Silicon optical chip, laser radar and distance measuring equipment

Abstract

The invention relates to the technical field of laser detection, and discloses a silicon optical chip, a laser radar and distance measuring equipment, and the silicon optical chip comprises a first optical amplifier which is used for amplifying a received initial detection optical signal to obtain a first detection optical signal; the first coupler is used for carrying out light splitting processing on the first detection light signal, so that one part of the first detection light signal is output from the second port, and the other part of the first detection light signal is output from the third port, so that a local reference light signal is formed; the second optical amplifier is used for amplifying the first detection optical signal output by the second port to obtain a second detection optical signal; the visible light unit is used for generating a visible light signal; and the second coupler is used for carrying out coupling processing on the second detection light signal and the visible light signal, so that the second detection light signal and the visible light signal are coaxially emitted to the target position of the target object from the sixth port. According to the invention, the laser radar can complete distance measurement without auxiliary equipment.

Description

Technical Field

[0001] The present invention relates to the field of laser detection technology, and in particular to a silicon photonic chip, a laser radar and a distance measuring device. Background Art

[0002] Lidar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of target objects. Its working principle is to first emit a detection light signal to the target object, and then compare the received echo light signal reflected from the target with the local reference light signal. After appropriate processing, relevant information about the target object can be obtained, such as target distance, direction, height, speed, attitude and shape parameters. Among them, frequency modulated continuous wave (FMCW) lidar combines frequency modulated continuous wave ranging with laser detection technology, and has the advantages of large ranging range, high distance resolution, and Doppler velocity measurement.

[0003] For eye safety reasons, LiDAR usually uses laser wavelengths that are invisible to the human eye (such as 1550nm), which increases the difficulty of locating the target when LiDAR is measuring distance. At present, in order to assist in positioning, a visible indicator light emitting component is installed outside the LiDAR, and the indicator light and the measuring light are adjusted to illuminate the target position at the same time along the same path.

[0004] However, when using the above method for positioning, on the one hand, it is necessary to use infrared imaging equipment for observation and calibration during installation and debugging; on the other hand, for long-distance ranging needs, infrared light and visible light need to be finely adjusted to meet the minimum optical axis angle, that is, approximately coaxial emission. The longer the distance, the higher the coaxiality requirement, which greatly increases the difficulty and cost of structural installation and debugging. Summary of the invention

[0005] In view of this, the present invention provides a silicon photonic chip, a laser radar and a ranging device to improve the problem that the laser radar requires additional positioning auxiliary devices, resulting in a complicated ranging process and high cost.

[0006] In a first aspect, the present invention provides a silicon photonic chip, which includes: a first optical amplifier, which is used to amplify a received initial detection light signal to obtain a first detection light signal, wherein the initial detection light signal is an invisible light signal; a first coupler, which includes a first port, a second port and a third port, wherein the first port is connected to the first optical amplifier and is used to receive the first detection light signal, and the first coupler is used to perform optical splitting processing on the first detection light signal, so that a part of the first detection light signal is output from the second port, and another part of the first detection light signal is output from the third port, so as to form a local reference light signal; a second optical amplifier, which is connected to the second port and is used to amplify the first detection light signal output from the second port to obtain a second detection light signal; a visible light unit, which is used to generate a visible light signal; a second coupler, which includes a fourth port, a fifth port and a sixth port, wherein the fourth port is connected to the second optical amplifier and is used to receive the second detection light signal, and the fifth port is connected to the visible light unit and is used to receive the visible light signal generated by the visible light unit, and the second coupler is used to perform coupling processing on the second detection light signal and the visible light signal, so that the second detection light signal and the visible light signal are coaxially emitted from the sixth port to the target position of the target object.

[0007] The silicon photonic chip provided in this embodiment is integrated with a visible light unit. Through the cooperation of the first optical amplifier, the first coupler, the second optical amplifier, the second coupler and the visible light unit, the visible light signal generated by the visible light unit can be coupled to the output optical path of the detection light signal generated by the light source unit, so that the visible light signal and the second detection light signal are coaxially emitted to the same position of the target object, thereby achieving synchronous alignment. There is no need to set up additional positioning auxiliary settings to determine the output position of the second detection light signal, thereby improving the ranging efficiency and reducing the ranging cost.

[0008] In an optional embodiment, the silicon photonic chip also includes a third optical amplifier and a third coupler, the visible light unit includes a microresonator, and the third coupler includes a seventh port, an eighth port and a ninth port; the seventh port is connected to the third port, and is used to receive a first detection light signal output from the third port; the third coupler is used to perform optical splitting processing on the first detection light signal, so that a part of the first detection light signal is output from the eighth port, and another part of the first detection light signal is output from the ninth port; the third optical amplifier is connected to the eighth port, and is used to amplify the first detection light signal output from the eighth port to obtain a third detection light signal; the microresonator is connected to the third optical amplifier, and is used to receive the third detection light signal, and is used to generate a nonlinear effect to convert the third detection light signal into a visible light signal.

[0009] In this embodiment, the detection light signal can be used to generate a visible light signal through the micro-resonator, and there is no need to set up an additional visible light unit, which has a higher integration level and a lower testing cost.

[0010] In an optional embodiment, the microresonator is a microring or a micro-nanocavity.

[0011] In an optional embodiment, the quality factor of the microresonator is greater than or equal to 10 6 .

[0012] In an optional embodiment, the wavelength of the initial detection light signal is 1550nm, 1310nm or 1064nm. When the wavelength of the initial detection light signal is 1550nm, the wavelength of the visible light signal is 775nm. When the wavelength of the initial detection light signal is 1310nm, the wavelength of the visible light signal is 655nm. When the wavelength of the initial detection light signal is 1064nm, the wavelength of the visible light signal is 532nm.

[0013] In an optional embodiment, the silicon photonic chip also includes a fourth coupler and a balanced detector, the fourth coupler includes a tenth port, an eleventh port and a twelfth port, the first coupler also includes a thirteenth port, the sixth port is also used to receive an echo optical signal, the echo optical signal passes through the fourth port, the second optical amplifier, the second port and the thirteenth port in sequence, and the echo optical signal is formed by reflecting the second detection optical signal from the target object; the tenth port is connected to the ninth port, and is used to receive the first detection optical signal output from the ninth port to obtain a local reference optical signal; the eleventh port is connected to the thirteenth port, and is used to receive the echo optical signal output from the thirteenth port; the fourth coupler is used to mix the echo optical signal output from the thirteenth port and the local reference optical signal to obtain a mixed optical signal; the balanced detector is connected to the twelfth port, and is used to receive the mixed optical signal, and is used to convert the mixed optical signal into an analog electrical signal, and the analog electrical signal is used to determine the distance between the target object and the silicon photonic chip.

[0014] In a second aspect, the present invention provides a laser radar, comprising a light source unit and a silicon photonic chip according to the first aspect or any corresponding embodiment thereof; the light source unit is connected to a first optical amplifier for generating an initial detection light signal.

[0015] In an optional embodiment, the silicon photonic chip includes a balanced detector, and the laser radar also includes an operational amplifier, an analog-to-digital converter and a frequency demodulation unit; the operational amplifier is connected to the balanced detector, for receiving an analog electrical signal determined by the balanced detector, and for amplifying the analog electrical signal; the analog-to-digital converter is connected to the operational amplifier, for converting the received amplified analog electrical signal into a digital electrical signal; the frequency demodulation unit is connected to the analog-to-digital converter, for extracting the beat frequency from the received digital electrical signal to determine the distance between the target object and the silicon photonic chip.

[0016] In an optional embodiment, the laser radar also includes an achromatic lens; the achromatic lens is located on the light output side of the second coupler, and is used to eliminate the chromatic aberration of the second detection light signal and the visible light signal coaxially emitted from the sixth port.

[0017] In a third aspect, the present invention provides a ranging device, which includes the silicon photonic chip of the first aspect or any corresponding embodiment thereof, or includes the laser radar of the second aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a schematic structural diagram of a silicon photonic chip according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of another silicon photonic chip according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a laser radar according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of another laser radar according to an embodiment of the present invention; Figure 5 is a schematic diagram of the structure of yet another laser radar according to an embodiment of the present invention.

[0020] Figure numerals: 100, silicon photonic chip; 101, first optical amplifier; 102, first coupler; 1021, first port; 1022, second port; 1023, third port; 1024, thirteenth port; 103, second optical amplifier; 104, second coupler; 1041, fourth port; 1042, fifth port; 1043, sixth port; 105, visible light unit; 1051, microresonator; 106, fourth coupler; 1061, tenth port; 1062, eleventh port; 1063, twelfth port; 107, third optical amplifier; 108, third coupler; 1081, seventh port; 1082, eighth port; 1083, ninth port; 109, balanced detector; 200, light source unit; 301, operational amplifier; 302, analog-to-digital converter; 303, frequency demodulation unit; 304, achromatic lens; 400, target object. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. According to the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] FMCW lidar is a technology that continuously modulates the frequency of the transmitted signal and uses the frequency difference between the detection light signal and the echo light signal (usually called the beat frequency) to obtain target information (such as distance, speed, etc.). It has important applications in the fields of lidar and so on.

[0023] For FMCW lidar, for eye safety considerations, the laser band usually chooses near-infrared light, such as a laser with a wavelength of 1550nm.

[0024] Specifically, different parts of the human eye have different absorption and sensitivity characteristics to light of different wavelengths. Light in the visible light band (roughly 400nm to 780nm) can be absorbed in large quantities by the retina of the human eye and focused on the retina to form a clear image. If the intensity of high-energy visible light exceeds a certain safety threshold, it can cause thermal or photochemical damage to the retina, seriously affecting vision.

[0025] For near-infrared light with a wavelength of around 1550nm, structures such as the lens and cornea of ​​the human eye have relatively strong absorption capacity. Most of the energy is absorbed in these front structures, and it is difficult to focus on the retina in large quantities like visible light, thereby reducing the possibility of damage to the retina, a fragile part that is critical to vision, and thus reducing the risk of serious harm to the overall function of the human eye.

[0026] For the application of lidar in single-point fixed-point ranging, since the human eye is invisible to 1550nm light, the operator cannot directly see the laser projected on the target with the naked eye, and it is difficult to intuitively judge whether the emitted detection light signal is aimed at the exact position on the target that needs to be measured, which increases the difficulty of target positioning.

[0027] To assist positioning, auxiliary detection equipment is needed, such as infrared detectors, thermal imaging equipment, etc. These auxiliary equipment require additional debugging, calibration, and coordination with the lidar, which increases the complexity and cost of the ranging process.

[0028] In view of this, the present invention provides a silicon photonic chip for forming a laser radar. By integrating a visible light unit on the silicon photonic chip and coupling it with a detection light signal waveguide, the visible light signal and the detection light signal are emitted coaxially, so that the laser radar can complete ranging without the aid of auxiliary equipment.

[0029] The structure of the silicon photonic chip provided by the present invention is first described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, the silicon photonic chip 100 provided by the present invention includes a first optical amplifier 101 , a first coupler 102 , a second optical amplifier 103 , a second coupler 104 and a visible light unit 105 .

[0031] Specifically, the first optical amplifier 101 is connected to a light source unit (not shown in the figure), the light source unit is used to generate an initial detection light signal, and the first optical amplifier 101 is used to amplify the received initial detection light signal to obtain a first detection light signal.

[0032] The initial detection light signal is an invisible light signal, that is, the initial detection light signal is invisible to human eyes. For example, the initial detection light signal may be near-infrared light, and the frequency of the initial detection light signal is The wavelength of the initial detection optical signal may be 193.55 THz, and the corresponding wavelength may be 1550 nm. For example, the wavelength of the initial detection optical signal may also be 1310 nm, 1064 nm or 2 wait.

[0033] An optical amplifier is a device that can amplify the power of an optical signal. For example, the first optical amplifier 101 can amplify the power of the input initial detection optical signal from P0 to P1, so that the initial detection optical signal is converted into a first detection optical signal, ensuring sufficient light intensity in the subsequent optical processing process. The waveguide structure of the first optical amplifier is the same as that of a conventional optical amplifier in the art, and is not described in detail here. Figure 1 Here, the optical amplifier is a semiconductor optical amplifier (Semiconductor Optical Amplifier, SOA), but is not limited to this.

[0034] The first coupler 102 includes a first port 1021, a second port 1022 and a third port 1023. The first port 1021 is connected to the first optical amplifier 101 and is used to receive the first detection optical signal. The first coupler 102 is used to perform optical splitting processing on the first detection optical signal, so that a part of the first detection optical signal is output from the second port 1022, and another part of the first detection optical signal is output from the third port 1023, so as to form a local reference optical signal.

[0035] Specifically, an optical coupler (such as the first coupler 102) is a device that can distribute optical signals from one input port to multiple output ports, or couple optical signals input from multiple input ports to one output port, and is used to perform optical splitting processing or optical combining (coupling) processing on optical signals. The waveguide structure of the first coupler 102 can be the same as the structure of a conventional optical coupler in the art, and will not be described in detail here.

[0036] The second optical amplifier 103 is connected to the second port 1022 and is used to amplify the first detection optical signal output by the second port 1022 to obtain a second detection optical signal.

[0037] Specifically, the second optical amplifier 103 can amplify the power of the first detection signal received from the second port 1022 to P3, so that the first detection light signal is converted into a second detection light signal, ensuring that the second detection light signal has sufficient light intensity to reach the target position of the target object. The power of the second detection light signal can be flexibly adjusted based on the target position of the target object, so that the final laser radar can adapt to the needs of different application scenarios. The waveguide structure of the second optical amplifier 103 is also the same as the structure of a conventional optical amplifier in the field, and is not described in detail here.

[0038] The second coupler 104 includes a fourth port 1041, a fifth port 1042 and a sixth port 1043. The fourth port 1041 is connected to the second optical amplifier 103 for receiving the second detection light signal. The fifth port 1042 is connected to the visible light unit 105 for receiving the visible light signal generated by the visible light unit 105. The second coupler 104 is used to couple the second detection light signal and the visible light signal so that the second detection light signal and the visible light signal are coaxially emitted from the sixth port 1043 to the target position of the target object.

[0039] The visible light unit 105 is used to generate a visible light signal, which can be a light signal visible to the human eye. The visible light unit 105 can be a semiconductor laser, and the wavelength of the laser generated by the semiconductor laser can be any value between the visible light band (400nm to 780nm). For example, the wavelength of the visible light signal can be 400nm, 520nm, 650nm, 700nm, 775nm or 780nm. The waveguide structure of the second coupler 104 can be the same as the structure of a conventional optical coupler in the art, and will not be described in detail here.

[0040] Specifically, the target object can be determined based on the application scenario of the lidar, and the target position can be determined based on the test requirements in the application scenario. For example, if the application scenario of the lidar is a surveying and mapping scenario, the target object can be street facilities, walls, roofs or trees of buildings, etc., and the target position can be the center or top of the wall, etc.; if the application scenario of the lidar is an industrial inspection scenario, the target object can be various industrial products, such as auto parts (engine, body frame), etc., and the target position can be a position point that characterizes the size or shape of the transmitter, etc.; if the application scenario of the lidar is an autonomous driving scenario, the target object can be vehicles, pedestrians, traffic signs, street lights, and various obstacles on the road (roadblocks or fallen cargo, etc.), etc., and the target position can be a license plate or the center point of the vehicle, etc.

[0041] When measuring distance, Figure 1 As shown, the initial detection light signal generated by the light source unit can be coupled into the first optical amplifier 101 from the left side of the silicon photonic chip 100, and the first detection light signal is obtained after being amplified by the first optical amplifier 101. The first detection light signal enters the first coupler 102 through the upper port on the left side of the first coupler 102 (i.e., the first port 1021), and is output from the two ports on the right side of the first coupler 102 after being split by the first coupler 102. A part of the first detection light signal enters the second optical amplifier 103 from the upper port on the right side (i.e., the second port 1022), and is amplified by the second optical amplifier 103 to obtain the second detection light signal. The second detection light signal enters the second coupler 104 through the upper port on the left side of the second coupler 104 (i.e., the fourth port 1041), and the other part of the second detection light signal enters the fourth coupler 106 from the lower port on the right side (i.e., the third port 1023) as a local reference light signal.

[0042] At the same time, the visible light signal generated by the visible light unit 105 enters the second coupler 104 through the lower port on the left side of the second coupler 104 (i.e., the fifth port 1042), and the second coupler 104 couples the received second detection light signal and the visible light signal, so that the second detection light signal and the visible light signal are emitted together from the port on the right side of the second coupler 104 (i.e., the sixth port 1043) and reach the target position of the target object at the same time.

[0043] Among them, relevant information of the target object (such as distance or speed) can be determined through the local reference light signal and the subsequent echo light signal reflected from the target object back to the silicon photonic chip.

[0044] The silicon photonic chip provided in this embodiment integrates a visible light unit 105. Through the cooperation of the first optical amplifier 101, the first coupler 102, the second optical amplifier 103, the second coupler 104 and the visible light unit 105, the visible light signal generated by the visible light unit 105 can be coupled to the output optical path of the detection light signal generated by the light source unit, so that the visible light signal and the second detection light signal are coaxially emitted to the same position of the target object, thereby realizing synchronous alignment. There is no need to additionally set up a positioning auxiliary setting to determine the output position of the second detection light signal, thereby improving the ranging efficiency and reducing the ranging cost.

[0045] Further, in some embodiments, Figure 2 As shown, the silicon photonic chip 100 further includes a third optical amplifier 107 and a third coupler 108 , the visible light unit 105 includes a microresonator 1051 , and the third coupler 108 includes a seventh port 1081 , an eighth port 1082 , and a ninth port 1083 .

[0046] Specifically, the seventh port 1081 is connected to the third port 1023, and is used to receive the first detection optical signal output by the third port 1023. The third coupler 108 is used to perform optical splitting processing on the first detection optical signal, so that a part of the first detection optical signal is output from the eighth port 1082, and another part of the first detection optical signal is output from the ninth port 1083, so as to form a local reference optical signal.

[0047] The third optical amplifier 107 is connected to the eighth port 1082, and is used to amplify the first detection light signal output by the eighth port 1082 to obtain a third detection light signal. The microresonator 1051 is connected to the third optical amplifier 107 and the fifth port 1042, and is used to receive the third detection light signal, and is used to generate a nonlinear effect to convert the third detection light signal into a visible light signal.

[0048] Specifically, the third optical amplifier 107 can amplify the power of the first detection signal received from the eighth port 1082 to P5, so that the first detection light signal is converted into a third detection light signal, ensuring that the power of the third detection light signal can reach the threshold value for generating frequency doubled light by nonlinear effect, and can adjust the output light intensity of the frequency doubled indication light to meet the human eye safety standard, such as for visible light, generally requiring a first-class laser standard of less than 0.5 mW. The waveguide structure of the third optical amplifier 107 is also the same as that of conventional optical amplifiers in the art, and will not be described in detail here.

[0049] After the microresonator 1051 receives the third detection light signal, the third detection light signal will produce a nonlinear effect in the microresonator 1051 and generate a frequency of 2 The frequency-doubled light is used to convert the third detection light signal into a visible light signal.

[0050] Nonlinear effect refers to the change in the frequency, phase, intensity and other characteristics of light when light interacts with matter, and this change is related to the nonlinear relationship of the light field intensity. Microresonator is an optical structure with a high quality factor (Q value). Based on the resonance principle, when light propagates in a microresonator, light of a specific frequency will resonate in the cavity, producing a resonance field enhancement effect. Due to the enhanced resonance field, the interaction between light and the microresonator material is amplified, making it easier for light to produce nonlinear optical effects.

[0051] Specifically, taking the wavelength of the third detection light signal of 1550nm as an example, based on the resonance field enhancement effect of the on-chip microresonator, the interaction between light and matter is amplified, and the 1550nm signal light can be doubled and converted into a visible red light wavelength of 775nm due to the nonlinear effect.

[0052] The wavelength of the third detection light signal (i.e., the wavelength of the initial detection light signal) and The relationship between can be shown as formula (1):

[0053] in, represents the wavelength of the third detection light signal, is the speed of light in vacuum, represents the angular frequency of the third detection light signal. The wavelength of the light signal output by the microresonator is That is, the wavelength of the optical signal output by the microresonator is half of the wavelength of the third detection optical signal. In order to make the wavelength of the optical signal output by the microresonator a visible light signal, half of the wavelength of the third detection optical signal needs to be in the visible light band.

[0054] Exemplarily, the wavelength of the initial detection light signal may also be 1310 nm or 1064 nm, etc. When the wavelength of the initial detection light signal is 1310 nm, the wavelength of the visible light signal is 655 nm, and when the wavelength of the initial detection light signal is 1064 nm, the wavelength of the visible light signal is 532 nm.

[0055] Optionally, the microresonator 1051 may be an on-chip micro-nano level local enhancement structure with a high quality factor such as a microring or a micro-nano cavity, and the quality factor of the microresonator 1051 is greater than or equal to 10 6 .

[0056] Specifically, a microring is a miniaturized optical resonant cavity structure, usually composed of a ring-shaped optical waveguide, in which light waves can circulate and propagate. The size of a microring is usually at the micron level, and its ring waveguide can be made of semiconductor materials (such as silicon), polymer materials or other media suitable for light propagation. A micro-nano cavity is an optical resonant cavity structure of a smaller scale, usually at the micro-nano level, and can have a variety of geometric shapes, such as circular, elliptical, cylindrical, etc. A micro-nano cavity is usually a closed or semi-closed space formed by a high refractive index material in a low refractive index medium.

[0057] In this embodiment, when performing ranging, Figure 2 As shown, the first detection signal output from the third port 1023 of the first coupler 102 does not directly enter the fourth coupler 106 as a local reference optical signal, but enters the third coupler 108 through the port on the left side of the third coupler 108 (i.e., the seventh port 1081), continues to be split by the third coupler 108, and is output from the two ports on the right side of the third coupler 108. A part of the first detection optical signal is output from the upper port on the right side of the third coupler 108 (i.e., the eighth port 1082) and enters the third optical amplifier 107, and another part of the first detection optical signal is output from the lower port on the right side of the third coupler 108 (i.e., the ninth port 1083) and enters the fourth coupler 106 as a local reference optical signal.

[0058] After receiving the first detection light signal, the third optical amplifier 107 amplifies the first detection light signal to obtain a third detection light signal. Then, the third detection light signal enters the microresonator 1051, where a significant nonlinear effect occurs to generate a frequency of 2 Then the microresonator 1051 transmits the output visible light signal to the second coupler 104 through the optical waveguide, and the visible light signal is coaxially emitted from the sixth port 1043 of the second coupler 104 with the second detection light signal.

[0059] Furthermore, if Figure 1 and Figure 2 As shown, the silicon photonic chip 100 also includes a fourth coupler 106 and a balanced detector 109, the fourth coupler 106 includes a tenth port 1061, an eleventh port 1062 and a twelfth port 1063, the first coupler 102 also includes a thirteenth port 1024, and the sixth port 1043 is also used to receive an echo light signal, the echo light signal passes through the fourth port 1041, the second optical amplifier 103, the second port 1022 and the thirteenth port 1024 in sequence, and the echo light signal is formed by reflecting the second detection light signal from the target object.

[0060] The tenth port 1061 is connected to the ninth port 1083, and is used to receive the first detection optical signal output from the ninth port 1083 to obtain a local reference optical signal. Specifically, the first detection optical signal output from the ninth port 1083 can be directly used as the local reference optical signal. The eleventh port 1062 is connected to the thirteenth port 1024, and is used to receive the echo optical signal output from the thirteenth port 1024.

[0061] The fourth coupler 106 is used to mix the echo optical signal outputted from the thirteenth port 1024 and the local reference optical signal to obtain a mixed optical signal. The balanced detector 109 is connected to the twelfth port 1063, and is used to receive the mixed optical signal and to convert the mixed optical signal into an analog electrical signal, which is used to determine the distance between the target object and the silicon photonic chip.

[0062] Exemplarily, the balanced detector 109 may be composed of two photodetectors for detecting optical signals and converting them into electrical signals. The structure of the balanced detector 109 may be the same as that of a conventional balanced detector in the art, and the waveguide structure of the fourth coupler 106 may be the same as that of a conventional optical coupler in the art, which will not be described in detail herein.

[0063] Specifically, when performing ranging, the return light (i.e., the echo light signal) on the surface of the target object can be coupled to the silicon photonic chip waveguide and transmitted along the original optical waveguide loop, that is, the echo light signal returns to the first coupler 102 through the second coupler 104 and the second optical amplifier 103, and is transmitted to the fourth coupler 106 through the waveguide portion of the lower left port (i.e., the thirteenth port 1024) of the first coupler 102, and is mixed with the local reference light signal from the third coupler 108. The obtained mixed light signal is received by a balanced detector 109 composed of two photodetectors and converted into an analog electrical signal. The analog electrical signal is converted and collected by a subsequent operational amplifier and an external analog-to-digital converter (ADC), and is calculated and processed by a frequency demodulation unit to obtain target distance information.

[0064] The embodiment of the present invention further provides a laser radar, such as Figure 3 As shown, the laser radar includes a light source unit 200 and a silicon photonic chip 100 as shown in any of the above embodiments. The light source unit 200 is connected to a first optical amplifier 101 to generate an initial detection optical signal.

[0065] In some optional embodiments, the silicon photonic chip includes a balanced detector 109, such as Figure 4 As shown, the laser radar also includes an operational amplifier 301 , an analog-to-digital converter 302 and a frequency demodulation unit 303 .

[0066] Specifically, the operational amplifier 301 is connected to the balanced detector 109, and is used to receive the analog electrical signal determined by the balanced detector 109, and is used to amplify the analog electrical signal. The analog-to-digital converter 302 is connected to the operational amplifier 301, and is used to convert the received amplified analog electrical signal into a digital electrical signal. The frequency demodulation unit 303 is connected to the analog-to-digital converter 302, and is used to extract the beat frequency from the received digital electrical signal to determine the distance between the target object and the silicon photonic chip.

[0067] It should be understood that in FMCW laser radar, the frequency of the emitted light (i.e., the above-mentioned detection light signal) is modulated over time. When the emitted light encounters the target and is reflected back, the frequency of the beat frequency signal (i.e., the analog electrical signal) generated by mixing the reflected light (i.e., the above-mentioned echo light signal) with the local reference light signal is related to the target distance. The process of frequency demodulation is to extract the frequency information from the beat frequency signal and then calculate the target distance. In the digital signal processing stage, the beat frequency is extracted by the frequency demodulation algorithm, and the distance between the target object and the silicon photonic chip can be obtained according to the speed of light and the parameters of the frequency modulation. Among them, the frequency demodulation algorithm is the same as the conventional frequency demodulation algorithm used in the art to determine the distance. The operational amplifier 301 can be a conventional operational amplifier in the art, and the analog-to-digital converter 302 can also be a conventional analog-to-digital converter in the art.

[0068] The frequency demodulation unit 303 in this embodiment may refer to an application specific integrated circuit (ASIC), a processor and a memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0069] In some optional embodiments, such as Figure 5 As shown, the laser radar further includes an achromatic lens 304 , which is located on the light-emitting side of the second coupler 104 and is used to eliminate the chromatic aberration of the second detection light signal and the visible light signal coaxially emitted from the sixth port 1043 .

[0070] Chromatic aberration is caused by the different refractive indices of different wavelengths of light when passing through the lens material. Achromatic lens is an optical lens used to correct chromatic aberration. Specifically, achromatic lens uses a combination of multiple optical materials with different dispersion characteristics (such as crown glass and flint glass) to ensure that the two wavelengths of light will not be dispersed due to chromatic aberration, but will be accurately focused on the target position, thereby ensuring the accuracy of positioning and measurement.

[0071] For example, the following is combined Figure 5 The specific process of laser radar ranging is explained.

[0072] Specifically, the frequency is The fundamental frequency light (i.e., the initial detection optical signal) of (e.g., 193.55THz, corresponding to a wavelength of 1550nm) is coupled into the optical waveguide from the left side of the silicon photonic chip, with an optical power of P0. After being amplified by the first optical amplifier 101, it is input into the first coupler 102, with an optical power of P1. The light input into the first coupler 102 is output from the two ports on the right side. A part of the light enters the second optical amplifier 103 from the upper port and enters the second coupler 104 after being amplified, with a power of P3. The other part of the light continues to be split through the third coupler 108. One part of it is output through the lower port on the right side of the third coupler 108 and enters the fourth coupler 106 as a local reference optical signal, with a power of P4. The other part of the light is output through the upper port on the right side of the third coupler 108 and enters the third optical amplifier 107, with a power of P5, and then input into the microresonator 1051. The light undergoes a significant nonlinear effect in the microresonator 1051 and generates a frequency of 2. The doubled frequency light (such as 775nm wavelength red light) is generated here. The doubled frequency light is transmitted to the second coupler 104 through the optical waveguide and is coupled to the light having an intensity of P3 and a frequency of The fundamental frequency light of the chip is emitted from the right port of the chip, and after passing through the achromatic lens 304, it is collimated and emitted to the same position on the surface of the target object 400. The return light on the surface of the target object 400 is received by the lens and coupled into the chip waveguide, and is transmitted along the original optical waveguide loop, that is, the frequency is The fundamental frequency return light (i.e., the echo optical signal) is returned to the first coupler 102 through the second coupler 104 and the second optical amplifier 103, and is transmitted to the fourth coupler 106 through the waveguide part on the left side of the first coupler 102, and is mixed with the local reference optical signal with power P4 from the third coupler 108. The mixed light is received by the balanced detector 109 and converted into an analog electrical signal, which is converted and collected by the operational amplifier 301 and the external analog-to-digital converter 302, and is calculated and processed by the frequency demodulation unit 303 to obtain the target distance information, thereby achieving Fundamental frequency light measurement, 2 Synchronous positioning measurement operation of frequency-doubled visible light positioning.

[0073] An embodiment of the present invention further provides a ranging device, which includes the silicon photonic chip provided by any of the above embodiments, or includes the laser radar provided by any of the above embodiments.

[0074] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0075] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0077] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0078] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A silicon photonic chip, characterized in that: The silicon photonic chip comprises: A first optical amplifier, used to amplify the received initial detection light signal to obtain a first detection light signal, wherein the initial detection light signal is an invisible light signal; a first coupler, comprising a first port, a second port and a third port, wherein the first port is connected to the first optical amplifier and is used to receive the first detection optical signal, and the first coupler is used to perform optical splitting processing on the first detection optical signal, so that a part of the first detection optical signal is output from the second port, and another part of the first detection optical signal is output from the third port, so as to form a local reference optical signal; a second optical amplifier connected to the second port and configured to amplify the first detection optical signal output by the second port to obtain a second detection optical signal; A visible light unit, used for generating a visible light signal; The second coupler includes a fourth port, a fifth port and a sixth port, wherein the fourth port is connected to the second optical amplifier and is used to receive the second detection light signal, the fifth port is connected to the visible light unit and is used to receive the visible light signal generated by the visible light unit, and the second coupler is used to couple the second detection light signal and the visible light signal so that the second detection light signal and the visible light signal are coaxially emitted from the sixth port to a target position of a target object.

2. The silicon photonic chip according to claim 1, characterized in that: The silicon photonic chip further includes a third optical amplifier and a third coupler, the visible light unit includes a microresonator, and the third coupler includes a seventh port, an eighth port, and a ninth port; The seventh port is connected to the third port and is used to receive the first detection light signal output by the third port, and the third coupler is used to perform optical splitting processing on the first detection light signal, so that a part of the first detection light signal is output from the eighth port, and another part of the first detection light signal is output from the ninth port; The third optical amplifier is connected to the eighth port and is used to amplify the first detection optical signal output by the eighth port to obtain a third detection optical signal; The microresonator is connected to the third optical amplifier, and is used to receive the third detection light signal, and to generate a nonlinear effect to convert the third detection light signal into the visible light signal.

3. The silicon photonic chip according to claim 2, characterized in that: The micro-resonator is a micro-ring or a micro-nano cavity.

4. The silicon photonic chip according to claim 3, characterized in that: The quality factor of the microresonator is greater than or equal to 10 6 .

5. The silicon photonic chip according to any one of claims 2 to 4, characterized in that: The wavelength of the initial detection light signal is 1550nm, 1310nm or 1064nm. When the wavelength of the initial detection light signal is 1550nm, the wavelength of the visible light signal is 775nm. When the wavelength of the initial detection light signal is 1310nm, the wavelength of the visible light signal is 655nm. When the wavelength of the initial detection light signal is 1064nm, the wavelength of the visible light signal is 532nm.

6. The silicon photonic chip according to any one of claims 2 to 4, characterized in that: The silicon photonic chip further includes a fourth coupler and a balanced detector, the fourth coupler includes a tenth port, an eleventh port and a twelfth port, the first coupler further includes a thirteenth port, the sixth port is further used to receive an echo optical signal, the echo optical signal sequentially passes through the fourth port, the second optical amplifier, the second port and the thirteenth port, and the echo optical signal is formed by reflecting the second detection optical signal through the target object; The tenth port is connected to the ninth port and is used to receive the first detection optical signal output from the ninth port to obtain a local reference optical signal; The eleventh port is connected to the thirteenth port and is used to receive the echo optical signal output from the thirteenth port; The fourth coupler is used to perform mixing processing on the echo optical signal output by the thirteenth port and the local reference optical signal to obtain a mixed optical signal; The balanced detector is connected to the twelfth port, and is used to receive the mixed optical signal and convert the mixed optical signal into an analog electrical signal, wherein the analog electrical signal is used to determine the distance between the target object and the silicon photonic chip.

7. A laser radar, characterized in that: A method comprising a light source unit and a silicon photonic chip according to any one of claims 1 to 5; The light source unit is connected to the first optical amplifier and is used to generate an initial detection light signal.

8. The laser radar according to claim 7, characterized in that: The silicon photonic chip includes a balanced detector, and the laser radar also includes an operational amplifier, an analog-to-digital converter, and a frequency demodulation unit; The operational amplifier is connected to the balanced detector, and is used to receive the analog electrical signal determined by the balanced detector, and is used to amplify the analog electrical signal; The analog-to-digital converter is connected to the operational amplifier and is used to convert the received amplified analog electrical signal into a digital electrical signal; The frequency demodulation unit is connected to the analog-to-digital converter and is used to extract the beat frequency from the received digital electrical signal to determine the distance between the target object and the silicon photonic chip.

9. The laser radar according to claim 7, characterized in that: The laser radar also includes an achromatic lens; The achromatic lens is located at the light-emitting side of the second coupler, and is used to eliminate the chromatic aberration of the second detection light signal and the visible light signal coaxially emitted from the sixth port.

10. A distance measuring device, characterized in that: The ranging device includes the silicon photonic chip described in any one of claims 1 to 6, or includes the laser radar described in any one of claims 7 to 9.

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