Optical detection equipment and optical systems including it

Abstract

An optical detection device is provided, comprising: an optical input device configured to receive light; a plurality of waveguides extending from the optical input device, the plurality of waveguides being configured to transmit a plurality of portions of the light received by the optical input device; a plurality of modulators disposed on the plurality of waveguides and configured to modulate the phase of the plurality of portions of the light transmitted in the plurality of waveguides; at least one graphene layer configured to absorb the plurality of portions of the light transmitted in the plurality of waveguides; and at least one first electrode and at least one second electrode electrically connected to the at least one graphene layer.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0002145, filed on January 7, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Example embodiments of this disclosure relate to a light detection device and an optical system including the light detection device. Background Technology

[0004] Techniques have been developed to acquire information by reflecting electromagnetic waves onto objects or terrain within detection range and to use that information to measure distance, position, and shape. As one such technique, the Light Detection and Ranging (LiDAR) system is gaining attention.

[0005] A LiDAR system includes a light deflector for directing light to a desired location and a light detection device for detecting light reflected from an object after being emitted from the light deflector. To deflect the light, a method of mechanically rotating the light irradiation section and a method of utilizing the interference of light emitted from multiple unit cells or multiple waveguides using an optical phased array (OPA) method are employed. Summary of the Invention

[0006] One or more example embodiments provide a light detection device and an optical system including the light detection device.

[0007] Additional aspects will be set forth in part in the description which follows, and will also be apparent in part from the description, or may be learned by practice of exemplary embodiments of this disclosure.

[0008] According to one aspect of an example embodiment, a light detection device is provided, comprising: an optical input device configured to receive light; a plurality of waveguides extending from the optical input device, the plurality of waveguides being configured to transmit portions of the light received by the optical input device, respectively; a plurality of modulators disposed on the plurality of waveguides and configured to modulate the phase of the portions of the light transmitted in the plurality of waveguides, respectively; at least one graphene layer configured to absorb portions of the light transmitted in the plurality of waveguides; and at least one first electrode and at least one second electrode, respectively electrically connected to the at least one graphene layer.

[0009] The at least one graphene layer can be disposed on the plurality of waveguides.

[0010] The optical detection device may further include: an intermediate layer disposed between the at least one graphene layer and the plurality of waveguides, the intermediate layer comprising a material having a refractive index less than that of each of the plurality of waveguides.

[0011] The at least one graphene layer may be disposed on at least one of the top and side surfaces of the plurality of waveguides.

[0012] The at least one graphene layer may include graphene layers corresponding to all of the plurality of waveguides.

[0013] The at least one graphene layer may include multiple graphene layers corresponding to some of the multiple waveguides.

[0014] The plurality of waveguides may be integrated into one waveguide at one end of each of the plurality of waveguides, and the at least one graphene layer may include a graphene layer disposed on the integrated waveguide.

[0015] The photodetector may further include a gate insulating layer disposed on the at least one graphene layer and a gate electrode disposed on the gate insulating layer.

[0016] The optical input device may include an antenna array disposed at the ends of the plurality of waveguides and configured to receive light from outside the optical detection device.

[0017] The plurality of waveguides may include at least one of group IV semiconductor materials, group III-V semiconductor materials, group II-VI semiconductor materials, oxides, and nitrides.

[0018] The plurality of modulators can be configured to form a phase distribution by independently modulating the phase of each portion of the light transmitted in the plurality of waveguides.

[0019] The plurality of modulators can also be configured to modulate the phase based on applying an electrical signal or heat to each of the plurality of waveguides.

[0020] The optical input device, the plurality of waveguides, the plurality of modulators, the at least one graphene layer, and the at least one first electrode and the at least one second electrode can be disposed on the same substrate.

[0021] According to another aspect of an example embodiment, an optical system is provided, comprising: a light deflection device configured to deflect light; and a light detection device configured to detect light deflected by the light deflection device, wherein the light detection device comprises: a light input device; a plurality of waveguides extending from the light input device and configured to respectively transmit portions of light input to the light input device; a plurality of modulators disposed on the plurality of waveguides and configured to respectively modulate the phase of portions of light transmitted in the plurality of waveguides; at least one graphene layer configured to absorb portions of light transmitted in the plurality of waveguides; and at least one first electrode and at least one second electrode electrically connected to the at least one graphene layer.

[0022] A light steering device may include a laser source and a steering device configured to deflect a portion of the light emitted from the laser source.

[0023] The optical input device may further include an antenna array disposed at the ends of the plurality of waveguides and configured to receive light directed by the optical deflector.

[0024] The at least one graphene layer can be disposed on the plurality of waveguides.

[0025] The optical input device may further include: an intermediate layer disposed between the at least one graphene layer and the plurality of waveguides, the intermediate layer comprising a material with a refractive index less than that of the plurality of waveguides.

[0026] The plurality of waveguides may be integrated into one waveguide at the ends of the plurality of waveguides, and the at least one graphene layer may include a graphene layer disposed on the integrated waveguide.

[0027] The light steering device and the light detection device can be mounted on the same substrate.

[0028] The at least one first electrode and the at least one second electrode can be directly disposed on the at least one graphene layer.

[0029] The at least one first electrode and the at least one second electrode can be connected to the at least one graphene layer via wires.

[0030] Each of the plurality of graphene layers may correspond to each of the plurality of waveguides, and each of the plurality of graphene layers may be spaced apart from each other. Attached Figure Description

[0031] The above and / or other aspects, features, and advantages of exemplary embodiments of the present disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0032] Figure 1This is a schematic perspective view of a light detection device according to an example embodiment;

[0033] Figure 2 It is along Figure 1 A cross-sectional view taken by line A-A';

[0034] Figure 3 It is shown Figure 2 Figures showing multiple variations of waveguides;

[0035] Figure 4 yes Figure 1 A cross-sectional view of the antenna of the optical input unit;

[0036] Figure 5 It is along Figure 1 A cross-sectional view taken from line B-B';

[0037] Figure 6 It is shown Figure 5 A diagram showing variations of multiple modulators;

[0038] Figure 7 It is along Figure 1 A cross-sectional view taken from line C-C';

[0039] Figure 8 It is shown Figure 7 A diagram showing a modified example of the first and second electrodes;

[0040] Figure 9 This is a diagram of a light detection device according to another example embodiment;

[0041] Figure 10 This is a diagram of a light detection device according to another example embodiment;

[0042] Figure 11 This is a diagram of a light detection device according to another example embodiment;

[0043] Figure 12 This is a diagram of a light detection device according to another example embodiment;

[0044] Figure 13 This is a diagram of a light detection device according to another example embodiment;

[0045] Figure 14 This is a diagram of a light detection device according to another example embodiment;

[0046] Figure 15 This is a schematic perspective view of a light detection device according to another example embodiment; and

[0047] Figure 16 This is a diagram schematically illustrating an optical system according to an example embodiment. Detailed Implementation

[0048] Referring now to the exemplary embodiments shown in the accompanying drawings, wherein the same reference numerals refer to the same elements throughout the drawings. In this respect, the exemplary embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, the exemplary embodiments are described below only with reference to the accompanying drawings to explain various aspects. As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items. Expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0049] In the following text, content described as “above” or “on” can indicate not only being directly above and in contact with, but also being above without contact. As used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context clearly indicates otherwise. Additionally, unless otherwise stated, when a part “includes” a component, that part may also include another component rather than excluding others.

[0050] The term "the" and similar terms can be used to correspond to both the singular and the plural. When an embodiment can be implemented differently, a particular order of processes can be performed in a sequence different from that described. For example, two consecutively described processes can be performed substantially simultaneously or in the reverse order of their description.

[0051] In the following description, terms such as “unit” and “module” refer to a unit for performing at least one function or operation, wherein the unit and module may be implemented as hardware or software, or by a combination of hardware and software.

[0052] Furthermore, the connecting lines or connectors shown in the various accompanying drawings are intended to illustrate exemplary functional relationships and / or physical or logical connections between various components. It should be noted that many alternative or additional functional relationships, physical connections, or logical connections may exist in actual devices.

[0053] All examples or exemplary terms are used only to describe the technical ideas in detail, and unless defined in the claims, such examples and exemplary terms do not limit the scope of this disclosure.

[0054] Figure 1 A light detection device 100 according to an example embodiment is shown. Figure 1The image shows a light detection device 100 for detecting a portion of light input from the outside (e.g., a portion of light input after being reflected by an object) using an optical phased array (OPA) method.

[0055] Reference Figure 1 The optical detection device 100 includes a plurality of waveguides 130, an optical input device 120, a plurality of modulators 140, and a graphene layer 150. Here, the components forming the optical detection device 100 can be disposed on the same substrate 110. However, the embodiment is not limited thereto. The plurality of waveguides 130 can be arranged in an array. For example, the plurality of waveguides 130 can be arranged in one direction (e.g., Figure 1 They are arranged in a one-dimensional (1D) array on the substrate 110 along the y-axis direction. Figure 1 In this embodiment, sixteen waveguides 130 are disposed on the substrate 110, but the number of waveguides 130 can be varied.

[0056] Figure 2 It is along Figure 1 Cross-sectional views of multiple waveguides 130 cut along line A-A'. As an example, in... Figure 2 The following diagram shows four waveguides 130.

[0057] Reference Figure 2 A plurality of waveguides 130 are disposed on a substrate 110. The substrate 110 may include a material having an insulating surface. For example, the substrate 110 may include a base substrate 111 and an insulating layer 112 disposed on the top surface of the base substrate 111. The base substrate 111 may include, for example, a semiconductor substrate, such as a silicon substrate, but is not limited thereto. For example, the base substrate 111 may include various other materials. The insulating layer 112 may include, for example, silicon oxide, but is not limited thereto, and the insulating layer 112 may include various other materials. Additionally, an insulating substrate may be used as the substrate 110.

[0058] Multiple waveguides 130 are spaced apart from each other on the top surface of the substrate 110. The multiple waveguides 130 are arranged such that a portion of the light L input from an external source to the optical input device 120 propagates therein. The waveguides 130 may include at least one of semiconductor materials, oxides, and nitrides. Here, the semiconductor material may include, for example, group IV semiconductor materials (such as silicon (Si) or germanium (Ge)), group III-V semiconductor materials, or group II-VI semiconductor materials. However, the semiconductor material is not limited to these.

[0059] Extensions 135 extending from multiple waveguides 130 can be disposed on the substrate 110 with a certain thickness. Figure 2In this embodiment, the extensions 135 are spaced apart from each other between adjacent waveguides 130. However, the embodiment is not limited to this. For example, the extensions 135 may be connected to each other between adjacent waveguides 130.

[0060] Figure 3 An example embodiment is shown. Figure 2 Examples of multiple waveguides 130. See reference. Figure 3 Multiple waveguides 130' are spaced apart from each other on the top surface of the substrate 110. Here, the aforementioned [features / structures] are not arranged between the multiple waveguides 130'. Figure 2 The extension part 135.

[0061] Reference Figure 1 A portion of the light L is input from the outside via an optical input device 120 disposed at one end of a plurality of waveguides 130. The optical input device 120 may include an antenna array, wherein a plurality of antennas 121 are arranged in an array. The plurality of antennas 121 may extend from the ends of the plurality of waveguides 130, respectively. Here, the plurality of antennas 121 may include the same material as the plurality of waveguides 130, but the embodiment is not limited thereto.

[0062] Figure 4 It shows Figure 1 A cross-sectional view of the antenna 121 of the optical input device 120. Figure 4 The diagram shows that in the longitudinal direction of antenna 121 (e.g., Figure 1 The cross section of one of the antennas 121 included in the optical input device 120 is cut along the x-axis direction.

[0063] Reference Figure 4 The antenna 121 may have a grating structure in which a plurality of grooves 121a are formed at intervals. When a portion of light L (e.g., a portion of laser light) is input from the outside to the optical input device 120 including the antenna array, that portion of light L may propagate inside a plurality of waveguides 130 while its phase is modulated by a plurality of modulators 140 described below, and may then be extracted by the graphene layer 150.

[0064] Reference Figure 1 Multiple modulators 140 are disposed on multiple waveguides 130. The multiple modulators 140 modulate the phase of a portion of light L propagating within the multiple waveguides 130. The multiple modulators 140 can form a specific phase distribution by independently modulating the phase of a portion of the light L propagating within the multiple waveguides 130. The phase distribution thus formed can depend on the angle at which the outer portion of the light L is incident on the optical input device 120. Therefore, when the multiple modulators 140 control the phase distribution of a portion of light L propagating within the multiple waveguides 130, the light reception efficiency of a portion of light emitted from an object located in a specific direction can be improved, and the position of the object can be determined.

[0065] Figure 5 It shows along Figure 1 A cross-sectional view of multiple modulators 140 taken from line B-B'.

[0066] Reference Figure 5 Each of the multiple modulators 140 includes a pair of electrodes, namely a first electrode 141 and a second electrode 142, disposed around the waveguide 130. Here, when a certain electrical signal is applied between the first electrode 141 and the second electrode 142, the refractive index of the waveguide 130 disposed between the first electrode 141 and the second electrode 142 changes due to the electrical signal. Furthermore, the phase of light propagating inside the waveguide 130 can be modulated by the change in the refractive index of the waveguide 130. Thus, by applying a certain electrical signal between the first electrode 141 and the second electrode 142 of the modulators 140 disposed corresponding to each of the multiple waveguides 130, a certain phase distribution can be formed by independently modulating the phase of portions of light propagating inside the multiple waveguides 130.

[0067] Figure 6 Another example of a plurality of modulators 140 according to an example embodiment is shown.

[0068] Reference Figure 6 Each of the plurality of modulators includes a heating element 145 disposed around the waveguide 130. An intermediate insulating layer 170 may be disposed between the waveguide 130 and the heating element 145 to prevent contact between the heating element 145 and the waveguide 130. When heat is applied to the waveguide 130 through a heating element 145, the refractive index of the waveguide 130 changes. Furthermore, the phase of light propagating within the waveguide 130 can be modulated by the change in the refractive index of the waveguide 130. Thus, when heat is applied to the waveguide 130 according to the heating element 145 disposed in each of the plurality of waveguides 130, the phase of a portion of the light propagating within the plurality of waveguides 130 is independently modulated, thereby forming a specific phase distribution.

[0069] Furthermore, the methods of applying an electrical signal or heat to waveguide 130 have been described above as ways to change the refractive index of waveguide 130. However, this is only an example, and other methods can be used to change the refractive index of waveguide 130. For example, piezoelectric devices can be placed around waveguide 130, and waveguide 130 can be modified via the piezoelectric devices to change the refractive index of waveguide 130.

[0070] Reference Figure 1A graphene layer 150 is disposed on a plurality of waveguides 130 passing through a plurality of modulators 140. Here, the graphene layer 150 can absorb most of the light L propagating inside the plurality of waveguides 130. A first electrode 161 and a second electrode 162 are electrically connected to two ends of the graphene layer 150, respectively.

[0071] The graphene layer 150 can have a single-layer or multi-layer structure. For example, the graphene layer 150 may include one to ten graphene atoms, but is not limited thereto. Graphene is a material having a hexagonal honeycomb structure in which carbon atoms are connected in a two-dimensional manner, and has a thin atomic thickness.

[0072] In the current embodiment, by arranging the graphene layer 150 on a plurality of waveguides 130, most of the light L propagating inside the plurality of waveguides 130 can be absorbed by the graphene layer 150, thus enabling a light detection device 100 with high light receiving efficiency.

[0073] Figure 7 It shows along Figure 1 A cross-sectional view of graphene layer 150 cut along line C-C'.

[0074] Reference Figure 7 A graphene layer 150 is disposed on a plurality of waveguides 130. Here, the graphene layer 150 is configured to contact the top and side surfaces of each of the plurality of waveguides 130. In this configuration, a portion of the light propagating within the plurality of waveguides 130 can be absorbed by the graphene layer 150 via the top and side surfaces of each of the plurality of waveguides 130. The graphene layer 150 can be formed by growing at least one graphene on the plurality of waveguides 130 or by transferring at least one graphene onto the plurality of waveguides 130. Furthermore, a reflective or non-reflective film can be coated on the other end of the waveguide 130 through which the graphene layer 150 passes.

[0075] The first electrode 161 and the second electrode 162 can be electrically connected to the two ends of the graphene layer 150. Here, the first electrode 161 and the second electrode 162 can include materials with excellent conductivity. The first electrode 161 and the second electrode 162 can be disposed on the top surface of the substrate 110.

[0076] When a certain voltage is applied between the first electrode 161 and the second electrode 162, a portion of the light propagating inside the plurality of waveguides 130 can be largely absorbed by the graphene layer 150. At this time, electrons can be generated within the graphene layer 150, and these electrons can move between the first electrode 161 and the second electrode 162 to generate a photoreceiving current. This photoreceiving current is measured via the first electrode 161 and the second electrode 162 to detect a portion of the light propagating inside the plurality of waveguides 130. Here, the voltage applied between the first electrode 161 and the second electrode 162 can be adjusted to control the photoreceiving current and the photoreceiving efficiency.

[0077] Figure 8 It shows Figure 7 Examples of the first electrode 161 and the second electrode 162. See also... Figure 8 The first electrode 163 and the second electrode 164 can be electrically connected to both ends of the graphene layer 150 via the first wire 165 and the second wire 166, respectively. Here, the first electrode 163 and the second electrode 164 can be spaced apart from the substrate 110. However, this is only an example, and the first electrode 163 and the second electrode 164 can be disposed on the top surface of the substrate 110.

[0078] In the optical detection device 100 with this structure, when an external portion of light (e.g., a portion of light reflected from an object) is input to the optical input device 120, this portion of light propagates along a plurality of waveguides 130. Furthermore, the phase of this portion of light propagating within the plurality of waveguides 130 is modulated by a plurality of modulators 140, and this portion of light is absorbed by graphene layers 150 disposed on the plurality of waveguides 130, thereby being detected by a first electrode 161 and a second electrode 162.

[0079] In the example embodiment, because the graphene layer 150 absorbs most of the light propagating inside the plurality of waveguides 130, a light detection device 100 with relatively high light receiving efficiency can be realized. Furthermore, when the plurality of modulators 140 control the phase distribution by independently modulating the phase of a portion of the light propagating inside the plurality of waveguides 130, the light receiving efficiency can be further improved, and the location where the outer portion of the light is incident can be determined.

[0080] Thus, because the light detection device 100 is configured to efficiently receive light in a specific direction, it is easier, for example, to realize a long-distance light detection and ranging (LiDAR) system. Furthermore, because the LiDAR system can reduce the intensity of the output light from the light-emitting device, eye safety can be improved, and the system can be miniaturized and reduced in cost.

[0081] Figure 9 A light detection device according to another example embodiment is shown.

[0082] Reference Figure 9 The graphene layer 151 can be configured to contact the top surface of each of the plurality of waveguides 130. In this case, a portion of the light propagating inside the plurality of waveguides 130 can be absorbed by the graphene layer 151 via the top surface of each waveguide 130. The cross-sectional shape of this portion of the light propagating inside the plurality of waveguides 130 can vary depending on the optical mode. When this portion of the light propagating inside the plurality of waveguides 130 has an elliptical cross-section that is relatively long in the vertical direction, such as... Figure 9 As shown, the graphene layer 151 can be configured to contact the top surface of the waveguide 130, for example, to effectively absorb that portion of the light propagating inside the waveguide 130.

[0083] Figure 10 A light detection device according to another example embodiment is shown.

[0084] Reference Figure 10 The graphene layer 152 can be configured to contact the side surface of each of the plurality of waveguides 130. Here, a portion of the light propagating inside the plurality of waveguides 130 can be absorbed by the graphene layer 152 via the side surface of each waveguide 130. The portion of the graphene layer 152, except for the portion in contact with the side surface of the waveguide 130, can be integrally connected to each other.

[0085] When this portion of the light propagating inside multiple waveguides 130 has a relatively long elliptical cross-section in the left-right direction, such as Figure 10 As shown, the graphene layer 152 can be configured to contact the side surface of the waveguide 130 to more effectively absorb that portion of the light propagating inside the waveguide 130.

[0086] Figure 11 A light detection device according to another example embodiment is shown.

[0087] Reference Figure 11 An intermediate layer 180 is disposed between the waveguide 130 and the graphene layer 150. Here, the intermediate layer 180 may comprise a material having a lower refractive index than the waveguide 130. By adjusting the material or thickness of the intermediate layer 180, the amount of light absorbed by the graphene layer 150 can be controlled.

[0088] Figure 12 A light detection device according to another example embodiment is shown.

[0089] Reference Figure 12A gate insulating layer 190 is disposed on the top surface of each of the plurality of waveguides 130, and a gate electrode 195 is disposed on the top surface of the gate insulating layer 190. The first electrode 161 and the second electrode 162 may respectively comprise a source electrode and a drain electrode. In this case, the light receiving characteristics of the photodetector can be controlled by adjusting the voltage applied to the first electrode 161, the second electrode 162, and the gate electrode 195.

[0090] In the above example embodiment, a graphene layer 150 is disposed corresponding to all of the plurality of waveguides 130. However, as described below, multiple graphene layers can be disposed for some of the plurality of waveguides. In this case, photodetection can be performed by driving all graphene layers or by driving each graphene layer independently.

[0091] Figure 13 A light detection device according to another example embodiment is shown.

[0092] Reference Figure 13 Multiple graphene layers 150' are disposed on multiple waveguides 130. Figure 13 In this configuration, two graphene layers 150' are disposed on four waveguides 130. Each graphene layer 150' can correspond to two waveguides 130. Furthermore, a first electrode 161' and a second electrode 162' are electrically connected to each graphene layer 150'.

[0093] Figure 14 A light detection device according to another example embodiment is shown.

[0094] Reference Figure 14 Multiple graphene layers 150” are arranged in a one-to-one manner on multiple waveguides 130. Figure 14 In this configuration, four graphene layers 150” are respectively disposed on four waveguides 130. Here, each graphene layer 150” can correspond to one waveguide 130, and the first electrode 161” and the second electrode 162” are electrically connected to each graphene layer 150”.

[0095] Figure 15 A light detection device 200 according to another exemplary embodiment is shown. Reference has been made above. Figure 1 The optical detection device 100 describes Figure 15 The optical detection device 200 includes multiple waveguides 130, optical input devices 120, and multiple modulators 140.

[0096] Reference Figure 15 Multiple waveguides 130 passing through multiple modulators 140 can be combined with each other to be integrated into a single waveguide 230. A graphene layer 250 is disposed on the waveguide 230, and a first electrode 261 and a second electrode 262 are electrically connected to the two ends of the graphene layer 250.

[0097] A portion of the light propagating within the multiple waveguides 130 combines with each other in the waveguide 230, and the combined portion of the light is absorbed by the graphene layer 250 to be detected via the first electrode 261 and the second electrode 262.

[0098] Based on the above example embodiments, since the graphene layer absorbs most of the light propagating inside the multiple waveguides, a light detection device with relatively high light receiving efficiency can be realized. Furthermore, since multiple modulators independently modulate the phase of portions of the light propagating inside the multiple waveguides to control the phase distribution, the light receiving efficiency can be further improved.

[0099] Because the aforementioned light detection device can efficiently receive light in a specific direction, it can more easily realize, for example, a LiDAR system for long distances. Furthermore, since LiDAR systems can reduce the intensity of the output light from the light-emitting device, eye safety can be improved, and the system can be miniaturized and reduced in cost.

[0100] This optical detection device can be applied to fields that use light to identify objects or terrain, or to measure position, distance, and shape. For example, optical detection devices can be used in image sensors, distance sensors, environmental sensors, autonomous vehicles, flying objects such as drones, mobile devices, walking vehicles, and security devices.

[0101] Figure 16 An optical system 1000 according to an example embodiment is shown.

[0102] Reference Figure 16 The optical system 1000 may include a light steering device 1100, a light detection device 1200, and a driving device 1300. Here, the driving device 1300 may include a driving circuit for driving the light steering device 1100 and the light detection device 1200. The components forming the optical system 1000 may be disposed on the same substrate 1005. However, the embodiments are not limited thereto, and some components forming the optical system 1000 may not be disposed on the same substrate 1005.

[0103] The light steering device 1100 includes a laser source 1110 that emits a laser beam L' and a steering device 1120 that scans the laser beam L' emitted from the laser source 1110. For example, a laser diode can be used as the laser source 1110, but the embodiments are not limited thereto.

[0104] The steering device 1120 can be configured to scan the laser beam L' using, for example, an optical phased array (OPA) method. In this case, the steering device 1120 can scan the laser beam L' by using the interference of portions of light that are phase-modulated and emitted from multiple device units having a metastructure or from multiple waveguides.

[0105] When the steering device 1120 includes multiple waveguides, the laser beam L' can be scanned in two dimensions via phase modulation and wavelength modulation. Furthermore, when the steering device 1120 includes multiple units arranged in two dimensions, the laser beam L' can be scanned in two dimensions.

[0106] In addition to the OPA method described above, the steering device 1120 can also use a method of mechanically moving the laser source 1110, or a flashing method of simultaneously emitting laser beams from multiple laser sources.

[0107] The laser beam L' reflected from the object 1600 in the laser beam L' scanned by the light steering device 1100 can be detected by the light detection device 1200. Here, the light detection device 1200 can be one of the light detection devices according to the above example embodiment.

[0108] The optical system 1000 described above can be used in, for example, LiDAR systems, depth sensors, or 3D sensors. However, this is only an example, and the optical system 1000 can be applied to a wide variety of other fields.

[0109] According to the above example embodiments, since the graphene layer absorbs most of the light propagating inside the multiple waveguides, a light detection device and optical system with relatively high light receiving efficiency can be realized. Furthermore, when multiple modulators control the phase distribution by independently modulating the phase of portions of light propagating inside the multiple waveguides, light receiving efficiency can be improved, and the location where the outer portion of the light is incident can be determined. Since the light detection device can efficiently receive light in a specific direction, for example, a LiDAR system for long distances can be easily realized. Additionally, because the LiDAR system can reduce the intensity of the output light from the light-emitting device, eye safety can be improved, and the system can be miniaturized and reduced in cost.

[0110] It should be understood that the exemplary embodiments described herein should be considered descriptive only and not for limiting purposes. The description of features or aspects in each exemplary embodiment should typically be regarded as other similar features or aspects that can be used in other embodiments.

[0111] Although exemplary embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope defined by the claims.

Claims

1. A light detection device, comprising: An optical input device is configured to receive light; Multiple waveguides extend from the optical input device, and the multiple waveguides are configured to respectively transmit portions of the light received by the optical input device; Multiple modulators are disposed on the multiple waveguides and configured to form a phase distribution by independently modulating the phase of each portion of light transmitted in the multiple waveguides, so as to improve the light reception efficiency of each portion of light in a specific direction. At least one graphene layer is configured to absorb said portion of the light transmitted in the plurality of waveguides; as well as At least one first electrode and at least one second electrode are electrically connected to the at least one graphene layer, respectively.

2. The optical detection device according to claim 1, wherein, The at least one graphene layer is disposed on the plurality of waveguides.

3. The optical detection device according to claim 2, further comprising: An intermediate layer is disposed between the at least one graphene layer and the plurality of waveguides, the intermediate layer comprising a material having a refractive index less than that of each of the plurality of waveguides.

4. The optical detection device according to claim 2, wherein, The at least one graphene layer is disposed on at least one of the top and side surfaces of the plurality of waveguides.

5. The optical detection device according to claim 2, wherein, The at least one graphene layer includes graphene layers corresponding to all of the plurality of waveguides.

6. The optical detection device according to claim 2, wherein, The at least one graphene layer includes a plurality of graphene layers corresponding to some of the plurality of waveguides.

7. The optical detection device according to claim 6, wherein, Each of the plurality of graphene layers corresponds to each of the plurality of waveguides, and Each of the plurality of graphene layers is spaced apart from the others.

8. The optical detection device according to claim 1, wherein, The plurality of waveguides are integrated into one waveguide at one end of each of the plurality of waveguides, and the at least one graphene layer comprises a graphene layer disposed on the integrated waveguide.

9. The photodetector according to claim 1 further includes a gate insulating layer disposed on the at least one graphene layer and a gate electrode disposed on the gate insulating layer.

10. The optical detection device according to claim 1, wherein, The optical input device includes an antenna array disposed at the ends of the plurality of waveguides and configured to receive light from outside the optical detection device.

11. The optical detection device according to claim 1, wherein, The plurality of waveguides include at least one of group IV semiconductor materials, group III-V semiconductor materials, group II-VI semiconductor materials, oxides, and nitrides.

12. The optical detection device according to claim 1, wherein, The plurality of modulators are also configured to modulate the phase based on applying an electrical signal or heat to each of the plurality of waveguides.

13. The optical detection device according to claim 1, wherein, The optical input device, the plurality of waveguides, the plurality of modulators, the at least one graphene layer, the at least one first electrode, and the at least one second electrode are disposed on the same substrate.

14. The optical detection device according to claim 1, wherein, The at least one first electrode and the at least one second electrode are directly disposed on the at least one graphene layer.

15. The optical detection device according to claim 1, wherein, The at least one first electrode and the at least one second electrode are connected to the at least one graphene layer via wires.

16. An optical system comprising: A light deflector is configured to redirect light. as well as A light detection device is configured to detect light deflected by the light deflector. The optical detection device includes: Optical input devices; Multiple waveguides extend from the optical input device and are configured to transmit portions of the light input to the optical input device, respectively. Multiple modulators are disposed on the multiple waveguides and configured to form a phase distribution by independently modulating the phase of each portion of light transmitted in the multiple waveguides, so as to improve the light reception efficiency of each portion of light in a specific direction. At least one graphene layer is configured to absorb said portion of the light transmitted in the plurality of waveguides; and At least one first electrode and at least one second electrode are electrically connected to the at least one graphene layer.

17. The optical system according to claim 16, wherein, The light steering device includes a laser source and a steering device configured to deflect a portion of the light emitted from the laser source.

18. The optical system according to claim 16, wherein, The optical input device further includes an antenna array disposed at the ends of the plurality of waveguides and configured to receive light directed by the optical steering device.

19. The optical system according to claim 16, wherein, The at least one graphene layer is disposed on the plurality of waveguides.

20. The optical system according to claim 19, wherein, The optical detection device further includes an intermediate layer disposed between the at least one graphene layer and the plurality of waveguides, wherein the intermediate layer comprises a material with a refractive index lower than that of the plurality of waveguides.

21. The optical system according to claim 16, wherein, The plurality of waveguides are integrated into one waveguide at the ends of the plurality of waveguides, and the at least one graphene layer comprises a graphene layer disposed on the integrated waveguide.

22. The optical system according to claim 16, wherein, The light steering device and the light detection device are mounted on the same substrate.

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