JPWO2019207638A1 - Optical phased array and LIDAR sensor using the same - Google Patents

Abstract

An optical phased array (OPA) capable of providing a beam steering or beam scanning function with a relatively small phase shift without requiring a complicated calibration process for determining a phase shift compensation amount is realized. This optical phased array is composed of an optical waveguide formed on a substrate, and a bus waveguide in which the input light propagates and a part of the light propagating in the bus waveguide arranged on the bus waveguide, respectively. A plurality of optical couplers for extracting, a plurality of waveguide lines for propagating the lights extracted by the plurality of optical couplers, and a phase shifter provided in the bus waveguide are provided. The plurality of waveguide lines have the same optical path length, and the phase shifter is provided in each section sandwiched by adjacent optical couplers in the bus waveguide.

Description

  The present invention relates to an optical phased array that controls the emission direction of a light beam to provide a function of beam steering or beam scanning, and a LiDAR (Light Detection and Ranging) sensor using the same.

  The LiDAR sensor is used for remote sensing and distance measurement applications, and is used for real-time three-dimensional mapping and object detection, tracking, and identification in, for example, an automatic driving system.

  The LiDAR sensor scans a laser beam in an observation space, irradiates an object in the space, and the flight time until the irradiated beam reaches the object, is reflected, and returns to a receiver in the LiDAR sensor. The position and distance of the object are measured by measuring (TOF, Time of Flight).

  As such a LiDAR sensor, one that scans a laser beam by using a mechanical rotary component is known, but in some systems such as an advanced driver assistance system (ADAS) and an autonomous driving system. It is desirable to use a solid state beam scanner that can have various advantages. Such advantages include higher sensor reliability, longer sensor life, smaller sensor size, lower sensor weight, and more affordable sensor cost, It is not limited to these.

  One of such solid-state type beam scanners is an optical phased array (OPA). The application of optical phased arrays makes LiDAR sensors faster, more adaptable, and more useful than conventional LiDARs using mechanical beam scanning.

  Conventionally, as a technique related to an optical phased array, it is known to use a zigzag type optical waveguide including a plurality of light receivers in a high frequency phase shifter for a high frequency phased array antenna (Patent Document 1). This high frequency phase shifter propagates the light modulated by the high frequency signal to the zigzag type optical waveguide, and receives and detects the light at each position by a plurality of light receivers arranged at different positions along the optical waveguide, A plurality of high frequency signals to which different phase shifts are applied are extracted. Then, a high frequency signal to which a desired phase shift has been applied is selectively output from the extracted plurality of high frequency signals. However, this high frequency phase shifter merely uses the optical waveguide as a means for giving a delay time to the high frequency signal, and does not give a phase shift to the light itself. Therefore, this technique cannot be used for optical phased arrays.

  As another related prior art, there is known an optical signal processing device having a monolithic integrated semiconductor structure including an optical waveguide forming an optical phase shifter or the like (Patent Documents 2 and 3). In this optical signal processing device, the input light is branched into a plurality of lights by the two-branch waveguides connected in multiple stages. Then, an individual phase shift is given to each of the branched lights by the phase shifter provided in the output waveguide that outputs each of the branched lights. However, this optical signal processing device does not form an optical phased array. In other words, this device simply splits light and controls the phase individually, and an antenna element array for outputting diffracted light (phase-controlled light so that the main maximum beam of diffracted light is generated Is not provided in the LiDAR as it is.

  Further, when trying to transfer the configuration of the optical signal processing device to an optical phased array, the phases of the light output from the output waveguides arranged in a line are linearly changed from the end to the linear as shown by the following equation. Need to increase.

  Here, m is a number sequentially assigned from the end to the antenna elements arranged in a row when the output waveguides arranged in a row are regarded as the antenna elements arranged in a row in the optical phased array. Further, P is the arrangement interval of the antenna elements, λ is the wavelength of the output light, and θ is the direction angle of the main maximum beam of the diffracted light with respect to the normal to the plane formed by the light emitting end of the antenna element. As is clear from the equation (1), the phase shifter provided in each channel (that is, each antenna element and each of the optical transmission lines connected to the antenna element) can provide different phase shifts. And the accumulated value of the phase shift must be able to exceed 2π.

  However, in the above optical signal processing device, the phase of the light output from each output waveguide is determined only by the phase shifter provided in each output waveguide, and the phase shifter of each output waveguide is Since they are controlled independently of each other, the process for correctly finding the value of the cumulative phase shift exceeding 2π becomes complicated. Therefore, the control operation for causing the above configuration to function as the optical phased array becomes considerably complicated.

  As a prior art most relevant to the present invention, LiDAR configured as a device based on a photo integrated circuit (PIC) is known (Non-Patent Document 1). This device has a bus waveguide, cascaded thermal phase shifters, and cascaded evanescent couplers, which are grating-based antenna elements. It is connected. In this device, the function of beam steering is provided by controlling the phase increment of the bus waveguide.

  However, this device has the following drawbacks. That is, the distances of the waveguides inserted between the evanescent coupler and the antenna element of the grating base are not equal to each other. That is, the total optical path length (total OPL (Optical Path Length)) of each waveguide is not equal. Therefore, the phase relationship of the output light between the adjacent antenna elements is not constant when the phase shifter is idle (when the phase shifter is not energized).

  Such a difference in OPL (OPL difference, optical path difference) may cause a channel having an undesirable phase shift. In general, when the phase shift output from the antenna element does not follow the linear rule shown in the equation (1), the beam width of the main maximum beam (main beam or main lobe) of the diffracted light output from the antenna element array. Spread, resulting in poor angular resolution.

  Further, even when the phase shift in the bus waveguide maintains the linearity depending on the refractive index and maintains the linear phase tilt as shown in the equation (1), the main beam has a certain beam angle. Since it is in a shifted state, a calibration process is required to give an additional phase shift to all beam shifters to compensate for the beam angle.

  In the calibration process, it is necessary to specify the magnitude of these additional phase shifts and include the initial bias voltage in the heater control voltage of the phase shifter to compensate for the additional phase shifts. This makes the operation and control of the optical phased array more complicated.

  A further problem arises when the optical phased array operates in a wide frequency band (ie, in a wide wavelength band). In this case, due to the wavelength dependence of the refractive index, the phase shift will be different at different wavelengths, and the calibration process will be considerably complicated.

US Pat. No. 5,222,162 US Pat. No. 5,770,472 US Pat. No. 5,930,031

Christopher V. Paulton, Ami Yaacobi, David B. Cole, Matthew J.C. Byrd, Manan Raval, Diedrik Vermeulen, Michael R. et al. Watts, Coherent solid-state LIDAR with silicon photonic optical phased arrays, Optics Letters, Vol. 42, No. 20 / October 15, 2017.

  It is an object of the present invention to realize an optical phased array (OPA) capable of providing a beam steering or beam scanning function with a relatively small phase shift without requiring a complicated calibration process for determining a phase shift compensation amount. Is.

One aspect of the present invention is an optical phased array configured by an optical waveguide formed on a substrate, wherein a bus waveguide in which input light propagates and the bus waveguide arranged on the bus waveguide are provided. A plurality of optical couplers respectively extracting a part of the light propagating through the waveguide, a plurality of waveguide lines respectively propagating the light extracted by the plurality of optical couplers, a phase shifter provided in the bus waveguide, The plurality of waveguide lines have equal optical path lengths, and the phase shifter is provided in each section of the bus waveguide sandwiched by the adjacent optical couplers.
According to another aspect of the present invention, a light emitting end of each of the plurality of waveguide lines respectively connected to the plurality of optical couplers has a predetermined length along a line parallel to the first direction of the substrate. The plurality of optical couplers are spaced apart from each other with a first predetermined distance along a second direction orthogonal to the first direction, and along the first direction. The plurality of waveguide lines are arranged so as to be separated from each other by a second predetermined distance that is a sum of a predetermined interval and the first predetermined distance, and the plurality of waveguide lines are respectively one of the plurality of optical couplers A linear waveguide having one end connected to the linear waveguide and extending in the first direction, and a curved guide connected to the linear waveguide for converting the propagation direction of light by 90 ° toward the output end of the waveguide line. A waveguide, and the bus waveguide , A plurality of serpentine waveguides part constitutes a part of the optical coupler is configured by cascade-connected.
According to another aspect of the present invention, the optical coupler is composed of an evanescent coupler, each of the meandering waveguides constituting the bus waveguide has a straight waveguide and a curved waveguide, and A part of the curved waveguide of the meandering waveguide constitutes a part of the evanescent coupler.
According to another aspect of the present invention, the meandering waveguide includes one first curved waveguide for converting a light propagation direction by 180 ° and two second curved waveguides for converting a light propagation direction by 90 °. A waveguide and two linear waveguides that connect the first curved waveguide to the two second curved waveguides, respectively, and a part of each of the two second curved waveguides is formed. , Constitutes a part of the adjacent evanescent coupler.
According to another aspect of the present invention, the phase shifter is provided in one or both of the two linear waveguides connecting the first curved waveguide to the two second curved waveguides.
According to another aspect of the present invention, each of the phase shifters includes a heater provided in a part of the bus waveguide, and the heaters have the same temperature when being supplied with the same current. , The size including the length, the width, and the thickness, and the shape are the same as each other.
According to another aspect of the present invention, each section between the adjacent optical couplers along the bus waveguide is configured to have the same length, so that the lights extracted from the adjacent optical couplers are adjacent to each other. All the phase differences are configured to have a predetermined value.
According to another aspect of the invention, the predetermined value is an odd multiple of π or an integral multiple of 2π.
According to another aspect of the present invention, each of the waveguide lines is connected to a grating-based antenna element composed of a perturbation waveguide whose size in the width direction or the depth direction is changed, Light is output from the surface of the substrate by each of the waveguides.
According to another aspect of the present invention, the material of the substrate is any one of Si ₃ N ₄ , Si, SiON, LiNbO ₃ , LiTaO ₃ , and SiC.

According to the present invention, an optical phased array (OPA) capable of providing a beam steering (scanning) function with a relatively small phase shift without requiring a complicated calibration process for determining the amount of phase shift compensation is provided. Can be realized.
According to the present invention, all the heaters connected by the two electrode pads are not required without requiring a complicated calibration process for determining the phase shift compensation amount and without individually controlling the plurality of heaters. It becomes possible to realize an optical phased array (OPA) capable of providing a beam steering (scanning) function by a method of linearly changing the accumulated phase shift difference.

FIG. 1 is a diagram showing a configuration of a LiDAR sensor using an optical phased array according to an embodiment of the present invention. FIG. 2 is a diagram showing a configuration of the optical phased array according to the embodiment of the present invention. FIG. 3 is a diagram showing the configuration of one meandering waveguide that constitutes the bus waveguide of the optical phased array shown in FIG. FIG. 4A is a diagram showing an example of a far-field image of light emitted when the phase shifter is in a non-operating state in the optical phased array shown in FIG. 2 (when the phase difference is an odd multiple of π). FIG. 4B is a diagram showing another example (in the case where the phase difference is an integral multiple of 2π) of the far-field image of the light emitted when a phase shift is given by the phase shifter in the optical phased array shown in FIG. 2. Is. FIG. 5A is a diagram showing an example of a perturbation waveguide that can be used as an antenna element of the optical phased array shown in FIG. 2. 5B is a diagram showing another example of a perturbation waveguide that can be used as an antenna element of the optical phased array shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment described below is a LiDAR sensor using the optical phased array of the present invention. However, the LiDAR sensor is an example, and the application field of the optical phased array of the present invention is not limited to this. For example, the optical phased array of the present invention can be used for security applications such as surveillance devices, flight navigation applications such as drones, and any other applications that require three-dimensional information.

  FIG. 1 is a diagram showing a configuration of a LiDAR sensor using an optical phased array according to an embodiment of the present invention. The LiDAR sensor 100 includes a light source 102, an optical phased array (OPA) 104, a light receiving sensor 106, and a processing device 108.

  The light source 102 includes, for example, a semiconductor laser, and outputs modulated light that is modulated based on a signal from the processing device 108. This modulation is performed, for example, by modulating the current supplied to the semiconductor laser with a signal from the processing device 108. Instead, the light source 102 is further provided with an optical modulator, and the optical modulator is operated by a signal from the processing device 108, and the light from the semiconductor laser is modulated by the optical modulator and output. Can be This modulated light output from the light source 102 becomes the input light of the OPA 104.

  The OPA 104 splits the input light from the light source 102 into a plurality of lights and outputs the plurality of split lights from the antenna element array. As a result, the OPA 104 outputs a main maximum beam (main beam or main lobe) of the diffracted light, which is generated by diffracting the output lights and interfering with each other. Further, the OPA 104 imparts a predetermined phase shift to each of the plurality of branched lights, deflects the output direction of the main maximum beam, and performs beam steering or beam scanning of the main maximum beam. The specific configuration of the OPA 104 will be described later.

  The light receiving sensor 106 is composed of, for example, a condenser lens and a light receiving element array such as a CCD. The light receiving sensor 106 detects light (reflected return light) in which the main maximum beam output from the OPA 104 is reflected or scattered by an object and returns.

  The processing device 108 causes the light source 102 to output modulated light. As described above, the processing device 108 gives a signal to, for example, a semiconductor laser or an optical modulator included in the light source 102, and causes the light source 102 to output modulated light. Further, the processing device 108 outputs the main maximum beam from the OPA 104, and after the light is reflected or scattered by the object, it becomes a reflected return light and is received by the light receiving sensor 106 as a flight time (Time) of the beam. Of Flight) is calculated. The processing device 108 also identifies the arrival direction of the reflected return light that reaches the light receiving sensor 106. As a result, the processing device 108 outputs space mapping information indicating the shape and position of the object in space. The processing device 108 may be configured by a processor such as a digital signal processor (DSP, Digital Signal Processor) or the like, or a computer.

FIG. 2 is a diagram showing the configuration of the OPA 104. The OPA 104 is configured as a solid state type OPA using an optical waveguide formed on the substrate 200. In the present embodiment, the substrate 200 is an oxidized silicon substrate or quartz glass containing SiO ₂ as a main component, and an optical waveguide is formed of, for example, Si ₃ N ₄ embedded in SiO ₂ . However, this configuration is an example, and the substrate 200 may be configured using a material such as Si ₃ N ₄ , Si, SiON, LiNbO ₃ , LiTaO ₃ , or SiC.

  The OPA 104 serves as an optical waveguide formed on the substrate 200, and includes a bus waveguide 202 to which input light from the light source 102 is input and four waveguide lines 204a, 204b, 204c, and 204d (shown as diagonally hatched portions in the drawing, respectively). A waveguide portion including a cross-hatched portion), and antenna elements 206a, 206b, 206c, 206d that generate a main maximum beam 236 of diffracted light. The antenna elements 206a, 206b, 206c, and 206d form an antenna element array 208 arranged at a predetermined interval p. The antenna elements 206a, 206b, 206c, and 206d are linear waveguides in this embodiment.

  The bus waveguide 202 is provided with a plurality of optical couplers 220a, 220b, 220c, 220d for extracting a part of the light propagating through the bus waveguide 202. Two phase shifters 222a and 224a, 222b and 224b, and 222c and 224c are provided between the adjacent optical couplers 220a and 220b, 220b and 220c, and 220c and 220d, respectively. Has been.

  In the present embodiment, the optical couplers 220a, 220b, 220c, 220d are evanescent couplers that utilize the coupling of light via evanescent waves between two optical waveguides that are adjacent to each other with a predetermined distance. The phase shifters 222a, 222b, 222c and 224a, 224b, 224c are respectively composed of heaters 226a, 226b, 226c and 228a, 228b, 228c provided in a part of the bus waveguide 202.

  As a result, the phase shifter 222a and the like change the refractive index in the portion of the bus waveguide 202 immediately below the heater 226a and the like due to the temperature change given by the heater 226a and the like due to the thermo-optical effect of the material forming the bus waveguide 202. And change the phase of the light passing through the part. Here, the heaters 226a, 226b, 226c, and 228a, 228b, 228c are, in the present embodiment, a layer of gold (Au) on titanium (Ti) which is a base layer formed on the bus waveguide 202, for example. It is a thin film heater formed by forming.

  A part of the light propagating in the bus waveguide 202 extracted by the optical couplers 220a, 220b, 220c, and 220d propagates in the waveguide lines 204a, 204b, 204c, and 204d, respectively. The light output ends 210a, 210b, 210c, 210d of the waveguide lines 204a, 204b, 204c, 204d are arranged at predetermined intervals p along a line 232 parallel to the Y direction which is the first direction of the substrate 200. They are arranged and connected to the antenna elements 206a, 206b, 206c, and 206d, which are linear waveguides, respectively. The antenna elements 206a, 206b, 206c, 206d have the same optical path length as each other, and their light emitting ends 212a, 212b, 212c, 212d are arranged along the lower edge 234 of the substrate 200, which is parallel to the Y direction, as shown in FIG. The light output ends 210a and the like are arranged at the same predetermined interval p.

  As a result, the antenna elements 206a, 206b, 206c, and 206d forming the antenna element array 208 output lights having a predetermined phase difference between them, and the main maximum of the diffracted light formed by the output lights. The beam 236 is output in the direction determined by the phase difference. Then, by changing the phase difference with the phase shifter 222a or the like, the deflection angle θ of the main maximum beam 236 is changed, and the beam steering operation is performed. Here, the deflection angle θ is defined as an angle formed by the main maximum beam 236 with respect to a normal line 238 of a plane (in this embodiment, the edge 234 of the substrate 200) including the light emitting ends 212a, 212b, 212c, and 212d. It

  Particularly, in the OPA 104 of this embodiment, the waveguide lines 204a, 204b, 204c, and 204d have the same optical path length. Further, as described above, the phase shifters 222a and the like are provided in the respective sections of the bus waveguide 202 sandwiched by the adjacent optical couplers 220a and the like. Further, when the phase shifters 222a, 224a, etc. are in the non-operating state (that is, the heaters 226a, 228a, etc. are in the non-energized state), the respective optical couplers 220a, etc. between the adjacent optical couplers 220a, etc. along the bus waveguide 202 are each. The sections are configured such that the phase differences between the lights extracted from the adjacent optical couplers 220a and the like are odd multiples of π (that is, opposite phases).

  As a result, in the OPA 104, since the waveguide lines 204a and the like have the same optical path length, the adjacent light output ends 210a and the like (and thus the adjacent light emission ends 212a and the like) when the phase shifters 222a and the like are in the non-operating state. The phase difference of the light output from the optical waveguide is a phase difference determined by the mutual positional relationship of the optical coupler 220a and the like along the bus waveguide 202. That is, since there is no phase shift additionally generated with respect to the phase difference determined by the positional relationship, it is not necessary to compensate the phase shift offset, and the OPA 104 can be operated by simple control.

  Further, when the phase shifter 222a or the like is operated, the phase shift amount of the light output from the optical coupler 220a or the like toward the waveguide line 204a or the like is the light closest to the light input end 230 along the bus waveguide 202. The phase shift amounts generated by the plurality of phase shifters 222a and the like are sequentially accumulated from the coupler 220a and the like, and become the phase shift amount that is sequentially accumulated. Therefore, in the OPA 104, a relatively small phase shift is applied to each of the phase shifters 222a and the like to linearly and accurately generate a cumulative phase shift exceeding 2π and the main maximum beam 236 emitted from the antenna element array 208. The emission direction can be changed without increasing the spread width.

  Further, when the phase shifter 222a or the like is operated to change the deflection angle θ of the main maximum beam 236, between all the adjacent optical couplers 220a and the like, the lights extracted from the adjacent optical couplers 220a and the like are mutually separated. It suffices that the changes in the phase difference of are the same. Therefore, the phase shifters 222a and the like provided between the adjacent optical couplers 220a and the like respectively correspond to the phases of the light extracted from the closest optical coupler 220a and the like upstream in the light propagation direction of the bus waveguide 202. , And only the same amount of phase shift should be applied.

  Therefore, if the phase shifters 222a and the like and 224a and the like are configured with the same design, respectively, the phase shifters 222a and the like and 224a and the like are adjacent to each other by applying a current of substantially the same magnitude. The deflection angle θ of the main maximum beam 236 can be changed by causing the same phase difference between the lights extracted from the optical coupler 220a and the like. Specifically, the lengths, widths, and thicknesses of the heaters 226a and 228a and 228a and the like that configure the phase shifters 222a and 224a and the like are set so that they are at the same temperature when the same current is applied. The sizes and shapes included may be configured to be the same as each other. Two terminals of each heater such as the heaters 226a and 228a are connected to, for example, an electrode pad (not shown) provided on the substrate 200, and electricity is supplied from the outside of the substrate 200 via the electrode pad. This makes it possible to generate equal phase shifts in all the phase shifters 222a, 224a, etc., and operate the OPA 104 more easily.

  In the present embodiment, the heater 226a and the like configure the light extracted from the adjacent optical coupler 220a and the like so that the mutual phase difference is an odd multiple of π (that is, the opposite phase). Due to the temperature dependence of the refractive index of the substrate 200, the phase shift that can be realized by the phase shifter 222a or the like becomes only one of the increasing and decreasing directions with respect to the increase of the absolute value of the current to the heater 226 and the like. This is because. In this case, since the main maximum beam 236 moves only in one direction as the absolute value of the current passing through the phase shifter 222a or the like increases, the main maximum beam 236 can be continuously moved from one end of the operating angle range to the other. This is because it is necessary to arrange the main maximum beam 236 at the end of the operating angle range when the phase shifter 222a and the like are in the non-operating state.

Therefore, for example, a substrate having an electro-optical effect such as LiNbO ₃ is used as the substrate 200, and a phase shifter capable of increasing or decreasing the phase of light by reversing the direction of the electric field applied to the substrate 200 is used as the phase shifter 222a. In this case, the section of the bus waveguide 202 between the adjacent optical couplers 220a and the like need not necessarily be configured so that the lights extracted from the adjacent optical couplers 220a and the like have opposite phases. In this case, depending on whether the main maximum beam 236 is placed at the center of the operating angle range or at the position of the predetermined deflection angle θ when the phase shifter 222a or the like is in the non-operating state, the adjacent optical coupler 220a or the like is separated. The section of the bus waveguide 202 between them can be configured such that the phase difference between the lights extracted from the adjacent optical couplers 220a and the like becomes an integral multiple of 2π or a predetermined value.

Returning to FIG. 2, the OPA 104 is more specifically configured as follows.
As described above, the optical output ends 210a and the like of the waveguide lines 204a and the like connected to the optical coupler 220a and the like are provided along the line 232 parallel to the Y direction, which is the first direction of the substrate 200. They are arranged at intervals p. The optical couplers 220a, 220b, 220c, 220d are separated from each other by a first predetermined distance d along the X direction, which is the second direction orthogonal to the first direction, and along the Y direction. They are arranged so as to be separated from each other by a second predetermined distance s (= d + p) which is a sum of the predetermined distance p and the first predetermined distance d.

  In addition, the waveguide lines 204a, 204b, 204c, and 204d are connected to the optical couplers 220a, 220b, 220c, and 220d at their one ends, and the linear waveguides 204a-1, 204b-1, and 204c extend in the Y direction. -1, 204d-1 (diagonally hatched portions) and the curved waveguide 204a connected to each of the linear waveguides and converting the propagation direction of light by 90 ° toward the light output ends 210a, 210b, 210c, 210d. -2, 204b-2, 204c-2, 204d-2 (each shown in the cross-hatched portion). Here, the curved waveguides 204a-2, 204b-2, 204c-2, and 204d-2 have the same curvature r.

  Accordingly, the difference in the length of the linear waveguides 204b-1, 204c-1, 204d-1 with respect to the length of the linear waveguide 204a-1 is determined by the arrangement interval s of the optical coupler 220a and the like in the Y direction and the optical output end. It is determined by the arrangement interval p of 210a, etc., and becomes −s + p, −2s + 2p, and −3s + 3p, respectively. As described above, since s = d + p, the above differences are -d, -2d, and -3d, respectively.

  The curved waveguides 204a-2, 204b-2, 204c-2, and 204d-2 connected to the straight waveguides 204a-1, 204b-1, 204c-1, and 204d-1 are arranged in a line 232. The lengths to the respective light output ends 210a, 210b, 210c, 210d are determined by the arrangement distance d of the optical coupler 220a and the like in the X direction and are 0, d, 2d, 3d, respectively.

  Therefore, the difference -d, -2d, -3d in the lengths of the linear waveguides 204b-1, 204c-1, 204d-1 with respect to the linear waveguide 204a-1 is defined by the curved waveguides 204a-2, 204b-2, The waveguide lines 204a, 204b, 204c, 204d have the same length, and thus the same optical path length, offset by the difference in length from 204c-2, 204d-2 to the light output ends 210a, 210b, 210c, 210d. Will have.

  Further, the bus waveguide 202 of the OPA 104 is configured by cascade-connecting a plurality of meandering waveguides, a part of which constitutes a part of the optical coupler 220a and the like. More specifically, the bus waveguide 202 includes a meandering waveguide 202-1 connecting the points A1 and A2 shown in FIG. 2, a meandering waveguide 202-2 connecting the points A2 and A3, and A meandering waveguide 202-3 connecting the point A3 and the point A4 is connected in cascade.

  Since the meandering waveguides 202-1, 202-2, and 202-3 have the same configuration, the details of the configuration will be described below by taking the meandering waveguide 202-1 as an example.

  FIG. 3 is a partial detailed view showing the configuration of the meandering waveguide 202-1. The meandering waveguide 202-1 has two straight waveguides 300 and 302 (both are hatched portions in the drawing) and three curved waveguides 310, 312 and 314. The curved waveguides 310, 312, 314 are, for example, arcuate waveguides having the same radius of curvature r. The curved waveguide 310 is a first curved waveguide that converts the propagation direction of light by 180 °, and the curved waveguides 312 and 314 are two second curved waveguides that convert the propagation direction of light by 90 °. is there.

  In FIG. 3, the phase shifters 222a and 224a and the heaters 226a and 228a are not shown in order to simplify the drawing and facilitate understanding, but in reality, the linear waveguides 300 and 302 are not shown. , And phase shifters 222a and 224a, respectively.

  The straight waveguides 300 and 302 connect the curved waveguide 310 to the curved waveguides 312 and 314, respectively. Therefore, a part of the curved waveguides 312 and 314, which are the second curved waveguides connected to the points A1 and A2, respectively, configure a part of the adjacent optical couplers 220a and 220b, which are evanescent couplers ( (Fig. 2).

  Here, as described above, since the adjacent optical couplers 220a and the like are arranged so as to be separated from each other by the second predetermined distance s along the Y direction which is the first direction, the Y between the points A1 and A2. The distance in the direction is s. Further, since the curved waveguides 312 and 314 have the same radius of curvature r, the Y direction between the position where the curved waveguide 312 connects to the linear waveguide 300 and the position where the curved waveguide 314 connects to the linear waveguide 302. The distance along is also s.

Further, since the adjacent optical couplers 220a and the like are arranged so as to be separated by the first predetermined distance d along the X direction which is the second direction, the distance in the X direction between the points A1 and A2 is d. is there. Further, since the meandering waveguide 202-1 and the like of the present embodiment do not include a linear waveguide extending in the X direction in order to reduce the size in the X direction,
d = 4r (2)
Is.

When the lengths of the straight waveguides 300 and 302 are q and b, respectively, the path length Lc of the meandering waveguide 202-1 (that is, the path length Lc from the points A1 to A2) is
Lc = b + q + 2πr (3)
Becomes Also, from FIG.
b = s + q (4)
The relationship is established.

Here, the phase difference φ _{0 of the} light output from the adjacent optical couplers 220a and 220b to the waveguide lines 204a and 204b is given by the following equation, where the wavelength of the input light is λ ₀ .

As described above, in the present embodiment, the phases of the lights output from the adjacent optical couplers 220a and the like are opposite to each other (hence, the phase difference is an odd multiple of π).
φ ₀ = π (2i + 1) (i = 0, 1, 2, ...) (6)
Is. Therefore, it is understood from the equations (5) and (6) that the following equation must be satisfied.

Further, the equation (7) is the following equation using the equation (3).

  Here, the radius of curvature r is given as a design value in which the bending waveguide loss of the bending waveguides 310, 312, 314 does not exceed a predetermined amount. Therefore, the first predetermined distance d of the meandering waveguide 202-1 is given as a design value of optical characteristics. Further, the arrangement interval p is given as a design value of the optical characteristic determined by the requirements of the wavelength of the light used and the deflection angle θ of the main maximum beam 236. That is, the second predetermined distance s (= d + p) is also given from the design value of the optical characteristic.

  Therefore, Lc is determined by adjusting the lengths b and q of the linear waveguides 300 and 302 with respect to s and d determined from the optical characteristic design. Since b and q satisfy the formula (4) and d satisfies the formula (2), the formula (4) and the formula (2) are applied to the formula (8) to obtain the following formula.

  In conclusion, it is understood that the condition for making the phases of the lights output from the optical couplers 220a and 220b adjacent to each other by the meandering waveguide 202-1 to the waveguide lines 204a and 204b mutually opposite phases is as follows.

  In other words, by setting the distances q and b of the linear waveguides 300 and 302 so as to have the lengths q and b that satisfy the expressions (10) and (4), the adjacent optical couplers 220a and 220b can be separated from each other. The phases of the lights output to the waveguide lines 204a and 204b can be opposite to each other.

  By designing the other meandering waveguides 202-2 and 202-3 in the same manner as the meandering waveguide 202-1, the corresponding meandering lines 204a and the like are provided between all the adjacent optical couplers 220a and the like. The phases of the output lights can be opposite to each other. Then, if an equal amount of phase shift is generated between all the adjacent optical couplers 220a and the like by energizing the phase shifter 222a and the like, the deflection angle of the main maximum beam 236 output from the antenna element array 208 is changed. Can be changed.

  In the present embodiment, the phase shifters 222a and 224a are provided on both the linear waveguides 300 and 302 of the meandering waveguide 202-1. However, the required phase shift amount and power consumption conditions for control are required. Accordingly, the phase shifter 222a or the like can be provided on one or both of the linear waveguides 300 and 302. The same applies to the meandering waveguides 202-2 and 202-3.

  4A and 4B are diagrams showing far-field images of light output from the antenna element array 208. 4A and 4B, the horizontal axis represents the value of sin θ with respect to the deflection angle θ measured from the normal line 238 of the edge 234 of the substrate 200, and the vertical axis represents the light intensity.

  FIG. 4A is a far-field image when the phase shifters 222a and the like are in a non-operating state and the phases of lights output from the adjacent antenna elements 206a and the like are opposite to each other (that is, the phase difference is an odd multiple of π). Is shown. Two main lobes 400 and 402 corresponding to the two main maximum beams are located at both ends of the operating range (that is, the movable angular range of the main maximum beam).

  In FIG. 4B, a phase shifter 222a or the like introduces a phase shift of magnitude π between adjacent antenna elements 206a or the like, and the phases of the light output from the adjacent antenna elements 206a or the like are the same (that is, the phase difference is The far-field image when it becomes (integral multiple of 2π) is shown. One main maximum beam moves, and one main lobe 404 corresponding to the main maximum beam is located at the center of the operating range.

  In the above-described embodiment, the antenna element 206a or the like is an ordinary straight waveguide and outputs the light propagated by the waveguide line 204a or the like from the light emitting end 212a or the like arranged at the edge 234 of the substrate 200. However, it is not limited to this. For example, the antenna element 206a or the like is a grating-based antenna element configured by a perturbation waveguide whose width or thickness changes periodically, and the light propagated by the waveguide line 204a or the like is linear from the surface of the substrate 200. Can be output as light. In this case, by operating the phase shifter 222a or the like, it is possible to change the deflection angle of the main maximum beam with respect to the surface normal of the substrate 200 when viewed from the X direction.

  5A and 5B are diagrams showing examples of the perturbation waveguide as described above, which can be used instead of the antenna element 206a and the like. 5A and 5B, the same elements as those in FIG. 2 are denoted by the same reference numerals.

  In FIG. 5A, the left side of the drawing is a plan view showing a portion of the surface of the substrate 200 on which a grating-based antenna element formed of a perturbation waveguide is formed, and the right side of the drawing is a DD sectional view in the plan view on the left side. .. In FIG. 5A, antenna elements 206a-1, 206b-1, 206c-1, 206d-1 which are perturbation waveguides in which the width of the waveguide seen from the surface of the substrate 200 changes periodically are used. The antenna element 206a-1 and the like are connected to the waveguide line 204a and the like at the position of the line 232. Each of the antenna elements 206a-1 and the like emits light, which is distributed along the length direction thereof, from the surface of the substrate 200 in a direction indicated by an arrow in the DD cross-sectional view. As a result, each of the antenna elements 206a-1 and the like acts as a linear light source extending in the X direction on the surface of the substrate 200, and generates a main maximum beam upward from the surface of the substrate 200. In this structure, the deflection angle of the main maximum beam with respect to the surface normal of the substrate 200 when viewed from the X direction can be changed by operating the phase shifter 222a and the like.

  In FIG. 5B, the left side of the drawing is a plan view showing a portion of the surface of the substrate 200 where the antenna element of the grating base formed of the perturbation waveguide is formed, and the right side of the drawing is an EE cross-sectional view in the plan view on the left side of the drawing. .. In FIG. 5B, antenna elements 206a-2, 206b-2, 206c-2, 206d-2 which are perturbation waveguides in which the thickness of the waveguide periodically changes are used. The antenna element 206a-2 and the like are connected to the waveguide line 204a and the like at the position of the line 232. Each of the antenna elements 206a-2 and the like emits light, which is distributed along the length direction thereof, from the surface of the substrate 200 in a direction indicated by an arrow in the EE sectional view. As a result, each of the antenna elements 206a-2 and the like acts as a linear light source extending in the X direction on the surface of the substrate 200, and generates a main maximum beam upward from the surface of the substrate 200. In this configuration, similarly to FIG. 5A, by operating the phase shifter 222a and the like, it is possible to change the deflection angle of the main maximum beam with respect to the surface normal of the substrate 200 when viewed from the X direction. ..

  As described above, the OPA 104 of the present invention is a solid-state type optical phased array configured by the optical waveguide formed on the substrate 200. The OPA 104 includes a bus waveguide 202 through which input light propagates, and a plurality of optical couplers 220 a and the like arranged on the bus waveguide 202 that extract a part of light propagating through the bus waveguide 202. .. The OPA 104 also includes a plurality of waveguide lines 204a and the like that propagate the lights extracted by the plurality of optical couplers 220a and the like, and a phase shifter 222a and the like provided in the bus waveguide 202. Further, the plurality of waveguide lines 204a and the like have equal optical path lengths, and the phase shifters 222a and the like are provided in respective sections of the bus waveguide 202 sandwiched by adjacent optical couplers 220a and the like.

  According to this configuration, since the waveguide lines 204a and the like have the same optical path length, the adjacent light output ends 210a and the like (and thus the adjacent light emission ends 212a and the like) when the phase shifters 222a and the like are in the non-operating state. The phase difference of the light output from is mainly determined by the mutual positional relationship of the plurality of optical couplers 220a and the like along the bus waveguide 202. That is, since there is no phase shift additionally generated with respect to the phase difference determined by the positional relationship, it is not necessary to compensate the phase shift offset, and the OPA 104 can be operated by simple control.

  Further, when the phase shifter 222a or the like is operated, the phase shift amount of the light output from the optical coupler 220a or the like toward the waveguide line 204a or the like is closest to the light input end 230 along the bus waveguide 202. Since the phase shifts generated by the plurality of phase shifters 222a and the like are sequentially accumulated, the phase shift amounts are sequentially accumulated. Therefore, by providing a relatively small phase shift to each of the phase shifters 222a and the like, accumulated phase shifts exceeding 2π can be accurately performed. The emission direction of the main maximum beam 236 emitted from the antenna element array 208 can be changed.

  The OPA 104 is also a line in which the light output ends 210a and the like of respective lights such as the plurality of waveguide lines 204a and the like connected to the plurality of optical couplers 220a and the like are parallel to the Y direction which is the first direction of the substrate 200. 232 are arranged at a predetermined interval p. Further, the plurality of optical couplers 220a and the like are separated from each other with a first predetermined distance d along the X direction, which is a second direction orthogonal to the Y direction, and with a second predetermined distance s (along the Y direction. = D + p) so as to be separated from each other. Each of the plurality of waveguide lines 204a and the like is connected to one of the plurality of optical couplers 220a and the like at one end thereof and extends in the X direction. The curved waveguides 204a-2 and the like are connected to the optical waveguides 204a-2 and the like and convert the propagation direction of light by 90 ° toward the light output end 210a of the waveguide line 204a and the like. Further, the bus waveguide 202 is configured by cascade-connecting a plurality of meandering waveguides 202-1 and the like, a part of which constitutes a part of the optical coupler 220a and the like.

  With this configuration, the waveguide line 204a and the like having the same optical path length can be simply configured. Further, in order to provide more channels, it is only necessary to additionally arrange the serpentine waveguides 202-1 and the like connected in cascade and the corresponding waveguide lines 204a and the like at a predetermined interval, so that an OPA with high design expandability is realized. be able to.

  Further, in the OPA 104, the optical coupler 220a and the like are configured by an evanescent coupler that utilizes the coupling of light via an evanescent wave between two optical waveguides that are close to each other with a predetermined distance. Further, the meandering waveguides 202-1 and the like that form the bus waveguide 202 have straight waveguides 300 and 302 and curved waveguides 310, 312 and 314, and the curved waveguides such as the meandering waveguide 202-1 and the like. Some of 312 and 314 form part of an evanescent coupler such as the optical coupler 220a.

  According to this configuration, the light propagating through the bus waveguide 202 can be distributed to the waveguide line 204a and the like without increasing the propagation loss of the bus waveguide 202.

  Further, in the OPA 104, the curved waveguides forming the meandering waveguide 202-1 are one first curved waveguide 310 that converts the propagation direction of light by 180 ° and two curved waveguides that convert the propagation direction of light by 90 °. The second curved waveguides 312 and 314 and the two straight waveguides 300 and 302 that connect the first curved waveguide 310 to the two second curved waveguides 312 and 314, respectively. Then, a part of each of the two second curved waveguides 312 and 314 constitutes a part of the adjacent optical couplers 220a and 220b which are evanescent couplers.

  According to this configuration, the adjacent optical couplers 220a and the like arranged at a predetermined distance are connected by the meandering waveguides 202-1 and the like having the same predetermined optical path length. It is possible to make the phase difference between the respective lights emitted from the optical waveguides etc. to the waveguide line 204a constant.

  Further, in the OPA 104, the phase shifter 222a and the like are provided on one or both of the two linear waveguides 300 and 302 that connect the first curved waveguide 310 to the two second curved waveguides 312 and 314. .. According to this configuration, the total length of the phase shifters 222a and 224a along the meandering waveguide 202-1 can be freely selected within a range of lengths obtained by adding the lengths of the linear waveguides 300 and 302. Therefore, the degree of freedom in designing the operating voltage of the phase shifters 222a and 224a is improved.

  Further, in the OPA 104, the phase shifter 222a and the like are configured by the heaters 226a and 228a and the like that are provided in a part of the bus waveguide 202. The heaters 226a, 228a, etc. are configured to have the same size and shape including length, width, and thickness so that they have the same temperature when the same current is applied. There is. According to this configuration, a phase shift can be given to the light propagating through the bus waveguide 202 with a simple configuration in which a metal thin film or the like is provided on the bus waveguide 202. Further, the same phase shift can be generated between the lights emitted from the adjacent optical coupler 220a and the like to the waveguide line 204a and the like only by passing the same current through the heaters 226a and 228a and the like.

  Further, in the OPA 104, all the sections between the adjacent optical couplers 220a and the like along the bus waveguide 202 are configured to have the same length, and the phase difference between the lights extracted from the adjacent optical couplers 220a and the like. Are all set to the same predetermined value.

  With this configuration, the emission direction (initial direction) of the main maximum beam 236 when the phase shifter 222a and the like are in a non-operating state can be set to any predetermined direction. Thereby, for example, when the present optical phased array is used in a LiDAR sensor, the initial direction of the main maximum beam 236 can be set in advance to the direction to be searched first at the start of the operation, so that the desired direction can be set. Spatial information can be acquired quickly.

  Further, in the OPA 104, all the sections between the adjacent optical couplers 220a and the like along the bus waveguide 202 are configured to have the same length, and the phase difference between the lights extracted from the adjacent optical couplers 220a and the like. Are all odd multiples of π or integral multiples of 2π.

  According to this configuration, the emission direction of the main maximum beam 236 when the phase shifter 222a or the like is in the non-operating state is set to the end or the center of the operation range, and the main maximum beam 236 is moved from end to end at the start of the operation. Then, the entire operation range can be scanned, or the center of the operation range can be moved in a desired direction to perform scanning.

  In addition, in the OPA 104, as the antenna element 206a or the like connected to each of the waveguide lines 204a or the like, a grating-based antenna element configured by a perturbation waveguide whose size in the width direction or the depth direction changes is used, and the perturbation is performed. Light can be output from the surface of the substrate 200 by each of the waveguides. According to this configuration, a linear main maximum beam can be emitted from the surface of the substrate 200 along the length of the perturbation waveguide, and thus, for example, a LiDAR sensor that performs three-dimensional space mapping can be easily configured. You can

  Further, the present invention is a LiDAR sensor 100 using the OPA 104. According to this configuration, it is possible to realize a LiDAR sensor that is highly reliable and easy to control by using the solid-state OPA 104 that operates with a relatively small phase shift without requiring complicated control.

  The present invention is not limited to the configuration of the above embodiment, and can be implemented in various modes without departing from the scope of the invention.

  For example, in the above embodiment, the antenna element 206a and the like are also configured on the same one substrate 200 as the bus waveguide 202 and the like, but the invention is not limited to this. For example, assuming that the antenna element 206a and the like are formed on a substrate different from the substrate 200, the waveguide line 204a and the antenna element 206a and the like are optically coupled via a linear waveguide or an optical fiber formed on the substrate 200. Can be connected to each other.

  100 ... LiDAR sensor, 102 ... Light source, 104 ... Optical phased array (OPA), 106 ... Photosensor, 108 ... Processing device, 200 ... Substrate, 202 ... Bus waveguide, 202-1, 202-2, 202-3 ... Meandering waveguide, 204a, 204b, 204c, 204d ... Waveguide line, 204a-1, 204b-1, 204c-1, 204d-1, 300, 302 ... Straight waveguide, 204a-2, 204b-2, 204c- 2, 204d-2, 310, 312, 314 ... Curved waveguide, 206a, 206a-1, 206a-2, 206b, 206b-1, 206b-2, 206c, 206c-1, 206c-2, 206d, 206d- 1, 206d-2 ... Antenna element, 208 ... Antenna element array, 210a, 210b, 210c, 2 0d ... Optical output end, 212a, 212b, 212c, 212d ... Optical output end, 220a, 220b, 220c, 220d ... Optical coupler 222a, 222b, 222c, 224a, 224b, 224c ... Phase shifter 226a, 226b, 226c, 228a, 228b, 228c ... Heater, 230 ... Light input end, 232 ... Line, 234 ... Edge, 236 ... Main maximum beam, 238 ... Normal line, 400, 402, 404 ... Main lobe.

One aspect of the present invention is an optical phased array configured by an optical waveguide formed on a substrate, wherein a bus waveguide in which input light propagates and the bus waveguide arranged on the bus waveguide are provided. A plurality of optical couplers respectively extracting a part of the light propagating through the waveguide, a plurality of waveguide lines respectively propagating the light extracted by the plurality of optical couplers, a phase shifter provided in the bus waveguide, wherein the plurality of optical couplers, the cascaded along the bus waveguide, said phase shifter, said optical coupler is provided, et al in their respective sections sandwiching the adjacent of the bus waveguide, said bus electrically The respective sections between the adjacent optical couplers along the waveguide are all configured to have the same length, and the phases of the lights extracted from the adjacent optical couplers in the state in which none of the phase shifters are energized are mutually phased. Are all configured to have the same predetermined value, the plurality of waveguide lines have equal optical path lengths to each other, and the plurality of waveguide lines respectively correspond to the plurality of corresponding optical couplers. The light emitting ends of the plurality of waveguide lines, which have portions extending in the same direction, are arranged at a predetermined interval along one line parallel to the extending direction, and the extending direction. It is configured to emit light in a direction orthogonal to .
According to another aspect of the invention, the predetermined value is an odd multiple of π or an integral multiple of 2π.
According to another aspect of the present invention, a light emitting end of each of the plurality of waveguide lines respectively connected to the plurality of optical couplers has a predetermined length along a line parallel to the first direction of the substrate. The plurality of optical couplers are spaced apart from each other with a first predetermined distance along a second direction orthogonal to the first direction, and along the first direction. The plurality of waveguide lines are arranged so as to be separated from each other by a second predetermined distance which is a sum of a predetermined distance and the first predetermined distance, and each of the plurality of waveguide lines is one of the plurality of optical couplers. A linear waveguide having one end connected to the linear waveguide and extending in the first direction, and a curved guide connected to the linear waveguide for converting the propagation direction of light by 90 ° toward the output end of the waveguide line. and waveguide, and it is composed of.
According to another aspect of the present invention, the bus waveguide is configured by cascade-connecting a plurality of meandering waveguides, a part of which forms a part of the optical coupler, and the optical coupler is an evanescent coupler. Each of the meandering waveguides forming the bus waveguide has a straight waveguide and a curved waveguide, and a part of the curved waveguide of the meandering waveguide is a part of the evanescent coupler. Make up.
According to another aspect of the present invention, the phase shifter is provided in the straight waveguides in which the meander waveguide has.
According to another aspect of the present invention, each of the phase shifters includes a heater provided on the substrate, and the heaters have the same linear temperature so that they are at the same temperature when the same current is applied. The size and shape including the length, width, and thickness along the waveguide are configured to be the same as each other.
According to another aspect of the present invention, the meandering waveguide includes one first curved waveguide for converting a light propagation direction by 180 ° and two second curved waveguides for converting a light propagation direction by 90 °. A waveguide and two straight waveguides respectively connecting the first curved waveguide to the two second curved waveguides, and a part of each of the two second curved waveguides is formed. , Constitutes a part of the adjacent evanescent coupler.
According to another aspect of the present invention, each of the waveguide lines is connected to a grating-based antenna element composed of a perturbation waveguide whose size in the width direction or the depth direction is changed, Light is output from the surface of the substrate by each of the waveguides.
According to another aspect of the present invention, the material of the substrate is any one of Si ₃ N ₄ , Si, SiON, LiNbO ₃ , LiTaO ₃ , and SiC.
Another aspect of the present invention is a LiDAR sensor using an optical phased array having any of the above configurations.

Claims (11)

An optical phased array composed of an optical waveguide formed on a substrate,
A bus waveguide through which the input light propagates,
A plurality of optical couplers arranged on the bus waveguide, each of which extracts a part of light propagating through the bus waveguide,
A plurality of waveguide lines that respectively propagate the light extracted by the plurality of optical couplers,
A phase shifter provided in the bus waveguide,
Equipped with
The plurality of waveguide lines have equal optical path lengths,
The phase shifter is provided in each section sandwiched by the adjacent optical couplers of the bus waveguide.
Optical phased array. The respective light emitting ends of the plurality of waveguide lines respectively connected to the plurality of optical couplers are arranged at predetermined intervals along a line parallel to the first direction of the substrate,
The plurality of optical couplers are separated from each other with a first predetermined distance along a second direction orthogonal to the first direction, and the predetermined distance and the first distance along the first direction. The second predetermined distance, which is the sum of the predetermined distance and the distance, is arranged so as to be separated from each other,
Each of the plurality of waveguide lines is connected to one of the plurality of optical couplers and has a linear waveguide extending in the first direction, and the waveguide is connected to the linear waveguide. A curved waveguide that converts the propagation direction of light by 90 ° toward the output end of the line,
The bus waveguide is configured by cascade-connecting a plurality of meandering waveguides, a part of which constitutes a part of the optical coupler.
The optical phased array according to claim 1. The optical coupler is composed of an evanescent coupler,
Each of the meandering waveguides forming the bus waveguide has a linear waveguide and a curved waveguide,
A portion of the curved waveguide of the serpentine waveguide constitutes a portion of the evanescent coupler,
The optical phased array according to claim 2. The meandering waveguide includes one first curved waveguide that converts a light propagation direction by 180 °, two second curved waveguides that convert a light propagation direction by 90 °, and the first curved waveguide. It is composed of two straight waveguides respectively connecting the waveguide to the two second curved waveguides,
A portion of each of the two second curved waveguides constitutes a portion of the adjacent evanescent coupler,
The optical phased array according to claim 3. The phase shifter is provided on one or both of the two straight waveguides that connect the first curved waveguide to the two second curved waveguides.
The optical phased array according to claim 4. Each of the phase shifters includes a heater provided in a part of the bus waveguide,
The heater is configured to have the same size and shape including length, width, and thickness so that they have the same temperature when the same current is applied,
The optical phased array according to claim 1. The respective sections between the adjacent optical couplers along the bus waveguide are all configured to have the same length, and the phase differences of the lights extracted from the adjacent optical couplers are all the same predetermined values. Is configured to be,
The optical phased array according to any one of claims 1 to 6. The predetermined value is an odd multiple of π or an integral multiple of 2π,
The optical phased array according to claim 7. Each of the waveguide lines is connected to a grating-based antenna element composed of a perturbation waveguide whose size changes in the width direction or the depth direction, and the surface of the substrate is connected by each of the perturbation waveguides. Is configured to output light from,
The optical phased array according to any one of claims 1 to 8. The material of the substrate is any one of Si ₃ N ₄ , Si, SiON, LiNbO ₃ , LiTaO ₃ , and SiC.
The optical phased array according to any one of claims 1 to 9.   A LiDAR sensor using the optical phased array according to claim 1.

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