Optical one-dimensional phased-array antenna based on integrated photon technology and signal transmitting and receiving method and parameter calculation method thereof

Abstract

The invention relates to an optical signal receiving and transmitting device, in particular to an optical one-dimensional phased-array antenna based on an integrated photon technology and a signal receiving and transmitting method and a parameter calculation method thereof, and aims to solve the problem that adjacent waveguides of an existing optical one-dimensional phased-array antenna have serious signal crosstalk. The waveguide array comprises two auxiliary waveguide arrays which are respectively arranged at the upper end and the lower end of a linear waveguide array, wherein each auxiliary waveguide array comprises K auxiliary waveguides; each auxiliary waveguide comprises a second end, and the second end of each auxiliary waveguide is connected with the inner end of the corresponding optical antenna; and each auxiliary waveguide is used for receiving and transmitting the optical signal diffused into the auxiliary waveguide due to coupling in the corresponding linear waveguide to the corresponding optical antenna, or diffusing part of the optical signal received by the optical antenna into the corresponding linear waveguide through coupling. According to the invention, signal crosstalk between antennas is thoroughly eliminated, and the antenna units are identical, so that perfect interference can be achieved.

Description

Technical Field

[0001] The present invention relates to an optical signal transceiver, and in particular to an optical one-dimensional phased array antenna based on integrated photon technology, a signal transceiver method and a parameter calculation method thereof. Background Art

[0002] A one-dimensional optical phased array is a phased array composed of multiple optical antennas arranged according to a specific one-dimensional rule, which can be used to transmit (or receive) optical signals in a directional manner. In actual application scenarios, the optical signal transmission (or reception) direction of the one-dimensional optical phased array can be adjusted by controlling the phase relationship between different optical antennas in the phased array; and by changing the phase relationship between different optical antennas in a certain time pattern, scanning within a certain angle range can also be achieved, which is an important component of the phased array radar. Periodically arranged antenna arrays were first used in phased array radars due to their advantages in easy processing and data processing. In the antenna array, the spacing between adjacent antennas is an important indicator of the phased array radar. When the spacing between adjacent antennas is greater than half the wavelength of the signal carrier, multi-level interference phenomena will occur. Figure 4 The grating lobe shown in the figure. The generation of grating lobes brings two negative effects to phased array radar. First, the grating lobes divide the energy of the main lobe, greatly reducing the effective output (or received) signal power of the phased array radar. Second, the existence of grating lobes limits the scanning angle range of the phased array radar. The scanning angle range of the phased array radar is generally smaller than the angular spacing Δθ between the main lobe and the grating lobe.

[0003] Therefore, the antenna array in the phased array radar generally requires that the spacing between adjacent antennas be less than half the wavelength of the signal carrier to eliminate the grating lobes.

[0004] Under normal conditions, optical phased array radar uses a fully identical antenna array solution, that is, each antenna is completely consistent. Its advantages are the following two points:

[0005] 1) The light spots emitted by each antenna are completely consistent, and the far-field envelope is also completely consistent, which can achieve ideal interference and thus enhance the transmission efficiency;

[0006] 2) Phase modulation and data processing of antenna arrays are easy to implement. However, the homogeneity of the antennas will make the effective refractive index of each antenna channel equal. Combined with the half-wavelength antenna spacing limit, signal interference between antennas is inevitable, and it will be aggravated as the wavelength of the transmitted carrier decreases.

[0007] In order to solve this problem, some researchers have proposed using non-identical antennas as a solution (see Phare CT, Shin MC, Sharma J, et al. Silicon optical phased array with grating lobe-free beam formation over 180 degree field of view [C] / / CLEO: Science and Innovations. Optica Publishing Group, 2018: SM3I.2. and CT Phare, MC Shin, SA Miller, B. Stern, and M. Lipson, "Silicon optical phased array with high-efficiency beam formation over 180 degree field of view," arXiv: 1802.04624 (2018).). Non-identical antennas destroy the consistency of the effective refractive index of the antenna channel and reduce the coupling efficiency between the antenna channels, thereby reducing the effect of signal crosstalk between antennas. Specific implementation examples include Figure 5 As shown in the figure, this case uses an end-emitting waveguide as an antenna, and the working band is 1.55μm, so the spacing between each antenna is set to half a wavelength, that is, 0.775μm. In this case, the end-emitting waveguide is used as the antenna, and three waveguides with different widths are selected as antennas, with widths of 0.290μm, 0.347μm and 0.397μm respectively. According to the calculation results, the coupling efficiency between these three antennas is reduced by 1 to 2 orders of magnitude compared with the same antenna, which ultimately greatly reduces the signal crosstalk between antennas.

[0008] This scheme has other manifestations (see Liu Y, Hu H. Silicon optical phased array with a 180-degree field of view for 2D optical beam steering [J]. Optica, 2022, 9 (8): 903-907.). Figure 6 As shown, the only difference between this solution and the above solution is that a larger grating transmitting antenna is connected to the rear end of the non-identical waveguide antenna to realize vertical transmission of the optical signal. At the same time, scanning in another direction can be achieved by adjusting the wavelength of the optical signal.

[0009] Although the use of non-identical antenna arrays can reduce signal crosstalk to a certain extent when the spacing between adjacent antennas is less than half a wavelength, it still has the following limitations:

[0010] 1) There is still a certain degree of signal interference between different optical antennas, which has not been completely eliminated;

[0011] 2) When the working wavelength is further shortened from the current C-band to the O-band or even the 850-band, the above scheme has limited effect on reducing the signal crosstalk between different optical antennas and can hardly meet the actual needs;

[0012] 3) Non-identical antennas can easily destroy the consistency of the transmitted optical signal patterns of each optical antenna, which will weaken the interference between the optical antennas of the phased array radar, and ultimately seriously reduce the transmission (or reception) efficiency of the phased array.

[0013] The common optical one-dimensional phased array antenna in the current state of the art can be found in Figure 2 , which only includes the waveguide array, but not the auxiliary waveguide array. Due to the lack of the auxiliary waveguide array, the number of waveguides in the optical signal transmission module of the traditional optical one-dimensional phased array antenna must be consistent with the number of antennas, and each waveguide corresponds to an antenna unit. This architecture makes the optical signal coupling between adjacent waveguides in the optical signal transmission module directly correspond to the signal interference between antenna units, so that the adjacent waveguide spacing that is too close causes serious signal interference. Summary of the invention

[0014] The purpose of the present invention is to solve the serious signal interference problem of adjacent waveguides of existing optical one-dimensional phased array antennas, and to provide an optical one-dimensional phased array antenna based on integrated photonic technology and its signal receiving and sending method and parameter calculation method.

[0015] To achieve the above purpose, the technical solution provided by the present invention is:

[0016] An optical one-dimensional phased array antenna based on integrated photon technology comprises a beam splitter, a phase shifter array, a curved waveguide array, a linear waveguide array, an overall antenna, a circulator, a receiver and a laser; the phase shifter array comprises N phase shifters respectively connected to N second ends of the beam splitter, the curved waveguide array comprises N curved waveguides respectively connected to the N phase shifters, the linear waveguide array comprises N linear waveguides respectively connected to the N curved waveguides, the overall antenna comprises a plurality of optical antennas respectively connected to the N linear waveguides, N is a positive integer, the first end of the beam splitter is connected to the A end of the circulator, the B end of the circulator is connected to a receiver for receiving an optical signal, and the C end of the circulator is connected to a laser for generating an optical signal; each phase shifter, a corresponding curved waveguide, a linear waveguide and an optical antenna constitute an antenna unit, and the antenna unit is used to receive or transmit an optical signal at a specific angle; the special feature of the antenna is that:

[0017] The number of the optical antennas is S, where S is a positive integer;

[0018] It also includes two auxiliary waveguide arrays respectively arranged on both sides of the linear waveguide array, each auxiliary waveguide array includes K auxiliary waveguides, K is a positive integer, 2K+N=S; each auxiliary waveguide is connected to a corresponding optical antenna;

[0019] The curved waveguide, the straight waveguide and the auxiliary waveguide all include a light guiding layer and a cladding layer enveloping the light guiding layer, wherein the cross section of the light guiding layer is a rectangle, the length of the bottom side of the rectangle is defined as the width of the waveguide, and the length of the side perpendicular to the bottom side is defined as the thickness of the waveguide;

[0020] Define the width of each curved waveguide as w1, the width of each straight waveguide as w2, and the width of each auxiliary waveguide as w3; define the thickness of each curved waveguide as h1, the thickness of each straight waveguide as h2, and the thickness of each auxiliary waveguide as h3; the length of each straight waveguide is L2, and the length of each auxiliary waveguide is L3; the distance between the central axes of two adjacent straight waveguides is d2, and the distance between the central axes of two adjacent auxiliary waveguides is d3, and the number of adjacent auxiliary waveguides affected by each straight waveguide is 2N0; then: w1=w2=w3, h1=h2=h3, d2=d3, L2=L3; K≥N0; d3≤λ / 2, where λ is the wavelength of the working optical signal;

[0021] Each auxiliary waveguide is used to receive and transmit the optical signal diffused into the auxiliary waveguide due to coupling in the corresponding straight waveguide to the corresponding optical antenna, or diffuse part of the optical signal received by the optical antenna into the corresponding straight waveguide through coupling.

[0022] Furthermore, the light guiding layers of the curved waveguide, the straight waveguide and the auxiliary waveguide are all made of silicon, silicon nitride or lithium niobate, and the cladding layers are all made of silicon dioxide.

[0023] Furthermore, the number of the antenna units is sixty-four, λ=1.31 μm, w1=w2=w3=0.5 μm, h1=h2=h3=0.22 μm, d2=d3=0.655 μm, L2=L3=20 μm; and K=3.

[0024] Furthermore, the phase shifter is a thermal phase shifter or an electro-optical phase shifter; and the optical antenna is a grating antenna, a grating array antenna or a metasurface antenna.

[0025] At the same time, the present invention also provides a signal receiving and transmitting method of the optical one-dimensional phased array antenna based on integrated photonic technology, which is special in that:

[0026] Including signal receiving method and signal transmitting method;

[0027] The signal receiving method comprises the following steps:

[0028] Step 1-1: Receive the scanning angle θ of the optical signal as required j ,θ j represents the scanning angle of the jth received optical signal, j is an integer greater than or equal to 1, each scanning angle corresponds to a preset phase, and the phase of each phase shifter is set to the corresponding preset phase;

[0029] Step 1-2, scanning angle is θ j The optical signal enters from the optical antenna, and a part of it passes through each straight waveguide, the corresponding curved waveguide, and the phase shifter in sequence, and then converges into the beam splitter; the other part of the optical signal enters the auxiliary waveguide, is coupled and diffused to the corresponding straight waveguide through the auxiliary waveguide, and then passes through the corresponding straight waveguide, the curved waveguide, and the phase shifter in sequence, and finally converges into the beam splitter;

[0030] Step 1-3, the combined optical signal enters the circulator through the beam splitter and the A end of the circulator;

[0031] Step 1-4: The optical signal enters the receiver from the B end of the circulator, completing a scan angle of θ j Optical signal reception;

[0032] Step 1-5, if the optical signals of all scanning angles are received, then the signal reception is terminated; if there is at least one scanning angle whose optical signal has not been received, then return to step 1-1 to receive the optical signal of the next scanning angle until the optical signals of all scanning angles are received;

[0033] The signal transmission method comprises the following steps:

[0034] Step 2-1: The light signal angle θ is emitted as required f ,θ f represents the angle of the f-th transmitted optical signal, where f is an integer greater than or equal to 1, and sets the phase of each phase shifter to the corresponding preset phase;

[0035] Step 2-2: The laser generates an initial optical signal, which enters the circulator from the C end and then enters the beam splitter from the A end of the circulator.

[0036] Step 2-3, the beam splitter divides the initial optical signal into N parts, and each of them enters the corresponding phase shifter;

[0037] Step 2-4, N optical signals respectively pass through the phase shifter and the corresponding curved waveguide into the straight waveguide in sequence, some optical signals directly pass through the corresponding straight waveguide to reach the corresponding optical antenna, and the other optical signals are diffused to the corresponding auxiliary waveguide due to coupling and transmitted, and pass through the corresponding auxiliary waveguide to reach the optical antenna;

[0038] Step 2-5: Each optical antenna transmits at an angle of θ f The light signal completes one transmission at an angle of θ f The optical signal is transmitted;

[0039] Step 2-6: If the light signals at all angles have been transmitted, the signal transmission is terminated; if there is at least one angle where the light signal has not been transmitted, return to step 2-1 and transmit the light signal at the next angle until the light signals at all angles have been transmitted.

[0040] In addition, the present invention also provides a method for calculating parameters of the above-mentioned optical one-dimensional phased array antenna based on integrated photonic technology, which is special in that it includes the following steps:

[0041] Step 1, obtaining the thickness h of the main waveguide, the working wavelength λ of the main waveguide, the minimum spacing p of the phase shifter, and the minimum bending radius r of the curved waveguide, wherein the main waveguide includes a curved waveguide and a straight waveguide; defining the width of the main waveguide as w, the length of the main waveguide as L, and the distance between the central axes of two adjacent straight waveguides as d, using a finite difference eigenmode algorithm to calculate different values ​​of d, w, and L, to obtain the near-field electric field intensity distribution of a single antenna unit, and using the working wavelength λ of the main waveguide and d=λ / 2, to obtain d;

[0042] Step 2: Perform Fourier transform on the near-field electric field intensity distribution of a single main waveguide to obtain the far-field electric field intensity distribution of the entire phased array antenna, and then calculate the scanning range of the entire phased array antenna based on the far-field electric field intensity distribution;

[0043] Step 3: Combine the far-field scanning range of the entire phased array antenna and the actual application scenario, use the single-mode condition of the waveguide to determine w, and use d and w to obtain the number N and the length L of the main waveguide;

[0044] Step 4: According to the number of waveguides N, the number of adjacent auxiliary waveguides 2N0 affected by each main waveguide is calculated using the finite difference time domain algorithm. The number of auxiliary waveguides K is calculated according to N0, and the calculation is completed if K≥N0.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The optical one-dimensional phased array antenna based on integrated photonic technology provided by the present invention adds an auxiliary waveguide array so that the signal crosstalk between the optical antennas is no longer related to the waveguide spacing, thereby completely eliminating the signal crosstalk between the antennas, and each antenna unit is identical, which can achieve perfect interference;

[0047] 2. The optical one-dimensional phased array antenna based on integrated photonic technology provided by the present invention breaks through the limitation of waveguide spacing and can achieve a waveguide spacing d less than half the wavelength λ / 2 under shorter working wavelength conditions, completely eliminating the grating lobe. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic structural diagram of an embodiment of an optical one-dimensional phased array antenna based on integrated photonic technology of the present invention;

[0049] Figure 2 It is a structural schematic diagram of an existing one-dimensional phased array antenna;

[0050] Figure 3 It is a schematic structural diagram of an embodiment of an optical one-dimensional phased array antenna based on integrated photonic technology of the present invention (the overall antenna, circulator, receiver and laser are not shown);

[0051] Figure 4 It is the normalized electric field strength-transmission angle diagram of the phased array antenna transmission signal when each antenna unit is in equal phase, where the stronger electromagnetic wave beam transmitted in the 0° direction is the main lobe, and the other two stronger electromagnetic wave beams transmitted are grating lobes;

[0052] Figure 5 Schematic diagram of an existing antenna array, wherein (a) is a schematic diagram of the structure of the antenna array, and (b) is an enlarged view of the end face output waveguide array in (a);

[0053] Figure 6 Schematic diagram of another existing antenna array, wherein (a) is a schematic diagram of the structure of the antenna array, and (b) is an enlarged view of the end face output waveguide array in (a);

[0054] Figure 7 1 is a far-field analysis diagram of a single antenna unit in an embodiment of an optical one-dimensional phased array antenna based on integrated photonic technology of the present invention, wherein (a) is a transmission field diagram of an optical signal in a single antenna unit in a linear waveguide and an auxiliary waveguide under the conditions of determining the parameters L, d and w of this embodiment, (b) is an output near-field diagram of an optical signal of a single antenna unit, (c) is an output far-field diagram of an optical signal through a waveguide array (i.e., the result of Fourier transform of the output near-field diagram), and (d) is a far-field distribution diagram of an optical phased array emission light beam;

[0055] Description of reference numerals:

[0056] 1. Beam splitter; 2. Phase shifter array; 201. Phase shifter; 3. Bent waveguide array; 301. Bent waveguide; 4. Straight waveguide array; 401. Straight waveguide; 5. Overall antenna; 501. Optical antenna; 6. Antenna unit; 7. Circulator; 8. Auxiliary waveguide array; 801. Auxiliary waveguide; 701. Receiver; 702. Laser; 91. Grating lobe; 92. Main lobe. DETAILED DESCRIPTION

[0057] In order to better illustrate this embodiment, the concept of antenna unit is first clarified here. According to the optical phased array theory, the light beam emitted by the optical phased array antenna is formed by the interference of the light beams emitted by each antenna unit in the optical phased array, see formula (I):

[0058]

[0059] Among them, E F is the electric field intensity of the directional light beam emitted by the optical phased array antenna, θ is the scanning angle, E k is the field intensity of the light beam emitted by the kth antenna unit, d is the spacing between adjacent antenna units, λ is the operating wavelength, is the phase of the light beam emitted by the kth antenna unit. As can be seen from formula (I), the amplitude and electric field strength of the light beam emitted by each antenna unit remain unchanged, while the phase is continuously modulated. It can be considered that when the optical signal is modulated by the same phase shifter, no matter what distribution it is processed into by the subsequent optical path, it does not affect the fact that these optical signals belong to the same antenna unit. Therefore, the definition of an antenna unit should be the sum of the phase shifter modulation and all optical devices through which the optical signal modulated by the phase shifter passes.

[0060] This embodiment adds an auxiliary waveguide array on the basis of the prior art, so that the number of waveguides in the optical signal transmission module is greater than the number of antennas. On this basis, multiple waveguides in the optical signal transmission module of this embodiment correspond to one antenna unit, and each waveguide also serves as a signal transmission waveguide for multiple antenna units. Figure 1 and Figure 3When the optical signal of the antenna unit passes through its corresponding phase shifter and then enters the waveguide array with a waveguide spacing less than half a wavelength through the curved waveguide array, the coupling between the waveguides causes the optical signal to diffuse into the K waveguides at the upper and lower ends of the waveguide, and then enter the overall antenna to be emitted to the outside. It should be noted that the 2K waveguides in the antenna unit into which the optical signal diffuses are also multiplexed as transmission waveguides in other adjacent antenna units.

[0061] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0062] An optical one-dimensional phased array antenna based on integrated photonic technology, see Figure 1 and Figure 3 , including a beam splitter 1, a phase shifter array 2, a curved waveguide array 3, a linear waveguide array 4, an overall antenna 5, a circulator 7, a receiver 701 and a laser 702; the phase shifter array 2 includes sixty-four phase shifters 201 respectively connected to the sixty-four second ends of the beam splitter 1, the curved waveguide array 3 includes sixty-four curved waveguides 301 respectively connected to the sixty-four phase shifters 201, the linear waveguide array 4 includes sixty-four linear waveguides 401 respectively connected to the sixty-four curved waveguides 301, the overall antenna 5 includes seventy optical antennas 501 respectively connected to the sixty-four linear waveguides 401, the beam splitter 1 The first end of the circulator 7 is connected to the A end, the B end of the circulator 7 is connected to the receiver 701 for receiving the optical signal, and the C end of the circulator 7 is connected to the laser 702 for generating the optical signal; each phase shifter 201 and its corresponding curved waveguide 301, straight waveguide 401 and optical antenna 501 constitute an antenna unit 6, and the antenna unit 6 is used to receive or transmit the optical signal at a specific angle; it also includes two auxiliary waveguide arrays 8 respectively arranged on both sides of the straight waveguide array 4, each auxiliary waveguide array 8 includes three auxiliary waveguides 801; each auxiliary waveguide 801 is connected to the corresponding optical antenna 501;

[0063] The curved waveguide 301, the straight waveguide 401 and the auxiliary waveguide 801 all include a light guiding layer and a cladding layer enveloping the light guiding layer, wherein the cross section of the light guiding layer is a rectangle, the length of the bottom side of the rectangle is defined as the width of the waveguide, and the length of the side perpendicular to the bottom side is the thickness of the waveguide;

[0064] The width of each curved waveguide 301 is defined as w1, the width of each straight waveguide 401 is defined as w2, and the width of each auxiliary waveguide 801 is defined as w3; the thickness of each curved waveguide 301 is defined as h1, the thickness of each straight waveguide 401 is defined as h2, and the thickness of each auxiliary waveguide 801 is defined as h3; the length of each straight waveguide 401 is defined as L2, and the length of each auxiliary waveguide 801 is defined as L3; the distance between the central axes of two adjacent straight waveguides 401 is defined as d2, and the distance between the central axes of two adjacent auxiliary waveguides 801 is defined as d3; the number of adjacent auxiliary waveguides 801 affected by each straight waveguide 401 is 2N0; then: w1=w2=w3=0.5μm, h1=h2=h3=0.22μm, d2=d3=0.655μm, L2=L3=20μm; K≥N0; wherein λ is the wavelength of the working optical signal, λ=1.31μm;

[0065] Each auxiliary waveguide 801 is used to receive and transmit the optical signal diffused into the auxiliary waveguide 801 due to coupling in the corresponding straight waveguide 401 to the corresponding optical antenna 501, or diffuse part of the optical signal received by the optical antenna 501 into the corresponding straight waveguide 401 through coupling.

[0066] The light-guiding layer material of each curved waveguide 301 , straight waveguide 401 and auxiliary waveguide 801 is silicon, and the cladding material is silicon dioxide; the phase shifter 201 is a thermal phase shifter; and the optical antenna 501 is a grating antenna.

[0067] In this embodiment, by combining w, L and d, it is known that after the optical signal enters the waveguide array from the curved waveguide, it will enter the three waveguides from the upper and lower ends thereof. The calculation result is as follows: Figure 7 As shown in a, the number of waveguides in the auxiliary waveguide array is K = 3. Figure 7 The antenna unit in b transmits the near field of the beam, and its far field distribution can be calculated, as shown in Figure 7 c. Combining the phased array principle and formula (I), the far-field distribution of the optical phased array emission beam under different phase relationship conditions of each antenna unit can be calculated, as shown in Figure 7 As shown in d.

[0068] At the same time, this embodiment also provides a signal transceiving method of the above-mentioned optical one-dimensional phased array antenna based on integrated photonic technology, including a signal receiving method and a signal transmitting method;

[0069] The signal receiving method comprises the following steps:

[0070] Step 1-1: Receive the scanning angle θ of the optical signal as required j ,θ jrepresents the scanning angle of the j-th received optical signal, j is an integer greater than or equal to 1, each scanning angle corresponds to a preset phase, and the phase of each phase shifter 201 is set to the corresponding preset phase;

[0071] Step 1-2, scanning angle is θ j The optical signal enters from the optical antenna 501, and a part of it passes through each straight waveguide 401, the corresponding curved waveguide 301, and the phase shifter 201 in sequence, and then converges and enters the beam splitter 1; the other part of the optical signal enters the auxiliary waveguide 801, is coupled and diffused to the corresponding straight waveguide 401 through the auxiliary waveguide 801, and then passes through the corresponding straight waveguide 401, the curved waveguide 301, and the phase shifter 201 in sequence, and finally converges and enters the beam splitter 1;

[0072] Step 1-3, the combined optical signal enters the circulator 7 through the A end of the circulator 7 from the beam splitter 1;

[0073] Step 1-4: The optical signal enters the receiver 701 from the B end of the circulator 7, completing a scan with an angle of θ j Optical signal reception;

[0074] Step 1-5, if the optical signals of all scanning angles are received, then the signal reception is terminated; if there is at least one scanning angle whose optical signal has not been received, then return to step 1-1 to receive the optical signal of the next scanning angle until the optical signals of all scanning angles are received;

[0075] The signal transmission method comprises the following steps:

[0076] Step 2-1: The light signal angle θ is emitted as required f ,θ f represents the angle of the f-th transmitted optical signal, where f is an integer greater than or equal to 1, and sets the phase of each phase shifter 201 to a corresponding preset phase;

[0077] Step 2-2: Laser 702 generates an initial optical signal, which enters circulator 7 from the C end of circulator 7 and then enters beam splitter 1 from the A end of circulator 7.

[0078] Step 2-3, the beam splitter 1 divides the initial optical signal into N parts, and makes them enter the corresponding phase shifter 201 respectively;

[0079] Step 2-4, N optical signals respectively pass through the phase shifter 201 and the corresponding curved waveguide 301 into the straight waveguide 401 in sequence, part of the optical signals directly pass through the corresponding straight waveguide 401 to reach the corresponding optical antenna 501, and another part of the optical signals is diffused to the corresponding auxiliary waveguide 801 due to coupling and transmitted, and passes through the corresponding auxiliary waveguide 801 to reach the optical antenna 501;

[0080] Step 2-5: Each optical antenna 501 transmits at an angle of θ f The light signal completes one transmission at an angle of θ f The optical signal is transmitted;

[0081] Step 2-6: If the light signals at all angles have been transmitted, the signal transmission is terminated; if there is at least one angle where the light signal has not been transmitted, return to step 2-1 and transmit the light signal at the next angle until the light signals at all angles have been transmitted.

[0082] In addition, this embodiment also provides a parameter calculation method for the above-mentioned optical one-dimensional phased array antenna based on integrated photonic technology, comprising the following steps:

[0083] Step 1, obtaining the thickness h of the main waveguide, the working wavelength λ of the main waveguide, the minimum spacing p of the phase shifter 201, and the minimum bending radius r of the curved waveguide 301, wherein the main waveguide includes the curved waveguide 301 and the straight waveguide 401; defining the width of the main waveguide as w, the length of the main waveguide as L, and the distance between the central axes of two adjacent straight waveguides 401 as d, using the finite difference eigenmode algorithm to calculate different values ​​of d, w and L, to obtain the near-field electric field intensity distribution of a single antenna unit 6, and using the working wavelength λ of the main waveguide and d=λ / 2, to obtain d;

[0084] Step 2: Perform Fourier transform on the near-field electric field intensity distribution of a single main waveguide to obtain the far-field electric field intensity distribution of the entire phased array antenna, and then calculate the scanning range of the entire phased array antenna based on the far-field electric field intensity distribution;

[0085] Step 3: Combine the far-field scanning range of the entire phased array antenna and the actual application scenario, use the single-mode condition of the waveguide to determine w, and use d and w to obtain the number N and the length L of the main waveguide;

[0086] Step 4: According to the number of waveguides N, the number of adjacent auxiliary waveguides 2N0 affected by each main waveguide is calculated using the finite difference time domain algorithm. According to N0, the number of auxiliary waveguides 801 K is calculated to meet: K ≥ N0, and the calculation is completed.

[0087] This embodiment avoids the physical process of converting the optical signal coupling between waveguides into signal crosstalk between antenna units. Therefore, the signal crosstalk between antenna units is completely unaffected by the optical signal coupling efficiency between waveguides, breaking through the limitation of waveguide coupling on the spacing between optical phased array antenna units. Ultimately, it can be achieved that when the spacing between adjacent antennas is less than half a wavelength, the signal crosstalk between antenna units can be completely eliminated by using identical antenna units, which can be applied to other suitable fields such as radar signal transmission.

Claims

1. An optical one-dimensional phased array antenna based on integrated photon technology, comprising a beam splitter (1), a phase shifter array (2), a curved waveguide array (3), a linear waveguide array (4), an overall antenna (5), a circulator (7), a receiver (701) and a laser (702); the phase shifter array (2) comprises N phase shifters (201) respectively connected to N second ends of the beam splitter (1); the curved waveguide array (3) comprises N curved waveguides (301) respectively connected to the N phase shifters (201); the linear waveguide array (4) comprises N linear waveguides (401) respectively connected to the N curved waveguides (301); The overall antenna (5) comprises a plurality of optical antennas (501) respectively connected to N linear waveguides (401), N being a positive integer; the first end of the beam splitter (1) is connected to the A end of the circulator (7), the B end of the circulator (7) is connected to a receiver (701) for receiving optical signals, and the C end of the circulator (7) is connected to a laser (702) for generating optical signals; each phase shifter (201) and its corresponding curved waveguide (301), the linear waveguide (401) and the optical antenna (501) form an antenna unit (6), and the antenna unit (6) is used to receive or transmit optical signals at a specific angle; the characteristics are as follows: The number of the optical antennas (501) is S, where S is a positive integer; It also includes two auxiliary waveguide arrays (8) respectively arranged on both sides of the linear waveguide array (4), each auxiliary waveguide array (8) includes K auxiliary waveguides (801), K is a positive integer, 2K+N=S; each auxiliary waveguide (801) is connected to a corresponding optical antenna (501); The curved waveguide (301), the straight waveguide (401) and the auxiliary waveguide (801) all include a light guiding layer and a cladding layer enveloping the light guiding layer, wherein the cross section of the light guiding layer is a rectangle, the length of the bottom side of the rectangle is defined as the width of the waveguide, and the length of the side perpendicular to the bottom side is defined as the thickness of the waveguide; The width of each curved waveguide (301) is defined as w1, the width of each straight waveguide (401) is defined as w2, and the width of each auxiliary waveguide (801) is defined as w3; the thickness of each curved waveguide (301) is defined as h1, the thickness of each straight waveguide (401) is defined as h2, and the thickness of each auxiliary waveguide (801) is defined as h3; the length of each straight waveguide (401) is defined as L2, and the length of each auxiliary waveguide (801) is defined as L3; the distance between the central axes of two adjacent straight waveguides (401) is defined as d2, and the distance between the central axes of two adjacent auxiliary waveguides (801) is defined as d3; the number of adjacent auxiliary waveguides (801) affected by each straight waveguide (401) is 2N0; then the following conditions are satisfied: w1=w2=w3, h1=h2=h3, d2=d3, L2=L3; K≥N0; d3≤λ / 2, where λ is the wavelength of the working optical signal; Each auxiliary waveguide (801) is used to receive and transmit an optical signal diffused into the auxiliary waveguide (801) due to coupling in the corresponding straight waveguide (401) to the corresponding optical antenna (501), or diffuse part of the optical signal received by the optical antenna (501) into the corresponding straight waveguide (401) through coupling.

2. The optical one-dimensional phased array antenna based on integrated photonic technology according to claim 1, characterized in that: The light-guiding layer materials of the curved waveguide (301), the straight waveguide (401) and the auxiliary waveguide (801) are all made of silicon, silicon nitride or lithium niobate, and the cladding materials are all made of silicon dioxide.

3. The optical one-dimensional phased array antenna based on integrated photonic technology according to claim 2, characterized in that: The number of the antenna units (6) is sixty-four, λ=1.31 μm, w1=w2=w3=0.5 μm, h1=h2=h3=0.22 μm, d2=d3=0.655 μm, L2=L3=20 μm; K=3.

4. The optical one-dimensional phased array antenna based on integrated photonic technology according to claim 3, characterized in that: The phase shifter (201) is a thermal phase shifter or an electro-optical phase shifter; and the optical antenna (501) is a grating antenna, a grating array antenna or a metasurface antenna.

5. A signal receiving and transmitting method of an optical one-dimensional phased array antenna based on integrated photonic technology according to any one of claims 1 to 4, characterized in that: Including signal receiving method and signal transmitting method; The signal receiving method comprises the following steps: Step 1-1: Receive the scanning angle θ of the optical signal as required j ,θ j represents a scanning angle of the jth received optical signal, j is an integer greater than or equal to 1, each scanning angle corresponds to a preset phase, and the phase of each phase shifter (201) is set to the corresponding preset phase; Step 1-2, scanning angle is θ j An optical signal enters from an optical antenna (501), a portion of which passes through each straight waveguide (401), a corresponding curved waveguide (301), and a phase shifter (201) in sequence, and then converges and enters a beam splitter (1); another portion of the optical signal enters an auxiliary waveguide (801), is coupled and diffused to a corresponding straight waveguide (401) through the auxiliary waveguide (801), and then passes through a corresponding straight waveguide (401), a curved waveguide (301), and a phase shifter (201) in sequence, and finally converges and enters a beam splitter (1); Step 1-3, the combined optical signal enters the circulator (7) from the beam splitter (1) through the A end of the circulator (7); Step 1-4: The optical signal enters the receiver (701) from the B end of the circulator (7), completing a scan angle of θ j Optical signal reception; Step 1-5, if the optical signals of all scanning angles are received, then the signal reception is terminated; if there is at least one scanning angle whose optical signal has not been received, then return to step 1-1 to receive the optical signal of the next scanning angle until the optical signals of all scanning angles are received; The signal transmission method comprises the following steps: Step 2-1: The light signal angle θ is emitted as required f ,θ f represents the angle of the f-th transmitted optical signal, where f is an integer greater than or equal to 1, and sets the phase of each phase shifter (201) to a corresponding preset phase; Step 2-2: The laser (702) generates an initial optical signal. The initial optical signal enters the circulator (7) from the C end of the circulator (7), and then enters the beam splitter (1) from the A end of the circulator (7). Step 2-3, the beam splitter (1) divides the initial optical signal into N parts, and makes them enter the corresponding phase shifter (201) respectively; Step 2-4, N optical signals respectively pass through the phase shifter (201) and the corresponding curved waveguide (301) in sequence and enter the straight waveguide (401), part of the optical signal directly passes through the corresponding straight waveguide (401) to reach the corresponding optical antenna (501), and another part of the optical signal is diffused to the corresponding auxiliary waveguide (801) due to coupling and transmitted, and reaches the optical antenna (501) through the corresponding auxiliary waveguide (801); Step 2-5, each optical antenna (501) transmits an optical signal at an angle of θ f The light signal completes one transmission at an angle of θ f The optical signal is transmitted; Step 2-6: If the light signals at all angles have been transmitted, the signal transmission is terminated; if there is at least one angle where the light signal has not been transmitted, return to step 2-1 and transmit the light signal at the next angle until the light signals at all angles have been transmitted.

6. A method for calculating parameters of an optical one-dimensional phased array antenna based on integrated photonic technology according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, obtaining the thickness h of the main waveguide, the working wavelength λ of the main waveguide, the minimum spacing p of the phase shifter (201), and the minimum bending radius r of the curved waveguide (301), wherein the main waveguide includes the curved waveguide (301) and the straight waveguide (401); defining the width of the main waveguide as w, the length of the main waveguide as L, and the distance between the central axes of two adjacent straight waveguides (401) as d, using a finite difference eigenmode algorithm to calculate different values ​​of d, w and L, to obtain the near-field electric field intensity distribution of a single antenna unit (6), and using the working wavelength λ of the main waveguide and d=λ / 2 to obtain d; Step 2: Perform Fourier transform on the near-field electric field intensity distribution of a single main waveguide to obtain the far-field electric field intensity distribution of the entire phased array antenna, and then calculate the scanning range of the entire phased array antenna based on the far-field electric field intensity distribution; Step 3: Combine the far-field scanning range of the entire phased array antenna and the actual application scenario, use the single-mode condition of the waveguide to determine w, and use d and w to obtain the number N and the length L of the main waveguide; Step 4: According to the number of waveguides N, the number of adjacent auxiliary waveguides 2N0 affected by each main waveguide is calculated using the finite difference time domain algorithm. According to N0, the number of auxiliary waveguides (801) K is calculated to satisfy: K≥N0, and the calculation is completed.

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