Laser generation system and method based on polarized beam

Abstract

Embodiments of the present disclosure provide a laser beam generating system. The laser beam generating system includes a first laser chip configured to generate a first polarized laser beam and a second laser chip configured to generate a second polarized laser beam. The laser beam generating system also includes a polarizer configured to combine the first polarized laser beam and the second polarized laser beam to generate a third laser beam.

Description

Technical Field

[0001] The present disclosure relates to optical sensing devices such as light detection and ranging (LiDAR) devices, and more particularly, to enabling laser generation in optical sensing devices by combining polarized laser beams. Background Art

[0002] Optical sensing systems such as LiDAR systems have been widely used in autonomous driving and producing high-resolution maps. For example, a typical LiDAR system measures the distance to a target by illuminating the target with a pulsed laser beam and measuring the reflected pulses with a sensor such as a photodetector. The laser return time difference and / or wavelength and / or phase can then be used to make a digital three-dimensional (3D) representation of the target. Since the use of a narrow laser beam as the incident light enables mapping of physical features at very high resolution, LiDAR systems are particularly suitable for applications such as sensing in autonomous driving and / or high-definition mapping.

[0003] The sensing range of a typical LiDAR device is generally related to the intensity of the pulsed laser beam used to illuminate the target. For example, in order to achieve a larger sensing range (e.g., to detect targets farther away from the LiDAR device), a higher intensity is generally required. In addition, illuminating the target with a higher intensity laser beam can improve the signal-to-noise ratio (SNR), thereby achieving higher sensing accuracy. However, generating high-intensity laser beams is challenging because conventional laser sources used to generate high-intensity laser beams also generate a lot of heat during operation, which shortens their lifespan compared to generating only low-intensity laser beams. Moreover, the concentration of the large amount of heat generated can damage peripheral components within the LiDAR device. Therefore, efforts to increase the intensity of laser sources in LiDAR devices have largely remained unsuccessful.

[0004] The disclosed embodiments address the above-mentioned problems by providing systems and methods for generating laser light in an optical sensing system by combining polarized laser beams. Summary of the invention

[0005] Embodiments of the present disclosure provide a laser beam generating system. The laser beam generating system includes a first laser chip configured to generate a first polarized laser beam and a second laser chip configured to generate a second polarized laser beam. The laser beam generating system also includes a polarizer configured to combine the first polarized laser beam and the second polarized laser beam to generate a third laser beam.

[0006] Embodiments of the present disclosure also provide a method for controlling laser generation. The method includes generating a first polarized laser beam by a first laser chip and generating a second polarized laser beam by a second laser chip. The method also includes combining the first polarized laser beam and the second polarized laser beam using a polarizer to generate a third laser beam.

[0007] An embodiment of the present disclosure also provides an optical sensing device. The optical sensing device includes a laser beam generator, a scanner, and at least one photodetector. The laser beam generator includes a first laser chip for generating a first polarized laser beam, a second laser chip for generating a second polarized laser beam, and a polarizer for combining the first polarized laser beam and the second polarized laser beam to generate a third laser beam. The scanner is configured to scan the surrounding environment of the optical sensing device using the third laser beam. The at least one photodetector is configured to detect a returning laser beam reflected by an object in the surrounding environment.

[0008] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

[0009] BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram showing an exemplary vehicle equipped with a LiDAR optical sensing system according to an embodiment of the present disclosure.

[0011] Figure 2 A block diagram of an exemplary LiDAR optical sensing device having a transmitter and a receiver according to an embodiment of the present disclosure is shown.

[0012] Figure 3 A circuit diagram of an exemplary laser beam generating system according to an embodiment of the present disclosure is shown.

[0013] Figure 4 A flow chart illustrating an exemplary method for controlling laser generation according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] Reference will now be made in detail to these exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0015] An optical sensing system such as a LiDAR system can use a laser chip to generate a pulsed laser beam for scanning the surrounding environment of the optical sensing system. For example, the laser chip may include a laser diode, a semiconductor device capable of converting electrical energy into light, or other suitable laser generating devices. When voltage-driven electrons drop from a higher energy level of voltage to a lower energy level, a laser beam (e.g., a photon array) can be generated. In order to increase the intensity of the generated laser beam, a higher voltage needs to be applied to the laser chip. After the laser chip has been operating for a period of time, this will cause a large amount of heat to be generated in a concentrated area (e.g., at and / or around the laser chip). The heat may cause damage or deformation to the chip itself or other precision components within the system, such as a microelectromechanical system (MEMS) scanner.

[0016] The disclosed embodiments provide an improved optical sensing system that generates a high intensity laser beam by combining individual polarized laser beams. An exemplary system may include a printed circuit board that includes two laser chips that can generate polarized laser beams that are combined to form another laser beam for LiDAR scanning.

[0017] In one example, the first and second polarized laser beams generated by two laser chips, respectively, can be combined to generate a third laser beam having an intensity substantially equal to the sum of the intensities of the first polarized laser beam and the second polarized laser beam. For example, the intensity of the third laser beam can be equal to the sum of the intensities of the first laser beam and the second laser beam or higher than 75% of the sum, such as 75%, 80%, 85%, 90%, 95%, 100%, or within any range defined by these values, and is considered to be "substantially equal to" the sum of the intensities of the first laser beam and the second laser beam. In this way, each of the two laser chips used to generate independent laser beams and then combine into a laser beam (e.g., a third laser beam) for LiDAR scanning may have an intensity level that is relatively lower than the intensity level of a single laser chip required to provide an intensity similar to that of the combined laser beam. The relatively low intensity level can contribute to less heat generated during operation.

[0018] In another example, two laser chips can generate the first laser beam and the second laser beam alternately at different time slots. For example, the first laser chip can generate the first laser beam at the 1st, 3rd, 5th, 7th, 9th... time slots, and the second laser chip can generate the second laser beam at the 2nd, 4th, 6th, 8th, 10th... time slots. In this way, the first laser beam and the second laser beam can be combined in a time-division manner. The intensity of the third laser beam can be substantially equal to the average value of the intensities of the first polarized laser beam and the second polarized laser beam. Since the two laser chips can be turned on alternately to emit laser beams, the working time of each of the first laser chip and the second laser chip is reduced, thereby reducing the generation of heat. Thus, instead of using a single laser chip to work continuously, two laser chips can be turned on alternately, and each laser chip generates less heat than a single laser chip. For example, when two laser chips are arranged separately from each other in space, the problem of heat concentration can be better handled, thereby improving the life of each independent laser chip.

[0019] In any case, the heat generated by each of the two laser chips can be reduced while maintaining the intensity of the combined laser beam for LiDAR scanning. In another example, the intensity of the laser beam used for LiDAR scanning can be further increased by combining the laser beams generated by the two laser chips while maintaining the heat level generated by each individual laser chip.

[0020] Figure 1 A schematic diagram of an exemplary vehicle 100 equipped with a LiDAR optical sensing system 102 (or simply LiDAR system 102) according to an embodiment of the present disclosure is shown. Consistent with some embodiments, the vehicle 100 may be an autonomous vehicle or a survey vehicle configured to acquire data for building high-resolution maps or performing urban modeling.

[0021] like Figure 1 As shown, a vehicle 100 may be equipped with a LiDAR system 102 mounted to a vehicle body 104 via a mounting structure 108. The mounting structure 108 may be an electromechanical device mounted or otherwise attached to the vehicle body 104 of the vehicle 100.

[0022] It is contemplated that vehicle 100 may be an electric vehicle, a fuel cell vehicle, a hybrid vehicle, or a conventional internal combustion engine vehicle. Figure 1 As shown, vehicle 100 may have a body 104 and at least one wheel. Body 104 may be any body style, such as a sports car, a coupe, a sedan, a pickup truck, a station wagon, a sports utility vehicle (SUV), a minivan, or a modified van. In some embodiments, vehicle 100 may include a pair of front wheels and a pair of rear wheels, such as Figure 1 However, it is contemplated that the vehicle 100 may have more or fewer wheels or an equivalent structure that enables the vehicle 100 to move around. The vehicle 100 may be configured as all-wheel drive (AWD), front-wheel drive (FWR), or rear-wheel drive (RWD). In some embodiments, the vehicle 100 may be configured to be operated by an operator occupying the vehicle, remotely controlled, and / or autonomously operated.

[0023] In some embodiments of the present disclosure, the mounting structure 108 may use screws, adhesives, or other mounting mechanisms. The vehicle 100 may additionally be equipped with the sensor 110 inside or outside the vehicle body 104 using any suitable mounting mechanism. The sensor 110 may include sensors used in navigation units, such as a global positioning system (GPS) receiver and one or more inertial measurement unit (IMU) sensors. It is contemplated that the manner in which the LiDAR system 102 or the sensor 110 may be mounted on the vehicle 100 is not limited to Figure 1The examples shown may be modified specifically depending on the type of LiDAR system 102 , sensor 110 , and / or vehicle 100 to achieve desired sensing performance.

[0024] As with some embodiments, the LiDAR system 102 and the sensor 110 can be configured to capture data as the vehicle 100 moves along the track. For example, the transmitter of the LiDAR system 102 can be configured to scan the surrounding environment and acquire 3D data (e.g., point cloud data). The LiDAR system 102 can include one or more LiDAR sensing devices that are configured to measure the distance to the target by illuminating the target with a pulsed laser beam and measuring the reflected pulses with a receiver. The laser beam used by the LiDAR system 102 can be ultraviolet, visible light, or near infrared. As the vehicle 100 moves along the track, the LiDAR system 102 can continuously capture data. Each set of data captured within a certain time range is called a data frame.

[0025] Figure 2 A block diagram of an exemplary LiDAR optical sensing device 200 (or simply LiDAR device 200) is shown, such as used in LiDAR system 102. LiDAR device 200 may include a transmitter 202 and a receiver 204. As it moves (e.g., rotates, swings, etc.), transmitter 202 may emit a laser beam within a scanning angle. Transmitter 202 may include one or more laser sources 206 and a scanner 210. In some embodiments, laser source 206 and scanner 210 may be separate devices or components. In other embodiments, laser source 206 and scanner 210 may be integrated into a single device / component.

[0026] In some embodiments, the emitter 202 may sequentially emit a series of pulsed laser beams in different directions within its scanning angle as it moves (eg, rotates, swings, etc.). Figure 2 As shown. The laser source 206 can be configured to provide a laser beam 207 (also referred to as a "native laser beam") that reaches the scanner 210 in respective incident directions. In some embodiments, the laser source 206 can be disposed within the scanner 210 or integrated with the scanner 210 (for example, the scanner 210 is formed as a rotator for scanning the surrounding environment). In some embodiments of the present disclosure, the laser source 206 can generate a pulsed laser beam in the wavelength range of ultraviolet, visible light, or near infrared.

[0027] In some embodiments of the present disclosure, the laser source 206 may include a pulsed laser diode (PLD), a vertical-cavity surface-emitting laser (VCSEL), a fiber laser, etc. For example, the PLD may be a semiconductor device that generates a laser beam at the junction of a diode similar to a light emitting diode (LED). In some embodiments of the present disclosure, the PLD includes a PIN diode, in which the active region is located in the intrinsic (I) region, and carriers (electrons and holes) are pumped into the active region from the N region and the P region, respectively. Depending on the specific semiconductor material, the wavelength of the incident laser beam 207 provided by the PLD may be less than 1,100 nm, such as 405 nm, between 445 nm and 465 nm, between 510 nm and 525 nm, 532 nm, 635 nm, between 650 nm and 660 nm, 670 nm, 760 nm, 785 nm, 808 nm, or 848 nm. It should be understood that any suitable laser source may be used as the laser source 206 that emits the laser beam 207.

[0028] The scanner 210 can be configured to emit a laser beam 209 toward the object 212 in a first direction. In some embodiments, when a scanner (e.g., a MEMS scanner) is not used or when a rotating scanner is integrated with the laser source 206, the laser beam 209 can be the same as the laser beam 207. The object 212 can include a variety of materials, including, for example, non-metallic objects, rocks, rain, compounds, aerosols, clouds, and even single molecules. The wavelength of the laser beam 209 can vary depending on the composition of the object 212. In some embodiments, at each time point during the scan, the scanner 210 can emit the laser beam 209 toward the object 212 in a certain direction within the scanning angle by rotating the micromechanical mirror group. In some embodiments of the present disclosure, the scanner 210 may also include an optical component (e.g., a lens, a reflector, etc.) capable of focusing the pulsed laser into a narrow laser beam to increase the scanning resolution and the range of the scanned object 212.

[0029] In some embodiments, receiver 204 can be configured to detect a returning laser beam 211 returning from object 212. Returning laser beam 211 can be in a different direction than beam 209. Receiver 204 can collect the laser beam returning from object 212 and output an electrical signal reflecting the intensity of the returning laser beam. Laser light can be reflected by object 212 through backscattering, such as Rayleigh scattering, Mie scattering, Raman scattering, and fluorescence. Figure 2As shown, receiver 204 may include lens 214 and photodetector 216. Lens 214 may be configured to collect light from a corresponding direction in its field of view (FOV). At each time point during the scan, return laser beam 211 may be collected by lens 214. Return laser beam 211 may be returned from object 212 and may have the same wavelength as laser beam 209.

[0030] The photodetector 216 may be configured to detect a returning laser beam 211 returning from the object 212. In some embodiments, the photodetector 216 may convert the laser light (e.g., the returning laser beam 211) collected by the lens 214 into an electrical signal 218 (e.g., a current or voltage signal). When a photon is absorbed in a photodiode included in the photodetector 216, an electrical signal 218 may be generated. In some embodiments of the present disclosure, the photodetector 216 may include a PIN detector, a PIN detector array, an avalanche photodiode (APD) detector, an APD detector array, a single photon avalanche diode (SPAD) detector, a SPAD detector array, a silicon photomultiplier tube (SiPM / MPCC) detector, a SiP / MPCC detector array, and the like.

[0031] Although the scanner 210 is described herein as part of the transmitter 202, it should be understood that in some embodiments, the scanner 210 can also be included in the receiver 204, for example, before the photodetector 216 in the optical path. Including the scanner 210 in the receiver 204 can improve the ability of the photodetector 216 to capture only the return laser beam 211 from the desired direction, thereby reducing interference caused by other light sources, such as the sun and / or other LiDAR systems. In addition, the aperture of the receiver 204 can be increased to increase the sensitivity of the photodetector 216.

[0032] In some embodiments, the LiDAR device 200 may include a signal processor 220 configured to process the electrical signal 218. For example, the signal processor 220 may include an analog-to-digital converter to convert the electrical signal 218, which may be an analog signal, into a digital signal. In another example, the signal processor 220 may include one or more filters, noise reducers, signal enhancers, etc. to improve the signal-to-noise ratio (SNR) of the electrical signal 218. The signal processor 220 may include a microprocessor, a digital signal processor (DSP), a microcontroller, a field programmable gate array (FPGA), and / or other suitable devices or chips capable of processing the electrical signal 218.

[0033] Figure 3 A circuit diagram of an exemplary laser beam generating system 300 according to an embodiment of the present disclosure is shown. In some embodiments, the laser beam generating system 300 may be Figure 2A portion of the laser source 206 in the laser source 206, which provides a laser beam for LiDAR sensing / scanning. Unlike a typical laser generator that uses only one laser chip (e.g., a laser diode) to generate a scanning laser beam, the laser beam generation system 300 uses two laser chips to generate a scanning laser beam. As discussed above, in one example, the first laser chip and the second laser chip can generate the first laser beam and the second laser beam simultaneously. The first laser beam can then be combined with the second laser beam to form a third laser beam for sensing / scanning. The intensity of the combined laser beam can be substantially equal to the intensity of the first laser beam and the second laser beam generated by the first laser chip and the second laser chip, respectively. In another example, the first laser chip and the second laser chip can alternately generate the first laser beam and the second laser beam at different time slots. The first laser beam and the second laser beam can be combined in a time-division manner to form a third laser beam that can be used as a scanning laser beam. Therefore, as used herein, the term "combination" includes combining in intensity (e.g., combining two laser beams simultaneously on a laser beam) and combining in time (e.g., combining two laser beams alternately on a laser beam).

[0034] like Figure 3 As shown, the laser beam generating system 300 may include a printed circuit board (PCB) 302, a first laser chip 304, a second laser chip 306, and a polarizer 308. In some embodiments, the printed circuit board 302 may be a circuit board having one or more etched layers (e.g., layers having etched conductive traces, pads, and / or other suitable conductive features) disposed on a non-conductive substrate. Electronic components such as the first laser chip 304 and the second laser chip 306 may be disposed on the etched layers and may be mechanically supported and electrically connected by the etched layers. In some embodiments, the printed circuit board 302 may include a ceramic material (e.g., a ceramic board), wherein the ceramic material may include a non-oxide ceramic such as aluminum nitride (AlN), an oxide ceramic such as aluminum oxide (Al2O3), or other suitable high thermal conductivity materials. Using a high thermal conductivity material such as a ceramic, the heat generated by the first laser chip 304 and the second laser chip 306 may be quickly dissipated during operation. Since heat resistance may limit the power level applied to the laser chip, which in turn is related to the laser intensity generated by the laser chip, improving heat dissipation can generate a higher intensity laser beam.

[0035] It is contemplated that the first laser chip 304 and the second laser chip 306 are not limited to being disposed on the same printed circuit board. For example, in some embodiments, the first laser chip 304 and the second laser chip 306 may be disposed on separate printed circuit boards, which may be functionally coupled to each other via a wired or wireless connection.

[0036] In some embodiments, the first laser chip 304 and the second laser chip 306 may include semiconductor devices such as laser diodes that convert electrical energy into laser light. For example, the first laser chip 304 and the second laser chip 306 may generate double heterostructure lasers, quantum well lasers, quantum cascade lasers, interbond cascade lasers, separated confined heterostructure lasers, distributed Bragg reflector lasers, distributed feedback lasers, vertical cavity surface emitting lasers, vertical external cavity surface emitting lasers, and / or external cavity diode lasers.

[0037] In some embodiments, the first laser chip 304 and / or the second laser chip 306 may be configured to generate a polarized laser beam. For example, a first polarized laser beam 305 may be generated by the first laser chip 304. A second polarized laser beam 307 may be generated by the second laser chip 306. In some embodiments, the first polarized laser beam 305 may include a laser in a first polarization state and the second polarized laser beam 307 may include a laser in a second polarization state. For example, the first polarization state and the second polarization state may include two orthogonal linear polarization states, such as a P polarization state and an S polarization state. The P polarization state refers to a light state in which the electric field of the polarized light is parallel to the incident plane. The S polarization state refers to a light state in which the electric field of the polarized light is perpendicular to the incident plane. In another example, the first polarization state and the second polarization state may include other orthogonal linear polarization states different from the PS deflection state.

[0038] In some embodiments, the first polarization state may include a condition in which the electric field of the first polarized laser beam 305 has a component in the same direction as the first reference direction (e.g., a direction parallel to the incident plane, as in the case of the P polarization state). For example, the electric field of the first polarized laser beam 305 may be at an angle less than 90 degrees relative to the first reference direction, such as 0 degrees, 10 degrees, 20 degrees, 30 degrees, 45 degrees, 50 degrees, or 60 degrees. Similarly, the second polarization state may include a condition in which the electric field of the second polarized laser beam 307 has a component in the same direction as the second reference direction (e.g., a direction perpendicular to the incident plane, as in the case of the S polarization state). For example, the electric field of the second polarized laser beam 307 may be at an angle less than 90 degrees relative to the second reference direction, such as 0 degrees, 10 degrees, 20 degrees, 30 degrees, 45 degrees, 50 degrees, or 60 degrees.

[0039] In some embodiments, polarizer 308 may include any suitable linear polarizer, such as a transmissive-reflective polarizer. For example, polarizer 308 may include a plurality of thin lines arranged parallel to each other. Polarized laser light polarized along these lines is reflected, while polarized laser light polarized perpendicular to these lines is transmitted. In another example, polarizer 308 may use Brewster's angle, where when the incident angle is at a specific value (e.g., Brewster's angle), an S-polarized laser beam will be reflected and a P-polarized laser beam will be transmitted. Figure 3 In the example shown, the incident angle and / or polarization state of the first laser beam 305 can be configured / controlled so that the first laser beam 305 can be transmitted through the polarizer 308. Similarly, the incident angle and / or polarization state of the second laser beam 307 can be controlled / configured so that the second laser beam 307 can be reflected by the polarizer 308.

[0040] The intensity of light transmitted through the polarizer 308 can be calculated according to Malus's law:

[0041] I=I0cos 2 θ (1)

[0042] where I0 is the intensity of the incident polarized laser beam, I is the intensity of the transmitted polarized laser beam, and θ is the angle between the incident linear polarization and the polarization axis.

[0043] The degree of polarization or polarization efficiency of polarizer 308 can be calculated as:

[0044]

[0045] Where T1 and T2 are the principal transmittances of the polarizer. T1 is the maximum transmission of the polarizer 308, which occurs when the axis of the polarizer 308 is parallel to the polarization plane of the incident polarized laser beam. T2 is the minimum transmission of the polarizer 308, and occurs when the axis of the polarizer 308 is perpendicular to the polarization plane of the incident polarized light beam.

[0046] The transmitted portion of laser beam 305 may be combined with the reflected portion of laser beam 307 to form a combined laser beam 320. As discussed above, laser beam 320 may be used to perform LiDAR scanning / sensing.

[0047] It is conceivable that the incident angles of the first laser beam 305 and the second laser beam 307 are not limited to Figure 3 The incident angles are shown. Figure 3 The design shown in is for illustration purposes only. The exact incident angles of the first laser beam 305 and the second laser beam 307 can be determined by a skilled person based on the polarization states of the first laser beam 305 and the second laser beam 307, the type and parameters of the polarizer 308, and the principles disclosed herein.

[0048] In some embodiments, the laser beam generation system 300 may include collimating lenses 310 and 312. The first laser beam 305 and the second laser beam 307 generated by the first laser chip 304 and the second laser chip 306, respectively, may diverge when leaving the first laser chip 304 and the second laser chip 306. The collimating lenses 310 and 312 may be configured to collimate (e.g., parallelize) the first laser beam 305 and the second laser beam 307, respectively.

[0049] In some embodiments, the laser beam generation system 300 may include a wave plate 314 configured to change the laser light in the second polarized laser beam 307 from a second polarization state to a third polarization state. In some embodiments, the wave plate 314 may be made of a birefringent material (e.g., quartz or mica). By controlling the thickness of the birefringent material, the wave plate 314 may be configured as a half-wave plate, wherein the polarization direction of the laser beam passing through the wave plate 314 is shifted to another direction, such as perpendicular to the polarization direction of the laser beam before reaching the wave plate 314. In some embodiments, the wave plate 314 may be an optical device configured to select a specific polarized light and exclude other polarized lights. This selection may be achieved by delaying (or delaying) a polarization component relative to its orthogonal component.

[0050] In some embodiments, the wave plate 314 may be disposed between the second laser chip 306 and the polarizer 308 so that the polarization state of the second laser beam 307 may be changed (e.g., from a P polarization state to an S polarization state) before the second laser beam 307 reaches the polarizer 308. In this way, even if the first laser chip 304 and the second laser chip 306 emit laser beams having the same polarization state, the laser beams reaching the polarizer 308 may still have different polarization states for transmission and reflection. For example, after being generated by the laser chips 304 and 306, respectively, the laser beam 305 may be P polarized, and the laser beam 307 may also be P polarized. The wave plate 314 may change the polarization of the laser beam 307 from P to S. Thus, the S-polarized laser beam 307 after passing through the wave plate 314 may be reflected by the polarizer 308, while the P-polarized laser beam 305 may be transmitted through the polarizer 308. In this way, the reflected laser beam 307 may be combined with the transmitted laser beam 305 to form a combined laser beam.

[0051] When both laser chips 304 and 306 are turned on to simultaneously emit laser beams 305 and 307, a combined laser beam (e.g., laser beam 320) may have an intensity substantially equal to the sum of the intensity of the first laser beam 305 and the intensity of the second laser beam 307. When laser chips 304 and 306 are turned on alternately (e.g., in different time slots), combined laser beam 320 may have an intensity substantially equal to an average of the intensity of the first laser beam 305 and the intensity of the second laser beam 307 as long as the duty cycles of the two laser chips are substantially the same.

[0052] Figure 4 Flowchart showing an exemplary method 400 for controlling laser generation according to an embodiment of the present disclosure. In some embodiments, the method 400 may be implemented by the LiDAR system 102 or the optical sensing device 200 having the laser beam generation system 300. It should be appreciated that some steps in the method 400 may be optional and additional steps may be inserted. In addition, some steps of the method 400 may be performed simultaneously or in combination. Figure 4 The different orders are shown.

[0053] Consistent with some embodiments, in steps S402 and S404 , first and second polarized laser beams are generated by a first laser chip (eg, laser chip 304 ) and a second laser chip (eg, laser chip 306 ), respectively.

[0054] In step S406, a polarizer (e.g., polarizer 308) may be used to combine the first and second polarized laser beams (e.g., laser beams 305 and 307) to generate a third laser beam (e.g., laser beam 320). As discussed above, when the first and second laser chips simultaneously emit the first and second laser beams, the third laser beam may have an intensity substantially equal to the sum of the intensities of the first and second laser beams. When the first and second laser chips emit the first and second laser beams alternately (e.g., in different time slots), the third laser beam may have an intensity substantially equal to an average of the intensities of the first and second laser beams.

[0055] In some embodiments, the first and second laser beams (e.g., laser beams 305 and 307) can be collimated by collimating lenses (e.g., collimating lenses 312 and 310) and then combined by a polarizer (e.g., polarizer 308). As discussed above, the collimating lenses can be configured to collimate (e.g., parallelize) the laser beams, which may become dispersed after being emitted by the corresponding laser chips.

[0056] In some embodiments, the first or second polarized laser light (e.g., Figure 3At least one of the laser beams 307 shown in FIG. 3 can be directed through a wave plate (e.g., wave plate 314) to change its polarization state. By manipulating the polarization state, the combination of the laser beams can be performed more flexibly at the polarizer (e.g., polarizer 308). For example, it is not necessary to use a laser chip with specific parameters to generate a laser beam with a specific polarization state. Instead, the polarization state can be adjusted after the laser beam is generated but before it reaches the polarizer.

[0057] In step S408, the combined laser beam (e.g., laser beam 320) may be used to scan the surroundings of the optical sensing device (e.g., optical sensing device 200). The combined laser beam may have an enhanced intensity to achieve a greater range and / or a higher SNR. In another example, heat generation may be reduced due to the laser chips being arranged in a distributed manner and the high thermal conductivity material used when constituting the PCB carrying the laser chips.

[0058] In step S410, a photodetector (e.g., photodetector 216) can receive a laser beam reflected by an object (e.g., object 212). The photodetector can convert an optical signal contained in the reflected laser beam into an electrical signal (e.g., electrical signal 218). As discussed above, utilizing a laser beam with increased intensity can also increase the SNR of the reflected optical signal, thereby increasing the SNR of the electrical signal. Moreover, reducing heat generation can also increase the sensitivity of the photodetector, thereby increasing the SNR of the electrical signal generated by the photodetector.

[0059] It will be apparent to those skilled in the art that various modifications and variations may be made to the disclosed systems and related methods.Other embodiments will be apparent to those skilled in the art by reference to the specification and practice of the disclosed systems and related methods.

[0060] It is intended that the specification and examples be considered exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

1. A laser beam generating system, comprising: a first laser chip configured to generate a first polarized laser beam; a second laser chip configured to generate a second polarized laser beam; as well as a polarizer configured to combine the first polarized laser beam and the second polarized laser beam to generate a third laser beam; The system further comprises a printed circuit board, the printed circuit board is arranged in an L shape and comprises a first portion extending along a first direction and a second portion extending along a second direction, the first direction and the second direction are perpendicular to each other, the first laser chip is arranged on the first portion and the direction of the first polarized laser beam is parallel to the second direction, the second laser chip is arranged on the second portion and the direction of the second polarized laser beam is parallel to the first direction, and the printed circuit board is made of a high thermal conductivity ceramic material to dissipate heat generated by the first laser chip and the second laser chip; The printed circuit board has an etched sheet layer, on which electronic components of the first laser chip and the second laser chip are arranged and mechanically supported and electrically connected by the etched sheet layer.

2. The laser beam generating system of claim 1, wherein: The first polarized laser beam includes laser light in a first polarization state; The second polarized laser beam includes laser light in a second polarization state; and The polarizer is configured to transmit laser light in the first polarization state and reflect laser light in the second polarization state.

3. The laser beam generating system of claim 1, wherein: The first polarized laser beam includes laser light in a first polarization state; The second polarized laser beam includes laser light in a second polarization state; The laser beam generating system includes a wave plate configured to change laser light in the second polarized laser beam from the second polarization state to a third polarization state; and The polarizer is configured to transmit laser light in the first polarization state and reflect laser light in the third polarization state.

4. The laser beam generating system according to claim 1, wherein: The intensity of the third laser beam is equal to the sum of the intensities of the first polarized laser beam and the second polarized laser beam.

5. The laser beam generating system according to claim 1, wherein: The first laser chip and the second laser chip are configured to simultaneously generate the first polarized laser beam and the second polarized laser beam, respectively.

6. The laser beam generating system according to claim 1, wherein: The intensity of the third laser beam is equal to an average value of the intensities of the first polarized laser beam and the second polarized laser beam.

7. The laser beam generating system of claim 1, wherein: The first laser chip and the second laser chip are configured to generate the first polarized laser beam and the second polarized laser beam in different time slots, respectively.

8. The laser beam generating system of claim 1, comprising at least one collimating lens configured to parallelize the first polarized laser beam or the second polarized laser beam.

9. A method for controlling laser generation, comprising: generating a first polarized laser beam by a first laser chip; generating a second polarized laser beam by a second laser chip; as well as combining the first polarized laser beam and the second polarized laser beam using a polarizer to generate a third laser beam; The printed circuit board is configured in an L shape and includes a first portion extending along a first direction and a second portion extending along a second direction, the first direction and the second direction are perpendicular to each other, the first laser chip is configured on the first portion and the direction of the first polarized laser beam is parallel to the second direction, the second laser chip is configured on the second portion and the direction of the second polarized laser beam is parallel to the first direction, and the printed circuit board is composed of a high thermal conductivity ceramic material to dissipate heat generated by the first laser chip and the second laser chip; The printed circuit board has an etched sheet layer, on which electronic components of the first laser chip and the second laser chip are arranged and mechanically supported and electrically connected by the etched sheet layer.

10. The method according to claim 9, wherein: The first polarized laser beam includes laser light in a first polarization state; The second polarized laser beam includes laser light in a second polarization state; and The method comprises the following steps: transmitting the laser light in the first polarization state through the polarizer; and The laser light in the second polarization state is reflected by the polarizer.

11. The method according to claim 9, wherein: The first polarized laser beam includes laser light in a first polarization state; The second polarized laser beam includes laser light in a second polarization state; and The method comprises the following steps: Using a wave plate, the laser light in the second polarized laser beam is changed from the second polarization state to a third polarization state; transmitting the laser light in the first polarization state through the polarizer; and The laser light in the third polarization state is reflected by the polarizer.

12. The method according to claim 9, wherein: The intensity of the third laser beam is equal to the sum of the intensities of the first polarized laser beam and the second polarized laser beam.

13. The method according to claim 9, comprising: The first polarized laser beam and the second polarized laser beam are generated simultaneously by the first laser chip and the second laser chip, respectively.

14. The method according to claim 9, wherein: The intensity of the third laser beam is equal to an average value of the intensities of the first polarized laser beam and the second polarized laser beam.

15. The method according to claim 9, comprising: The first polarized laser beam and the second polarized laser beam are generated by the first laser chip and the second laser chip in different time slots, respectively.

16. An optical sensing device, comprising: A laser beam generator, the laser beam generator comprising: a first laser chip configured to generate a first polarized laser beam; a second laser chip configured to generate a second polarized laser beam; and a polarizer configured to combine the first polarized laser beam and the second polarized laser beam to generate a third laser beam; a scanner configured to scan a surrounding environment of the optical sensing device using the third laser beam; and at least one photodetector configured to detect a returning laser beam reflected by an object in the surrounding environment; Wherein, the optical sensing device further comprises a printed circuit board, the printed circuit board is arranged in an L shape and comprises a first portion extending along a first direction and a second portion extending along a second direction, the first direction and the second direction are perpendicular to each other, the first laser chip is arranged on the first portion and the direction of the first polarized laser beam is parallel to the second direction, the second laser chip is arranged on the second portion and the direction of the second polarized laser beam is parallel to the first direction, and the printed circuit board is made of a high thermal conductivity ceramic material to dissipate heat generated by the first laser chip and the second laser chip; The printed circuit board has an etched sheet layer, on which electronic components of the first laser chip and the second laser chip are arranged and mechanically supported and electrically connected by the etched sheet layer.

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