A chip-type optical direction-finding and positioning device

Abstract

The present application provides a chip-type optical direction-finding and positioning device, comprising a spatial spectrum acquisition module, a driving module, a photocurrent processing module, and a direction-finding calculation module; the spatial spectrum acquisition module comprises a plurality of interference baseline units for acquiring the spatial spectrum of a target light source; the driving module provides a phase-modulated current so that each interference baseline unit achieves constructive and destructive interference under two external phase difference conditions of 0 and π / 2; the photocurrent processing module amplifies and measures the photocurrent to obtain the corresponding photocurrent intensity; the direction-finding calculation module calculates the intensity and phase information of the spatial spectrum points based on the photocurrent intensities corresponding to the constructive and destructive interference under the two external phase difference conditions of 0 and π / 2; an inverse Fourier transform is performed to complete the reconstruction of the target light source image, and the direction of the target light source is determined with the center of the reconstructed image as the direction-finding origin, thereby achieving high-resolution light source image reconstruction, thereby accurately measuring the relative direction of the light source, and improving the accuracy of light source direction-finding.

Description

Technical Field

[0001] The present application relates to the technical field of optical direction finding, and in particular to a chip-type optical direction finding and positioning device. Background Art

[0002] Currently, mainstream optical direction-finding technologies primarily employ light field scanning or imaging. Light field scanning direction-finding leverages the fact that the response current intensity of a small-aperture photoreceiver is correlated with the incident angle of the light field. At the detection point, the intensity is scanned and sampled at all incident angles. The angular spatial distribution of the light field intensity at the detection point is then used to determine the direction of the light source. This technique, due to its relatively simple principle and structure, has long been the mainstream for luminous target direction-finding. However, the mechanical scanning method places extremely high demands on the rotational accuracy and resolution of the rotating stage, and mechanical scanning speed is difficult to significantly increase. Consequently, this technique has been limited in large-scale application in high-precision, high-speed, and real-time light source direction-finding systems. With the development of CCD imaging devices, high-resolution angular spatial imaging has become a new mainstream technology for optical direction-finding. This technique leverages the focusing function of lenses to converge incident light beams from different directions onto different locations on the imaging surface. Each pixel of the CCD sensor corresponds to a different incident angle of the light source. The position of the focused light spot on the pixel array of the sensor determines the incident direction of the light beam, enabling precise direction-finding of the light source. However, the convergence diffraction limit of the lens and the minimum pixel size of the imaging sensor limit the maximum direction-finding accuracy of optical direction-finding systems. To improve direction-finding accuracy and resolution, the lens size must be increased and the pixel size of the imaging sensor must be compressed. This significantly increases the size, volume, and manufacturing cost of the optical direction-finding system, making it difficult to use in miniaturized and mass-produced equipment. CCD stands for Charge Coupled Device.

[0003] The emergence of phase difference measurement technology has provided a new approach to measuring the direction of a point source. Radio direction tracking technology, which uses a pair of radio signal receiving antennas and a signal interference system to measure the phase difference of the radio signals from the two antennas using interferometry, calculates the relative direction of the radiating source and the receiving antenna pair based on this phase difference, and thus achieves precise directionality of the radiating source. Compared to radio signals, the wavelength of light is reduced to the micrometer and nanometer scale. Even slight system and environmental fluctuations can introduce significant errors in the antenna phase difference measurement, making optical phase difference measurement extremely challenging. Although free-space optical interferometry can reflect the antenna phase difference information in the positional distribution of interference fringes, the low contrast and stability of the fringe distribution make it difficult to accurately measure the relative position of the fringes, making it difficult to improve the phase difference measurement accuracy and miniaturize the system. Therefore, the inability to measure the optical phase difference of the antenna with high precision and stability has become a major factor limiting the application of antenna phase difference direction finding technology in optical direction finding. Summary of the Invention

[0004] In view of this, the present application provides a chip-type optical direction-finding and positioning device to achieve high-precision light source direction-finding.

[0005] The present application provides a chip-based optical direction-finding and positioning device, comprising:

[0006] Spatial spectrum acquisition module, driving module, photocurrent processing module and direction finding calculation module;

[0007] The spatial spectrum acquisition module includes a plurality of interference baseline units for acquiring the spatial spectrum of the target light source, and each interference baseline unit correspondingly acquires a spatial frequency point;

[0008] The driving module is used to provide a phase modulation current to each of the interference baseline units, so that each of the interference baseline units can achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2;

[0009] The photocurrent processing module is used to amplify and measure the photocurrent output by each interference baseline unit to obtain the photocurrent intensities corresponding to constructive and destructive interference under two external phase difference conditions of 0 and π / 2, respectively;

[0010] The direction-finding calculation module is configured to control the driving module to provide a phase-modulated current to each of the interferometric baseline units; calculate the intensity and phase information of the spatial spectrum points collected by each of the interferometric baseline units based on the photocurrent intensities corresponding to constructive and destructive interference under the two external phase difference conditions of 0 and π / 2 output by the photocurrent processing module; combine the intensity and phase information of all spatial spectrum points and perform an inverse Fourier transform to reconstruct the target light source image, and determine the direction of the target light source using the center of the reconstructed image as the direction-finding origin.

[0011] In a possible implementation, the interference baseline unit includes: two light collection devices, a phase modulator, an interference component, and a light detection component, wherein the two light collection devices are paired to form an interference baseline;

[0012] Two light collection devices are respectively connected to the interference component through waveguides, and the phase modulator is arranged between one of the light collection devices and the interference component;

[0013] The light from the target light source collected by the two light collection devices enters the interference component for interference, and the direction finding calculation module controls the phase modulator through the driving module to achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2 in the interference component;

[0014] The light detection component is used to detect the interference result of the interference component and convert the interference result into an electrical signal.

[0015] In a possible implementation, the light collection device adopts a grating coupler or an end face coupler.

[0016] In a possible implementation, the optical detection component adopts a balanced detector or an optical power meter.

[0017] In a possible implementation, the interference component uses a 2×2 multimode interference coupler.

[0018] In a possible implementation, the phase modulator is a titanium nitride thermally controlled phase modulator or an electrically controlled on-chip phase modulator.

[0019] In a possible implementation, the multiple interference baseline units in the spatial spectrum acquisition module are arranged in a one-dimensional structure to achieve one-dimensional optical direction finding.

[0020] In a possible implementation, the multiple interference baseline units in the spatial spectrum acquisition module are arranged in a two-dimensional structure to achieve two-dimensional optical direction finding.

[0021] Compared with the prior art, the chip-type optical direction-finding and positioning device provided in the present application includes a spatial spectrum acquisition module, a driving module, a photocurrent processing module and a direction-finding calculation module; the spatial spectrum acquisition module includes multiple interference baseline units for acquiring the spatial spectrum of the target light source, and each interference baseline unit corresponds to acquiring a spatial frequency point; the driving module provides a phase-modulated current so that each of the interference baseline units can achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2, and output a corresponding photocurrent; the photocurrent processing module amplifies and measures the photocurrent to obtain the corresponding photocurrent intensity; the direction-finding calculation module calculates the intensity and phase information of the spatial spectrum point based on the photocurrent intensities corresponding to the constructive and destructive interference under the two external phase difference conditions of 0 and π / 2; the intensity and phase information of all spatial spectrum points are combined and inverse Fourier transform is performed to complete the reconstruction of the target light source image, and the direction of the target light source is determined with the center of the reconstructed image as the direction-finding origin. Compared with the existing technology, this application is based on the principles of interferometric phase measurement and optical interferometric imaging. By collecting the intensity and phase information of the far-field frequency space of the target light source and the frequency space inverse Fourier transform, it realizes high-resolution light source image reconstruction, and then accurately measures the relative direction of the light source, thereby improving the accuracy of light source direction finding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0023] Figure 1 A schematic diagram of a chip-based optical direction-finding and positioning device provided by the present application is shown;

[0024] Figure 2 The schematic diagram of the chip-based interferometric baseline direction finding principle provided by the present application is shown;

[0025] Figure 3 A physical diagram of an interferometric direction-finding photonic chip provided by the present application is shown;

[0026] Figure 4 A schematic diagram showing a chip-type optical direction-finding and positioning device provided by the present application performing one-dimensional optical direction-finding;

[0027] Figure 5 The following is a schematic diagram showing the design of a two-dimensional chip-based optical direction-finding and positioning device provided by the present application;

[0028] Figure 6 A schematic diagram of a point light source direction finding simulation based on a two-dimensional baseline design provided by the present application is shown;

[0029] Figure 7 The diagram shows the actual test effect of direction finding provided by the present application when the point light source moves from the origin position to two different distances in the positive direction and the negative direction parallel to the baseline. DETAILED DESCRIPTION

[0030] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0031] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which this application belongs.

[0032] In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0033] An embodiment of the present application provides a chip-based optical direction-finding and positioning device. Based on the principles of interferometric phase measurement and optical interferometric imaging, it collects the intensity and phase information of the far-field frequency space of the target light source to be measured and performs an inverse Fourier transform in the frequency space to achieve high-resolution light source image reconstruction, thereby accurately measuring the relative direction of the target light source. This is explained below with reference to the accompanying drawings.

[0034] Please refer to Figure 1 , which shows a schematic diagram of a chip-type optical direction-finding and positioning device provided by an embodiment of the present application, such as Figure 1 As shown, the chip-type optical direction-finding and positioning device includes: a spatial spectrum acquisition module 10 , a driving module 20 , a photocurrent processing module 30 and a direction-finding calculation module 40 .

[0035] The spatial spectrum acquisition module 10 includes a plurality of interference baseline units 100 for acquiring the spatial spectrum of the target light source, and each interference baseline unit 100 correspondingly acquires one spatial frequency point.

[0036] The driving module 20 is used to provide a phase modulation current to each interference baseline unit 100, so that each interference baseline unit 100 can achieve constructive interference with a phase difference of 0 or destructive interference with a phase difference of π / 2, and output a corresponding photocurrent.

[0037] The photocurrent processing module 30 is used to amplify and measure the photocurrent output by each interference baseline unit 100 to obtain the photocurrent intensities corresponding to constructive and destructive interference under two external phase difference conditions of 0 and π / 2, respectively.

[0038] The direction-finding calculation module 40 is used to control the driving module 20 to provide a phase-modulated current to each interferometric baseline unit 100. The module also calculates the intensity and phase information of the spatial spectrum points collected by each interferometric baseline unit 100 based on the photocurrent intensities corresponding to constructive and destructive interference under the two external phase difference conditions of 0 and π / 2 output by the photocurrent processing module 30. The module then combines the intensity and phase information of all spatial spectrum points and performs an inverse Fourier transform to reconstruct the target light source image. The direction of the target light source is determined using the center of the reconstructed image as the direction-finding origin.

[0039] Figure 2 The following is a schematic diagram of the chip-based interferometric baseline direction finding principle: Figure 2 As shown, in some embodiments, the interference baseline unit 100 includes: two light collection devices 110, a phase modulator 120, an interference component 130 and a light detection component 140, and the two light collection devices 110 are paired to form an interference baseline.

[0040] Two light-collecting devices 110 are connected to an interference component 130 via waveguides. A phase modulator 120 is disposed between one of the light-collecting devices 110 and the interference component 130. Specifically, the light-collecting device 100 can employ a grating coupler or an end-face coupler. The interference component 130 can employ a 2×2 multimode interference coupler (MMI). The phase modulator 120 can employ a titanium nitride (TiN) thermally controlled phase modulator, other types of thermally controlled phase modulators, or an electrically controlled on-chip phase modulator.

[0041] The light from the target light source collected by the two light collecting devices 110 enters the interference component 130 for interference respectively. The direction finding calculation module 40 controls the phase modulator 120 to realize constructive and destructive interference under two external phase difference conditions of 0 and π / 2 in the interference component 130.

[0042] The optical detection component 140 is used to detect the interference result of the interference component 130 and convert the interference result into an electrical signal. Specifically, the optical detection component 140 can be a balanced detector or an optical power meter.

[0043] like Figure 2As shown, each interferometric baseline unit (also called an optical receiving antenna) corresponds to a fixed interferometric baseline length B. When the probe beam is incident on the baseline axis of the optical receiving antenna at a certain angle, an optical phase difference related to the baseline length and wavelength is generated at both ends of the antenna. Based on the light intensity information detected by the interference at both ends of the antenna, the phase difference at both ends of the antenna can be calculated, and thus the incident angle θ of the beam relative to the baseline perpendicular can be calculated. In a direction-finding system composed of multiple interferometric baseline units, each interferometric baseline length and direction also corresponds to a specific spatial frequency point in the light field. By measuring the baseline interference intensity, the intensity and phase information corresponding to each spatial frequency point of the baseline can be obtained.

[0044] In some embodiments, the multiple interference baseline units 100 in the spatial spectrum acquisition module 10 are arranged in a one-dimensional structure to achieve one-dimensional optical direction finding. In practical applications, the spatial spectrum acquisition module 10 can use a photonic chip that contains multiple interference baselines of different lengths arranged in a one-dimensional manner. For example, the longest interference baseline is 383 microns, and the baseline lengths decrease in 60 microns, such as Figure 3 shown.

[0045] like Figure 4 The schematic diagram of the chip-type optical direction-finding and positioning device provided by the present application for one-dimensional optical direction-finding is shown. First, a control current with a phase difference of 0 and π / 2 is provided to each interference baseline of the photonic chip, such as Figure 2 As shown, the output power I of the 2×2MMI device at both ends is read when each interference baseline has a zero phase difference. A and I B The difference I (I=I A -I B ) and a phase difference of π / 2, the output power I of the 2×2MMI device at both ends is C and I D The difference Q(Q=I C -I D ),by Figure 4 Taking the direction-finding chip design as an example, the intensities of I and Q are respectively reflected in the balanced detector output currents of two different phase difference states of 0 and π / 2; then, according to the interference output power difference measurement value of each interference baseline, the phase and intensity information of the corresponding frequency domain space point is calculated, where the phase Depend on Determined by the strength Confirm and complete the information collection of the target light source frequency domain space.

[0046] In some embodiments, the multiple interference baseline units in the spatial spectrum acquisition module 10 are arranged in a two-dimensional structure to achieve two-dimensional optical direction finding. In practical applications, the spatial spectrum acquisition module 10 can adopt the above-mentioned two photonic chips arranged orthogonally. Figure 5The figure shows the design schematic diagram of the two-dimensional chip-type optical direction-finding and positioning device provided by the present application, which includes orthogonally arranged interferometric direction-finding photonic chips (equivalent to Figure 1 The spatial spectrum acquisition module 10), DAC DC drive and transimpedance amplifier circuit (equivalent to Figure 1 Driving module 20 and photocurrent processing module 30), signal processing and direction finding calculation circuit (equivalent to Figure 1 The direction-finding calculation module 40) consists of three parts: the interference direction-finding photonic chip performs interference collection of the target light source spectrum space; the DAC DC drive and transimpedance amplifier circuit provides the photonic chip with a stable phase-modulated current and performs photocurrent amplification and measurement; the signal processing and direction-finding calculation circuit performs digital reading of the induced photocurrent analog signal and digital control of the phase-modulated current, and calculates the intensity and phase information of the spatial spectrum point of each interference baseline collection based on the read photocurrent intensity, and finally performs inverse Fourier transform calculation to realize light source direction-finding. The one-dimensional optical receiving antenna design can only realize one-dimensional optical direction-finding in the direction of the baseline axis. By setting two groups of optical receiving antennas orthogonally, two-dimensional high-precision optical direction-finding can be realized, such as Figure 5 The design method shown can realize optical antenna reception, phase modulation, spatial frequency acquisition, direction-finding data calculation and angular space image reconstruction of two-dimensional light fields with high integration.

[0047] In practical applications, the light field acquisition and interferometry system of the embodiment of the present application can be established on a photonic chip platform, using multiple sets of light field coupling devices as optical receiving baselines to realize paired light field acquisition, and using on-chip devices such as 2×2 MMI devices and TiN thermally controlled phase shifters to realize constructive and destructive interference under two external phase difference conditions of interference baseline 0 and π / 2, such as Figure 2 As shown, the intensity and phase information of the frequency-space acquisition point corresponding to the interference baseline length are calculated based on the light field intensity at the constructive and destructive interference output ends of the MMI device. The interference baseline design of the photonic chip adopts a one-dimensional or two-dimensional structural arrangement based on the required optical direction-finding angular spatial dimension. The length and direction of the interference baseline are set according to the spatial frequency distribution to be collected. The two-dimensional interference baseline interference optical path can be integrated on a single photonic chip or divided into multiple one-dimensional interference direction-finding chips. Finally, by combining the frequency-space information collected from each set of interference baselines and performing an inverse Fourier transform, a reconstructed image of the target light source to be measured is obtained, thereby achieving accurate direction-finding of the light source.

[0048] For ease of understanding, the construction process of the chip-based optical direction-finding and positioning device of the present application is described in detail below.

[0049] 1. Design the number, length and direction of interference baselines. Using the principle of interference imaging, the maximum angular resolution of imaging is: R angular=λ / B, where λ is the wavelength of the light source to be measured and B is the maximum interference baseline length. According to the far-field frequency distribution characteristics of the light source to be measured, the frequency domain sampling points that meet the requirements are selected, and the interference baseline with the corresponding length and direction is designed. Using the method of light source far-field spectrum analysis, spectrum sampling and light field spatial domain reconstruction, the imaging effect of the designed interference baseline combination is simulated to verify the theoretical point light source direction finding effect. Figure 6 Taking the simulation verification shown as an example, several point light sources are set at different positions in the horizontal and vertical directions of the direction finding origin. The light source image at each position is Fourier transformed to obtain the spectrum matrix of the light source image. The spatial frequency points corresponding to the interference baseline are selected, and the inverse Fourier transform is performed to obtain the simulated point source direction finding effect. Figure 6 (a) shows the direction-finding effect of the point light source moving horizontally, and (b) shows the direction-finding effect of the point light source moving vertically.

[0050] 2. Design an interference imaging photonic chip. Based on the photonic chip platform, design free-space light collection devices such as gratings or end couplers, design high-precision optical phase modulation devices, and design 2×2MMI devices. Layout the overall interference optical path so that the direction of the interference baseline is consistent with the distribution of the spectrum collection points. The free-space light field is coupled into the waveguide through the light collection device, and then through the phase modulator and 2×2MMI to achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2. Design a light intensity detection device or optical path to read the light intensity after baseline interference. Finally, design the electrode arrangement for electronically controlled devices such as phase modulators and balanced detectors to complete the design of the photonic chip. Figure 5 Taking the photonic chip part of the optical direction-finding system as an example, two or more groups of interference baselines with mutually orthogonal baseline directions or two-dimensional distribution are designed, a grating coupler is designed as the light collection device of the interference baseline, and a waveguide phase modulator that can realize 0-2π optical phase modulation is designed. At least one phase modulator is set for each interference baseline to realize flexible control of the baseline phase difference. A 2×2 MMI device is designed to realize constructive and destructive interference of each baseline under two external phase difference conditions of 0 and π / 2. Finally, a balanced detector matched with the waveguide at the interference output end is designed to realize high-sensitivity measurement of the power difference between the two ports of the interference output.

[0051] 3. Photonic chip preparation and integration. Based on the designed photonic chip material and structural dimensions, high-precision micro-nano fabrication processes such as photolithography or electron beam lithography are selected to complete the photonic chip's processing and preparation. To achieve high integration and high stability phase control and balanced detector output current reading, a multi-channel current reading and control circuit board is designed and prepared, combining the arrangement of the photonic chip phase modulator and balanced detector electrodes. The photonic chip is fixed in the reserved position of the multi-channel current drive and amplification circuit board, and the photonic chip and circuit board are connected by wire bonding, completing the preparation and integration of the photonic chip.

[0052] 4. Photonic chip phase calibration. Power on each phase modulator and select the position of a point light source as the origin of imaging and direction finding, such as Figure 4 As shown, this point is set as the center of the image or the zero-degree direction for direction finding. By varying the operating current of the phase modulator, the phase difference of each interferometric baseline is modulated. By reading the interferometric output power of the 2×2 MMI device, the phase modulator operating current is obtained when the outputs at both ends of the interferometric component are identical and when the phase difference is maximum. These currents are used as the phase modulation currents when the interferometric optical path phase difference of the photonic chip is 0 and π / 2, respectively. This method can calibrate the difficult-to-determine baseline optical path difference caused by the design or processing of the photonic chip, and obtain the control currents for the two external phase difference conditions of 0 and π / 2 for accurate interferometric baselines.

[0053] 5. Spatial frequency information collection. In actual point light source direction finding measurement, the frequency information collection method of each set of interference baseline is as follows: Figure 4 As shown, for each light source position to be measured, first provide each interference baseline of the photonic chip with two external phase difference conditions of 0 and π / 2 to control the current, read the output power difference I of the two ends of the 2×2MMI device when the external phase difference of each baseline is 0, and the output power difference Q of the two ends of the 2×2MMI device when the external phase difference of π / 2 is Figure 4 Taking the direction-finding chip design as an example, the intensities of I and Q are respectively reflected in the balanced detector output currents of two different external phase difference states of 0 and π / 2; then, according to the measured value of the interference output power difference of each baseline, the phase and intensity information of the corresponding frequency domain space point is calculated, where the phase Determined by Q / I, the intensity is determined by OK, complete the information collection of the point light source frequency domain space.

[0054] 6. Point light source image reconstruction and direction finding. Perform an inverse Fourier transform on the acquired spatial spectrum to obtain a reconstructed image of the point light source. The deflection angle between the brightest point of the reconstructed image spot and the center (0 degrees) is the incident direction of the point light source, completing the optical direction finding of the point light source.

[0055] Using the above method, the present application designed, prepared and tested a version of the interferometric direction finding silicon-based photonic chip. The photonic chip contains six interferometric baselines of different lengths, arranged in a one-dimensional manner. The longest interferometric baseline is 383 microns, and the baseline length decreases in sequence by 60 microns. Figure 3 As shown in the figure; the light collection device is a grating coupler with a light receiving aperture of about 10 microns; a TiN thermally controlled phase modulator is designed on one interferometer arm of each interference baseline to achieve phase calibration and precise modulation of the π / 2 external phase difference; the interference of each baseline is achieved by a 2×2 MMI device, and the interference output end uses a grating coupler matched to the fiber mode field. The light in the waveguide is guided into an external optical power meter through fiber coupling to measure the intensity after interference. The actual picture of the photonic chip is shown in the figure. Figure 3As shown, the size of the interference direction-finding optical path is less than 1.6mm×0.8mm, and the thickness is less than 1mm. In the chip test, a driver circuit board is used to realize the control of the multi-channel phase modulator by means of jumpers. Before the optical direction-finding test, the point light source is first set at a position relative to the center of the entire one-dimensional direction-finding angle range, which is used as the origin of the optical direction-finding. The phase of each interference baseline is calibrated for the direction-finding origin, and the control current for achieving 0 and π / 2 plus phase differences is obtained respectively; then the point light source is moved to two known positions on the left and right sides along the baseline direction, and the intensity of the interference output under the control of 0 and π / 2 phase differences of each baseline at each position is measured to complete the acquisition of the frequency space of the point light source. Through calculation, the spectrum information collected by the point light source at different positions is obtained, and the inverse Fourier transform calculation is performed to complete the reconstruction of the point light source image, and finally the direction of the point light source is determined. The reconstructed images of the point light source at the four test positions and the origin are shown as follows. Figure 7 As shown, from Figure 7 As shown in the actual test effect diagram of direction finding when the point light source moves two different distances in the positive and negative directions from the origin position along the baseline axis, the present application performs direction finding of point light sources at multiple positions with a maximum angle of 14 mrad, and the direction finding error is ≤125 μrad.

[0056] Compared to previous optical direction-finding technologies, the chip-based optical direction-finding and positioning device provided by this application achieves an imaging resolution in the light field angular space determined by the interferometric baseline length B, surpassing the limitations of the traditional imaging lens' optical diffraction limit, which is limited by the lens aperture size. The direction-finding principle shifts from traditional light field convergence to intensity and phase acquisition in the frequency space. The direction-finding accuracy and precision (the difference between the measured point source incident direction angle and the true value) are no longer affected by the imaging spot size, the imaging CCD pixel size, or the angular space scanning accuracy. Instead, the direction-finding accuracy is determined solely by the phase and intensity measurement accuracy. Based on a high-precision power meter's ±2.5% power measurement error and a relatively easy-to-implement 1mm interferometric baseline length, the theoretical near-infrared (1550nm) direction-finding accuracy can reach as high as ±12.34 μrad, ignoring any added phase modulation error. Even with a relatively poor phase modulation error of ±π / 20, the direction-finding accuracy can still reach ±51.09 μrad. This significantly improves the direction-finding accuracy compared to the mrad-level direction-finding errors of previous optical direction-finding technologies. Furthermore, this technology's photonic chip interferometry system significantly improves system integration and stability compared to traditional free-space optical interferometry systems. It completely eliminates the need for heavy optical lenses, integrating all critical spatial frequency measurement components onto a single photonic chip. The system's size and weight are significantly smaller than those of mainstream technologies with the same direction-finding accuracy. Furthermore, the integrated optical path and drive control circuitry significantly simplify optical path alignment and significantly improve the high-precision direction-finding system's ability to withstand vibration interference.

[0057] This application innovatively adopts integrated optical interference technology to achieve high-precision, high-stability, and high-integration optical direction finding. The phase difference direction finding method overcomes the problem that the measurement accuracy and resolution of mainstream optical direction finding technology are limited by the diffraction limit or the size of the photosensitive pixel; by designing a photonic chip integrated interference optical path, it overcomes the problems of poor system stability, low integration, and low phase modulation and measurement accuracy of traditional free-space optical phase detection technology; the interference imaging principle is innovatively applied to the optical direction finding system. Compared with the current mainstream optical direction finding technology, the chip-type optical direction finding and positioning device provided by this application not only greatly improves the accuracy of light source direction finding, but also effectively enhances the resolution capability of multi-target light source direction finding.

[0058] It should be noted that:

[0059] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0060] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0061] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A chip-type optical direction-finding and positioning device, characterized in that: include: Spatial spectrum acquisition module, driving module, photocurrent processing module and direction finding calculation module; The spatial spectrum acquisition module includes a plurality of interference baseline units for acquiring the spatial spectrum of the target light source, and each interference baseline unit correspondingly acquires a spatial frequency point; The driving module is used to provide a phase modulation current to each of the interference baseline units, so that each of the interference baseline units can achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2; The photocurrent processing module is used to amplify and measure the photocurrent output by each interference baseline unit to obtain the photocurrent intensity corresponding to constructive and destructive interference under two external phase difference conditions of 0 and π / 2; The direction finding calculation module is used to control the driving module to provide a phase modulation current to each of the interferometric baseline units; And according to the photocurrent intensities corresponding to the constructive and destructive interference under the two external phase difference conditions of 0 and π / 2 output by the photocurrent processing module, the intensity and phase information of the spatial spectrum points collected by each interference baseline unit are calculated; the intensity and phase information of all spatial spectrum points are combined and inverse Fourier transform is performed to complete the reconstruction of the target light source image, and the direction of the target light source is determined with the center of the reconstructed image as the direction finding origin.

2. The device according to claim 1, characterized in that The interference baseline unit includes: two light collection devices, a phase modulator, an interference component and a light detection component, and the two light collection devices are paired to form an interference baseline; Two light collection devices are respectively connected to the interference component through waveguides, and the phase modulator is arranged between one of the light collection devices and the interference component; The light from the target light source collected by the two light collection devices enters the interference component respectively for interference, and the direction finding calculation module controls the phase modulator through the driving module to achieve constructive and destructive interference under two external phase difference conditions of 0 and π / 2 in the interference component; The light detection component is used to detect the interference result of the interference component and convert the interference result into an electrical signal.

3. The device according to claim 2, characterized in that The light collection device adopts a grating coupler or an end face coupler.

4. The device according to claim 2, characterized in that The optical detection component adopts a balanced detector or an optical power meter.

5. The device according to claim 2, characterized in that The interference component adopts a 2×2 multi-mode interference coupler.

6. The device according to claim 2, characterized in that The phase modulator adopts a titanium nitride thermally controlled phase modulator or an electrically controlled on-chip phase modulator.

7. The device according to claim 1, characterized in that The multiple interference baseline units in the spatial spectrum acquisition module are arranged in a one-dimensional structure to achieve one-dimensional optical direction finding.

8. The device according to claim 1, characterized in that The multiple interference baseline units in the spatial spectrum acquisition module are arranged in a two-dimensional structure to achieve two-dimensional optical direction finding.

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