Silicon assisted packaging of high power integrated soa arrays

Abstract

A photonic integrated circuit (PIC) assembly includes a semiconductor optical amplifier (SOA) array and a U-turn chip. The SOA array includes an input SOA and a plurality of SOAs. The input SOA and the plurality of SOAs are arranged parallel to each other. The U-turn chip includes a splitter and a waveguide assembly. The splitter is configured to receive amplified input light propagating from the input SOA along a first direction and split the amplified light into a plurality of light beams. The waveguide assembly directs each of the plurality of light beams to a corresponding SOA of the plurality of SOAs and adjusts a propagation direction of each of the directed light beams to be substantially parallel to a second direction substantially opposite the first direction. And each of the plurality of SOAs is configured to amplify their respective light beams to produce a plurality of amplified output light beams.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 960,688, filed January 13, 2020, under 35 U.S. SC §119(e), which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to frequency modulated continuous wave (FMCW) optical detection and ranging (LiDAR), and more specifically, to solid-state FMCW LiDAR systems. Background Technology

[0004] Traditional LiDAR systems use mechanical moving parts and bulk optical lens elements (i.e., refractive lens systems) to steer the laser beam. However, for many applications (such as automotive), this approach is too bulky, too expensive, and unreliable. Summary of the Invention

[0005] A photonic integrated circuit (PIC) component includes a semiconductor optical amplifier (SOA) array and a U-shaped bend chip. The semiconductor optical amplifier (SOA) array includes an input SOA and multiple SOAs. The input SOA and multiple SOAs are arranged parallel to each other. The U-shaped bend chip includes a beam splitter and a waveguide assembly. The beam splitter is configured to receive amplified input light propagating from the input SOA along a first direction and split the amplified light into multiple beams. The waveguide assembly is configured to guide each of the multiple beams to a corresponding SOA among the multiple SOAs. The waveguide assembly also adjusts the propagation direction of each of the guided beams to be substantially parallel to a second direction, which is substantially opposite to the first direction. Each of the multiple SOAs is configured to amplify its respective beam to produce multiple amplified output beams. The PIC component may be, for example, part of a frequency-modulated continuous wave (FMCW) LiDAR system.

[0006] In some embodiments, the PIC component includes a semiconductor optical amplifier (SOA) module. The SOA module includes an SOA array and may also include a U-shaped bend chip (in an alternative embodiment, the U-shaped bend chip may be part of the PIC chip to which the SOA module is coupled). The SOA array is located on the SOA chip. The SOA array includes an input SOA and a plurality of SOAs, and the input SOA and the plurality of SOAs are arranged parallel to each other. The U-shaped bend chip is coupled to the SOA chip and includes a beam splitter and a waveguide assembly. The beam splitter is configured to receive amplified input light propagating from the input SOA along a first direction and split the amplified light into a plurality of beams. The waveguide assembly is configured to guide each of the plurality of beams to a corresponding SOA among the plurality of SOAs, wherein the waveguide assembly adjusts the propagation direction of each of the guided beams to be substantially parallel to a second direction substantially opposite to the first direction, and wherein each of the plurality of SOAs is configured to amplify its respective beam to produce a plurality of amplified output beams. Attached Figure Description

[0007] The embodiments of this disclosure have other advantages and features, which will become more apparent from the following detailed description and the appended claims when taken in conjunction with the examples in the accompanying drawings, in which:

[0008] Figure 1 A top view of a photonic integrated circuit assembly according to one or more embodiments is shown, the assembly including two SOA array chips and two corresponding U-shaped turn chips coupled to a PIC chip.

[0009] Figure 2 A cross-section of one embodiment of an SOA array module according to one or more embodiments is depicted.

[0010] Figure 3 Another embodiment depicts a cross-section of an SOA array module coupled to a PIC chip.

[0011] Figure 4A -B describes an example manufacturing process according to one or more embodiments.

[0012] Figure 5A -B describes a PIC assembly including a suspended U-shaped turn chip according to one or more embodiments.

[0013] Figure 6 A PIC assembly comprising a suspended U-shaped turning chip and a plurality of comb-shaped drivers is described according to one or more embodiments.

[0014] Figure 7 A top view of a PIC assembly including an external cavity laser is shown according to one or more embodiments. Detailed Implementation

[0015] The SOA module includes an SOA array (on an SOA array chip) and may include a U-shaped bend chip (in other embodiments, the U-shaped bend chip is part of a PIC circuit to which the SOA module is coupled), and the SOA module may be coupled to a photonic integrated circuit (PIC) chip. The SOA array includes an input SOA and a plurality of SOAs. In some embodiments, the input SOA is identical to one or more of the plurality of SOAs. In alternative embodiments, the input SOA and the plurality of SOAs may be different (e.g., having different amplification levels). In some embodiments, each of the plurality of SOAs is configured to provide the same amplification level. In other embodiments, at least one of the plurality of SOAs provides a different amplification level than the input SOA and / or another SOA among the plurality of SOAs. The input SOA and the plurality of SOAs may be arranged parallel to each other. The PIC chip, the U-shaped bend chip, or some combination thereof may be made of silicon, silicon nitride, silicon dioxide, or some combination thereof, while the SOA array chip may be made of a III-V compound semiconductor material composed of Al, Ga, In, N, P, As, and other elements.

[0016] The U-turn chip includes a beam splitter and a waveguide assembly. The beam splitter is configured to receive amplified input light propagating from an input SOA along a first direction and split the amplified light into multiple beams. The waveguide assembly guides each of the multiple beams to its corresponding SOA among the multiple SOA arrays. The waveguide assembly also adjusts the propagation direction of each guided beam to be substantially parallel to a second direction, which is substantially opposite to the first direction. In this way, the light guided by the waveguide assembly performs a "U-turn" back towards the SOA array.

[0017] Each of the multiple SOA modules is configured to amplify its respective beam to produce multiple amplified output beams. Since the SOA module can be part of a photonic integrated circuit (PIC) component, the amplified output beams can be provided to the PIC component for use, for example, in a frequency-modulated continuous wave (FMCW) LiDAR system. FMCW LiDAR measures the distance and velocity of an object directly by pointing a frequency-modulated collimated beam at it. Light reflected from the object is combined with a tapped version of the beam. Once corrected for the Doppler shift required for a second measurement, the frequency of the resulting beat is proportional to the distance of the object relative to the LiDAR system. These two measurements, which may or may not be performed simultaneously, provide both distance and velocity information.

[0018] Note that a PIC assembly can include multiple SOA modules, a light source, and multiple waveguides to supply light from the light source to the multiple SOA modules. The multiple waveguides can also be arranged to provide a similar U-turn function. This, combined with the parallel arrangement of the SOA and U-turn chips, facilitates easy integration and packaging of the SOA modules with the PIC chip. In contrast, a typical high-power SOA array has optical input and output on opposite sides of a III-V chip. This makes packaging the SOA with other photonic chips both expensive and difficult.

[0019] Figure 1 A top view of a photonic integrated circuit (PIC) assembly 100 according to one or more embodiments is shown. The assembly includes two SOA array chips 110 (also referred to as SOA chips) and two corresponding U-shaped turn chips 113 coupled to a PIC chip 102. The PIC chip 102, SOA array chips 110, U-shaped turn chips 113, or some combination thereof may be made of silicon, silicon nitride, silicon dioxide, or some combination thereof.

[0020] The output optical power of the integrated laser source 101 is located on top of the PIC chip 102. The light from this source is coupled into a waveguide 103 patterned on the PIC chip 102.

[0021] The optical power in the waveguide is uniformly divided into two output waveguides 105 and 106 by a beam splitter 104. The beam splitter 104 can be, for example, a beam splitter. Although two SOA modules (i.e., 208 and 208) are demonstrated in this example, different numbers of SOA modules may be used in other embodiments. Each of the SOA modules 107 and 108 includes a respective SOA array chip 110 (also referred to as an SOA chip) and a U-shaped bend chip 113, which are placed in a cavity etched into the top surface of the PIC 102.

[0022] As shown in the figure, output waveguide 105 is configured to provide a first beam to SOA module 107 (and specifically to its corresponding SOA array), and output waveguide 108 is configured to provide a second beam to SOA module 108 (and specifically to its corresponding SOA array). Note that, as shown in the figure, the propagation direction of light at the entrances of output waveguides 105 and 106 is substantially opposite to the propagation direction at the outputs of output waveguides 105 and 106.

[0023] Each SOA array chip includes an SOA array. The SOA array includes input SOA (e.g., input SOA 111) and multiple SOA (e.g., SOA 116). As shown, the input SOA and multiple SOA are arranged parallel to each other. In other embodiments, the input SOA and multiple SOA may have been positioned relative to each other in a different manner.

[0024] In the context of SOA module 107, output waveguide 105 is coupled to SOA array chip 110 through the edge of front chip face 109.

[0025] The light passes through the input SOA 111, which acts as a preamplifier to compensate for losses associated with chip-to-chip coupling. The amplified light propagates along a first direction.

[0026] The pre-amplified light leaving the SOA is coupled to the U-shaped bend chip 113 via the edge of the back side 112 of the SOA chip 110.

[0027] The light in the input waveguide passes through a 1xM beam splitter 114 (where M equals 1 minus the total number of SOAs, including the input SOA, in the SOA array 110), which distributes the pre-amplified optical power equally among the M waveguides (e.g., waveguide 115) of the waveguide assembly. Each waveguide of the waveguide assembly includes a guided beam corresponding to a portion of the pre-amplified optical power.

[0028] The waveguide assembly aligns the propagation direction of each guided beam to be substantially parallel to a second direction, which is substantially opposite to the first direction. For example, these waveguides are curved and the light is coupled back into the SOA array chip 110 via the back surface 112. Each optical path then amplifies the light to a desired output level via individual SOA 116 on the SOA array chip (i.e., each of the plurality of SOAs is configured to amplify its respective beam to produce a plurality of amplified output beams). In some embodiments, each SOA 116 in the SOA array chip is configured to provide the same level of amplification. In other embodiments, at least two SOA 116 have different levels of amplification. Similarly, in some embodiments, the plurality of SOA modules on the PIC chip 102 are identical. And in other embodiments, at least one SOA module on the PIC chip 102 is different from another SOA module on the PIC chip 102. For example, one SOA module may have a different number of SOA 116 than another SOA module.

[0029] The amplified light is edge-coupled back into the PIC chip 102 via the front chip face 109 and then edge-coupled back into the waveguide 117. Light from the output waveguide 106 to the SOA module 108 is amplified in the SOA module 108 in a manner substantially similar to that described above for the SOA module 107, and then output to the waveguide 118. Waveguides 117 and 118 in the PIC chip 102 transmit light from the packaged SOA array to the photonic circuitry contained within the PIC chip 102.

[0030] Figure 2A cross-section of one embodiment of an SOA array module 200 (also referred to as an SOA module) coupled to a PIC chip 205 is depicted. The SOA array chip 201 is bonded to a carrier 203 that provides structural support and thermal management. The carrier 203 may be made of silicon, other thermally conductive ceramics such as AlN or Al2O3, or some combination thereof. The SOA array chip 201 may be an embodiment of an SOA array chip 110.

[0031] The U-shaped bend chip 202 is actively coupled to the SOA array chip 201 with the aid of a spacer 204, which provides the necessary mechanical offset relative to the carrier 203. The spacer 204 can be made of any material, although it is advantageous to use one with a similar coefficient of thermal expansion to the SOA 201, as the alignment between the SOA 201 and the U-shaped bend chip 202 is better maintained during temperature fluctuations. The U-shaped bend chip 202 is an embodiment of the U-shaped bend chip 113. The U-shaped bend chip 202 is thinned so that the combined module is fitted into a recess etched into the PIC chip 205. This arrangement of the bonded SOA array chip 201, carrier 203, spacer 204, and U-shaped bend chip 202 forms the SOA array module 200.

[0032] The SOA array module 200 is then placed on the PIC chip 205, which utilizes the optical power provided by the SOA array chip 201. The PIC chip 205 includes a patterned base 206 that provides mechanical support, precise out-of-plane alignment, and means of securing the SOA array chip 201 to the PIC chip 205. The SOA array module is placed on top of these bases 206, with its front side close to the chip surface 207 and actively aligned to provide effective optical coupling between the SOA array chip 201 and the PIC chip 205. Note that in the illustrated embodiment, the U-shaped bend chip 202 is located on the side of the SOA array chip 201 opposite to the chip surface 207. In other embodiments, the position of the chip surface 207 relative to the U-shaped bend chip 202 may differ.

[0033] If additional support is required, the U-shaped bend chip 202 can be bonded to the silicon photonic chip using a low-shrinkage adhesive 208.

[0034] Figure 3 Another embodiment depicts a cross-section of an SOA array module 300 coupled to a PIC chip 304. The SOA array module 300 simplifies the chip assembly process, thereby reducing the cost of mass production.

[0035] In this embodiment, the PIC chip 304 and the U-shaped bend chip 302 are fabricated on the same wafer, such that waveguide 310 in the PIC 304 and waveguide 311 in the U-shaped bend chip 302 are self-aligned in the vertical direction, i.e., they are at the same depth below the chip surface (e.g., aligned in the same plane). Furthermore, the patterned substrates (e.g., substrate 305) in the PIC chip 304 and the patterned substrates (e.g., substrate 303) in the U-shaped bend chip 302 are formed such that when the SOA chip 301 is located on these substrates, waveguide 309 in the SOA chip 301 is aligned vertically with waveguides 310 and 311. Since precise vertical alignment during chip assembly affects performance, the mechanical constraints provided by the self-aligned waveguides 309, 310, and 311, along with the correctly formed substrates, significantly improve the yield and quality of the final chip assembly, which can lead to higher throughput and lower manufacturing costs.

[0036] Figure 4A -B describes an example manufacturing process according to one or more embodiments. Figure 4A The process shown in -B can be performed by components of the circuit manufacturing system. Other entities can perform it. Figure 4A -B Some or all of the steps in other embodiments. Embodiments may include different and / or additional steps, or perform these steps in a different order.

[0037] like Figure 4A As shown, PIC 404 and U-shaped bend 402 are formed on the same wafer. The wafer can be made of silicon, silicon nitride, silicon dioxide, some other suitable material, or some combination thereof. Waveguides 410 and 411 are at the same depth below the wafer surface. Similarly, bases 405 and 403 are formed such that the tops of bases 405 and 403 are at the same depth below the wafer surface. Note that in the illustrated embodiment, there are four bases 405 and two bases 403. In other embodiments, there may be more or fewer bases 405 and / or more or fewer bases 403.

[0038] Figure 4B The diagram illustrates how to assemble an SOA module 400, comprising an SOA array chip 401 and a U-shaped bend chip 402. The U-shaped bend chip 402 is derived from... Figure 4A The wafer shown is cut out and can be thinned.

[0039] SOA array chip 401 is bonded to carrier 406. Carrier 406 may be an embodiment of carrier 203. A U-shaped bend chip 402 is then inverted, aligned, and bonded to SOA array chip 401, with base 403 contacting the top surface of SOA array chip 401 to provide mechanical constraint in the vertical direction. Primary adhesion is provided by an adhesive (e.g., solder or glue) 408 surrounding base 403, while secondary adhesion may be achieved using low-shrinkage adhesive 408' and, if necessary, a spacer 407 added between U-shaped bend chip 402 and carrier 406 for better mechanical stability. Because the height of base 403 is precisely controlled, this method allows for passive alignment between SOA array chip 401 and U-shaped bend chip 402.

[0040] Then the SOA module 400 is inverted and bonded to the PIC chip 404. For example, as shown... Figure 3 As shown, the SOA module 400 is then inverted, aligned with the waveguide 310 in the PIC 304, and bonded to a cavity in the base (e.g., base 305) housing the PIC chip 304 using adhesive 308 as a mechanical stop to ensure vertical alignment of the components.

[0041] Figure 5A -B describes a PIC assembly 500 including a suspended U-shaped turn chip 502 according to one or more embodiments. The PIC assembly 500 includes a PIC chip 505 and an SOA module connected to the suspended U-shaped turn chip 502. The SOA module includes an SOA array chip 501 and a carrier 503. Figure 5A This is a cross-sectional view of the PIC component 500, and Figure 5B This is a top view of the PIC component 500. The PIC chip 505 and the U-shaped bend chip 502 are fabricated on the same wafer (e.g., similar to the above regarding...). Figure 4A (Described embodiment). When the bottom of the U-shaped bend chip 502 is hollowed out by the cavity or through-hole 510, the U-shaped bend chip 502 is not cut off from the wafer, but is attached and suspended by the flexure 509. The U-shaped bend chip 502 has a degree of freedom to move in the plane, while out-of-plane movement is constrained. This ensures vertical alignment between the PIC 505, the SOA array chip 501, and the U-shaped bend chip 502, but allows the U-shaped bend chip 502 to move left / right to accommodate variations in the length of the SOA array chip 501. During assembly, the pre-assembled SOA 501 on the carrier 503 is flipped, aligned, and bonded to the base (e.g., base 506) of the PIC chip 505. The U-shaped bend chip 502 is then pushed toward the SOA array chip 501 and permanently fixed in place with adhesive 508 to form the PIC assembly 500.

[0042] Figure 6A PIC assembly 600 according to one or more embodiments is described, wherein a PIC chip 605 includes a suspended U-shaped bend chip 602 and a plurality of comb drivers 611. Comb drivers 611 are added to use electrostatic forces to move the U-shaped bend chip 602 in a plane. As shown, the comb drivers 611 are configured to control the translation of the U-shaped bend chip 602 relative to an SOA array chip 601 in two orthogonal directions. The comb drivers 611 are formed from portions of the U-shaped bend chip 602 and the PIC chip 605 and are configured to position the U-shaped bend chip 602 relative to the SOA array chip 601. Once the waveguides in the SOA array chip 601 are aligned with those in the U-shaped bend chips 602, an adhesive 608 is applied to permanently secure the U-shaped bend chip 602 in place. Although three comb drivers 611 are illustrated, in other embodiments, the PIC chip 605 may include one or more comb drivers 611.

[0043] Figure 7 A top view of a PIC assembly 700 including an external cavity laser according to one or more embodiments is shown. The PIC assembly 700 includes an SOA array chip 110 and a gain dielectric chip 701, which are packaged into a PIC chip 702 including a resonator 718 with the aid of a U-shaped bend chip 113. The gain dielectric chip 701 and the resonator 718 form an external cavity laser (ECL), i.e., the laser source in this embodiment. The resonator 718 and the gain dielectric chip 701 together select and amplify a specific wavelength band of emitted light.

[0044] Light from the ECL source is coupled into the SOA array chip 110 via waveguide 705. The SOA array chip 110 is connected to the SOA array chip 110 as described above. Figure 1 The same method is used to operate the incident coupled light.

[0045] Additional configuration information

[0046] The accompanying drawings and the foregoing description relate to preferred embodiments only by way of illustration. It should be noted that, based on the foregoing discussion, alternative embodiments of the structures and methods disclosed herein will readily be considered as feasible alternatives that can be employed without departing from the claimed principles.

[0047] While the detailed description contains numerous details, these should not be construed as limiting the scope of the invention, but are merely illustrative of different examples. It should be understood that the scope of this disclosure includes other embodiments not discussed in detail above. Various other modifications, alterations, and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation, and details of the methods and apparatus disclosed herein without departing from the spirit and scope defined by the appended claims. Therefore, the scope of the invention should be determined by the appended claims and their legal equivalents.

[0048] Alternative embodiments may be implemented using computer hardware, firmware, software, and / or combinations thereof. Implementations may be implemented in a computer program product tangibly contained in a machine-readable storage device for execution by a programmable processor; and the method steps may be executed by a programmable processor, which executes an instruction program to perform a function by manipulating input data and producing output. Embodiments may advantageously be implemented in one or more computer programs executable on a programmable system comprising: at least one programmable processor coupled to receive and send data and instructions to a data storage system; at least one input device; and at least one output device. Each computer program may be implemented in a high-level procedural or object-oriented programming language, if desired, or in assembly or machine language; and in any case, the language may be a compiled or interpreted language. Suitable processors include, for example, general-purpose and special-purpose microprocessors. Typically, the processor receives instructions and data from read-only memory and / or random access memory. Generally, a computer includes one or more mass storage devices for storing data files; such devices include: disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly representing computer program instructions and data include all forms of non-volatile memory, such as: semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM disks. Any of the above may be supplemented by or included within ASICs (Application-Specific Integrated Circuits) and other forms of hardware.

Claims

1. A frequency-modulated continuous wave (FMCW) LiDAR system, comprising a photonic integrated circuit (PIC) component, the PIC component comprising: Semiconductor optical amplifier (SOA) chip; A semiconductor optical amplifier (SOA) array, the SOA array comprising an input SOA and a plurality of SOAs, wherein the input SOA and the plurality of SOAs are arranged parallel to each other, wherein the SOA array is located on the SOA chip; and U-shaped turning chip, the U-shaped turning chip comprising: A beam splitter configured to receive amplified input light propagating from the input SOA along a first direction and split the amplified input light into multiple beams; and A waveguide assembly configured to guide each of a plurality of light beams to a corresponding SOA among a plurality of SOA, wherein the waveguide assembly is configured to adjust the propagation direction of each of the guided light beams to be substantially parallel to a second direction substantially opposite to a first direction, and wherein the plurality of SOA are configured to amplify their respective light beams to produce a plurality of amplified output light beams, wherein the SOA chip includes a front side and a back side opposite to the front side, and an input light is edge-coupled into the front side before being amplified by the input SOA, the amplified input light is edge-coupled into the U-shaped bend chip through the back side edge, the guided light beam is edge-coupled into the back side from the U-shaped bend chip edge, and the plurality of amplified output light beams are edge-coupled out of the SOA chip from the front side edge.

2. The LiDAR system according to claim 1, wherein, The SOA array is located on an SOA chip coupled to multiple bases of a PIC chip, the PIC chip having a front side, and the SOA chip being configured to output the multiple amplified output beams into the front side.

3. The LiDAR system according to claim 2, wherein, The U-shaped turn chip is located on the opposite side of the SOA chip to the front of the PIC chip.

4. The LiDAR system according to claim 2, further comprising a carrier coupled to a first side of the SOA chip and a first side of the spacer, wherein, The second side of the SOA chip is coupled to the plurality of bases of the PIC chip, and the second side of the pad is coupled to the U-shaped bend chip, wherein the carrier is configured to provide thermal and structural support to the SOA chip.

5. The LiDAR system according to claim 2, wherein, The U-shaped turn chip and the PIC chip are fabricated on the same wafer, such that the waveguide in the waveguide assembly is aligned with the waveguide in the PIC chip.

6. The LiDAR system according to claim 2, wherein, The U-shaped bend chip and the PIC chip are fabricated on the same wafer, and the U-shaped bend chip is coupled to and suspended from the PIC chip via one or more flexures fabricated on the same wafer.

7. The LiDAR system according to claim 6, wherein, There are one or more comb drivers formed by portions of the U-shaped turn chip and the PIC chip, wherein the one or more comb drivers are configured to position the U-shaped turn chip relative to the SOA chip.

8. The LiDAR system according to claim 7, wherein, The one or more comb drivers control the translation of the U-shaped turn chip relative to the SOA chip in two orthogonal directions.

9. The LiDAR system according to claim 1, further comprising: The second SOA array includes a second input SOA and a plurality of SOA, wherein the second input SOA and the plurality of SOA are arranged parallel to each other and parallel to the plurality of SOA in the SOA array.

10. The LiDAR system according to claim 9, further comprising: A laser source, configured to emit light; as well as A beam splitter is configured to split the light into at least a first beam and a second beam, the first beam being provided to the SOA array and the second beam being provided to the second SOA array.

11. The LiDAR system of claim 10, further comprising a first waveguide and a second waveguide, the first waveguide being configured to provide the first beam to the SOA array, and the second waveguide being configured to provide the second beam to the second SOA array, wherein, The direction of light propagation at the entrances of the first and second waveguides is substantially opposite to the direction of light propagation at the outputs of the first and second waveguides.

12. The LiDAR system according to claim 1, wherein, The SOA array is located on an SOA chip coupled to a PIC chip, the PIC further comprising: An external cavity laser ECL source coupled to the PIC chip, the ECL source being configured to provide light to the SOA chip, the ECL source comprising: Configured as a light source to emit light. Gain medium chip, and A resonator, wherein the resonator and the gain dielectric chip are configured to jointly select and amplify a specific band of emitted light.

13. The LiDAR system according to claim 1, wherein, Each of the plurality of SOAs is configured to provide the same level of amplification.

14. The LiDAR system according to claim 1, wherein, The plurality of SOAs includes a first SOA and a second SOA, and the first SOA and the second SOA are configured to provide different amounts of corresponding amplification.

15. A semiconductor optical amplifier (SOA) module, said SOA module being part of a photonic integrated circuit (PIC) assembly, said SOA module comprising: An SOA array located on an SOA chip, the SOA array including an input SOA and a plurality of SOAs, and the input SOA and the plurality of SOAs are arranged in parallel to each other; as well as A U-shaped bend chip coupled to the SOA chip, the U-shaped bend chip comprising: A beam splitter configured to receive amplified input light propagating from the input SOA along a first direction and split the amplified light into multiple beams; and A waveguide assembly configured to guide each of a plurality of beams to a corresponding SOA among a plurality of SOAs, wherein the waveguide assembly adjusts the propagation direction of each of the guided beams to be substantially parallel to a second direction substantially opposite to a first direction, and wherein each of the plurality of SOAs is configured to amplify its respective beam to produce a plurality of amplified output beams, wherein the SOA chip includes a front side and a back side opposite to the front side, and an input light is edge-coupled into the front side before being amplified by the input SOA, the amplified input light is edge-coupled into the U-shaped bend chip through the back side edge, the guided beam is edge-coupled into the back side from the U-shaped bend chip edge, and the plurality of amplified output beams are edge-coupled out of the SOA chip from the front side edge, the plurality of amplified output beams being provided to the PIC assembly for use in a frequency-modulated continuous wave (FMCW) LiDAR system.

16. The SOA module according to claim 15, further comprising a carrier and a gasket, wherein, The carrier is separated from the U-shaped turning chip by the gasket.

17. The SOA module according to claim 16, wherein, The size of the spacer is set such that the waveguide of the SOA array and the waveguide of the U-shaped bend chip are aligned in the same plane.

18. The SOA module according to claim 16, wherein, The SOA module is configured to be coupled to a photonic integrated circuit chip.

Images