Optical alignment system for optical communication equipment

Abstract

A method and optical system for preemptively correcting for potential future misalignments of optical communication beams between a plurality of free space optical (FSO) or light fidelity (Li-Fi) units by intentionally creating a predetermined and repetitive motion of the beam path between the units using a conditioning mechanism. In some examples, the predetermined motion is a circular motion or a reciprocating and / or translational motion. The predetermined motion can be achieved by the conditioning mechanism, which can include a plurality of piezoelectric actuators or one or more MEMS controlled mirrors or microlenses.

Description

Technical Field

[0001] This disclosure generally relates to optical systems, and more particularly to systems and methods for optically preemptively correcting potential misalignment of a beam relative to a detector. Background Technology

[0002] Li-Fi and other free-space optical communications rely on a direct path between the source and target to provide wireless optical communication. Typically, the source and target are mounted or otherwise fixed to an elevated structure to prevent objects, vehicles, or people from interfering with the signal path. Especially in these elevated locations, each unit (i.e., the source and target) is prone to movement or drift relative to each other due to various factors—including, for example, swaying caused by weather and wind, and bending due to uneven thermal expansion of the materials used to construct the elevated structure. These environmental conditions can be so severe that misalignment between the source and target can occur, leading to data loss within the communication. Summary of the Invention

[0003] This disclosure relates to methods and systems for preemptively correcting potential future misalignment of optical communication beams among multiple free-space optical (FSO) units or light-fidelity (Li-Fi) units by intentionally generating predetermined and repetitive movements of beam paths between these units using an adjustment mechanism. For example, small, known, repetitive movements of the transmitting unit are induced simultaneously with alignment with the detector portion of the receiving unit, allowing correction of significant movements or drifts that would ultimately lead to future misalignment before significant amounts of data are lost. In some examples, the predetermined movements are circular or reciprocating and / or translational movements. The predetermined movements can be achieved by an adjustment mechanism that may include multiple piezoelectric actuators or one or more MEMS-controlled mirrors or microlenses.

[0004] In one example, a method for maintaining alignment of an optical communication beam is provided, the method comprising: generating an optical communication beam along a virtual alignment axis via a transmitting unit including at least one unit detector, the optical communication beam having a beam path between the transmitting unit and a receiving unit, the receiving unit including at least one detector portion and at least one reflector portion; receiving the optical communication beam at at least one detector portion of the receiving unit; preemptively changing the beam path relative to the virtual alignment axis using a predetermined movement; detecting potential misalignment of the virtual alignment axis when at least one unit detector of the transmitting unit receives at least a portion of the optical communication beam; and aligning the virtual alignment axis relative to the center of the at least one detector portion using an alignment mechanism based on the detected misalignment.

[0005] In one aspect, the predetermined motion is circular motion or reciprocating motion.

[0006] In one aspect, the alignment mechanism includes a plurality of piezoelectric actuators, wherein the plurality of piezoelectric actuators are radially spaced around an outer surface of a body of the transmitting unit, wherein each of the plurality of piezoelectric actuators is configured to be connected to a portion of the body of the transmitting unit, and wherein the plurality of piezoelectric actuators are arranged around a rear portion of the transmitting unit.

[0007] In one aspect, the transmitting unit includes an inertial navigation system to obtain movement information of the transmitting unit.

[0008] In one aspect, the alignment mechanism includes at least one microelectromechanical system (MEMS), which includes a mirror or microlens; or the alignment mechanism includes a rotating mass.

[0009] In one aspect, at least one detector portion has a first diameter, and the optical communication beam has a second diameter, wherein the first diameter is less than or equal to the second diameter.

[0010] In one aspect, the receiving unit also includes a central reflector section.

[0011] In another example, an optical system is provided, comprising: a transmitting unit configured to generate an optical communication beam along a virtual alignment axis, the transmitting unit including at least one unit detector; a receiving unit including at least one detector portion and at least one reflector portion; an alignment mechanism configured to preemptively change the beam path disposed between the transmitting unit and the receiving unit relative to the virtual alignment axis using a predetermined movement; and a controller configured to detect at least a portion of the optical communication beam at at least one unit detector and operate the alignment mechanism to preemptively align with the virtual alignment axis relative to the center of at least one detector portion.

[0012] In one aspect, the predetermined motion is circular motion or reciprocating motion.

[0013] In one aspect, the alignment mechanism includes a plurality of piezoelectric actuators, wherein the plurality of piezoelectric actuators are radially spaced around an outer surface of a rear portion of the body of the transmitting unit, and each of the plurality of piezoelectric actuators is configured to engage with a portion of the body of the transmitting unit.

[0014] In one aspect, the transmitting unit includes an inertial navigation system to obtain movement information of the transmitting unit.

[0015] In one aspect, the alignment mechanism includes at least one microelectromechanical system (MEMS), which includes a mirror or microlens; or the alignment mechanism includes a rotating mass.

[0016] In one aspect, at least one detector portion has a first diameter, and the optical communication beam has a second diameter, wherein the first diameter is less than or equal to the second diameter.

[0017] In one aspect, the receiving unit also includes a central reflector section.

[0018] In one aspect, the transmitting unit is a Li-Fi transmitter and the receiving unit is a Li-Fi receiver.

[0019] These and other aspects of the various embodiments will become clear and explained with reference to the embodiments described below. Attached Figure Description

[0020] In the accompanying drawings, similar reference numerals are used throughout the different views. Figure 1 Generally, the same parts are referred to. Furthermore, the accompanying drawings are not necessarily to scale; instead, the focus is usually on illustrating the principles of various embodiments.

[0021] Figure 1 This is a schematic perspective view of the optical system according to this disclosure.

[0022] Figure 2A This is a schematic diagram of the receiving unit according to this disclosure.

[0023] Figure 2B This is a schematic diagram of the receiving unit according to this disclosure.

[0024] Figure 3A This is a schematic diagram of the receiving unit according to this disclosure.

[0025] Figure 3B This is a schematic diagram of the receiving unit according to this disclosure.

[0026] Figure 3C This is a schematic diagram of the receiving unit according to this disclosure.

[0027] Figure 4A This is a schematic diagram of the receiving unit according to this disclosure.

[0028] Figure 4B This is a schematic diagram of the receiving unit according to this disclosure.

[0029] Figure 5A This is a schematic diagram of the receiving unit according to this disclosure.

[0030] Figure 5B This is a schematic diagram of the receiving unit according to this disclosure.

[0031] Figure 6 This is a schematic perspective view of the optical system according to this disclosure.

[0032] Figure 7 This is a schematic partial cross-sectional view of the transmitting unit according to this disclosure.

[0033] Figure 8 It is a schematic diagram of the alignment mechanism according to this disclosure.

[0034] Figure 9 This is a flowchart illustrating the steps of the method according to this disclosure. Detailed Implementation

[0035] This disclosure relates to preemptively correcting potential future misalignment of optical communication beams among multiple free-space optical (FSO) units or multiple Li-Fi units by intentionally generating predetermined and repetitive motions of beam paths through an adjustment mechanism. In some examples, the predetermined motion is circular motion or reciprocating and / or translational motion. The predetermined motion can be achieved by an adjustment mechanism that may include multiple piezoelectric actuators or one or more MEMS-controlled mirrors or microlenses.

[0036] Should be based on Figures 1-7 Please read the following description. Figure 1A schematic perspective view of an optical system 100 according to this disclosure is shown. As shown, the optical system 100 includes a transmitting unit 102 and a receiving unit 104. The transmitting unit 102 is intended to be a first free-space optical (FSO) unit (discussed below) or a transmitter for an L1-Fi based communication system, and the receiving unit 104 is intended to be a second FSO unit (discussed below) or a receiver for an L1-Fi based communication system. Although the transmitting unit 102 and the receiving unit 104 are illustrated and described herein as a first free-space optical (FSO) unit 102 and a second FSO unit 104, it should be understood that the following techniques and principles can also be used between units in a Li-Fi system (e.g., between a Li-Fi transmitter and a Li-Fi receiver). As will be discussed below, during operation of the optical system 100, the first FSO unit 102 and the second FSO unit 104 are intended to be mounted or otherwise fixed to a streetlamp, building, tower, or other elevated outdoor structure and separated by open air, making optical communication between each unit possible. The first FSO unit 102 includes an electromagnetic source 106 configured to generate focused electromagnetic radiation along a virtual alignment axis A (hereinafter referred to as "alignment axis A"). The electromagnetic source 106 may be selected from light-emitting diodes (LEDs), organic LEDs (organic light-emitting diodes), solid-state lasers, gas lasers, liquid lasers, semiconductor lasers, or any other electromagnetic radiation source (e.g., electromagnetic radiation in the visible and / or invisible spectra) capable of generating focused radiation along alignment axis A. In one example, the generated electromagnetic radiation is radio frequency (RF) radiation as illustrated, and the electromagnetic source 106 is a semiconductor laser comprising a one-dimensional or two-dimensional optical transmitter array configured to generate an optical communication beam 108 along a beam path BP and / or along alignment axis A. It should be understood that as the electromagnetic radiation leaves the first FSO unit 102 and propagates along the beam path BP, the electromagnetic source 106 may use one or more lenses or one or more microlenses to focus the electromagnetic radiation. The first FSO unit 102 also includes a unit detector 110 configured to receive at least a portion of the optical communication beam 108 reflected by the second FSO unit 104, as will be discussed below. As will be discussed in detail below, and as shown in Figure 2- Figure 4B , Figure 6 and Figure 7 As shown, when no predetermined motion (e.g., predetermined motion 126 discussed below) is applied to the first FSO unit 102 and / or the second FSU unit 104, the alignment axis A represents the trajectory of the beam path BP. In other words, in the absence of predetermined motion, the alignment axis A will be substantially parallel to the beam path BP.

[0037] Once focused along the beam path BP, the optical communication beam 108 has a first diameter D1 (as shown in the image). Figure 2A (as shown in the diagram) and intensity I. It should be understood that in some examples, as will be discussed below, the first diameter D1 can be substantially equal to or greater than the diameter of the detector section 120, i.e., the second diameter D2 (discussed below and in...). Figure 4B (As shown in the image). However, in some examples, such as... Figures 1-2B As shown, the diameter D1 is substantially smaller than the detector portion 120 (discussed below). The optical communication beam 108 can be configured and / or focused such that the intensity I is reduced as a function of the radius or distance from the center of the optical communication beam 108. For example, the optical communication beam 108 may have its highest intensity or peak intensity I at the center, and the intensity I may be reduced or decreased towards the outer edge of the beam diameter (i.e., the outer periphery of D1).

[0038] It should be understood that the first FSO unit 102 can utilize any technique or protocol for transmitting data in an optical communication beam. For example, the optical communication beam 108 can be information-encoded by modulating a carrier signal with a modulation signal containing information to be transmitted, such as information related to a predetermined motion 126 (discussed below). In addition to signal modulation, or as an alternative to signal modulation, the wavelength of the optical communication beam 108 can be set outside the visible spectrum if desired. This allows the second FSO unit 104 (discussed in detail below) to more easily distinguish the optical communication beam 108 from ambient light and thus detect the optical communication beam 108. In some example embodiments, the optical communication beam 108 is generated with known and measurable characteristics, such as a known wavelength outside the visible spectrum and / or modulated with a carrier signal having a set fundamental frequency. In some example embodiments, the wavelength and / or polarization of the optical communication beam 108 are varied depending on the time of day to account for changing environmental conditions, such as the spectral variation of the sun or other light sources throughout the day. Furthermore, the optical communication beam 108 can be emitted in a collimated or parallel manner with little or no divergence, for example, to facilitate precise long-distance transmission. For instance, the emitted optical communication beam 108 can be collimated by an optics device (e.g., an aspherical lens) to form one or more collimated beams pointing towards the second FSO unit 104. In other example embodiments, a flashlight may be included to focus the optical communication beam 108.

[0039] As will be discussed below, and as Figure 1 , Figure 6 and Figure 7 As shown, the first FSO unit 102 may include a body 112 configured to at least partially enclose the electromagnetic source 106. The body 112 includes an outer surface 114 and has a front portion 116 and a rear portion 118. In one example, as... Figure 1 and Figure 6 As shown, the outer surface 114 is a circumferential surface; however, it should be understood that the outer surface 114 can have any cross-sectional shape, including but not limited to: triangles, squares, rectangles, hexagons, octagons, etc. The front portion 116 is intended to be the portion of the body 112 closest to an opening, aperture, or surface of the body 112 from which the optical communication beam 108 is emitted. In other words, during operation of the optical system 100, the front portion 116 is the portion of the body 112 closest to the second FSO unit 104. Conversely, the rear portion 118 is intended to be the portion of the body 112 furthest from the second FSO unit 104 during operation. It should also be understood that, although not shown, the first FSO unit 102 may include a first circuit electrically connecting a first processor and a first memory, the first processor and the first memory being configured to execute and store a first plurality of non-transitory computer-readable instructions, respectively, to perform the functions of the first FSO unit 102, as will be discussed herein. Furthermore, as referred to below... Figures 6-7 As shown and described in detail, the first FSO unit 102 may also include an alignment mechanism 124.

[0040] The second FSO unit 104 is configured to receive the optical communication beam 108 from the first FSO unit 102. For example... Figures 1-5B As shown, the second FSO unit 104 includes a portion configured to receive at least one optical communication beam 108, namely a detector portion 120; and at least one portion configured to reflect the optical communication beam 108, namely a reflector portion 122. The detector portion 120 is intended to be a photodiode, a plurality of photodiodes, or any other detector or sensor capable of receiving and detecting modulation in the optical communication beam 108. In one example, the detector portion 120 may include at least one avalanche photodiode or at least one single-photon avalanche diode. The reflector portion 122 includes one or more passive reflective components or materials, such as a mirror or a smooth coated surface with high reflectivity. Figures 1-5BIn the example shown, both detector portion 120 and reflector portion 122 are circular; however, it should be understood that other shapes and combinations of shapes can be utilized. Although reflector portion 122 is reflective or includes reflective portions or materials, it should be understood that, depending on the wavelength chosen, detector portion 120 may reflect a very small portion of the electromagnetic radiation of the optical communication beam 108, but was originally intended to be optimized to absorb all light and therefore non-reflective. For example, reflector portion 122 may reflect radiation at exactly the same angle as the incident beam, which is useful in cases where communication is aligned (as will be discussed below) but not exactly at an angle perpendicular to the surface of the second FSO unit 104. It should also be understood that, although not shown, the second FSO unit 104 may include a second circuitry electrically connecting a second processor and a second memory, the second processor and the second memory being configured to execute and store a second plurality of non-transitory computer-readable instructions, respectively, to perform the functions of the second FSO unit 104, as will be discussed herein. The second circuit of the second FSO unit 104 can be configured to sense, detect, or otherwise receive the optical communication beam 108 and decode the optical communication beam 108 into information or data.

[0041] In the example embodiment, the first FSO unit 102 and the second FSO unit 104 can be mounted at an elevated position in any suitable outdoor structure (e.g., a streetlight) to avoid obstruction or interference between the optical communication beam 108 and people, vehicles, etc. The term "streetlight" or "road lamp" as used herein refers to any outdoor lighting infrastructure that includes luminaires (e.g., luminaires extending from a support such as a pole) to illuminate an area near the streetlight. The pole may be specifically constructed for a streetlight or may be used for some other purpose (e.g., a utility pole). It should be understood that in other examples, one or more streetlights may include or extend from other types of infrastructure, such as signs, buildings, bridges, or towers.

[0042] Advantageously, streetlights and electrically wired buildings can provide power to building systems and / or luminaires. These electrically wired buildings or luminaires can provide electrical connections for the first FSO unit 102 and the second FSO unit 104. Furthermore, streetlights are typically installed at regular intervals along roads, streets, sidewalks, or other paths, extending to various locations where people live, work, or otherwise expect high data rate communication and / or between these locations. In this way, the first FSO unit 102 and the second FSO unit 104 can be installed at streetlights, and multiple additional FSO units can form a network of interconnected FSO units, for example, extending in any desired direction throughout or in part of a city, town, or other location. Additionally, it should be understood that existing streetlight infrastructure can be utilized by retrofitting FSO units onto existing streetlights. It should also be understood that one FSO unit can be installed on a streetlight or stilt, and another can be installed on a building, tower, or other elevated structure.

[0043] As described above, one problem faced by free-space optical systems is maintaining optical alignment or a direct beam path (e.g., the shortest straight path) between the first FSO unit 102 and the second FSO unit 104. In operation, the first FSO unit 102 and the second FSO unit 104 can move relative to each other based on weather and other factors such as wind sway, thermal expansion, and vibration. Due to the diameter D1 of the emitted optical communication beam 108 and the limited field of view of the detector portion 120 at the second FSO unit 104, any slight movement caused by any of these environmental conditions can affect beam alignment and disrupt communication. In some examples, the first FSO unit 102 and the second FSO unit 104 are mounted on structures significantly separated by a distance (e.g., hundreds of meters or thousands of kilometers), and any minute angular displacement of the beam path BP of the optical communication beam 108 at the first FSO unit 102 can lead to significant misalignment near the second FSO unit 104. Even when the first FSO unit 102 and the second FSO unit 104 are not moving, other environmental conditions such as fog can disrupt communication.

[0044] Therefore, in one example, the object of this disclosure is to provide an optical system 100 configured to preemptively change the beam path BP of an optical communication beam 108 relative to an alignment axis A in a repeatable predetermined movement 126 to detect the possibility of future misalignment and correct potential future misalignment before any significant data loss occurs. To this end, the optical system 100 includes an alignment mechanism 124 configured to generate a predetermined movement 126 relative to the alignment axis A along the beam path BP of the optical communication beam 108.

[0045] like Figures 2A-3C As shown, the predetermined motion 126 can be a circular motion. Figure 2A A series of beam path BP positions located on the detector portion 120 of the second FSO unit 104 are shown and represented as a series of dashed circles of diameter D1. It should be understood that although shown as a series of dashed circles, the circumferential predetermined motion 126 is intended to be a fluid circumferential motion, and the dashed circles represent the positions of the optical communication beam 108 at different locations within the circumferential motion, for example, every 40 degrees around the alignment axis A. In other words, each dashed circle represents a snapshot of the optical communication beam 108 at a different point in time within the circumferential motion. Additionally, in one example, the circumferential predetermined motion 126 has a small radius—that is, a radius less than half the diameter of the detector portion 120 (i.e., the second diameter D2)—such that all the dashed circles (i.e., the entire circular path of the optical communication beam 108) contact the detector portion 120 of the second FSO unit 104 during the entire circumferential predetermined motion 126. Figure 2B As shown, if the first FSO unit 102 and / or the second FSO unit 104 experience movement or vibration due to, for example, environmental conditions, uneven heating of their support structure, etc., the alignment axis A may begin to drift or become misaligned relative to the center C of the detector section 120.

[0046] like Figure 2B As shown, the first FSO unit 102 and / or the second FSO unit 104 may begin to drift relative to each other, causing the alignment axis A to drift, for example, upward toward the top of the detector portion 120. As shown, the drift may continue until at least a portion of the optical communication beam 108 overlaps with and is reflected away from the reflector portion 122 of the second FSO unit 104 and is detected by the unit detector 110 on the first FSO unit 102 (indicated by the dashed circle with crosshairs). Due to the circular repeating pattern of the predetermined movement 126 relative to the alignment axis A, the beam path BP will only temporarily overlap with the reflector portion 122 of the second FSO unit 104 and will automatically return to full contact with the detector portion 120 as part of its circular path. Therefore, only a small amount or negligible data (i.e., data contained in the communication reflected back to the detection unit 108) may be lost. When at least a portion of the optical communication beam 108 is reflected back and detected by the unit detector 110 of the first FSO unit 102, the first FSO unit 102 can correct its potential future misalignment with the second FSO unit 104 based on the trajectory of the reflected data, and correct the misalignment before the next complete circular motion. In other words, the first FSO unit 102 can (e.g., using the alignment mechanism 124 discussed below) adjust its position to compensate for the drift experienced by the optical system 100, such that the alignment axis A is substantially aligned with the center C of the detector portion 120.

[0047] Figures 3A-3C It shows a larger radius—that is, slightly smaller than the second diameter D2 (e.g.) Figure 2A The predetermined circumferential movement 126 is half the radius of the circle shown. In other words, when the alignment axis A is aligned with the center C of the detector section (as shown in the diagram), Figure 3A As shown in the diagram, the circular path of the optical communication beam 108 substantially follows the peripheral shape of the detector portion 120 while maintaining all portions of the optical communication beam 108 in contact with the detector portion 120. In these examples, given the geometry of the illustrated circular motion, any drift between the first FSO unit 102 and the second FSO unit 104 will cause at least a portion of the optical communication beam 108 to overlap with the reflector portion 122 of the second FSO unit 104, indicating a potential future misalignment, such as... Figure 3B As shown in the diagram. Once a portion of the optical communication beam 108 is reflected back to the unit detector 110 of the first FSO unit 102, preemptive correction can be performed (e.g., using the alignment mechanism 124 discussed below) to bring the alignment axis A back into alignment with the center C of the detector portion 120 of the second FSO unit 104 (in Figure 3C (This is indicated by the deviation in the circular path).

[0048] It should be understood that the predetermined motion 126 can be any repetitive motion, such as translational reciprocating motion (discussed below), circular motion (discussed above), square motion (i.e., where the projection path of the optical communication beam 108 on any part of the second FSO unit 104 is substantially square), triangular motion, rectangular motion, hexagonal motion, octagonal motion, or any other repetitive motion. For example, as Figure 4AAs shown, the predetermined motion 126 is a reciprocating motion, i.e., a back-and-forth translational motion. It should be understood that the reciprocating motion can be: a vertical translational motion, i.e., an up-and-down movement relative to the alignment axis A; a horizontal translational motion, i.e., a movement from left to right or from right to left relative to the alignment axis A; or any reciprocating translational motion between those motions, such as a diagonal movement relative to the alignment axis A. It should also be understood that composite motions of any motion discussed herein are possible, for example, where the first portion of the reciprocating predetermined motion 126 is a vertical translational motion, and the second portion of the reciprocating predetermined motion 126 is a horizontal translational motion. Additionally, the predetermined motion 126 can be adapted in real time to misalignment detected by the optical system 100. For example, when the system detects a misalignment of the beam path BP as a substantially horizontal misalignment, the predetermined motion 126 can be selected as an elliptical motion with its longest axis in the horizontal plane. It should be understood that the experienced misalignment may be caused by a combination of motions occurring at the first FSO unit 102 and the second FSO unit 104. In these examples, the motion of the first FSO unit 102 and the second FSO unit 104 can be determined by an inertial measurement unit, which may include an accelerometer, a gyroscope and / or a magnetometer.

[0049] Similar to the example using circular motion described above, the first FSO unit 102 and / or the second FSO unit 104 may begin to drift relative to each other, causing the alignment axis A to drift, for example, drifting upwards and drifting to the right side of the detector section 120 (as described above). Figure 4A As shown in the diagram, drift can continue until at least a portion of the optical communication beam 108 overlaps with and is reflected away from the reflector portion 122 of the second FSO unit 104 and is detected by the unit detector 110 on the first FSO unit 102 (indicated by the dashed circle with crosshairs). Due to the reciprocating pattern of the predetermined movement 126 relative to the alignment axis A, the beam path BP will only temporarily overlap with the reflector portion 122 of the second FSO unit 104 and, as part of its reciprocating motion, will automatically return to full contact with the detector portion 120. Therefore, in some extreme cases, only a small amount or negligible data (i.e., data contained in the communication reflected back to the unit detector 110) may be lost. When at least a portion of the optical communication beam 108 is reflected back and detected by the unit detector 110 of the first FSO unit 102, the first FSO unit 102 can correct its potential future misalignment with the second FSO unit 104 based on the trajectory of the reflected data and correct the misalignment before the next complete reciprocating motion. In other words, the first FSO unit 102 can (e.g., using the alignment mechanism 124 discussed below) adjust its position to compensate for the drift experienced by the optical system 100, such that the alignment axis A is substantially aligned with the center C of the detector section 120.

[0050] like Figure 4B As shown, the first diameter D1 of the optical communication beam 108 can be larger than the second diameter D2 of the detector portion 120 of the second FSO unit 104. In this example, instead of measuring misalignment caused by any part of the optical communication beam 108 contacting the reflector portion 122 of the second FSO unit 104 and being reflected away, the misalignment can be determined as a function of the intensity I of the optical communication beam 108. For example, as described above, the optical communication beam 108 can have an intensity I that decreases radially from the center of the beam to the outer edge of the beam. In some examples, the luminous intensity I across the cross-sectional width of the optical communication beam 108 resembles a Gaussian distribution curve, a Gaussian intensity profile (i.e., an intensity profile with a Gaussian distribution), with its peak intensity located at the center of the beam, and the intensity I decreasing or diminishing to 1 / distance as you approach the outer edge of the beam. Given this intensity distribution, when no predetermined motion 126 is applied to the beam path BP, the alignment axis A will coincide with the region of highest intensity I as detected by the detector portion 120 of the second FSO unit 104. Conversely, misalignment can be determined based on the intensity of the reflected portion of the optical communication beam 108, which is reflected from the reflector portion 122 of the second FSO unit 104 and detected by the unit detector 110 of the first FSO unit 102. For example, after a predetermined movement 126 is applied to the beam path BP relative to the alignment axis A, any drift between the first FSO unit 102 and the second FSO unit 104 can be determined if any portion of the optical communication beam 108 reflected from the reflector portion 122 has an intensity I that satisfies a predetermined threshold. In one example, this threshold is 10% of the peak intensity I of the optical communication beam 108; however, it should be understood that other intensity thresholds, such as 1%, 2%, 5%, 7%, 15%, 20%, etc., can be considered.

[0051] Additionally, such as Figures 5A-5B As shown, the detector portion 120 of the second FSO unit 104 may further include a central reflector portion 128 located at the center of the detector portion 120. Similar to the reflector portion 122 discussed above, the central reflector portion 128 may include one or more passive reflective components or materials, such as a mirror with high reflectivity or a smooth coated surface. Figures 5A-5B In the example shown, the central reflector portion 128 is circular; however, it should be understood that other shapes (e.g., triangles, squares, rectangles, hexagons, octagons, etc.) can be utilized. In the alignment position, i.e., where the alignment axis A coincides with the center C of the detector portion 120, a predetermined movement 126 (e.g., circular motion) can be applied to the beam path BP. Figure 5AIn the example shown, the diameter of the central reflector portion 128 (i.e., the third diameter D3) is smaller than the diameter of the predetermined circular motion 126, such that when in the aligned position, no portion of the optical communication beam 108 overlaps with any portion of the central reflector portion 128. However, similar to the drift correction discussed above, in the example embodiment where the second FSO unit 104 includes the central reflector portion 128, the contact position of the alignment axis A and the contact portion of the beam path BP can drift relative to the center C of the detector portion 120. Figure 5B As shown, an upward drift (i.e., a drift of alignment axis A toward the upper part of detector portion 120) will cause a portion of the optical communication beam 108 (illustrated as one or more dashed circles with crosshairs) to overlap with the central reflector portion 128. This portion will be reflected back to the unit detector 110 of the first FSO unit 102 to signal a potential future misalignment. When at least a portion of the optical communication beam 108 is reflected back and detected by the unit detector 110 of the first FSO unit 102, the first FSO unit 102 can correct its potential future misalignment with the second FSO unit 104 based on the trajectory of the reflection data and correct the misalignment before the next complete circular motion. In other words, the first FSO unit 102 can (e.g., using alignment mechanism 124 discussed below) adjust its position to compensate for the drift experienced by the optical system 100 such that alignment axis A is substantially aligned with the center C of detector portion 120. It should be understood that this effect can be produced by using the central reflector portion 128 alone, that is, only when the central reflector portion 128 is possibly necessary, and the optical system 100 can use measurements, predetermined movements and detection of misalignment without the need for reflector portion 122, and rely solely on the central reflector portion 128 to determine any misalignment.

[0052] like Figure 6As shown, the predetermined movement 126 can be applied by an alignment mechanism (i.e., alignment mechanism 124). As shown, at least a portion of the alignment mechanism 124 is configured to be fixed to and / or surround at least a portion of the body 112 and / or outer surface 114 of the first FSO unit 102. In one example, the alignment mechanism 124 includes a front support structure 130 and a rear support structure 132. The front support structure 130 may be a frame-type structure configured to at least partially surround the front portion 116 of the body 112 of the first FSO unit 102. The front support structure 130 may include a plurality of front support arms extending radially inward toward the body 112 of the first FSO unit 102, these front support arms being configured to attach to the front portion 116 of the body 112 to suspend the front portion 116 in free space and potentially allow the front portion 116 to pivot. Similarly, the rear support structure 132 may be a frame-type structure configured to at least partially surround the rear portion 118 of the body 112 of the first FSO unit 102. The rear support structure 132 may include a plurality of rear support arms extending radially inward toward the body 112, which are configured to be attached to the rear portion 118 of the body 112 of the first FSO unit 102 to suspend the rear portion 118 in free space.

[0053] In some examples, each rear support arm may include a piezoelectric element, namely at least one of a plurality of piezoelectric actuators 134A-134D. Each actuator, operated individually, can push or pull each corresponding rear support arm, causing the rear portion 118 of the body 112 to move proportionally. Thus, each predetermined movement 126 discussed above can be achieved by activating one or more of the plurality of piezoelectric actuators 134A-134D. For example, activation of the first piezoelectric actuator 134A can operate to push or displace the rear portion 118 of the first FSO unit 102 in a downward direction (i.e., toward the third piezoelectric actuator 134C) while the first support structure 130 is configured to hold the first portion 116 of the FSO unit in a suspended position. Thus, the downward movement of the rear portion 118 and the pivoting of the body 112 about the front support structure 130 will cause the beam path BP to be emitted in an upward trajectory or angle and to contact the second FSO unit 104 at a position above the alignment axis A. Conversely, the first piezoelectric actuator 134A can also be configured to pull or shift the rear portion 118 in an upward direction, causing the beam path BP to be emitted along a downward trajectory or angle and to contact the second FSO unit 104 at a position below the alignment axis A. It should be understood that all piezoelectric actuators 134A-134D can operate in a similar manner to push or pull the rear portion, thereby changing the trajectory of the beam path BP horizontally or vertically relative to the alignment axis A. Additionally, one or more of the piezoelectric actuators 134A-134D can cooperate to achieve one-dimensional motion, such as upward or downward movement. For example, downward displacement of the rear portion 118 can be achieved through the coordinated action of the first piezoelectric actuator 134A pushing the rear portion downward and the third piezoelectric actuator 134C pulling the rear portion 118 downward. Furthermore, it should be understood that one or more of the piezoelectric actuators 134A-134D can operate in concert to produce more complex motions, such as circular motion, diagonal motion, or any other motion discussed herein. For example, each of the piezoelectric actuators 134A-134D can be activated remotely in sequence, i.e., starting with the activation of the first piezoelectric actuator 134A, proceeding to the second piezoelectric actuator 134B, then the third piezoelectric actuator 134C, and finally the fourth piezoelectric actuator 134D, to cause a synchronized clockwise circular motion of the rear portion 118, which in turn causes a clockwise circular motion of the beam path BP. It should also be understood that although four piezoelectric actuators are shown and described herein, more or fewer piezoelectric actuators can be used to produce more complex motions, such as hexagonal, octagonal, etc. It should be understood that only the rear support structure 132 may be necessary to apply the predetermined movement 126, and the front portion 116 may simply rest on or otherwise engage with a surface that allows the body 112 to pivot about the front portion 116.Furthermore, in some examples, the front support structure 130 of the front portion 116 may include a plurality of piezoelectric actuators 134A-134D to apply the predetermined motion 126 discussed herein, and the rear support structure 132 may be passive.

[0054] Furthermore, one or more lenses or microlenses can be used to apply the predetermined motion 126 to the beam path BP, for example, as Figure 7 As shown in the diagram (which illustrates a partial cross-sectional view of the first FSO unit 102), the first FSO unit 102 may include a controller 136 and a micro-laser scanning module, which includes at least one microelectromechanical system (MEMS) device 138 to operate one or more mirrors or microlenses 140. The controller 136 may include a dedicated processor and memory configured to execute and store a plurality of non-transitory computer-readable instructions, respectively, to perform the functions of the first FSO unit and / or alignment mechanism 124 as described herein. The controller 136 may be or may include one or more application-specific integrated circuits or chips (ASICs) to guide the MEMS device 138 to operate the mirrors or microlenses 140, thereby moving the optical communication beam 108 relative to the alignment axis A with any of the aforementioned movements. In some examples, the MEMS mirror is a millimeter-sized mirror that performs laser scanning or is located in the emitting portion of a solid-state laser. Furthermore, as... Figure 7 As shown, the first FSO unit 102 and / or the second FSO unit 104 may include an inertial navigation system INS, which may include one or more processors, one or more motion sensors, and one or more rotation sensors, such as accelerometers, gyroscopes, and magnetometers, configured to obtain the position, orientation, or velocity of movement (if any) of each respective device. Devices within the optical system 100 may use the inertial navigation system INS to determine the absolute or relative motion of the first FSO unit 102 with respect to the second FSO unit 104, and the optical system 100 may adjust a predetermined motion 126 selected based on known motion data provided by the inertial navigation system INS.

[0055] Additionally, such as Figure 8As illustrated, it should be understood that, in addition to or as an alternative to the piezoelectric actuators and / or MEMS machines discussed herein, the alignment mechanism 124 may include a movable or rotatable mass block RM located within the first FSO unit 102 and connected to or directly attached to the electromagnetic source 106, or positioned together with the second FSO unit 104 to generate a predetermined motion 126. For example, a rotation axis S may be disposed within the first FSO unit 102, which is non-rotatably fixed to the mass block RM, which may be in a semi-cylindrical shape, such as a cylindrical mass block already cut parallel to the long axis or height axis of a cylinder. When the partially cylindrical mass block RM rotates with the rotation axis S, the uneven distribution of mass during its rotation causes slight movement of the axis and the structures attached thereto due to the resulting impulse. Assuming a non-uniform mass distribution caused by a partially cylindrical mass block rotating around an axis, the resulting pulse-driven motion will be circular motion. Therefore, this application can utilize the rotating partially cylindrical mass block RM to apply a predetermined motion 126 in the form of circular motion. It should be understood that the rotating mass block can be disposed within the first FSO unit 102 and / or the second FSU unit 104 to generate the predetermined motion, as will be discussed below.

[0056] Instead of the foregoing or other than the foregoing, and although not shown, in some examples, the function applied by the alignment mechanism 124 may be implemented on the second FSO unit 104 instead of the first FSO unit 102. For example, instead of generating the predetermined circular or translational movement 126 of the optical communication beam 108 by applying movement to the body 112 of the first FSO unit 102, the FSO unit 102 may remain spatially fixed while the second FSO unit is displaced in a circular or translational movement mode. For this purpose, the second FSO unit 104 may include a separate adjustment mechanism having, for example, multiple piezoelectric actuators to generate any predetermined movement 126 relative to the alignment axis A discussed herein.

[0057] Figure 9This is a flowchart illustrating the steps of method 200 according to the present disclosure. Method 200 may include, for example, generating an optical communication beam 108 along a dummy alignment axis A via a transmitting unit 102, the transmitting unit 102 including at least one unit detector 110, the optical communication beam 108 having a beam path BP between the transmitting unit 102 and a receiving unit 104, the receiving unit 104 including at least one detector portion 120 and at least one reflector portion 122 (step 202); receiving the optical communication beam 108 at at least one detector portion 120 of the receiving unit 104 (step 204); preemptively changing the beam path BP relative to the dummy alignment axis A using a predetermined movement 126 (step 206); detecting a potential misalignment of the dummy alignment axis A when at least one unit detector 110 of the transmitting unit 102 receives at least a portion of the optical communication beam 108 (step 208); and aligning the dummy alignment axis A relative to the center C of at least one detector portion 120 using an alignment mechanism 124 based on the detected misalignment (step 210).

[0058] All definitions defined and used herein should be understood as controls over dictionary definitions, definitions incorporated by reference in other documents, and / or the general meaning of the defined terms.

[0059] Unless explicitly indicated to the contrary, the indefinite articles “a” and “an” (“a” and “an”) used herein in the specification and claims shall be understood to mean “at least one”.

[0060] The phrase “and / or” as used herein in the specification and claims should be understood to mean “any one or both” of the elements thus combined, i.e., elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be interpreted in the same way, i.e., “one or more” of the elements thus combined. Other elements may optionally exist in addition to those specifically identified by the “and / or” clause, whether related to or unrelated to those specifically identified.

[0061] As used herein in the specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” should be interpreted as inclusive, i.e., including multiple elements or at least one of the elements in the list, but also including multiple elements or more than one of the elements in the list, and optionally, additional unlisted items. Only terms that explicitly indicate the opposite, such as “only one of…” or “exact one of…”, or when used in the claims, “consisting of…” will refer to including multiple elements or exactly one of the elements in the list. In general, the term “or” as used herein, when preceded by an exclusive term such as “any,” “one of…,” “only one of…,” or “exact one of…,” should only be interpreted as indicating an exclusive alternative (i.e., “one or the other, but not both”).

[0062] As used herein in the specification and claims, the phrase "at least one" referring to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list, but does not necessarily include at least one of every element specifically listed in the list, and does not exclude any combination of elements in the list. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements referred to by the phrase "at least one," whether related to or unrelated to those specifically identified elements.

[0063] It should also be understood that, unless expressly indicated to the contrary, in any method claimed herein that includes more than one step or action, the order of the steps or actions of the method is not necessarily limited to the order in which the steps or actions of the method are described.

[0064] In the claims, and in the description above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “accommodating,” “containing,” etc., shall be understood as open-ended, meaning including but not limited to. Only the transitional phrases “consisting of” and “substantially consisting of” shall be closed or semi-closed transitional phrases, respectively.

[0065] While several embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing functions and / or obtaining results and / or one or more advantages described herein, and each such variation and / or modification is considered to be within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications in which the teachings of the invention are applied. Those skilled in the art will recognize or be able to determine many equivalents of the particular embodiments of the invention described herein using only conventional experimentation. Therefore, it is to be understood that the foregoing embodiments are presented by way of example only, and that the embodiments of the invention can be practiced in ways other than the specific descriptions and claims within the scope of the appended claims and their equivalents. The embodiments of the invention disclosed herein relate to each individual feature, system, article, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, kits, and / or methods is included within the scope of this disclosure if two or more such features, systems, articles, materials, kits, and / or methods do not contradict each other.

Claims

1. A method for maintaining the alignment of an optical communication beam (108), the method comprising: An optical communication beam (108) is generated along a virtual alignment axis (A) via a transmitting unit (102), the transmitting unit (102) including at least one unit detector (110), the optical communication beam (108) having a beam path (BP) between the transmitting unit (102) and a receiving unit (104), the receiving unit (104) including at least one detector portion (120) and at least one reflector portion (122) surrounding the at least one detector portion (120); The optical communication beam (108) is received at at least one detector portion (120) of the receiving unit (104); The beam path (BP) is preemptively changed relative to the virtual alignment axis (A) using a predetermined motion (126); When at least one unit detector (110) of the transmitting unit (102) receives at least a portion of the optical communication beam (108), it detects a potential misalignment of the virtual alignment axis (A); as well as Based on the detected misalignment, the alignment mechanism (124) is used to align the dummy alignment axis (A) relative to the center (C) of the at least one detector portion (120).

2. The method according to claim 1, wherein the predetermined motion (126) is a circular motion or a reciprocating motion.

3. The method according to claim 1, wherein the alignment mechanism (124) comprises a plurality of piezoelectric actuators (134A-134D), wherein the plurality of piezoelectric actuators (134A-134D) are radially spaced around the outer surface (114) of the body (112) of the transmitting unit (102), wherein each of the plurality of piezoelectric actuators (134A-134D) is configured to be connected to a portion of the body (112) of the transmitting unit (102), and wherein the plurality of piezoelectric actuators (134A-134D) are arranged around the rear portion (118) of the transmitting unit (102).

4. The method according to claim 1, wherein the transmitting unit (102) includes an inertial navigation system (INS) to obtain movement information of the transmitting unit (102).

5. The method according to claim 1, wherein the alignment mechanism (124) comprises at least one microelectromechanical system (MEMS) (138), the at least one MEMS comprising a mirror or microlens (140); or wherein the alignment mechanism (124) comprises a rotating mass (RM).

6. The method according to claim 1, wherein the at least one detector portion (120) has a first diameter (D2) and the optical communication beam has a second diameter (D1), wherein the first diameter (D2) is less than or equal to the second diameter (D1).

7. The method according to claim 1, wherein the receiving unit (104) further comprises a central reflector portion (128).

8. An optical system (100) for maintaining alignment of an optical communication beam, the system comprising: A transmitting unit (102) is configured to generate an optical communication beam (108) along a virtual alignment axis (A), the transmitting unit (102) including at least one unit detector (110); The receiving unit (104) includes at least one detector portion (120) and at least one reflector portion (122) surrounding the at least one detector portion (120); Alignment mechanism (124) is configured to preemptively change the beam path (BP) arranged between the transmitting unit (102) and the receiving unit (104) relative to the virtual alignment axis (A) using a predetermined movement (126); and A controller (136) is configured to detect at least a portion of the optical communication beam (108) at the at least one unit detector (110) and to operate the alignment mechanism (124) to preemptively align the virtual alignment axis (A) relative to the center (C) of the at least one detector portion (120).

9. The optical system according to claim 8, wherein the predetermined motion (126) is a circular motion or a reciprocating motion.

10. The optical system of claim 8, wherein the alignment mechanism (124) comprises a plurality of piezoelectric actuators (134A-134D), and wherein the plurality of piezoelectric actuators (134A-134D) are radially spaced around the outer surface (114) of the rear portion (118) of the body (112) of the transmitting unit (102), wherein each of the plurality of piezoelectric actuators (134A-134D) is configured to be connected to a portion of the body (112) of the transmitting unit.

11. The optical system of claim 8, wherein the transmitting unit (102) includes an inertial navigation system (INS) to obtain movement information of the transmitting unit (102).

12. The optical system of claim 8, wherein the alignment mechanism (124) comprises at least one microelectromechanical system (MEMS) (138), the at least one MEMS comprising a mirror or a microlens (140); or wherein the alignment mechanism (124) comprises a rotating mass (RM).

13. The optical system of claim 8, wherein the at least one detector portion (120) has a first diameter (D2) and the optical communication beam (108) has a second diameter (D1), wherein the first diameter (D2) is less than or equal to the second diameter (D1).

14. The optical system of claim 8, wherein the receiving unit (104) further comprises a central reflector portion (128).

15. The optical system according to claim 8, wherein the transmitting unit (102) is a Li-Fi transmitter and the receiving unit (104) is a Li-Fi receiver.

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