Phase shifter structure for optical beam steering device

Abstract

Embodiments of the present disclosure relate to a phase shifter structure for a beam steering device. A beam steering device and a beam steering method are described. The beam steering device comprises: a laser source coupled to an optical phased array (OPA). The OPA comprises: a beam splitter network optically coupled to the laser source and configured to split a laser beam generated by the laser source into N outputs to generate an output beam; a first network of first phase shifters configured to steer the output beam in a first direction away from a longitudinal direction; and a second network of second phase shifters configured to steer the output beam in a second direction away from the longitudinal direction, the second direction being opposite to the first direction.

Description

Technical Field

[0001] The present invention generally relates to beam steering, and in certain embodiments, to a phase shifter structure for a beam steering device. Background Technology

[0002] The use of devices utilizing free-space laser beams has proven effective in numerous applications in 3D mapping and imaging, such as geological surveying, and for steering and navigation of autonomous vehicles. Light detection and ranging (LiDAR) has emerged as a technique for determining the variable distance to an object by emitting a beam of light towards it and measuring the time it takes for the light to return after reflecting off the object. In this context, the beam must be directed towards the object. To map a target area around the sensor, the beam must be oriented or directed towards the sensor in different directions.

[0003] Of course, mechanically moving the sensor is one way to achieve beam steering. One way to steering the beam of a LiDAR sensor without mechanical movement of the sensor is through an optical phased array (OPA). OPAs offer a more flexible and efficient beam steering device.

[0004] OPAs are designed to generate beams with different phase shifts in order to produce patterns of constructive and destructive interference that form the output beam. However, conventional OPAs are not scalable and are complex in terms of architecture and electrical control when it comes to achieving large outputs. Summary of the Invention

[0005] According to an embodiment of the present invention, a beam steering device includes: a laser source coupled to an optical phased array (OPA), the OPA including: a beam splitter network optically coupled to the laser source and configured to split a laser beam generated by the laser source into N outputs to generate an output beam; a first network of first phase shifters configured to steering the output beam in a first direction away from the longitudinal direction; and a second network of second phase shifters configured to steering the output beam in a second direction away from the longitudinal direction, the second direction being opposite to the first direction.

[0006] According to an embodiment of the present invention, a beam steering device includes: a switching matrix including a plurality of z-outputs coupled to a plurality of optical phased arrays (OPAs) and configured to sequentially guide a laser beam emitted by a laser source to the plurality of OPAs, the laser being emitted around a main axis, each of the plurality of OPAs including an output beam direction oriented around a central beam axis, the central beam axes of each of the plurality of OPAs being different from each other, and each of the plurality of OPAs including: a beam splitter network coupled to the laser source, the beam splitter network being configured to split the laser beam into N outputs to generate corresponding output beams; a first network of a first phase shifter configured to steering the output beam in a first direction away from the central beam axis; and a second network of a second phase shifter configured to steering the output beam in a second direction away from the central beam axis, the second direction being opposite to the first direction.

[0007] According to an embodiment of the present invention, a method for beam steering includes: coupling a laser source to a first optical phased array (OPA), the first OPA including a beam splitter network having an output including N outputs around a first central beam axis; a first network of first phase shifters and a second network of second phase shifters; generating an output beam around the first central beam axis at the output of the beam splitter network by steering the output beam in a first direction away from the first central beam axis using the first network of first phase shifters; and steering the output beam in a second direction away from the first central beam axis using the second network of second phase shifters, the second direction being opposite to the first direction. Attached Figure Description

[0008] To gain a more complete understanding of the invention and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 A schematic diagram of a beam steering device according to an embodiment of this application is shown;

[0010] Figures 2A-2C A schematic diagram of an optical phased array of a beam steering device configured to steer the beam around a central beam axis, according to an embodiment of this application, is shown, wherein... Figure 2A A schematic diagram of an optical phased array is shown when it is configured to steer the output beam in a first direction. Figure 2B A schematic diagram of an optical phased array is shown when it is configured to redirect the output beam in a second direction opposite to the first direction. Figure 2C A side view of the beam steering device is shown;

[0011] Figures 3A-3B A schematic diagram of the optical phased array of a beam steering device according to an embodiment of this application is shown, wherein... Figure 3AA schematic diagram is shown of an optical phased array configured to have a central beam axis set at an offset angle in a first direction, and Figure 3B A schematic diagram is shown of an optical phased array configured to have a central beam axis set at an offset angle in a second direction;

[0012] Figure 4 The processing flow of a steerable output beam with improved coverage according to an embodiment of this application is shown.

[0013] Figures 5A-5B A schematic diagram of a beam steering device including multiple optical phased arrays (OPAs) according to an embodiment of this application is shown, wherein... Figure 5A A beam steering device with an even number of optical phased arrays (OPAs) is shown, and Figure 5B A beam steering device with an odd number of optical phased arrays (OPAs) is shown; and

[0014] Figure 6 The processing flow of a beam steering device comprising multiple optical phased arrays (OPAs) according to an embodiment of this application is shown. Detailed Implementation

[0015] OPA operates by transmitting multiple beams from an array of antennas stacked (i.e., combined) in the far field to form an output beam. Each of the multiple beams experiences a different phase shift, resulting in each transmitted beam being emitted at a different time. This can cause the output beam to propagate at an angle known as the beam steering angle. The coverage area of ​​the beam steering device can be defined by the range of the beam steering angle.

[0016] OPA typically comprises three components: a beam splitter network configured to split the OPA input into multiple channels; a phase shifter network used to generate phase differences between multiple antenna elements; and multiple antenna elements.

[0017] Typically, an OPA uses phase shifters on every channel except one to generate an equal phase difference (e.g., different phase offsets) between adjacent channels. However, to generate different phase offsets between adjacent channels, different voltage signals must be applied to each phase shifter in the individual phase shifters. This may require each phase shifter in the phase shifters to be turned by a single, interconnected electronic circuit.

[0018] While optical phased arrays (OPAs) allow for non-mechanical beam steering for LiDAR sensors, limitations remain. As the number of channels increases, so does the number of individual, interconnected electronic circuits required for steering phase offsets. The problem is that this leads to increased power consumption and makes steering the phase offset for each channel very difficult or even impossible.

[0019] Embodiments of this application disclose an optical emitter, such as a beam steering device, capable of steering an output beam with improved coverage without increasing the difficulty of steering channel phase offset. More specifically, embodiments of the invention relate to a beam steering device having an increased beam steering angle range and requiring no additional circuitry as the number of channels in the OPA increases.

[0020] exist Figure 1 The text describes an embodiment of a light emitter. It will use... Figures 2A-2B and Figures 3A-3B An embodiment of an optical phased array is described. An embodiment of a light emitter including multiple optical phased arrays (OPAs) will be described using Figure 5. Figure 4 and Figure 6 Describe the methods for operating the OPA and / or optical emitter.

[0021] Figure 1 This is a schematic diagram of a beam steering device according to an embodiment of this application.

[0022] refer to Figure 1 The beam steering device 100 may include a laser source 102 coupled to an optical phased array (OPA) 104. The OPA 104 may be formed on a silicon-based platform such as silicon nitride using silicon photonics techniques known in the art. The laser source 102 may be coupled to the OPA 104 via an optical fiber, or may be included within the OPA 104.

[0023] In various embodiments, OPA 104 may include a beam splitter network 103 configured to split a laser beam generated by laser source 102 into N outputs. The N outputs may be coupled to antenna 105, which is configured to couple and emit each of the N outputs into free space, thereby forming an optical output beam. (The following will...) Figures 2A-2B as well as Figures 3A-3B The OPA 104 is described in more detail below. As described in various embodiments, the OPA 104 can be configured to electronically steer the beam at a wider angle to obtain an improved coverage area.

[0024] Figures 2A-2B This is a schematic diagram of an optical phased array (OPA) configured to direct the output beam with improved coverage.

[0025] Figures 2A-2B A schematic diagram of an optical phased array of a beam steering device configured to steer the beam around a central beam axis, according to an embodiment of this application, is shown, wherein... Figure 2A A schematic diagram of an optical phased array is shown when it is configured to steer the output beam in a first direction, and Figure 2BA schematic diagram of an optical phased array is shown when it is configured to steer the output beam in a second direction opposite to the first direction.

[0026] refer to Figure 2A The optical phased array (OPA) 104 may include a beamsplitter network 103 having outputs including N outputs generated around a central beam axis 127, a first network of first phase shifters 110, and a second network of second phase shifters 112. The beamsplitter network 103 may be configured to distribute a laser beam generated by the laser source 102 into the N outputs to generate an output beam 126. The beamsplitter network 103 may include multiple stages of optical beamsplitters 114. The optical beamsplitters 114 may include 1×2Y cross-tree or multimode interference (MMI) optical splitters. Each optical beamsplitter in the optical beamsplitters 114 may include an input 118, a first output waveguide 120, and a second output waveguide 122.

[0027] Beam splitter network 103 may include i-th order optical beam splitters 114, where i is an integer greater than or equal to 1. The formula N = 2 can be used. i The value of i is determined based on the expected values ​​of N outputs. For example, as... Figure 2A As shown, the 8-output beam splitter network 103 may require a three-stage optical beam splitter 114 (i.e., 8 = 2). 3 ).although Figure 2A The OPA 104 with 8 outputs is shown, but the OPA 104 can support any appropriate number of outputs.

[0028] The number of optical beamsplitters 114 can increase with each progressive stage. In various embodiments, each stage of the beamsplitter network 103 may include 2 i-1 One optical beam splitter 114. For example, the first stage of the beam splitter network 103 (i.e., i = 1) may include one optical beam splitter 114, the second stage of the beam splitter network 103 (i.e., i = 2) may include two optical beam splitters 114, and the third stage of the beam splitter network 103 (i.e., i = 3) may include four optical beam splitters 114.

[0029] The first output waveguide 120 and the second output waveguide 122 of the final stage of the beam splitter network 103 can each be coupled to an antenna 105. The antenna 105 can be an array antenna. The antenna 105 can include a grating array 107. In one or more embodiments, the grating array 107 can include linear gratings. Each linear grating can have an equal length. In other words, the N outputs of the beam splitter network 103 can each be further coupled to the grating array 107.

[0030] The optical phased array (OPA) 104 may also include a first network of a first phase shifter 110 configured to deflect the output beam 126 in a first direction away from the longitudinal direction 128, and a second network of a second phase shifter 112 configured to deflect the output beam 126 in a second direction opposite to the first direction away from the longitudinal direction 128.

[0031] In various embodiments, the first network of the first phase shifter 110 may each be coupled to the first driver 106. The second network of the second phase shifter 112 may each be coupled to the second driver 108. Each phase shifter in the first phase shifter 110 and the second phase shifter 112 may be connected to a common reference potential such as ground terminal 116.

[0032] Each first output waveguide 120 of the beam splitter network 103 can be associated with at least one first phase shifter 110. The first output waveguide 120 of each stage can be associated with a different number of first phase shifters 110. The number of first phase shifters 110 associated with the first output waveguide 120 of the i-th stage of the beam splitter network 103 can be equal to... For example, such as Figure 2A As shown, the first output waveguide 120 of the optical beam splitter 114 in the first stage (i.e., i=1) can be associated with four first phase shifters 110, the first output waveguide 120 of each optical beam splitter 114 in the second stage (i.e., i=2) can be associated with two first phase shifters 110, and the first output waveguide 120 of each optical beam splitter 114 in the third stage (i.e., i=3) can be associated with one first phase shifter 110.

[0033] Similarly, each second output waveguide 122 of the beam splitter network 103 may be associated with at least one second phase shifter 112. The number of second phase shifters 112 may be equal to the number of first phase shifters 110 in each stage of the beam splitter network 103.

[0034] For example, such as Figure 2A As shown, the second output waveguide 122 of the optical beamsplitter 114 in the first stage (i.e., i = 1) can be associated with four second phase shifters 112, the second output waveguide 122 of each optical beamsplitter 114 in the second stage (i.e., i = 2) can be associated with two second phase shifters 112, and the second output waveguide 122 of each optical beamsplitter 114 in the third stage (i.e., i = 3) can be associated with one second phase shifter 112. The first phase shifter 110 and the second phase shifter 112 can be the same. The first phase shifter 110 and the second phase shifter 112 can include thermal or electro-optic phase shifters.

[0035] Advantageously, coupling two phase shifter networks to a single corresponding driver allows for an increase in the number of outputs to N without requiring additional drivers.

[0036] As described above, the optical phased array (OPA) 104 can be configured to steer the output beam 126 in a direction opposite to the longitudinal direction 128. As will be understood by those skilled in the art, the output beam 126 may have a phase leading edge 125. A first direction can be defined as a positive beam steering angle θ or a negative beam steering angle -θ measured relative to the central beam axis 127. A second direction can be defined as a beam steering angle with the opposite sign. In various embodiments, the central beam axis 127 can be positioned along an axis at an angle to the beam steering device 100 (see...). Figure 2C ).

[0037] exist Figure 2A In the example, the first network of the first phase shifter 110 can be configured to steer the output beam 126 in a first direction -θ away from the longitudinal direction 128.

[0038] The output beam 126 can be steered in a first direction -θ by activating the first driver 106. When activated, the first driver 106 can apply a first potential to each first phase shifter 110. The first potential can configure the first phase shifter 110 to add a first phase offset to each beam passing through the first output waveguide 120. A phase offset δФ can be added to each first phase shifter 110 through which the beam passes. When the first driver 106 is activated and the second driver 108 is idle, the first phase offset added to each beam passing through the first output waveguide 120 can be equal to Each beam passing through the second output waveguide 122 may not experience a phase shift. This can result in a constant phase difference equal to -δФ between N adjacent outputs along the longitudinal direction 128 (or vice versa).

[0039] For example, in the first stage of beam splitter network 103, the laser beam generated from laser source 102 can be split by beam splitter 114 into a first beam B1 propagating along a first path through first output waveguide 120 and a second beam B2 propagating along a second path through second output waveguide 122. A first phase shift may not be added to the second beam B2 because it does not pass through any of the first phase shifters 110. Each of the four first phase shifters 110 that can be passed through by the first beam B1 adds a first phase shift equal to δФ to the first beam B1, such that the total phase shift is equal to 4*δФ.

[0040] In the second stage of the beam splitter network 103, two optical beam splitters 114 can be configured to split a first beam B1 into a third beam B3 propagating along a third path and a fourth beam B4 propagating along a fourth path, and to split a second beam B2 into a fifth beam B5 propagating along a fifth path and a sixth beam B6 propagating along a sixth path. The third beam B3 and the fifth beam B5 can each pass through a first output waveguide 120 of one of the two optical beam splitters 114, while the second beam B2 and the fourth beam B4 can each pass through a second output waveguide 122 of one of the two optical beam splitters 114. The third beam B3 and the fifth beam B5 can each pass through two first phase shifters 110, while the fourth beam B4 and the sixth beam B6 do not. An additional first phase offset of 2*δФ can be added to the third beam B3 and the fifth beam B5 from the two first phase shifters 110 through which both the third beam B3 and the fifth beam B5 pass. An additional first phase offset may not be added to the fourth beam B4 and the sixth beam B6 because they do not pass through any of the first phase shifters 110. Therefore, the third beam B3 has an increased first phase offset equal to 6*δФ, the fourth beam B4 has an increased first phase offset equal to 4*δФ, the fifth beam B5 has an increased first phase offset equal to 2*δФ, and the sixth beam B6 has no increased first phase offset.

[0041] In the final stage of the beam splitter network 103, each optical beam splitter 114 can split the corresponding beam into two outputs. The index of each of the N outputs can be defined as n, and ranges from 1 to N along the longitudinal direction 128. (See also...) Figure 2A Each of the third to sixth beams can be split into two outputs by each of the four optical beam splitters 114, thereby generating eight outputs. The third beam B3 can be split into a first output O1 (e.g., n=1) and a second output O2, the fourth beam B4 can be split into a third output O3 and a fourth output O4, the fifth beam B5 can be split into a fifth output O5 and a sixth output O6, and the sixth beam B6 can be split into a seventh output O7 and an eighth output O8.

[0042] In the same manner as described above, beams passing through each first output waveguide 120 of each optical beamsplitter 114 in the third (and final) stages will pass through a first phase shifter 110, while other beams will not. Therefore, an additional first phase shift equal to δФ can be added to the beams passing through each first output waveguide 120. N outputs with odd n values ​​(i.e., first, third, fifth, and seventh) can pass through the first output waveguide 120, while N outputs with even n values ​​(i.e., second, fourth, sixth, and eighth) can pass through the second output waveguide 122. Therefore, the beam corresponding to the first output O1 can have a first phase offset equal to 7*δФ, the beam corresponding to the second output O2 can have a first phase offset equal to 6*δФ, the beam corresponding to the third output O3 can have a first phase offset equal to 5*δФ, the beam corresponding to the fourth output O4 can have a first phase offset equal to 4*δФ, the beam corresponding to the fifth output O5 can have a first phase offset equal to 3*δФ, the beam corresponding to the sixth output O6 can have a first phase offset equal to 2*δФ, and the beam corresponding to the seventh output O7 can have a first phase offset equal to δФ. The first phase offset may not be added to the beam corresponding to the eighth output.

[0043] Therefore, the first phase offset added to each of the N outputs can be equal to (Nn)δФ. This first phase offset added to each of the N outputs can have a constant phase difference along the longitudinal direction 128, ranging from (Nn)δФ to 0, regardless of the value of N. This results in a negative constant phase difference -δФ between the N outputs along the longitudinal direction 128. Therefore, the first phase shifter 110 can steer the output beam 126 in the first direction –θ (and vice versa).

[0044] As will be understood by those skilled in the art, the first phase shifter 110 can be configured with a phase difference of positive or negative sign based on a first potential to generate a positive or negative beam direction relative to the longitudinal direction 128. In other words, the first network of the first phase shifter 110 can be configured to turn the output beam 126 only by a positive beam turning angle θ or a negative beam turning angle -θ. Advantageously, the second network of the second phase shifter 112 can be configured to provide a phase shift with opposite signs. The advantage of doing so is that it allows the output beam 126 to be turned in both directions of the central beam axis 127. In other words, the range of beam turning angles can be doubled.

[0045] refer to Figure 2B After the beam is redirected in the first direction -θ, the first driver 106 can be deactivated and the second driver 108 can be activated. The second driver 108 can send a second potential to each of the second phase shifters 112. In various embodiments, the second potential may be the same as the first potential.

[0046] The second potential can be configured with a second phase shifter 112 to redirect the output beam 126 in a second direction θ. The second direction can be defined as a positive beam steering angle θ or a negative beam steering angle -θ, as long as it is opposite to the first direction.

[0047] The second potential can be configured with a second phase shifter 112 to add a second phase offset to each beam passing through the second output waveguide 122. The second phase offset can be different from the first phase offset. In various embodiments, the added second phase offset can be opposite to the first phase offset. In other words, the phase difference between the N outputs along the longitudinal direction 128 provided by the first phase shifter 110 and the second phase shifter 112 can have opposite signs. The second phase difference added to each of the N outputs can be equal to (n-1)δФ. This will be discussed in more detail below.

[0048] Continuing from the above Figure 2A In the example discussed, in the first stage of the beam splitter network 103, since the second beam B2 passes through each of the four second phase shifters 112, a second phase offset equal to 4*δФ can be added only to the second beam B2.

[0049] In the second stage of the beam splitter network, since both the fourth beam B4 and the sixth beam B6 pass through two second phase shifters 112, only a second phase shift of 2*δФ can be added to the fourth beam B4 and the sixth beam B6.

[0050] In the final stage of the beam splitter network, since the N outputs with even indices pass through a second phase shifter 112, the second phase offset δФ can be added only to the N outputs with even indices (i.e., the second, fourth, sixth, and eighth).

[0051] Therefore, the beam corresponding to the first output O1 can be without a second phase offset, the beam corresponding to the second output O2 can have a second phase offset equal to δФ, the beam corresponding to the third output O3 can have a second phase offset equal to 2*δФ, the beam corresponding to the fourth output O4 can have a second phase offset equal to 3*δФ, the beam corresponding to the fifth output O5 can have a second phase offset equal to 4*δФ, the beam corresponding to the sixth output O6 can have a second phase offset equal to 5*δФ, the beam corresponding to the seventh output O7 can have a second phase offset equal to 6*δФ, and the beam corresponding to the eighth output O8 can have a second phase offset equal to 7*δФ.

[0052] Advantageously, this allows the output beam 126 to be redirected in a second direction θ away from the longitudinal direction 128. One advantage of this is that it doubles the range of beam redirection angles.

[0053] Embodiments of this application consider a scenario where the optical phased array (OPA) 104 can be configured to have a central beam axis 127 set at a fixed offset angle. Advantageously, this allows the output beam to be positioned and steered around the central beam axis 127 pointing in different directions.

[0054] Figure 2C A side view of the beam steering device is shown. Figure 2C Used to understand how the central beam axis 127 is moved away from the device axis 129 perpendicular to the beam steering device 100. Reference Figure 2C As will be understood by those skilled in the art, the output beam 126 and the central beam axis 127 can be formed in a half-space above the device 100. In other words, the central beam axis 127 can be positioned at an emission angle Φ measured relative to the device axis 129, because the light emission from the antenna is at an angle to the surface of the device 100, referred to herein as the emission angle Φ.

[0055] Figures 3A-3B A schematic diagram of the optical phased array of a beam steering device according to an embodiment of this application is shown, wherein... Figure 3A A schematic diagram is shown of an optical phased array configured to have a central beam axis set at a certain offset angle in a first direction. Figure 3B A schematic diagram is shown of an optical phased array configured to have a central beam axis set at a certain offset angle in a second direction.

[0056] Unlike previous embodiments in which the central beam axis was symmetrically positioned along the principal axis, in these embodiments the central beam axis is offset at an angle relative to the principal axis. In other words, the beam angle is asymmetrical with respect to the principal axis. As will be explained in... Figures 5A-5B As described in the embodiments, these OPAs enable a greater extension of the beam angle in the beam steering device.

[0057] refer to Figure 3A The positive offset angle OPA 204A can be further configured to have a central beam axis 127 disposed in a first direction away from the main axis 130 perpendicular to the antenna 105. The first direction can be defined as the offset angle Ψ between the central beam axis 127 and the main axis 130 perpendicular to the antenna 105. For example, the central beam axis 127 disposed in the first direction can be defined as a central beam axis 127 having a positive fixed offset angle Ψ (and vice versa).

[0058] In various embodiments, antenna 105 may further include N linear waveguides 134 and (multiple) N fixed phase shifters 132. The (multiple) N fixed phase shifters 132 may be coupled between beam splitter network 103 and the N linear waveguides 134. In other words, the inputs of the N fixed phase shifters 132 may be coupled to the N outputs of beam splitter network 103, and the outputs of the N fixed phase shifters 132 may be coupled to the input of each of the N linear waveguides 134.

[0059] Each of the N fixed phase shifters 132 can have a different optical path length. The difference in optical path length between each of the N fixed phase shifters 132 can be equal. In various embodiments, the optical path length of each of the N fixed phase shifters 132 can be reduced along the longitudinal direction 128 to form a fixed offset angle Ψ in a first direction. As will be understood by those skilled in the art, the direction of the fixed offset angle Ψ will be in the direction of increasing optical path length. Furthermore, the longer the optical path length of the N fixed phase shifters 132, the larger the magnitude of the fixed offset angle Ψ. Therefore, the size and direction of the fixed offset angle Ψ can be configured based on the optical path length of each of the N fixed phase shifters 132.

[0060] See again Figure 3A Each of the N fixed phase shifters 132 may include N bent waveguides with different curvatures. As will be understood by those skilled in the art, a greater curvature results in a longer optical path length (or vice versa). Therefore, the optical path length can be reduced by decreasing the curvature of the N fixed phase shifters 132 along the longitudinal direction 128.

[0061] refer to Figure 3B The negative offset angle OPA 204B can be further configured to have a central beam axis 127 set in a second direction away from the main axis 130. The second direction can be opposite to the first direction. For example, the second direction can be defined as a negative fixed offset angle -Ψ (or vice versa), as long as it is opposite to the first direction.

[0062] For the same reasons described above, the amplitude and sign of the second direction can depend on the difference in optical path lengths of the N fixed phase shifters 132. Therefore, by increasing the optical path length (or curvature) of each of the N fixed phase shifters 132 along the longitudinal direction 128, the central beam axis 127 can be set with a negative fixed offset angle -Ψ.

[0063] Figure 4 The processing flow of a steerable output beam with improved coverage according to an embodiment of this application is shown.

[0064] As shown in box 402, and refer to Figures 2A-3BThe laser source 102 can be coupled to an optical phased array (OPA) 104 (or 204A, 204B). The OPA 104 (or 204A, 204B) may include a beam splitter network 103 comprising N outputs around a central beam axis 127, a first network of a first phase shifter 110, and a second network of a second phase shifter 112. The OPA 104 (or 204A, 204B) may have… Figures 2A-2B and Figures 3A-3B Any configuration disclosed in the document.

[0065] As shown below in box 404, and refer to Figures 2A-3B The output beam 126 can be generated around the central beam axis 127 at the output of the beam splitter network 103. The output beam 126 can be formed around the central beam axis by being redirected in a first direction – θ and a second direction θ (or vice versa).

[0066] By applying a first potential to each first phase shifter 110 using the first driver 106, the output beam 126 can be steered in a first direction. The first direction can be a positive beam steering angle θ or a negative beam steering angle -θ. The output beam 126 can be... Figure 2A The same method described herein is used to turn in the first direction.

[0067] The output beam 126 can be diverted in a second direction away from the central beam axis 127. This second diversion of the output beam 126 can be achieved by disabling the first driver 106 and supplying a second potential to each of the second phase shifters 112 using the second driver 108. The second direction can be defined as a beam diversion angle with the opposite sign to the first direction. Figure 2B The same method described herein is used to turn in the first direction.

[0068] The order in which the output beam 126 is turned is not limited by this application. In other words, the beam can be turned in the first direction before it can be turned in the second direction.

[0069] Embodiments of this application contemplate a beam steering device comprising multiple optical phased arrays (OPAs) to increase the coverage of the beam steering device without requiring additional circuitry.

[0070] Figures 5A-5B A schematic diagram of a beam steering device including multiple optical phased arrays (OPAs) according to an embodiment of this application is shown, wherein... Figure 5A A beam steering device with an even number of optical phased arrays (OPAs) is shown, and Figure 5B A beam steering device with an odd number of optical phased arrays (OPAs) is shown.

[0071] refer to Figure 5A The beam steering device 500 may include a laser source 102 coupled to an input of a switching matrix 502. The switching matrix 502 may include multiple z-outputs coupled to multiple OPAs 503. The switching matrix 502 may be configured to sequentially guide a laser beam emitted by the laser source 102 around a main axis 530 to each of the multiple OPAs 503.

[0072] In various embodiments, the center beam axis 127 of each of the plurality of OPA 503s can be different. This will be explained in more detail below.

[0073] See again Figure 5A In embodiments where z is an even number, the central beam axis 127 of each of the plurality of OPAs 503 can be configured to be positioned around the main axis 530. In other words, the central beam axis 127 of each of the plurality of OPAs 503 can be configured to be positioned with different fixed offset angles Ψ. The magnitude of the fixed offset angle Ψ of each central beam axis 127 can be configured to increase away from the main axis 530.

[0074] Multiple OPAs 503 may include a first group of OPAs 508 and a second group of OPAs 510. The first group of OPAs 508 may include each OPA located above the main axis 530. The second group of OPAs 510 may include each OPA located below the main axis 530. The first group of OPAs 508 and the second group of OPAs 510 may include the same number of OPAs.

[0075] Similar to Figure 3A In the positive offset angle OPA 204A, the first set of OPAs 508 may each have a center beam axis 127, which is configured to have a positive fixed offset angle Ψ that increases in amplitude away from the main axis 530 (similar to the positive offset angle Ψ in the main axis 530). Figure 3A The described OPA).

[0076] Similar to Figure 3B The negative offset angle OPA 204B in the middle, the second set of OPA 510 may each have a central beam axis 127, which is configured to have a negative fixed offset angle -Ψ (or vice versa) that increases in amplitude away from the main axis 530.

[0077] As described above, the OPAs in the first group of OPAs 508 may include N fixed phase shifters 132, each having an optical path length that decreases along the longitudinal direction 128. The OPAs in the second group of OPAs 510 may include N fixed phase shifters 132, each having an optical path length that increases along the longitudinal direction 128. In other words, the longest fixed phase shifter of the OPA in the first group of OPAs 508, which is closer to the main axis 530, will be shorter than the shortest fixed phase shifter of the OPA in the first group of OPAs 508, which is farther from the main axis 530. The same applies to the second group of OPAs 510. Furthermore, the optical path lengths of each of the N fixed phase shifters 132 in the OPAs of the first group of OPAs 508 and the OPAs of the second group of OPAs 510, which are equidistant from the main axis 530, can be equal. Therefore, the magnitude of the fixed offset angle Ψ of the OPAs equidistant from the main axis 530 can be equal. Advantageously, this allows the central beam axis 127 of each of the plurality of OPAs 503 to increase away from the main axis 530. One advantage of this approach is that it allows for an increase in the beam coverage of the beam steering device 500 without additional circuitry. In other words, the switching matrix 502 can be used to redirect the output direction of the beam steering device 500 by sequentially switching among multiple OPAs 503.

[0078] Figure 5B An alternative embodiment of the beam steering device is shown, which operates in situations where there is no possibility of center blindness. Although Figure 5A The embodiment described is optimized to direct the beam at a wider angle, but the device may not be effective when analyzing objects located on the device's main axis. To compensate for any such drawback, the embodiment includes an additional OPA located at the center.

[0079] refer to Figure 5B In embodiments where z is an odd number, the first group of OPAs 508 and the second group of OPAs 510 can be separated by a central OPA 504 and positioned along the main axis 530. The central OPA 504, positioned along the main axis 530, can be configured to have a central beam axis 127 formed along the main axis 530. Therefore, the central beam axis 127 of the central OPA 504 does not have a fixed offset angle, and thus the central OPA 504 is similar to... Figures 2A-2B OPA 104 as described in [the document].

[0080] Figure 6 The processing flow of a beam steering device comprising multiple optical phased arrays (OPAs) according to an embodiment of this application is shown.

[0081] As shown in box 602 and referenced Figures 5A-5BThe multiple outputs of the switching matrix 502 can be coupled between the laser source 102 and multiple optical phased arrays (OPAs) 503. Each of the multiple OPAs 503 can be configured to have an optical output direction around the main axis 530. As described above, each of the multiple OPAs 503 can be configured to generate an output beam 126 around a different central beam axis 127. The central beam axis 127 of each of the multiple OPAs 503 can be set around the main axis 530. Each central beam axis 127 can be... Figures 5A-5B The same method discussed in the text is used to set up around the main axis 530.

[0082] As shown below in box 604 and referenced Figures 5A-5B The switching matrix 502 can be used to sequentially switch between multiple OPAs 503 to direct the optical output from the multiple OPAs 503. As described above, this allows the beam steering device 500 to have improved coverage without additional circuitry.

[0083] Exemplary embodiments of the invention are summarized herein. Other embodiments may also be understood from the entirety of the description and claims submitted herein.

[0084] Example 1. A beam steering device comprising: a laser source coupled to an optical phased array (OPA), the OPA including: a beam splitter network optically coupled to the laser source and configured to split a laser beam generated by the laser source into N outputs to generate an output beam; a first network of a first phase shifter configured to steering the output beam in a first direction away from the longitudinal direction; and a second network of a second phase shifter configured to steering the output beam in a second direction away from the longitudinal direction, the second direction being opposite to the first direction.

[0085] Example 2. A beam steering device according to Example 1, wherein the beam splitter network includes multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with a first phase shifter in a first phase shifter, and each second output waveguide of the optical beam splitter being associated with a second phase shifter in a second phase shifter, the first phase shifter being configured to add a first phase shift to the beam passing through the first output waveguide, and the second phase shifter being configured to add a second phase shift to the beam passing through the second output waveguide.

[0086] Example 3. A beam steering device according to any one of Examples 1 or 2, wherein the first and second output waveguides of the final stage of each of a plurality of stages of an optical beam splitter are each connected to a linear grating array.

[0087] Example 4. A beam steering device according to any one of Examples 1 to 3, wherein the i-th stage of a plurality of stages of the optical beam splitter comprises: 2 i-1 1×2 optical splitters, where i is an integer greater than or equal to 1.

[0088] Example 5. A beam steering device according to any one of Examples 1 to 4, wherein a first network of first phase shifters includes: a first driver coupled to each first phase shifter, the first driver being configured to configure the first phase shifter to provide a first phase offset.

[0089] Example 6. A beam steering device according to any one of Examples 1 to 5, wherein a second network of second phase shifters includes: a second driver coupled to each second phase shifter, the second driver being configured to configure the second phase shifter to provide a second phase offset different from the first phase offset.

[0090] Example 7. A beam steering device according to any one of Examples 1 to 6, wherein the first phase shifter and the second phase shifter are identical.

[0091] Example 8. A beam steering device according to any one of Examples 1 to 7, wherein a first phase offset is opposite to a second phase offset.

[0092] Example 9. A beam steering device according to any one of Examples 1 to 8, wherein a first network of a first phase shifter and a second network of a second phase shifter comprise thermal or electro-optic phase shifters.

[0093] Example 10. The beam steering device according to any one of Examples 1 to 9 further includes: an antenna comprising N linear waveguides, the N linear waveguides corresponding to N outputs; and N fixed phase shifters coupled to a beam splitter network, each of the N fixed phase shifters having a different optical path length from another of the N fixed phase shifters, and each of the N linear waveguides being coupled to the output of one of the N fixed phase shifters.

[0094] Example 11. The beam steering device according to any one of Examples 1 to 10 further includes a switching matrix coupled between the laser source and the OPA.

[0095] Example 12. A beam steering device comprising: a switching matrix including a plurality of z-outputs coupled to a plurality of optical phased arrays (OPAs) and configured to sequentially guide a laser beam emitted by a laser source to the plurality of OPAs, the laser being emitted around a main axis, each of the plurality of OPAs including an output beam direction oriented around a central beam axis, the central beam axes of each of the plurality of OPAs being different from each other, each of the plurality of OPAs including: a beam splitter network coupled to the laser source, the beam splitter network being configured to split the laser beam into N outputs to generate corresponding output beams; a first network of a first phase shifter configured to steer the output beam in a first direction away from the central beam axis; and a second network of a second phase shifter configured to steer the output beam in a second direction away from the central beam axis, the second direction being opposite to the first direction.

[0096] Example 13. A beam steering device according to Example 12, wherein the beam splitter network includes multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with a first phase shifter in a first phase shifter, and each second output waveguide of the optical beam splitter being associated with a second phase shifter in a second phase shifter, the first phase shifter being configured to add a first phase shift to the beam passing through the first output waveguide, and the second phase shifter being configured to add a second phase shift to the beam passing through the second output waveguide.

[0097] Example 14. A beam steering device according to any one of Examples 12 or 13, wherein the i-th stage of a plurality of stages of an optical beam splitter comprises 2 i-1 One 1x2 optical beam splitter.

[0098] Example 15. A beam steering device according to any one of Examples 12 to 14, wherein a first network of first phase shifters includes: a first driver coupled to each first phase shifter, the first driver being configured to configure the first phase shifter to provide a first phase offset.

[0099] Example 16. A beam steering device according to any one of Examples 12 to 15, wherein a second network of second phase shifters includes: a second driver coupled to each second phase shifter, the second driver being configured to configure the second phase shifter to provide a second phase offset different from the first phase offset.

[0100] Example 17. A beam steering device according to any one of Examples 12 to 16, wherein the first OPA of a plurality of OPAs comprises: an antenna including N linear waveguides corresponding to N outputs of the first OPA of the plurality of OPAs; and N fixed phase shifters coupled to a beam splitter network, each of the N fixed phase shifters having a different optical path length from another of the N fixed phase shifters, and each of the N linear waveguides being coupled to the output of one of the N fixed phase shifters.

[0101] Example 18. A beam steering device according to any one of Examples 12 to 17, wherein each of the N fixed phase shifters includes a curved waveguide, wherein the curvature of each of the N fixed phase shifters is different from that of the other of the N fixed phase shifters.

[0102] Example 19. A beam steering device according to any one of Examples 12 to 18, wherein the central beam axes of a plurality of OPAs are arranged around a main axis, and the optical path length of each of the N fixed phase shifters increases away from the beam steering device.

[0103] Example 20. A beam steering device according to any one of Examples 12 to 19, wherein the central beam axis of the second OPA of a plurality of OPAs is oriented along the main axis.

[0104] Example 21. A method for beam steering, the method comprising: coupling a laser source to a first optical phased array (OPA), the first OPA including a beam splitter network having an output including N outputs around a first central beam axis; a first network of first phase shifters and a second network of second phase shifters; generating an output beam around the first central beam axis at the output of the beam splitter network by steering the output beam in a first direction away from the first central beam axis using the first network of first phase shifters; and steering the output beam in a second direction away from the first central beam axis using the second network of second phase shifters, the second direction being opposite to the first direction.

[0105] Example 22. The method according to Example 21, wherein the beam splitter network includes multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with one of the first phase shifters, and each second output waveguide of the optical beam splitter being associated with one of the second phase shifters, and wherein generating an output beam includes: applying a first potential to the first phase shifter using a first driver to add a first phase shift to the beam passing through the first output waveguide; and applying a second potential to the second phase shifter using a second driver to add a second phase shift to the beam passing through the second output waveguide.

[0106] Example 23. The method according to any one of Examples 21 or 22 further includes coupling multiple outputs of a switching matrix between a laser source and multiple optical phased arrays (OPAs) including a first plurality of optical phased arrays (OPAs), the plurality of OPAs being arranged to have optical output directions around a main axis, each of the plurality of OPAs including an output beam direction oriented around a central beam axis, the central beam axes of each of the plurality of OPAs being different from each other.

[0107] Example 24. The method according to any one of Examples 21 to 23 further includes: sequentially switching between a plurality of OPAs to steer the beam direction of the outputs from the plurality of OPAs.

[0108] Although the invention has been described with reference to illustrative embodiments, this description is not intended to be limiting. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to those skilled in the art based on the description. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A beam steering device, comprising: A laser source is coupled to an optical phased array (OPA), the OPA comprising: A beam splitter network, optically coupled to the laser source and configured to split the laser beam generated by the laser source into N outputs to generate an output beam; A first network of a first phase shifter is configured to steer the output beam in a first direction away from the longitudinal direction; and The second network of the second phase shifter is configured to steer the output beam in a second direction away from the longitudinal direction, the second direction being opposite to the first direction. The beam steering device also includes: The antenna includes N linear waveguides, the N linear waveguides corresponding to the N outputs; and N fixed phase shifters are coupled to the beam splitter network, each of the N fixed phase shifters having a different optical path length than the other N fixed phase shifters, and each of the N linear waveguides is coupled to the output of one of the N fixed phase shifters.

2. The beam steering device of claim 1, wherein the beam splitter network comprises multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with one of the first phase shifters, and each second output waveguide of the optical beam splitter being associated with one of the second phase shifters, the first phase shifter being configured to add a first phase shift to the beam passing through the first output waveguide, and the second phase shifter being configured to add a second phase shift to the beam passing through the second output waveguide.

3. The beam steering device of claim 2, wherein the first output waveguide and the second output waveguide of the final stage of each of the plurality of stages of the optical beam splitter are each connected to an array of linear gratings.

4. The beam steering device according to claim 2, wherein the i-th stage of the plurality of stages of the optical beam splitter comprises: 2 i-1 A 1×2 optical beam splitter, where i is an integer greater than or equal to 1.

5. The beam steering device according to claim 1, wherein the first network of the first phase shifter comprises: A first driver is coupled to each of the first phase shifters in the first phase shifter, and the first driver is configured to configure the first phase shifter to provide a first phase offset.

6. The beam steering device of claim 5, wherein the second network of the second phase shifter comprises: A second driver is coupled to each of the second phase shifters, and the second driver is configured to configure the second phase shifter to provide a second phase offset different from the first phase offset.

7. The beam steering device according to claim 6, wherein the first phase shifter and the second phase shifter are identical.

8. The beam steering device of claim 6, wherein the first phase offset is opposite to the second phase offset.

9. The beam steering device of claim 1, wherein the first network of the first phase shifter and the second network of the second phase shifter comprise thermal or electro-optic phase shifters.

10. The beam steering device according to claim 1, further comprising a switching matrix coupled between the laser source and the OPA.

11. A beam steering device, comprising: A switching matrix, comprising z outputs coupled to a plurality of optical phased arrays (OPAs), and the switching matrix is ​​configured to sequentially guide laser beams emitted by a laser source to the plurality of OPAs, the lasers being emitted around a main axis, each of the plurality of OPAs including an output beam direction oriented around a central beam axis, the central beam axes of each of the plurality of OPAs being different from each other, and each of the plurality of OPAs including: A beam splitter network is coupled to the laser source, and the beam splitter network is configured to split the laser beam into N outputs to generate corresponding output beams; A first network of a first phase shifter is configured to steer the output beam in a first direction away from the central beam axis; and The second network of the second phase shifter is configured to steer the output beam in a second direction away from the central beam axis, the second direction being opposite to the first direction.

12. The beam steering device of claim 11, wherein the beam splitter network comprises multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with one of the first phase shifters, and each second output waveguide of the optical beam splitter being associated with one of the second phase shifters, the first phase shifter being configured to add a first phase shift to the beam passing through the first output waveguide, and the second phase shifter being configured to add a second phase shift to the beam passing through the second output waveguide.

13. The beam steering device of claim 12, wherein the i-th stage of the optical beam splitter comprises 2 i-1 One 1x2 beam splitter.

14. The beam steering device of claim 11, wherein the first network of the first phase shifter comprises: A first driver is coupled to each of the first phase shifters in the first phase shifter, and the first driver is configured to configure the first phase shifter to provide a first phase offset.

15. The beam steering device of claim 14, wherein the second network of the second phase shifter comprises: A second driver is coupled to each of the second phase shifters, and the second driver is configured to configure the second phase shifter to provide a second phase offset different from the first phase offset.

16. The beam steering device of claim 11, wherein the first OPA of the plurality of OPAs comprises: The antenna includes N linear waveguides corresponding to the N outputs of the first OPA among the plurality of OPAs; as well as N fixed phase shifters are coupled to the beam splitter network, each of the N fixed phase shifters having a different optical path length than the other N fixed phase shifters, and each of the N linear waveguides is coupled to the output of one of the N fixed phase shifters.

17. The beam steering device of claim 16, wherein each of the N fixed phase shifters comprises a curved waveguide, wherein the curvature of each of the N fixed phase shifters is different from that of the other fixed phase shifter among the N fixed phase shifters.

18. The beam steering device of claim 16, wherein the central beam axis of the plurality of OPAs is arranged around the main axis, and the optical path length of each of the N fixed phase shifters increases away from the main axis of the beam steering device.

19. The beam steering device of claim 16, wherein the central beam axis of the second OPA of the plurality of OPAs is oriented along the main axis.

20. A method for beam steering, the method comprising: A laser source is coupled to a first optical phased array (OPA), the first OPA comprising: a beam splitter network having outputs, the outputs including a plurality of N outputs surrounding a first central beam axis; a first network of first phase shifters; a second network of second phase shifters; N fixed phase shifters coupled to the beam splitter network, each of the N fixed phase shifters having a different optical path length than the other N fixed phase shifters; and N linear waveguides, each of the N linear waveguides being coupled to the output of one of the N fixed phase shifters; An output beam around the first central beam axis is generated at the output of the beam splitter network in the following manner: The output beam is redirected in a first direction away from the first central beam axis by a first network of the first phase shifter; and The output beam is redirected in a second direction away from the first central beam axis by a second network of a second phase shifter, the second direction being opposite to the first direction.

21. The method of claim 20, wherein the beam splitter network comprises multiple stages of optical beam splitters, each optical beam splitter having an input, a first output waveguide, and a second output waveguide, each first output waveguide of the optical beam splitter being associated with one of the first phase shifters, and each second output waveguide of the optical beam splitter being associated with one of the second phase shifters, and wherein generating the output beam comprises: A first potential is applied to the first phase shifter using a first driver to add a first phase shift to the beam passing through the first output waveguide; as well as A second potential is applied to the second phase shifter using a second driver to add a second phase shift to the beam passing through the second output waveguide.

22. The method of claim 20, further comprising: Multiple outputs of a switching matrix are coupled between the laser source and multiple optical phased arrays (OPAs), including the first optical phased array (OPA). The multiple OPAs are arranged to have optical output directions around a main axis. Each of the multiple OPAs includes an output beam direction oriented around a central beam axis. The central beam axes of each of the multiple OPAs are different from each other.

23. The method of claim 22, further comprising: The beam direction is sequentially switched among the plurality of OPAs to direct the output from the plurality of OPAs.

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