at unequal intervals; and the middle parts of the plurality of curved waveguides are arranged at equal intervals.

[0018] Optionally, the input parts of the plurality of curved waveguides are arranged at unequal intervals; and the output parts of the plurality of curved waveguides are arranged at unequal intervals, comprising:

[0019] From the middle of the curved waveguide array to both sides of the curved waveguide array, the intervals between the input parts of the two adjacent curved waveguides gradually increase, and the intervals between the output parts of the two adjacent curved waveguides gradually increase.

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

[0021] Optionally, the interval between the output portions of any two adjacent curved waveguides is greater than or equal to the interval between the middle portions of any two adjacent curved waveguides.

[0022] As a second aspect of the present invention, an optical signal processing device is provided, wherein the optical signal processing device comprises the curved waveguide array, a signal modulation module, and a signal processing module according to the first aspect of the present invention; an input end of the curved waveguide array is connected to the signal modulation module, an 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 number information of each curved waveguide of the curved waveguide array for identifying and distinguishing optical signals corresponding to different waveguides.

[0023] 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 being transmitted through the curved waveguide array.

[0024] The curved waveguide array of the present invention realizes the Fourier transform of the optical signal by designing waveguide spacing and waveguide width with different changing trends for the input part, middle part, and output part of the plurality of curved waveguides. From the middle of the curved waveguide array to the two sides of the curved waveguide array, the spacing between the input parts of the two adjacent curved waveguides gradually increases. This design facilitates the input of multiple discrete optical signals and reduces the interference between optical signals. When the optical signal is transmitted from the input part of the curved waveguide to the middle part of the curved waveguide, the waveguide spacing between the two adjacent curved waveguides in the middle part is much smaller than the waveguide spacing of the input part, and the waveguide width of the middle part of the plurality of curved waveguides satisfies the distribution trend of gradually decreasing from the center waveguide to the two sides. This close coupling and gradual increase from the center waveguide to the two sides is conducive to the Fourier transform of the optical signal. The design of gradually decreasing waveguide width changes the light field distribution: when the waveguide width is wider, the light field distribution is wider, and the energy is more distributed in the core area of ​​the waveguide; when the waveguide width is narrower, the light field will be compressed, and the energy will be more extended to the cladding or external area of ​​the waveguide; this change in light field distribution directly affects the effective refractive index of the waveguide: when the waveguide width increases, more light field energy is concentrated in the core area of ​​the waveguide with a high refractive index, resulting in an increase in the effective refractive index; conversely, when the waveguide width decreases, the light field energy is more extended to the cladding area with a low refractive index, resulting in a decrease in the effective refractive index. Therefore, the waveguide width of the middle part of the plurality of curved waveguides gradually decreases from the center to the two sides, so that the effective refractive index of the waveguide also satisfies the quadratic function distribution in the propagation direction, thereby directly affecting the propagation path and phase of the optical signal. By guiding the optical signal to propagate along a predetermined path in the waveguide, the focusing of the light beam can be achieved; when the waveguide length of the middle part reaches the focal length of the equivalent lens, the Fourier transform is completed; when the light passes through the output part of the plurality of curved waveguides, the waveguide spacing of the output part gradually increases from the middle of the curved waveguide array to the two sides of the curved waveguide array, which helps to reduce the interference between the optical signals after the Fourier transform. Finally, the optical signal processing device connected to the output end of the curved waveguide array is used to identify and distinguish the optical signals transmitted by the curved waveguides with different numbers, and obtain the amplitude and phase information after the Fourier transform.

[0025] The curved waveguide array described in the present invention not only solves the problems of large optical device size, complex system, high design and manufacturing cost, difficult process and demanding manufacturing precision in realizing Fourier transform by other optical methods, but also has the characteristics and advantages of simple structure, high integration and high bandwidth.

[0026] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings:

[0028] Figure 1 is a structural diagram of a curved waveguide array provided by the present invention;

[0029] Figure 2 is a schematic diagram of the waveguide width of the middle portion of a plurality of the curved waveguides provided by the present invention;

[0030] Figure 3 is a variation trend diagram of the waveguide width of the middle portion of the plurality of curved waveguides provided by the present invention;

[0031] Figure 4 is a variation trend diagram of the waveguide refractive index of the plurality of curved waveguides provided by the present invention;

[0032] Figure 5 It is a schematic diagram of the width of the two ends of the curved waveguide array provided by the present invention, the waveguide width of the input part of the plurality of curved waveguides, and the waveguide width of the output part of the plurality of curved waveguides;

[0033] Figure 6 It is a schematic diagram of waveguide spacing of adjacent waveguides at the input part, the middle part, and the output part of a plurality of the curved waveguides provided by the present invention;

[0034] Figure 7 This is an embodiment of the invention providing a curved waveguide array for implementing Fourier transform;

[0035] Figure 8 It is a simulation result of Fourier transform of optical signals of different wavelengths by a curved waveguide array provided by the present invention;

[0036] Fig. 9 It is a schematic diagram of an optical signal processing device provided by the present invention;

[0037] Fig.10 (a) is a schematic diagram of the connection between the input end of the curved waveguide array provided by the present invention and the signal modulation module;

[0038] Fig.10(b) is a schematic diagram of the connection between the output end of the curved waveguide array provided by the present invention and the signal processing module;

[0039] Fig.11 (a) is a schematic diagram of a signal modulation module and a modulation unit provided by the present invention;

[0040] Fig.11 (b) is a schematic diagram of the signal processing module and the measurement unit provided by the present invention.

[0041] Description of Reference Numerals

[0042] Among them, 100, curved waveguide; 101, input part; 102, middle part; 103, output part; 200, curved waveguide array; 201, first end of the curved waveguide array; 202, second end of the curved waveguide array; 300, optical signal processing device; 301, signal modulation module; 302, signal processing module; 3011, modulation unit; 3021, measurement unit; 400, amplitude and phase modulation structure; 500, beam splitter; 600, reference light; 700, port. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

[0044] References to "one embodiment" or "example" or "example" in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment disclosed herein. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0045] At present, various optical Fourier transform technology solutions face challenges in terms of structural design, manufacturing process, system loss, and cost control. For example, the solution that relies on the optical properties of lenses or microlenses to complete the frequency domain transformation of signals requires a large space to arrange optical components, and there are problems such as the large size of optical devices, increased system size and complexity; the Mach-Zehnder interferometer cascade network requires precise design and manufacture of multiple interferometer units, and the coupling and alignment requirements between each unit are high, which increases the difficulty and cost of design and manufacturing, and also leads to higher system losses; the solution of directly building some photonic devices with diffraction structures on the integrated substrate of optoelectronic devices and directly realizing Fourier transform using the diffraction principle has the problem that the efficiency of the diffraction structure is low, and the optical signal will experience multiple reflections and refractions in the transition structure, resulting in large optical energy loss; the solution of building AWG units based on the integrated substrate of optoelectronic devices has extremely stringent requirements on manufacturing accuracy, and a slight deviation in the control of the optical waveguide spacing and refractive index in the AWG structure may cause optical signal distortion or performance degradation.

[0046] In addition, the above solutions are all highly sensitive to wavelength changes and have poor robustness for broadband multi-wavelength signals. This is because the optical properties 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 optical signals, thereby affecting the overall performance of the system.

[0047] In view of this, a first aspect of the present invention provides a curved waveguide array 200, comprising: the curved waveguide array 200 comprises a plurality of curved waveguides 100 arranged at intervals, the curved waveguide 100 comprises an input portion 101, a middle portion 102, and an output portion 103; the middle portion 102 is in a curved shape; the input portions 101 of the plurality of curved waveguides 100 are located at a first end 201 of the curved waveguide array, and the output portions 103 of the plurality of curved waveguides 100 are located at a second end 200 of the curved waveguide array;

[0048] 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 plurality of curved waveguides 100 gradually decreases, so that the refractive index variation law of the plurality of curved waveguides 100 is consistent with the waveguide width variation law of the middle portion 102 of the plurality of curved waveguides 100.

[0049] like Figure 1 The curved waveguide array 200 shown includes a plurality of curved waveguides 100 arranged at intervals. The curved waveguide 100 includes an input portion 101 , a middle portion 102 of the curved waveguide 100 , and an output portion 103 of the curved waveguide 100 . Figure 1The first end 201 of the curved waveguide array is shown as the left end, and the second end 200 of the curved waveguide array is shown as the right end. Figure 1 The curved waveguide array 200 shown is composed of multiple curved waveguides 100 arranged at intervals, and the middle parts 102 of the multiple curved waveguides 100 are all curved, and each waveguide has a certain curvature and the curvature is the same. Among them, there is no special limitation on the curvature of the middle part 102 of the curved waveguide 100, as long as it can reduce the arc shape of the optical signal transmission loss. The curvature can be a circular curvature, an elliptical curvature, or other smooth curve shapes that can achieve low-loss transmission. The transition zone between the input part and the middle part is a smooth arc shape, and the middle part and the output part also transition with a smooth arc to avoid large scattering and bending losses. The specific curvature design can be optimized and selected according to factors such as actual application requirements, waveguide material properties, and optical signal wavelength.

[0050] In a curved waveguide array 200 including five curved waveguides 100 arranged at intervals, the variation rule of the waveguide widths of the middle portions 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, w2. The waveguide widths are symmetrically distributed, with the waveguide width w0 in the middle being the widest, and the waveguide widths on both sides gradually decreasing (w1>w2). On the SOI (Silicon on Insulator) photonic integrated circuit platform, the waveguide width along the direction of waveguide width change approximately satisfies the following formula (2):

[0051] W=-kw×P 2 +bw (2)

[0052] Wherein, W is the waveguide width of the middle portion (102) of the curved waveguide (100) to be calculated;

[0053] P 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;

[0054] kw is the waveguide width variation coefficient, and 0<kw<1;

[0055] bw is the waveguide width compensation coefficient, and 500<bw<600.

[0056] 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 plurality of curved waveguides 100 is as follows: Figure 3As shown, the horizontal axis Position represents distance information, in μm; wherein 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, and the distance range is -15-15 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 380-540 nm. Specifically, the waveguide width of the middle portion 102 of the plurality of curved waveguides 100 starts from the central waveguide and gradually decreases toward 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 plurality of curved waveguides 100 is the largest, which is about 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, and the minimum value is about 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.

[0057] The change in the waveguide width of the middle portion 102 of the plurality of curved waveguides 100 affects the light field distribution in the waveguide, and further directly affects the effective refractive index of the waveguide. Figure 3 The waveguide refractive index corresponding to the variation trend of the waveguide width of the middle portion 102 of the plurality of curved waveguides 100 shown still satisfies formula (1). It should be noted that in SOI (Silicon on Insulator) photonic integrated circuit platform, the range of the refractive index variation coefficient is 0<kn<1, and the range of the refractive index compensation coefficient is 1<bn<3. As an optional implementation, Figure 3 In the corresponding formula (1), the refractive index variation coefficient kn=0.001422 and the refractive index compensation coefficient bn=2.5. The refractive index variation trend of the curved waveguide 100 is as follows: Figure 4As shown, the waveguide refractive index presents a quadratic distribution function in the direction of waveguide width change, and the horizontal axis Position represents distance information, in μm; wherein 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, and the distance range is -15-15 μm; the vertical axis n represents the refractive index, and the refractive index of the curved waveguide 100 to be calculated is between 2.1-2.6. Specifically, the refractive index of the middle portion 102 of the curved waveguide 100 at the center position (i.e., Position = 0 μm) of the plurality of curved waveguides 100 is the largest, which is about 2.5; as the distance between the curved waveguide 100 to be calculated and the curved waveguide 100 at the middle position gradually increases, the refractive index of the curved waveguide 100 to be calculated gradually decreases, and the minimum value is about 2.18, and the waveguide refractive index of the middle portion 102 of the curved waveguide 100 on both sides of the curved waveguide 100 at the center position is symmetrically distributed.

[0058] For the structure of the entire curved waveguide array 200, the waveguide width of the middle portion 102 of the plurality of curved waveguides 100 gradually decreases from the middle to both sides, and the two ends of the curved waveguide array 200 have the same width value. As an optional implementation, Figure 5In the curved waveguide array 200 shown, the width of the first end 201 of the curved waveguide array is wleft, the width of the second end 202 of the curved waveguide array is wright, and the widths of the first end 201 of the curved waveguide array and the second end 202 of the curved waveguide array are the same, that is, wleft=wright; the waveguide widths of the five curved waveguides 100 at the first end 201 of the curved waveguide array are wl1, wl2, wl3, wl4, and wl5, respectively, and the waveguide widths of the five curved waveguides 100 at the first end 201 of the curved waveguide array and the second end 202 of the curved waveguide array are the same, both being wd, and the value range of wd is 380≤wd≤540nm. It should be noted that the value of wd depends on the technology used. For example, in silicon photonics technology, the waveguide width wd of the plurality of curved waveguides 100 at the first end 201 of the curved waveguide array and the second end 202 of the curved waveguide array is the standard waveguide width of silicon photonics, wd=450nm. It can be seen that the input portion 101 of the plurality of curved waveguides 100 is a fixed waveguide width at the first end 201 of the curved waveguide array, and gradually transitions to a gradually changing waveguide width in the middle portion 102 of the plurality of curved waveguides 100, and the gradually changing waveguide width is specifically manifested as the widest waveguide width in the middle, the waveguide widths on both sides gradually decrease, and finally transitions to a fixed width at the second end 202 of the curved waveguide array again in the output portion 103 of the plurality of curved waveguides 100, and the waveguide width at the second end 202 of the curved waveguide array is the same as the waveguide width at the first end 201 of the curved waveguide array. As the waveguide width of the plurality of curved waveguides 100 changes, the effective refractive index of the waveguide satisfies the same rule as the change of the waveguide width in the propagation direction. Specifically, when the waveguide width of the middle portion 102 of the plurality of curved waveguides 100 gradually decreases from the middle to both sides, the refractive index of the waveguide presents a quadratic function distribution. The change of the 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, the focusing of the light beam can be achieved; when the waveguide length of the middle portion 102 of the plurality of curved waveguides 100 is the same as the focal length of the equivalent lens, the optical Fourier transform is achieved.

[0059] The waveguide widths of the input parts 101, the middle parts 102, and the output parts 103 of the plurality of curved waveguides 100 show the variation trend described above, and the waveguide intervals of the input parts 101, the middle parts 102, and the output parts 103 of the two adjacent curved waveguides 100 are arranged according to the corresponding waveguide intervals. As an optional embodiment, the input parts 101 of the plurality of curved waveguides 100 are arranged at non-equal intervals; the output parts 103 of the plurality of curved waveguides 100 are arranged at non-equal intervals; and the middle parts 102 of the plurality of curved waveguides 100 are arranged at equal intervals, and the above interval arrangement is specifically manifested as follows:

[0060] From the middle of the curved waveguide array 200 to both sides of the curved waveguide array 200 , the intervals between the input parts 101 of the two adjacent curved waveguides 100 gradually increase, and the intervals between the output parts 103 of the two adjacent curved waveguides 100 gradually increase.

[0061] The gradually increasing waveguide spacing of the input part 101 facilitates the input of multiple discrete optical signals and reduces the interference between the optical signals; the gradually increasing waveguide spacing of the output part 103 helps to reduce the interference between the transmitted optical signals.

[0062] Figure 6 The waveguide intervals between the input parts 101, the middle parts 102, and the output parts 103 of the plurality of curved waveguides 100 are described in detail. The intervals between the middle parts 102 of the curved waveguides 100 adjacent to each other are a fixed waveguide interval d0; the intervals between the input parts 101 of the curved waveguides 100 adjacent to each other gradually increase, specifically, from the middle of the curved waveguide array 200 to the two sides of the curved waveguide array 200, the intervals between the input parts 101 of the curved waveguides 100 adjacent to each other increase from d1 to d2; the intervals between the output parts 103 of the curved waveguides 100 adjacent to each other gradually increase, specifically, from the middle of the curved waveguide array 200 to the two sides of the curved waveguide array 200, the intervals between the output parts 103 of the curved waveguides 100 adjacent to each other increase from d1 to d2.

[0063] Since the intervals between two adjacent ones of the plurality of curved waveguides 100 gradually increase from the middle to both sides of the curved waveguide 100, the intervals between adjacent waveguides in the middle portion 102 of the curved waveguide 100 are fixed at d0. Figure 6 It can be seen that:

[0064] The interval between the input parts 101 of the two adjacent curved waveguides 100 is greater than or equal to the interval between the middle parts 102 of the two adjacent curved waveguides 100;

[0065] The interval between the output portions 103 of the curved waveguides 100 adjacent to each other is greater than or equal to the interval between the middle portions 102 of the curved waveguides 100 adjacent to each other.

[0066] The gradually increasing waveguide spacing between the input part 101 and the output part 103 of the plurality of curved waveguides 100 improves the light coupling efficiency, and the closely coupled manner of setting equal waveguide spacing in the intermediate wave part improves the discrete diffraction effect of multiple optical signals.

[0067] Example:

[0068] The specific structure and implementation process of Fourier transform using the curved waveguide array 200 proposed by the present invention are as follows: Figure 7 shown.

[0069] After passing through the beam splitter 500, the input light is equally divided into a plurality of signals. Due to manufacturing errors of components such as the beam splitter 500, the input light may be divided into a plurality of signals with inconsistent amplitudes and phases. The plurality of optical signals are first modulated by the amplitude and phase modulation structure 400 to form signal amplitudes that need to be Fourier transformed, and optical signals with consistent phases. The optical signals modulated by the amplitude and phase modulation structure 400 are input to the curved waveguide array 200, wherein the input portion 101 of each of the curved waveguides 100 receives a modulated optical signal and transmits the optical signal to the middle portion 102 of the plurality of curved waveguides 100. By means of the curved shape of the middle portion 102 of the plurality of curved waveguides 100, the fixed waveguide spacing, and the above Figure 3 As shown in the figure, the optical signals are coupled with each other and complete discrete diffraction during the propagation process. Since the effective refractive index of the plurality of curved waveguides 100 shows a consistent change trend with the waveguide width of the middle portion 102 (gradually decreasing from the central waveguide to both sides), the propagation path and phase of the optical signal are directly affected, especially the phase is shown as above. Figure 3 The quadratic function distribution trend shown in the figure is used to achieve the focusing of the light beam, so that the multiple curved waveguides 100 are 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, the optical Fourier transform is achieved. When the optical signal after Fourier transform passes through the output part 103 of the multiple curved waveguides 100, the amplitude and phase information after Fourier transform is obtained at the port 700 by means of the coherent detection method (the reference light 600 and the light output from the output part 103 of the curved waveguide 100 interfere with each other), wherein the number of the ports 700 corresponds to the number of the multiple curved waveguides 100, and each port 700 receives the optical signal after Fourier transform transmitted by the output part 103 of the corresponding curved waveguide 100. Figure 7The five ports 700 provided can obtain five Fourier transforms. It should be noted again that the waveguide lengths of the middle portions 102 of the plurality of curved waveguides 100 are the same. In the embodiment of the present invention, there is no special limitation on the specific value of N, for example, N can be 5, 16, or 30; there is no specific limitation on the type of the beam splitter 500, as long as the incident light beam can be evenly divided 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.

[0070] In the embodiment, the middle parts 102 of the plurality of curved waveguides 100 can be operated to change the focal length or other optical parameters of the lens to which they are equivalent, thereby giving the curved waveguide array 200 the ability to adjust, so that it can reconfigure the function of the lens, which is not only used for calibration, but also can realize multifunctional optical lens design. The operation mode of the middle parts 102 of the plurality of curved waveguides 100 can be to add hot metal (phase modulator) above the waveguide, adjust the effective refractive index of the waveguide by thermo-optical effect, inject carriers to change the refractive index distribution of the waveguide, and use materials with electro-optical effect to manufacture the waveguide array to realize dynamic adjustment.

[0071] The simulation results of Fourier transform of optical signals of different wavelengths by the curved waveguide array 200 of the present 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 1.71.4μm, respectively. The horizontal and vertical coordinates represent the position coordinates of the curved waveguide array in the horizontal and vertical directions, respectively. Figure 8 The simulation results show that light of different wavelengths can converge to one point after passing through the curved waveguide array 200 proposed by the present invention. This experimental result shows that the curved waveguide array 200 can effectively be equivalent to a lens to converge the incident light. It has a Fourier transform function that supports multiple wavelengths (1400-1700nm) and a wavelength division multiplexing function with a bandwidth of more than 200nm.

[0072] The curved waveguide array 200 of the present invention has a simple structural design and is easy to be highly integrated into a system on a chip. Its low-complexity design significantly reduces manufacturing costs and process difficulty. Experimental results show that the structure appears in the wavelength range of 1400-1700nm, is insensitive to wavelength changes, has a multi-wavelength Fourier transform function, a high-bandwidth wavelength division multiplexing capability of more than 200nm, and a higher optical signal transmission efficiency.

[0073] As a second aspect of the present invention, an optical signal processing device 300 is provided. Fig. 9As shown. The optical signal processing device 300 includes the curved waveguide array 200, a signal modulation module 301, and a signal processing module 302 as described in the first aspect of the present invention; 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 the unique number information of each curved waveguide 100 of the curved waveguide array 200, which is used to identify and distinguish the optical signals corresponding to different waveguides. Fig.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; Fig.10 As shown in (b), the second end 200 of the curved waveguide array is the output end of the curved waveguide array 200, and the output end of the curved waveguide array 200 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. Fig.11 (a); the signal processing module 302 includes a measuring unit 3021 for measuring the amplitude and phase information of the optical signal after being transmitted by the curved waveguide array 200, as shown in FIG. Fig.11 (b) is shown. The above are only specific embodiments of the present invention, but the protection scope 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 drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A curved waveguide array (200), characterized in that: The curved waveguide array (200) comprises a plurality of curved waveguides (100) arranged at intervals, wherein the curved waveguide (100) comprises an input portion (101), a middle portion (102), and an output portion (103); the middle portion (102) is in a curved shape; the input portions (101) of the plurality of curved waveguides (100) are located at a first end (201) of the curved waveguide array, and the output portions (103) of the plurality of curved waveguides (100) are located at a second end (202) of the curved waveguide array; The waveguide width of the middle portion (102) of the plurality of curved waveguides (100) gradually decreases from the middle of the curved waveguide array (200) to both sides of the curved waveguide array (200), so that the refractive index variation law of the plurality of curved waveguides (100) is consistent with the waveguide width variation law of the middle portion (102) of the plurality of curved waveguides (100).

2. The curved waveguide array (200) according to claim 1, characterized in that: The refractive index of the curved waveguide array (200) satisfies the following formula (1): N=-kn×P 2 +bn (1) Wherein, N is the refractive index of the curved waveguide (100) to be calculated; P 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; kn is the refractive index variation coefficient, and 0<kn<1; bn is a refractive index compensation coefficient, and 1<bn<3.

3. 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 portions (102) of the curved waveguides (100) at both sides; and the waveguide widths of the middle portions (102) of the curved waveguides (100) at both sides equidistant from the middle portion (102) of the curved waveguide (100) at the middle position are the same.

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

5. The curved waveguide array (200) according to claim 1, characterized in that: The input parts (101) of the plurality of curved waveguides (100) are arranged at unequal intervals; The output parts (103) of the plurality of curved waveguides (100) are arranged at unequal intervals; The middle parts (102) of the plurality of curved waveguides (100) are arranged at equal intervals.

6. The curved waveguide array (200) according to claim 5, characterized in that: From the middle of the curved waveguide array (200) to both sides of the curved waveguide array (200), the intervals between the input parts (101) of the two adjacent curved waveguides (100) gradually increase, and the intervals between the output parts (103) of the two adjacent curved waveguides (100) gradually increase.

7. The curved waveguide array (200) according to claim 6, characterized in that: The interval between the input portions (101) 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).

8. The curved waveguide array (200) according to claim 6, characterized in that: The interval between the output portions (103) of the two adjacent curved waveguides (100) is greater than or equal to the interval between the middle portions (102) of the two adjacent curved waveguides (100).

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

10. The optical signal processing device (300) according to claim 9, characterized in that: The signal modulation module (301) comprises a modulation unit (3011) for modulating the amplitude and phase of an input optical signal, and the signal processing module (302) comprises a measurement unit (3021) for measuring the amplitude and phase information of an optical signal transmitted through the curved waveguide array (200).

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