Frequency-modulated light source and solid-state frequency-modulated continuous-wave lidar

Abstract

The application is suitable for the technical field of laser radar, and provides a frequency-modulated light source and a solid-state frequency-modulated continuous wave laser radar. The frequency-modulated light source comprises a laser light source and a silicon optical chip. The silicon optical chip comprises a silicon substrate, a buried oxygen layer, a silicon waveguide and a cover layer which are sequentially stacked. The silicon waveguide comprises a P-type doped region, an N-type doped region, a first electrode formed on the N-type doped region and a second electrode formed on the P-type doped region. The laser light source is integrated on the cover layer. By adjusting the voltage between the first electrode and the second electrode, the refractive index of the silicon waveguide can be adjusted, and the frequency modulation bandwidth of the laser beam can be adjusted. The solid-state frequency-modulated continuous wave laser radar comprises the frequency-modulated light source, a beam control assembly and a silicon-based coherent receiver which are formed on the silicon optical chip. The frequency-modulated light source and the solid-state frequency-modulated continuous wave laser radar can effectively improve the frequency modulation bandwidth of the laser beam emitted by the frequency-modulated light source.

Description

Technical Field

[0001] This invention belongs to the field of lidar technology, and particularly relates to a frequency-modulated light source and a solid-state frequency-modulated continuous wave lidar. Background Technology

[0002] Based on the type of transmitted signal, lidar is divided into two categories: pulse lidar and continuous wave lidar. Continuous wave lidar can be further divided into phase-modulated lidar and frequency-modulated continuous wave (FMCW) lidar. Compared with pulse lidar, FMCW lidar has the following technical advantages: larger ranging range; higher range resolution; Doppler velocities; smaller size and easier integration. Thanks to these advantages, FMCW lidar has broad application prospects in fields such as high-precision mapping and autonomous driving.

[0003] However, the laser beam emitted by the light source used in current frequency-modulated continuous wave lidar has a relatively small frequency modulation bandwidth, which affects the range resolution capability of the lidar. Summary of the Invention

[0004] The purpose of this invention is to provide a frequency-modulated light source and a solid-state frequency-modulated continuous wave lidar, aiming to solve the technical problems of small frequency-modulation bandwidth and large size of the laser beam emitted by the light source used in the prior art.

[0005] The present invention is implemented as follows: In a first aspect, a frequency-modulated light source is provided, including a laser light source and a silicon photonic chip. The silicon photonic chip includes a silicon substrate, a buried oxide layer, a silicon waveguide, and a capping layer stacked sequentially. The silicon waveguide includes a P-type doped region, an N-type doped region, a first electrode formed on the N-type doped region, and a second electrode formed on the P-type doped region. The laser light source is integrated on the capping layer and is used to emit a laser beam. The laser beam can enter the silicon waveguide through the capping layer and be emitted through the silicon waveguide. By adjusting the voltage applied between the first electrode and the second electrode, the refractive index of the silicon waveguide can be adjusted, thereby adjusting the frequency modulation bandwidth of the laser beam.

[0006] In an alternative embodiment, the silicon waveguide further includes an intrinsic region located between the P-type doped region and the N-type doped region.

[0007] In an alternative embodiment, a positive voltage is applied between the first electrode and the second electrode, and the silicon waveguide forms a carrier injection structure;

[0008] Alternatively, a negative voltage is applied between the first electrode and the second electrode, and the silicon waveguide forms a carrier depletion-type structure.

[0009] In an optional embodiment, the silicon waveguide further includes a silicon oxide dielectric layer located between the P-type doped region and the N-type doped region, the silicon oxide dielectric layer forming a MOS capacitor with the P-type doped region and the N-type doped region.

[0010] In an alternative embodiment, a positive voltage is applied between the first electrode and the second electrode, and the silicon waveguide forms a carrier accumulation structure.

[0011] In one alternative embodiment, the silicon waveguide is a ridge waveguide.

[0012] In one alternative embodiment, the laser source is a distributed feedback laser.

[0013] In one optional embodiment, the laser source includes an N-type doped InP layer, an active layer, a grating layer, and a P-type doped InP layer stacked sequentially. A third electrode is formed on the P-type doped InP layer, and a fourth electrode is formed on the N-type doped InP layer. The N-type doped InP layer is formed on the capping layer.

[0014] In one alternative embodiment, the laser source is integrated onto the cover layer by wafer bonding, chip bonding, or epitaxial growth.

[0015] The technical advantages of this invention compared to existing technologies are as follows: The frequency-modulated light source provided in this embodiment includes an integrated silicon photonic chip and a laser light source. The silicon photonic chip comprises a silicon substrate, a buried oxide layer, a silicon waveguide, and a capping layer stacked sequentially. The laser light source is integrated on the capping layer. The laser beam generated by the laser light source can pass through the capping layer and enter the silicon waveguide, thereby forming a hybrid light mode under the action of the laser light source and the silicon waveguide. The effective refractive index of this mode is jointly determined by the laser light source and the silicon waveguide. The silicon waveguide includes a P-type doped region, an N-type doped region, a first electrode formed on the N-type doped region, and a second electrode formed on the P-type doped region. The frequency modulation characteristic of the frequency-modulated light source is achieved by changing the refractive index of the silicon waveguide. In use, the refractive index of the silicon waveguide can be adjusted by regulating the voltage applied between the first and second electrodes, thereby adjusting the frequency modulation bandwidth of the laser beam. Thus, the bandwidth of the laser beam generated by the frequency-modulated light source provided in this embodiment of the invention can be adjusted not only by the laser source itself, but also by adjusting the voltage applied across the silicon waveguide. This results in a wider bandwidth adjustment range for the laser beam generated by the frequency-modulated light source, thereby increasing the frequency modulation bandwidth of the laser beam. Furthermore, since the distance resolution and frequency modulation bandwidth follow the S... r The relationship is ≥c / 2B, where c is the speed of light, B is the frequency modulation bandwidth, and S is the speed of light. rThis provides a range resolution. Thus, by increasing the frequency modulation bandwidth of the laser beam generated by the frequency-modulated light source, the range resolution capability of the lidar using the frequency-modulated light source provided in this embodiment can be effectively improved.

[0016] Secondly, a solid-state frequency-modulated continuous wave lidar is provided, including the frequency-modulated light source provided in the above embodiments, as well as a beam control component and a silicon-based coherent receiver formed on the silicon photonic chip.

[0017] In one alternative embodiment, the beam control component is a silicon-based optical phased array.

[0018] In an optional embodiment, the solid-state frequency-modulated continuous wave lidar further includes a beam splitter, a coupler, and a detector formed on the silicon photonic chip.

[0019] The technical advantages of this invention compared to existing technologies are as follows: The solid-state frequency-modulated continuous wave lidar provided in this invention integrates the transmitter and receiver on the same silicon photonic chip, thereby effectively reducing the size of the solid-state frequency-modulated continuous wave lidar and lowering its production cost. Furthermore, since the solid-state frequency-modulated continuous wave lidar provided in this invention includes the frequency-modulated light source provided in the above embodiments, the bandwidth of the laser beam emitted by the light source is increased, thereby effectively improving the range resolution of the solid-state frequency-modulated continuous wave lidar. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a frequency-modulated light source provided in an embodiment of the present invention. The silicon waveguide in the figure adopts a carrier injection type structure.

[0022] Figure 2 This is a schematic diagram of the structure of a frequency-modulated light source provided in another embodiment of the present invention. The silicon waveguide in the figure adopts a carrier depletion type structure.

[0023] Figure 3 This is a schematic diagram of the structure of a frequency-modulated light source provided in another embodiment of the present invention. The silicon waveguide in the figure adopts a carrier accumulation type structure.

[0024] Explanation of reference numerals in the attached figures:

[0025] 100. Laser source; 110. N-type doped InP layer; 120. Active layer; 130. Grating layer; 140. P-type doped InP layer; 150. Third electrode; 160. Fourth electrode; 200. Silicon photonic chip; 210. Silicon substrate; 220. Buried oxide layer; 230. Silicon waveguide; 231. P-type doped region; 232. N-type doped region; 233. First electrode; 234. Second electrode; 235. Intrinsic region; 236. Silicon oxide dielectric layer; 240. Capping layer. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] Please refer to Figures 1 to 3 As shown, in this embodiment of the invention, a frequency-modulated light source is provided, including a laser light source 100 and a silicon photonic chip 200. The silicon photonic chip 200 includes a silicon substrate 210, a buried oxide layer 220, a silicon waveguide 230, and a capping layer 240 stacked sequentially. Specifically, the silicon photonic chip 200 is fabricated based on an SOI (Silicon-On-Insulator) structure. The capping layer 240 is generally a silicon oxide layer, but it can also be made of other insulating materials as needed, provided that the selected material does not affect the passage of the light beam emitted by the laser light source 100 into the silicon waveguide 230. The side of the capping layer facing away from the ridge waveguide is a horizontal plane, and the laser light source 100 is integrated on the horizontal plane of the capping layer 240. The capping layer 240 serves both to protect the silicon waveguide 230 and to provide a flat interface for the installation of the laser light source 100, ensuring its smooth and stable installation.

[0032] The silicon waveguide 230 includes a P-type doped region 231, an N-type doped region 232, a first electrode 233 formed on the N-type doped region 232, and a second electrode 234 formed on the P-type doped region 231. Specifically, the doping concentrations of the P-type doped region 231 and the N-type doped region 232 in the silicon waveguide 230 can be optimized according to the modulation effect. For ease of understanding, an example is given below: the silicon waveguide 230 can consist only of the P-type doped region 231 and the N-type doped region 232, or it can adopt a structure with an intrinsic region 235, or other structures that can achieve the above functions. In use, if a positive voltage is applied to the P-type doped region 231 and a negative voltage is applied to the N-type doped region 232, the silicon waveguide 230 forms a carrier injection type structure; if a negative voltage is applied to the P-type doped region 231 and a positive voltage is applied to the N-type doped region 232, the silicon waveguide 230 forms a carrier depletion type structure.

[0033] The laser source 100 is integrated on the capping layer 240. The laser source 100 is used to emit a laser beam. The laser beam can pass through the capping layer 240 into the silicon waveguide 230 and be emitted from the silicon waveguide 230. By adjusting the voltage applied between the first electrode 233 and the second electrode 234, the refractive index of the silicon waveguide 230 can be adjusted, thereby adjusting the frequency modulation bandwidth of the laser beam. Specifically, the laser source 100 is a narrow-linewidth semiconductor laser, which can be a distributed feedback laser or a distributed Bragg reflector laser, etc., depending on the application requirements; no single limitation is made here.

[0034] In use, the laser source 100 emits a laser beam, which is coupled into the silicon waveguide 230 through the cladding layer 240 and then emitted from the silicon waveguide 230. At this time, the laser beam forms a mixed light mode under the action of the laser source 100 and the silicon waveguide 230. The effective refractive index of this mode is jointly determined by the laser source 100 and the silicon waveguide 230. During operation, if it is necessary to adjust the frequency modulation bandwidth of the laser beam, it can be adjusted through the laser source 100 or by adjusting the voltage applied between the first electrode 233 and the second electrode 234. For ease of understanding, the working principle of the latter adjustment method is explained below, taking the silicon waveguide 230 as an example when it adopts a carrier injection type structure or a carrier depletion type structure:

[0035] a. When the silicon waveguide 230 adopts a carrier injection type structure, such as Figure 1 As shown, the silicon waveguide 230 has a PIN-type doping distribution. During frequency modulation, a forward voltage is applied between the first electrode 233 and the second electrode 234. Holes in the P-type doped region 231 and electrons in the N-type doped region 232 are injected into the intrinsic region 235 (i.e., the I-region) located between the P-type doped region 231 and the N-type doped region 232 under the influence of the electric field. At this time, the carrier concentration in the intrinsic region 235 increases. Based on the carrier dispersion effect, the refractive index of the silicon waveguide 230 decreases. Since the carrier concentration changes significantly throughout the intrinsic region 235, the modulation efficiency of this structure is very high. Thus, when the laser source 100 uses a laser for emitting a frequency-modulated beam, while keeping the frequency modulation drive signal of the laser source 100 (which can be a triangular wave injection current or a sawtooth wave with only a rising edge or a falling edge) unchanged, a positive voltage modulation is applied to the silicon waveguide 230. This causes the refractive index modulation range and adjustment bandwidth of the laser beam to increase after passing through the silicon waveguide 230. As a result, the mixed light mode under the combined action of the laser source 100 and the silicon waveguide 230 obtains a larger refractive index modulation range, thereby giving the laser beam emitted through the silicon waveguide 230 a larger frequency modulation bandwidth.

[0036] b. When the silicon waveguide 230 adopts a carrier depletion type structure, such as Figure 2As shown, the silicon waveguide 230 has a PN-type doping distribution. During frequency modulation, a reverse voltage is applied between the first electrode 233 and the second electrode 234, increasing the depletion region between the P-type doped region 231 and the N-type doped region 232, enhancing the built-in electric field, thus reducing the free carrier concentration within the silicon waveguide 230 and increasing its refractive index. In summary, the refractive index of the silicon waveguide 230 can be changed by altering the voltage applied to the P-type doped region 231 and the N-type doped region 232, thereby changing the frequency modulation bandwidth of the laser beam emitted through the silicon waveguide 230. That is, the frequency modulation characteristics of the frequency-modulated light source provided in this embodiment are achieved by simultaneously changing the refractive indices of the laser light source 100 and the silicon waveguide 230.

[0037] The frequency-modulated light source provided in this embodiment of the invention includes an integrated silicon photonic chip 200 and a laser light source 100. The silicon photonic chip 200 includes a silicon substrate 210, a buried oxide layer 220, a silicon waveguide 230, and a capping layer 240 stacked sequentially. The laser light source 100 is integrated on the capping layer 240. The laser beam generated by the laser light source 100 can pass through the capping layer 240 and enter the silicon waveguide 230, thereby forming a mixed light mode under the action of the laser light source 100 and the silicon waveguide 230. The effective refractive index of this mode is jointly determined by the laser light source 100 and the silicon waveguide 230. The silicon waveguide 230 includes a P-type doped region 231, an N-type doped region 232, a first electrode 233 formed on the N-type doped region 232, and a second electrode 234 formed on the P-type doped region 231. The frequency modulation characteristic of the frequency-modulated light source is achieved by changing the refractive index of the silicon waveguide 230. In use, the refractive index of the silicon waveguide 230 can be adjusted by regulating the voltage applied between the first electrode 233 and the second electrode 234, thereby adjusting the frequency modulation bandwidth of the laser beam. Thus, the frequency modulation bandwidth of the laser beam generated by the frequency-modulated light source provided in this embodiment can be adjusted not only by the laser light source 100 but also by adjusting the voltage applied across the silicon waveguide 230, thereby giving the laser beam generated by the frequency-modulated light source a wider bandwidth adjustment range, i.e., improving the bandwidth of the laser beam generated by the frequency-modulated light source. Furthermore, since the distance resolution and frequency modulation bandwidth follow S... r The relationship is ≥c / 2B, where c is the speed of light, B is the frequency modulation bandwidth, and S is the speed of light. r This provides a range resolution. Thus, by increasing the frequency modulation bandwidth of the laser beam generated by the frequency-modulated light source, the range resolution capability of the lidar using the frequency-modulated light source provided in this embodiment can be effectively improved.

[0038] In an optional embodiment, silicon waveguide 230 is a ridge waveguide. A ridge waveguide is a variation of a rectangular waveguide, offering advantages such as higher operating frequency, wider operating bandwidth, relatively stable structure, and resistance to deformation. The silicon waveguide 230, employing a ridge waveguide, exhibits superior performance.

[0039] Please refer to Figure 1 As shown, in an optional embodiment, the silicon waveguide 230 further includes an intrinsic region 235 located between the P-type doped region 231 and the N-type doped region 232. A forward voltage is applied to this PIN junction to form a carrier injection structure. Using the silicon waveguide 230 structure provided in this embodiment, the frequency modulation bandwidth of the laser beam can be effectively improved. Please refer to... Figure 1 As shown, in an optional embodiment, the first electrode 233 and the second electrode 234 in the above embodiments form a carrier injection structure with the silicon waveguide 230. Please refer to... Figure 2 As shown, a negative voltage is applied between the first electrode 233 and the second electrode 234, and the silicon waveguide 230 forms a carrier depletion-type structure. Using any of the above structures can effectively improve the frequency modulation bandwidth of the laser beam.

[0040] Please refer to Figure 3 As shown, in an optional embodiment, the silicon waveguide 230 further includes a silicon oxide dielectric layer 236 located between the P-type doped region 231 and the N-type doped region 232. The silicon oxide dielectric layer 236, together with the P-type doped region 231 and the N-type doped region 232, forms a MOS capacitor. When adjusting the bandwidth, a forward voltage can be applied between the first electrode 233 and the second electrode 234 to form a carrier accumulation structure. When the voltage is applied, majority carriers in the P-type doped region 231 and the N-type doped region 232 will accumulate on both sides of the MOS capacitor, i.e., on both sides of the silicon oxide dielectric layer 236, thereby reducing the refractive index of the silicon waveguide 230.

[0041] In an optional embodiment, the laser source 100 is integrated onto the cover layer 240 by wafer bonding, chip bonding or epitaxial growth to achieve a stable connection between the laser source 100 and the cover layer 240.

[0042] In an optional embodiment, the laser source 100 is a distributed feedback laser (DFB). The difference between a DFB and other lasers is that it incorporates a Bragg grating, making it a side-emitting semiconductor laser. Using a DFB laser, the laser source 100 can exhibit very good monochromaticity (i.e., spectral purity), a linewidth within 100 kHz, and a very high side-mode suppression ratio (SMSR), reaching over 40-50 dB.

[0043] Since silicon is an indirect bandgap semiconductor, its luminous efficiency is very low. In contrast, group III-V semiconductors such as indium phosphide (InP) and its quaternary compounds indium gallium arsenide phosphide (InGaAsP) and indium gallium aluminum arsenide (InGaAlAs) have high quantum efficiencies and are used to fabricate semiconductor lasers with a wavelength of 1550 nm. To improve luminous efficiency, the aforementioned DFB laser can be made of group III-V materials. Thus, by integrating the group III-V semiconductor laser with the silicon photonic chip 200, i.e., hybrid integration, the size of the lidar system using the frequency-modulated light source provided in this embodiment is further reduced, while the range resolution of the lidar system is also improved due to the large bandwidth of this structure.

[0044] Please refer to Figures 1 to 3 As shown, in an optional embodiment, the laser source 100 includes an N-type doped InP layer 110, an active layer 120, a grating layer 130 and a P-type doped InP layer 140 stacked sequentially. A third electrode 150 is formed on the P-type doped InP layer 140, and a fourth electrode 160 is formed on the N-type doped InP layer 110. The N-type doped InP layer 110 is connected to the capping layer 240.

[0045] Under current injection, a positive voltage is applied to the third electrode 150 on the P-type doped InP layer 140 (i.e., P-InP), and a negative voltage is applied to the fourth electrode 160 on the N-type doped InP layer 110 (i.e., N-InP). The quantum well in the active layer 120 emits light through stimulated emission. The light is then mode-selected by the grating layer 130, and with the help of the anti-reflection film at the output end and the anti-reflection film at the back end, the laser beam is emitted. The light field generated in the active layer 120 is coupled into the silicon waveguide 230 through the N-InP and the capping layer 240. During this process, the light forms a mixed mode under the combined action of the laser source 100 and the silicon waveguide 230. First, the laser beam emitted by the laser source 100 has a larger refractive index modulation range and frequency modulation bandwidth after passing through the silicon waveguide 230. This results in a larger refractive index modulation range for the mixed light mode under the combined action of the laser source 100 and the silicon waveguide 230, which in turn gives the laser beam emitted through the silicon waveguide 230 a larger frequency modulation bandwidth.

[0046] When adjusting the laser bandwidth, it can be achieved by adjusting either the frequency-modulated drive signal of the laser source 100 or the forward modulation signal of the silicon waveguide 230, or by adjusting both simultaneously. When adjusting the frequency-modulated drive signal of the laser source 100 to adjust the laser bandwidth, the bandwidth of the optical field generated in the active layer 120 can be adjusted by regulating the voltage applied between the third electrode 150 and the fourth electrode 160. This method is simple in structure and facilitates frequency modulation. More specifically, to increase the frequency modulation bandwidth, when the silicon waveguide 230 adopts a carrier injection type structure and a carrier accumulation type structure, the frequency modulation drive signal of the laser source 100 is in phase with the forward modulation signal of the silicon waveguide 230. In this case, a positive voltage is applied to the first electrode 233 and a negative voltage is applied to the second electrode 234. When the injection current of the laser source 100 increases, the forward voltage of the silicon waveguide 230 also increases; when the injection current of the laser source 100 decreases, the forward voltage of the silicon waveguide 230 also decreases. When the silicon waveguide 230 adopts a carrier depletion type structure, the frequency modulation drive signal of the distributed feedback laser is out of phase with the forward modulation signal of the silicon waveguide 230. In this case, a negative voltage is applied to the first electrode 233 and a positive voltage is applied to the second electrode 234. When the injection current of the laser source 100 increases, the reverse voltage of the silicon waveguide 230 must decrease; when the injection current of the laser source 100 decreases, the reverse voltage of the silicon waveguide 230 must increase. Otherwise, the bandwidth will decrease.

[0047] In another embodiment of the present invention, a solid-state frequency-modulated continuous wave lidar is provided, including the frequency-modulated light source provided in the above embodiments, as well as a beam control component and a silicon-based coherent receiver formed on a silicon photonic chip 200.

[0048] The beam control component and the frequency-modulated light source constitute the transmitter of the solid-state frequency-modulated continuous wave (FMCW) lidar. The receiver uses a silicon-based integrated coherent receiver (ICR) for coherent detection. Current FMCW lidar systems are mostly composed of discrete components, with the transmitter and receiver separate, resulting in a large system size, high cost, and limited range resolution. The solid-state FMCW lidar provided in this embodiment integrates the transmitter and receiver onto the same silicon photonic chip 200, effectively reducing the size and production cost. Furthermore, since the solid-state FMCW lidar provided in this embodiment includes the frequency-modulated light source provided in the above embodiments, the frequency modulation bandwidth of the emitted laser beam is increased, thereby effectively improving the range resolution of the solid-state FMCW lidar.

[0049] The aforementioned beam control components include a galvanometer or a silicon-based optical phased array (OPA). The galvanometer can be a microelectromechanical galvanometer or other types, depending on the application requirements; no single limitation is specified here. The silicon-based optical phased array can use existing commercially available structures or be custom-designed, again depending on the application requirements; no single limitation is specified here. This structure is simple and provides good beam control performance.

[0050] In an optional embodiment, the solid-state frequency-modulated continuous wave lidar also includes a beam splitter, a coupler, and a detector formed on the silicon photonic chip 200 to further reduce its size.

[0051] Furthermore, the solid-state frequency-modulated continuous wave lidar also includes passive components such as a beam combiner and a polarization rotation controller formed on the silicon photonic chip 200. The specific type of passive component can be set according to the application requirements. Ultimately, the solid-state frequency-modulated continuous wave lidar can realize a monolithically integrated optical component, which can greatly reduce its size.

[0052] The above description is merely a preferred embodiment of the present invention and only specifically describes the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, as well as other specific embodiments of the present invention that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present invention.

Claims

1. A frequency modulated light source, characterized in that, The system includes a laser source and a silicon photonics chip. The silicon photonics chip comprises a silicon substrate, a buried oxide layer, a silicon waveguide, and a capping layer stacked sequentially. The silicon waveguide includes a P-type doped region, an N-type doped region, a first electrode formed on the N-type doped region, and a second electrode formed on the P-type doped region. The laser source is integrated on the capping layer and is used to emit a laser beam. The laser beam can pass through the capping layer, enter the silicon waveguide, and be emitted through the silicon waveguide. The frequency modulation drive signal of the laser source and the forward modulation signal of the silicon waveguide are simultaneously adjusted. When the silicon waveguide adopts a carrier injection type structure and a carrier accumulation type structure, the frequency modulation drive signal of the laser source and the forward modulation signal of the silicon waveguide are in phase. A positive voltage is applied to the first electrode, and a negative voltage is applied to the second electrode. When the injection current of the laser source increases, the forward voltage of the silicon waveguide also increases; when the injection current of the laser source decreases, the forward voltage of the silicon waveguide also decreases, thereby achieving adjustment of the frequency modulation bandwidth of the laser beam.

2. The frequency-modulated light source of claim 1, wherein, The silicon waveguide also includes an intrinsic region located between the P-type doped region and the N-type doped region.

3. The frequency modulated light source of claim 1, wherein, The silicon waveguide also includes a silicon oxide dielectric layer located between the P-type doped region and the N-type doped region, and the silicon oxide dielectric layer forms a MOS capacitor with the P-type doped region and the N-type doped region.

4. The frequency modulated light source of claim 1, wherein, The silicon waveguide is a ridge waveguide.

5. A frequency modulated light source as claimed in any of claims 1-4, characterized in that The laser source is a distributed feedback laser.

6. The frequency modulated light source of claim 5, wherein, The laser source includes an N-type doped InP layer, an active layer, a grating layer, and a P-type doped InP layer stacked sequentially. A third electrode is formed on the P-type doped InP layer, and a fourth electrode is formed on the N-type doped InP layer. The N-type doped InP layer is formed on the capping layer.

7. A frequency modulated light source as claimed in any of claims 1-4, characterized in that The laser source is integrated onto the cover layer by means of wafer bonding, chip bonding, or epitaxial growth.

8. A solid-state frequency modulated continuous wave lidar, characterized by, It includes the frequency-modulated light source as described in any one of claims 1-7, as well as a beam control component and a silicon-based coherent receiver formed on the silicon photonic chip.

9. The solid-state frequency modulated continuous wave lidar of claim 8, wherein, Beam control components include galvanometers or silicon-based optical phased arrays.

10. The solid-state frequency modulated continuous wave lidar of claim 8 or 9, wherein, The solid-state frequency-modulated continuous wave lidar also includes a beam splitter, a coupler, and a detector formed on the silicon photonic chip.

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