CN110187440B - Grating device, light emitting module and light detection method - Google Patents

Grating device, light emitting module and light detection method Download PDF

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CN110187440B
CN110187440B CN201910368695.1A CN201910368695A CN110187440B CN 110187440 B CN110187440 B CN 110187440B CN 201910368695 A CN201910368695 A CN 201910368695A CN 110187440 B CN110187440 B CN 110187440B
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waveguide
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CN110187440A (en
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王强
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/124—Geodesic lenses or integrated gratings

Abstract

The application discloses a grating device, a light emitting module and a light detection method. The grating device includes: a substrate; a barrier layer on the substrate; a first waveguide over a first region of the barrier layer; and a second waveguide located above the second region of the barrier layer, wherein the grating device selectively propagates a first light beam in the first waveguide and/or a second light beam in the second waveguide, and obtains a propagation-direction-changed exit light beam by diffraction, the first light beam and the second light beam are respectively a TE mode and a TM mode and exit angles at least one wavelength are not equal. The grating device modulates the exit angle of the exit beam by adopting the wavelength of the source beam, and the beams of different polarization modes are respectively transmitted in the first waveguide and the second waveguide so as to expand the modulation range of the exit angle. The laser radar adopting the grating device can expand the detection angle.

Description

Grating device, light emitting module and light detection method
Technical Field
The invention belongs to the laser radar technology, and particularly relates to a grating device, a light emitting module and a light detection method.
Background
Lidar has been widely used in automotive applications, optical wireless communications, environmental topography measurements, and the like. The laser radar is similar to the microwave radar, and adopts a reflected light signal for irradiating an object and detecting the object by a transmitted light beam, and processes the reflected light signal to obtain information such as the position and the speed of a detection target.
The operation of the lidar system relies on expensive optical systems, for example, mirrors may be used to vary the exit angle of the laser beam, thereby extending the detection range of the lidar. In recent years, the basic functions of the lidar have been integrated on a common silicon substrate to form a single chip using emerging technologies such as silicon photonics to reduce the size of the lidar and to reduce manufacturing costs.
However, it is very difficult to integrate optical elements such as mirrors in the chip. Alternatively, two modulation methods may be employed to achieve the exit angle control of the laser beam: phase modulation and wavelength modulation. In the phase modulation, the phase difference of the laser beam between the adjacent optical elements is adjusted by the thermo-optical effect, and then, the outgoing beam is generated by the diffraction effect, so that the beam angle in the far field can be adjusted by the control of the phase difference. In the wavelength modulation, a laser beam of a corresponding wavelength is generated using a Tunable Laser Source (TLS), and then an exit beam having an exit angle corresponding to the wavelength is generated by a diffraction effect of a Grating Coupler (GC), so that the exit angle of the exit beam can be adjusted by controlling the wavelength. In laser radars, two modulation methods can be combined, for example, a phase modulation method for controlling the beam in the x direction and a wavelength modulation method for controlling the beam in the y direction.
The use of the wavelength modulation method for controlling the exit angle of the light beam is advantageous in that only the wavelength of the laser light source needs to be controlled without using an additional heating element, and is disadvantageous in that the range of the exit angle obtained by wavelength modulation is small. For example, only a 15 degree range of exit angles can be achieved with a wavelength range of about 80 nm.
Therefore, it is desirable to further expand the range of the light beam emergence angle obtained by the wavelength modulation method to expand the detection range of the laser radar.
Disclosure of Invention
In view of the above, the present invention is directed to a grating device, a light emitting module and a light detecting method, wherein light beams with different polarization modes are respectively transmitted in a first waveguide and a second waveguide of the grating device to combine the wavelength-modulated output angle ranges of the two waveguides, so as to expand the detection angle of the laser radar.
According to a first aspect of the present invention, there is provided a grating device comprising: a substrate; a barrier layer on the substrate; a first waveguide over a first region of the barrier layer; and a second waveguide located above the second region of the barrier layer, wherein the grating device selectively propagates a first light beam in the first waveguide and/or a second light beam in the second waveguide, and obtains a propagation-direction-changed exit light beam by diffraction, the first light beam and the second light beam are respectively a TE mode and a TM mode and exit angles at least one wavelength are not equal.
Preferably, the first waveguide and the second waveguide are each an array of a plurality of strips, the plurality of strips being parallel to each other and perpendicular to the direction of propagation of the first light beam and the second light beam.
Preferably, a fill factor of the first waveguide is greater than a fill factor of the second waveguide, the fill factor being a ratio between a width of the plurality of stripes and a repetition period.
Preferably, the first and second beams propagate in opposite directions to each other.
Preferably, the exit angle of the exit beam is modulated according to the wavelengths of the first and second beams.
Preferably, the first light beam produces an exit light beam of a first exit angle range and the second light beam produces an exit light beam of a second exit angle range, the first exit angle range being separate from, continuous with or partially overlapping the second exit angle range.
Preferably, the method further comprises the following steps: a slot for separating the first waveguide and the second waveguide.
Preferably, the method further comprises the following steps: a cladding layer over the first waveguide and the second waveguide.
Preferably, the refractive index of the first waveguide and the second waveguide is greater than the refractive index of the barrier layer.
Preferably, the first waveguide and the second waveguide are respectively composed of any one selected from silicon, silicon oxide, silicon nitride, gallium arsenide, indium phosphide, and liquid crystal.
Preferably, the substrate and the barrier layer are a silicon-on-insulator substrate and a buried layer, respectively, and the first waveguide and the second waveguide are formed by patterning a silicon layer of the silicon-on-insulator.
Preferably, the method further comprises the following steps: a cladding layer over the first waveguide and the second waveguide, the cladding layer comprised of silicon oxide.
According to a second aspect of the present invention, there is provided a light emitting module comprising: a polarization controller for generating a first beam in a TE mode and a second beam in a TM mode from the source beam; and at least one grating device connected with the polarization controller to obtain the first beam and the second beam, wherein the at least one grating device respectively comprises: a substrate; a barrier layer on the substrate; a first waveguide over a first region of the barrier layer; and a second waveguide located above the second region of the barrier layer, the at least one grating device selectively propagating a first light beam in the first waveguide and/or a second light beam in the second waveguide, obtaining an exit light beam with a changed propagation direction by diffraction, the exit angles of the first light beam and the second light beam at least one wavelength being unequal.
Preferably, the source light beam is polarized light in one of a TE mode and a TM mode, the polarization controller comprising: an optical switch for selectively providing a source beam to the first path or the second path, the source beam being the first beam; and a polarization rotator connected to the optical switch via the second path and converting the source light beam into a second light beam of a different polarization mode, wherein the optical switch provides the first light beam to the first waveguide via the first path and the polarization rotator provides the second light beam to the second waveguide via a third path.
Preferably, the source light beam is polarized light adjustable in TE mode and TM mode, and the polarization controller includes: an optical switch connected with the first waveguide via a first path and connected with the second waveguide via a second path, wherein the optical switch provides the source beam in the TE mode to the first path as a first beam and provides the source beam in the TM mode to the second path as a second beam.
Preferably, the source light beam is unpolarized light, the polarization controller comprising: a polarization beam splitter connected to the first waveguide via a first path and connected to the second waveguide via a second path, wherein the polarization beam splitter provides the first path with a first beam that polarizes the source beam into a TE mode and the second path with a second beam that polarizes the source beam into a TM mode.
Preferably, the source beam is unpolarized, preferably the at least one grating device comprises a plurality of grating devices sharing the substrate and the blocking layer.
Preferably, the method further comprises the following steps: a first beam splitter connected between the polarization controller and the plurality of grating devices for splitting the first light beam into a plurality of beams to be provided to respective first waveguides of the plurality of grating devices; and a second beam splitter connected between the polarization controller and the plurality of grating devices for splitting the second light beam into a plurality of beams to be provided to respective second waveguides of the plurality of grating devices.
Preferably, the first waveguide and the second waveguide are each an array of a plurality of strips, the plurality of strips being parallel to each other and perpendicular to the direction of propagation of the first light beam and the second light beam.
Preferably, a fill factor of the first waveguide is greater than a fill factor of the second waveguide, the fill factor being a ratio between a width of the plurality of stripes and a repetition period.
Preferably, the first and second beams propagate in opposite directions to each other.
Preferably, the exit angle of the exit beam is modulated according to the wavelengths of the first and second beams.
Preferably, the first light beam produces an exit light beam of a first exit angle range and the second light beam produces an exit light beam of a second exit angle range, the first exit angle range being separate from, continuous with or partially overlapping the second exit angle range.
Preferably, the at least one grating device further comprises: a slot for separating the first waveguide and the second waveguide.
Preferably, the at least one grating device further comprises: a cladding layer over the first waveguide and the second waveguide.
Preferably, the refractive index of the first waveguide and the second waveguide is greater than the refractive index of the barrier layer.
Preferably, the first waveguide and the second waveguide are respectively composed of any one selected from silicon, silicon oxide, silicon nitride, gallium arsenide, indium phosphide, and liquid crystal.
Preferably, the substrate and the barrier layer are a silicon-on-insulator substrate and a buried layer, respectively, and the first waveguide and the second waveguide are formed by patterning a silicon layer of the silicon-on-insulator.
Preferably, the at least one grating device further comprises: a cladding layer over the first waveguide and the second waveguide, the cladding layer comprised of silicon oxide.
According to a third aspect of the present invention, there is provided a light detection method comprising: generating a first light beam and a second light beam with different polarization modes by using the source light beam; changing the propagation directions of the first light beam and the second light beam by adopting a first waveguide and a second waveguide respectively to generate an emergent light beam, wherein the emergent angle of the emergent light beam corresponds to the wavelength and the polarization mode of the first light beam and the second light beam; irradiating the object with the emergent light beam; acquiring a reflected light beam from the object to generate a detection signal; and performing signal processing on the detection signal to obtain the distance of the object, wherein the emergence angles of the first light beam and the second light beam at least one wavelength are not equal.
Preferably, the source beam is polarized in one of TE mode and TM mode, and the step of generating the exit beam comprises: selectively providing a source beam to the first path or the second path, the source beam being the first beam; converting the source light beam into a second light beam of a different polarization mode; providing the first light beam to the first waveguide via the first path; and providing the second light beam to the second waveguide via a third path.
Preferably, the source light beam is polarized light adjustable in TE mode and TM mode, and the step of generating the outgoing light beam includes: providing a source beam of TE mode to a first path as a first beam; and providing the source beam in TM mode as a second beam.
Preferably, the source beam is a broadband beam, and the step of generating an exit beam comprises: providing a first light beam that polarizes the source light beam into a TE mode to a first path; and polarizing the source beam to provide a second path for a second beam of TM mode.
Preferably, the source light beam is in any one mode of unpolarized, linear polarization at 45 degrees, linear polarization at 135 degrees, left-hand circular polarization, and right-hand circular polarization.
Preferably, the method of generating an outgoing beam comprises: splitting the first light beam into a plurality of beams to be provided to respective first waveguides of the plurality of grating devices; and splitting the second light beam into a plurality of beams to be provided to respective second waveguides of the plurality of grating devices.
Preferably, the first and second beams propagate in opposite directions to each other.
Preferably, the exit angle of the exit beam is modulated according to the wavelengths of the first and second beams.
Preferably, the first light beam produces an exit light beam of a first exit angle range and the second light beam produces an exit light beam of a second exit angle range, the first exit angle range being separate from, continuous with or partially overlapping the second exit angle range.
According to a fourth aspect of the present invention, there is provided a lidar comprising: a laser light source for continuously generating a narrow-band source beam of a plurality of wavelengths; the light emitting module is connected with the laser light source to receive the source light beam, and generates a plurality of outgoing light beams with outgoing angle values corresponding to a plurality of wavelengths through diffraction, wherein the outgoing light beams irradiate on an object; a light detection module for acquiring a reflected light beam reflected from an object and generating a detection signal; and the signal processing module is connected with the optical detection module to acquire the detection signal and perform signal processing to obtain the distance of the object.
Preferably, the method further comprises the following steps: a lens positioned between the light detection module and the object, the lens for enhancing the intensity of the reflected light beam.
According to a fifth aspect of the present invention, there is provided a lidar comprising: a laser light source for generating a broadband source beam of a plurality of wavelengths; the light emitting module is connected with the laser light source to receive the source light beam, and generates a plurality of outgoing light beams with outgoing angle values corresponding to a plurality of wavelengths through diffraction, wherein the outgoing light beams irradiate on an object; a light detection module including a plurality of detection units that respectively acquire reflected light beams of respective wavelengths reflected from an object and generate detection signals; and the signal processing module is connected with the optical detection module to acquire the detection signal and perform signal processing to obtain the distance of the object.
Preferably, the method further comprises the following steps: a lens positioned between the light detection module and the object, the lens for enhancing the intensity of the reflected light beam.
According to the grating device provided by the embodiment of the invention, the wavelength of the source light beam is adopted to modulate the exit angle of the exit light beam, and light beams with different polarization modes are respectively propagated in the first waveguide and the second waveguide. Even if the laser source with the same wavelength is adopted to generate two light beams with different polarization modes, the equivalent refractive indexes of the two light beams are different, so that different emergent angles can be obtained by adopting the same wavelength. The grating device can combine beam modulated exit angle ranges of different polarization modes. Further, the detection angle of the laser radar can be expanded by adopting the grating device.
The structure of the grating device is compatible with the existing semiconductor process. Therefore, the optical transmission module can be formed using the grating device, and integrated with the light source and the signal processing circuit in a single chip or package structure to form a laser radar chip or package structure, so that the size and manufacturing cost of the laser radar can be reduced, and power consumption can be reduced.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Figure 1 shows a schematic cross-sectional view of a grating device according to the prior art.
Fig. 2 shows a schematic cross-sectional view of a grating device according to a first embodiment of the present invention.
Fig. 3 shows a graph of the relationship between the exit angle and the wavelength of the first waveguide and the second waveguide in the grating device according to the first embodiment of the present invention.
Fig. 4 shows a graph of the transmittance versus wavelength for the first waveguide and the second waveguide in the grating device according to the first embodiment of the present invention.
Fig. 5 shows a schematic block diagram of an optical transmit module according to a second embodiment of the present invention.
Fig. 6 shows a schematic block diagram of an optical transmit module according to a third embodiment of the present invention.
Fig. 7 shows a schematic block diagram of an optical transmit module according to a fourth embodiment of the present invention.
Fig. 8 shows a schematic block diagram of an optical transmit module according to a fifth embodiment of the present invention.
Fig. 9 and 10 show a schematic diagram of the optical splitter in the optical transmit module and the simulation calculation results, respectively.
Fig. 11 shows a schematic block diagram of a lidar in accordance with a sixth embodiment of the invention.
Fig. 12 is a flowchart showing a part of the steps of a light detection method of a laser radar according to a sixth embodiment of the present invention.
Fig. 13 shows a schematic block diagram of a lidar in accordance with a seventh embodiment of the invention.
Fig. 14 is a flowchart showing a part of the steps of a light detection method of a laser radar according to a seventh embodiment of the present invention.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.
In the following description, numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of the devices are described in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
Figure 1 shows a schematic cross-sectional view of a grating device according to the prior art. The grating device 10 includes a substrate 11, a barrier layer 12, a waveguide 13, and a cladding layer 14, which are stacked in this order.
The substrate 11 is composed of, for example, silicon. Transistors for signal processing circuitry may also be formed on the substrate 11, allowing the grating device to be integrated with the signal processing circuitry in a radar chip.
A barrier layer 12 is located between the substrate 11 and the waveguide 13 for confining the light beam to propagate in the waveguide 13. The barrier layer is composed of, for example, silicon oxide.
The waveguide 13 includes, for example, an array composed of a plurality of strips. The plurality of strips are parallel to each other. The waveguide 13 is for example made of silicon and the strips are for example patterned etched in a silicon layer, the strips being separated from each other by a plurality of trenches. The strips are arranged periodically in an array having a width LGCThe ratio to the repetition period Λ is called the filling factor.
A cladding layer 14 is located above the waveguide 13. The cover layer 14 is made of, for example, silicon oxide, and serves to protect the waveguide 13 from environmental contaminants and also to confine the light beam to propagate in the waveguide 13.
The plurality of strips in the waveguide 13 form a grating so as to change the propagation direction of the light beam by diffraction. For example, in the waveguide 13, the propagation direction of the source beam and the extending direction of the plurality of strips are perpendicular to each other, and then the source beam is deflected to exit at the main surface of the waveguide 13 opposite to the substrate 11, forming an exit beam.
The exit angle of the exit beam produced by the waveguide 13 can be calculated according to equation (1):
kneff＝kncsinθ+2πq/Λ (1)，
wherein n iseffRepresenting the effective refractive index, n, of the waveguidecDenotes the refractive index of the cladding layer (for example, 1.45 for silicon oxide), θ denotes the exit angle with respect to the normal direction of the main surface of the waveguide 13, Λ denotes the repetition period of the grating structure, and q denotes the diffraction orderFor example, the grating structure has a diffraction order of 1, k 2 pi/λ, and λ represents the wavelength of the laser source.
The exit angle of the exiting light beam can be modulated using the grating device 10. For example, a laser beam of different wavelengths is generated using a Tunable Laser Source (TLS), and then, the beam enters the grating device 10, and an exit beam of an exit angle corresponding to the wavelength is generated by a diffraction effect, so that the exit angle of the exit beam can be adjusted by control of the wavelength. As described above, the wavelength modulation of the grating device 10 results in a small range of exit angles. For example, only a 15 degree range of exit angles can be achieved with a wavelength range of about 80 nm.
Fig. 2 shows a schematic cross-sectional view of a grating device according to a first embodiment of the present invention. The grating device 20 includes a substrate 21, a barrier layer 22, a first waveguide 23, a second waveguide 24, and a cladding layer 25, which are sequentially stacked. Optionally, the grating device 20 further comprises a slot 26 for separating the first waveguide 23 and the second waveguide 24.
The substrate 21 is composed of, for example, silicon. Transistors for signal processing circuitry may also be formed on the substrate 21, allowing the grating device to be integrated with the signal processing circuitry in a radar chip.
A barrier layer 22 is located between the substrate 21 and the first and second waveguides 23, 24 for confining the light beam to propagate in the first and second waveguides 23, 24.
The first waveguide 23 and the second waveguide 24 each include an array of a plurality of strips. The plurality of strips are parallel to each other. The plurality of strips in the first waveguide 23 and the second waveguide 24 are, for example, patterns etched in the light transmission layer, and are separated from each other by a plurality of trenches.
A cladding layer 25 is located above the first waveguide 23 and the second waveguide 24. Cladding layer 25 is an optional layer for protecting first waveguide 23 and second waveguide 24 from environmental contaminants. And also serves to confine the light beam to propagate in the first waveguide 23 and in the second waveguide 24.
In this embodiment, the first waveguide 23 and the second waveguide 24 are each composed of, for example, any one selected from silicon, silicon oxide, silicon nitride, gallium arsenide, indium phosphide, and liquid crystal. The barrier layer 22 is composed of, for example, a material having a refractive index smaller than that of the first waveguide 23 and the second waveguide 24. The cover layer is composed of a light-transmitting material.
In a preferred embodiment, the substrate 21 and the barrier layer 22 are a silicon-on-insulator (SOI) substrate and a buried layer, respectively, and the first waveguide 23 and the second waveguide 24 are patterned from a silicon layer (transmission layer) of silicon-on-insulator (SOI). The capping layer 25 is comprised of deposited silicon oxide.
The plurality of strips in the first waveguide 23 and the second waveguide 24 form a grating so that the propagation direction of the light beam is changed by diffraction. For example, in the first waveguide 23 and the second waveguide 24, the propagation direction of the source beam and the extending direction of the plurality of strips are perpendicular to each other, and then the source beam is deflected to exit at the main surface on the side opposite to the substrate 21, forming an exit beam. The first waveguide 23 and the second waveguide 24 may be aligned or staggered with respect to each other. Preferably, the first waveguide 23 and the second waveguide 24 are separated from each other with a gap 26 to prevent crosstalk between the two waveguides.
In this embodiment, the slot 26 extends from the surface of the cladding layer 25 down to the surface of the barrier layer 22, penetrating the transmission layer for forming the first waveguide 23 and the second waveguide 24. In an alternative embodiment, the slot 26 only penetrates through the transmission layers forming the first waveguide 23 and the second waveguide 24, and the cover layer 25 fills the slot 26.
The exit angle of the exiting beam is modulated using a grating device 20. For example, a Tunable Laser Source (TLS) is used to generate a laser beam of a corresponding wavelength, which then enters the grating device 20 to produce an exit beam by diffraction effects. Referring to formula (1), the exit angle of the exit beam corresponds to the wavelength, so that the exit angle of the exit beam can be adjusted by control of the wavelength.
The exit angle θ of the exit beams generated by the first waveguide 23 and the second waveguide 24 and the effective refractive index n are determined according to the formula (1)effAnd (4) correlating.
Two light beams of different polarization modes, for example, a first light beam of a TE (trans-electric) mode and a second light beam of a TM (trans-magnetic) mode, propagate in the first waveguide 23 and the second waveguide 24, respectively, and their effective refractive indices are expressed as follows:
Figure BDA0002049117550000101
Figure BDA0002049117550000102
wherein n isTEAnd nTMRespectively representing the effective refractive indices of the TE mode and TM mode beams in the respective waveguides, ncIndicating the refractive index of the cladding layer (e.g. 1.45 for silica), nsiRepresenting the refractive index of the transmission layer of the first waveguide and the second waveguide (e.g. 3.47 for silicon), fyRepresenting the fill factor of the grating structure of a waveguide, in the structure shown in fig. 2, the waveguide comprises a plurality of strips arranged periodically, the fill factor fyEqual to the strip width and LGCThe ratio to the repetition period Λ.
As can be seen from the equations (1) to (3), the first light beam in the TE mode selectively propagates in the first waveguide 23 of the grating device 20, and the second light beam in the TM mode propagates in the second waveguide 24 of the grating device 20, and the outgoing light beam with the changed propagation direction is obtained by diffraction. In the case where the wavelength ranges of the laser light sources are equal, i.e., λ 1 to λ 2, the difference in the filling factor of each of the first waveguide 23 and the second waveguide 24, and the difference in the polarization mode of each light beam, the first exit angle range θ 1 to θ 2 of the exit light beam from the first waveguide 23 and the second exit angle range θ 3 to θ 4 of the exit light beam from the second waveguide 24 will be caused to be different.
The grating device 20 combines the above-described first and second ranges of exit angles. For example, the first exit angle range is separate from, continuous with, or partially overlapping the second exit angle range. The range of the exit angle of the combined modulation of the beams of different polarization modes by the grating device 20 is larger than the range of the exit angle of the beam modulation of the grating device with a single polarization mode. Therefore, the grating device can expand the modulation range of the exit angle even in the case where the wavelength range of the laser light source is not changed.
Fig. 3 and 4 show graphs of the relationship between the exit angle and the wavelength and the relationship between the transmittance and the wavelength of the first waveguide and the second waveguide, respectively, in the grating device according to the first embodiment of the present invention.
The first beam of TE mode propagates in the first waveguide 23 of the grating device 20 and the second beam of TM mode propagates in the second waveguide 24 of the grating device 20.
In this embodiment, the propagation directions of the first and second light beams are towards each other, i.e. towards the slit 26, respectively. In an alternative embodiment, the propagation directions of the first and second light beams diverge from each other, i.e. propagate away from the slit 26, respectively.
Selecting a fill factor f for the first waveguide 23 and the second waveguide 24ySuch that the exit angle of the exit beam modulated by the first waveguide 23 changes from-18.1 degrees to-34.3 degrees and the exit beam modulated by the second waveguide 24 changes from-18.1 degrees to-4.7 degrees as the wavelength of the laser source changes between 1.22 microns and 1.3 microns. The first range of exit angles is continuous with the second range of exit angles and the grating device 20 can achieve a continuously modulated range of exit angles from-34.3 to-4.7 degrees.
In the above wavelength range, the transmittance of the outgoing light beam modulated by the first waveguide 23 changes from 0.75 to 0.5, and the transmittance of the outgoing light beam modulated by the second waveguide 24 changes from 0.67 to 0.5. The difference of the transmissivity of the outgoing light beams of the first waveguide 23 and the second waveguide 24 causes the difference of the light intensity irradiated on the object, the difference is not so large as to affect the detection of the detection signal, and the normal operation of the laser radar can still be ensured.
Fig. 5 shows a schematic block diagram of an optical transmit module according to a second embodiment of the present invention. The optical transmission module 110 includes a grating device 20 and a polarization controller 111.
The grating device 20 has a structure as shown in fig. 2, and includes a first waveguide 23 and a second waveguide 24.
The light source 101 generates a source beam in TE mode, for example. The polarization controller 111 generates a second beam of TM mode light from the source beam and may selectively provide one of the first and second beams.
The grating device 20 is connected to the polarization controller 111, the first waveguide 23 obtains a first light beam in TE mode, the second waveguide 24 obtains a second light beam in TM mode, and the first light beam and the second light beam respectively obtain emergent light beams with different propagation directions through diffraction, and the emergent angles of the first light beam and the second light beam at least one wavelength are not equal.
In this embodiment, the source light beam generated by the light source 101 is polarized in the TE mode. The polarization controller 111 includes an optical switch 1111 and a polarization rotator 1112. The optical switch 1111 selectively provides the source beam to the first path or the second path as the first beam. The polarization rotator 1112 is connected to the optical switch 1111 via the second path and converts the source beam into a second beam of TM mode. The optical switch 1111 provides the first light beam to the first waveguide of the grating device 20 via a first path, and the polarization rotator 1112 provides the second light beam to the second waveguide of the grating device 20 via a third path.
The grating device 20 propagates a first light beam of TE mode in the first waveguide 23 and a second light beam of TM mode in the second waveguide 24, and obtains an outgoing light beam of changed propagation direction by diffraction. In the case where the wavelength ranges of the laser light sources are equal, the exit angle range in which the grating device 20 employs wavelength modulation is a combination of a first exit angle range in which the first waveguide 23 exits the light beam and a second exit angle range in which the second waveguide 24 exits the light beam. For example, the first exit angle range is separate from, continuous with, or partially overlapping the second exit angle range. The range of the exit angle of the grating device 20 modulated with the combination of the first waveguide and the second waveguide is larger than the range of the exit angle of the grating device modulated with a single waveguide.
Therefore, even in the case where the wavelength range of the laser light source 101 is not changed, the optical transmission module 110 diffracts the light beams of different polarization modes in the first waveguide and the second waveguide to generate the outgoing light beams of different outgoing angles, and thus the modulation range of the outgoing angles can be expanded.
Fig. 6 shows a schematic block diagram of an optical transmit module according to a third embodiment of the present invention. The light emitting module 210 includes a plurality of grating devices 20, a polarization controller 111, a first beam splitter 211, and a second beam splitter 212.
The plurality of grating devices 20 are arranged in an array, preferably sharing a substrate and a barrier layer, and thus may be integrated in a single chip. The structure of each grating device 20 is the same as that shown in figure 2, including a first waveguide 23 and a second waveguide 24 respectively.
The light source 101 generates a source beam in TE mode, for example. The polarization controller 111 generates a first beam in a TE mode and a second beam in a TM mode from the source beam. The light source 101 and the polarization controller 111 in the light emitting module according to the third embodiment are the same as those of the second embodiment, and will not be described in detail.
The first beam splitter 211 is connected between the polarization controller 111 and the plurality of grating devices 20 for splitting the first light beam into a plurality of beams to be supplied to the respective first waveguides 23 of the plurality of grating devices 20. The second beam splitter 212 is connected between the polarization controller 111 and the plurality of grating devices 20 for splitting the second light beam into a plurality of beams to be provided to the respective first waveguides 24 of the plurality of grating devices 20. Therefore, in each grating device 20, the first waveguide 23 obtains a first light beam in TE mode, the second waveguide 24 obtains a second light beam in TM mode, and obtains exit light beams with changed propagation directions by diffraction, respectively, and the exit angles of the first light beam and the second light beam at least one wavelength are not equal.
The plurality of grating devices 20 propagate a first light beam of a TE mode in the first waveguide 23 and a second light beam of a TM mode in the second waveguide 24, respectively, and obtain an outgoing light beam of which the propagation direction is changed by diffraction. In the case where the wavelength ranges of the laser light sources are equal, the exit angle range in which the plurality of grating devices 20 employ wavelength modulation is a combination of a first exit angle range in which the first waveguide 23 exits the light beam and a second exit angle range in which the second waveguide 24 exits the light beam. For example, the first exit angle range is separate from, continuous with, or partially overlapping the second exit angle range. The range of the exit angle of the grating device 20 modulated with the combination of the first waveguide and the second waveguide is larger than the range of the exit angle of the grating device modulated with a single waveguide.
The optical transmission module 220 according to this embodiment uses a plurality of grating devices 20 to simultaneously generate a plurality of outgoing beams having the same outgoing angle, so that a single beam of line scanning can be expanded into a plurality of beams of surface scanning, the emitting area of the laser radar can be further expanded, and the collimation detection range of the far field can be improved.
Fig. 7 shows a schematic block diagram of an optical transmit module according to a fourth embodiment of the present invention. The optical transmission module 310 includes a plurality of grating devices 20, an optical switch 311, a first optical splitter 211, and a second optical splitter 212.
The plurality of grating devices 20 are arranged in an array, preferably sharing a substrate and a barrier layer, and thus may be integrated in a single chip. The structure of each grating device 20 is the same as that shown in figure 2, including a first waveguide 23 and a second waveguide 24 respectively.
The source light beam generated by the light source 102 is a polarized light that can be modulated in TE mode and TM mode. The optical switch 311, acting as a polarization controller, is connected to the light source 102 to obtain a source light beam, which is provided via a first path to a first waveguide of the plurality of grating devices 20 and via a second path to a second waveguide of the plurality of grating devices 20.
The first beam splitter 211 is connected between the optical switch 311 and the plurality of grating devices 20 for splitting the first light beam into a plurality of beams to be supplied to the respective first waveguides 23 of the plurality of grating devices 20. The second beam splitter 212 is connected between the optical switch 311 and the plurality of grating devices 20, and splits the second light beam into a plurality of beams to be supplied to the respective first waveguides 24 of the plurality of grating devices 20. Therefore, in each grating device 20, the first waveguide 23 obtains a first light beam in TE mode, the second waveguide 24 obtains a second light beam in TM mode, and obtains exit light beams with changed propagation directions by diffraction, respectively, and the exit angles of the first light beam and the second light beam at least one wavelength are not equal.
The plurality of grating devices 20 propagate a first light beam of a TE mode in the first waveguide 23 and a second light beam of a TM mode in the second waveguide 24, respectively, and obtain an outgoing light beam of which the propagation direction is changed by diffraction. In the case where the wavelength ranges of the laser light sources are equal, the exit angle range in which the plurality of grating devices 20 employ wavelength modulation is a combination of a first exit angle range in which the first waveguide 23 exits the light beam and a second exit angle range in which the second waveguide 24 exits the light beam. For example, the first exit angle range is separate from, continuous with, or partially overlapping the second exit angle range. The range of the exit angle of the grating device 20 modulated with the combination of the first waveguide and the second waveguide is larger than the range of the exit angle of the grating device modulated with a single waveguide.
The optical transmission module 310 according to this embodiment simultaneously generates a plurality of outgoing beams having the same outgoing angle using a plurality of grating devices 20, and thus can expand a single beam of line scanning into a plurality of beams of surface scanning, further expanding the detection range of the laser radar. Further, the source light beam generated by the light source 102 is polarized light that can be adjusted by TE mode and TM mode, which not only can reduce the optical components of the polarization controller, but also can reduce the light loss introduced by the polarization controller.
Fig. 8 shows a schematic block diagram of an optical transmit module according to a fifth embodiment of the present invention. The light emitting module 410 includes a plurality of grating devices 20, a polarization splitter 411, a first splitter 211, and a second splitter 212.
The plurality of grating devices 20 are arranged in an array, preferably sharing a substrate and a barrier layer, and thus may be integrated in a single chip. The structure of each grating device 20 is the same as that shown in figure 2, including a first waveguide 23 and a second waveguide 24 respectively.
The source light beam generated by the light source 103 is, for example, an unpolarized light beam. The polarization splitter 411, which serves as a polarization controller, is connected to the light source 103 to obtain a source beam, which is polarized into a first beam in the TE mode or a second beam in the TM mode. The polarization beam splitter 411 provides the first light beam to the first waveguides 23 of the plurality of grating devices 20 via a first path, and the polarization beam splitter 411 provides the second light beam to the second waveguides 24 of the plurality of grating devices 20 via a second path.
The first beam splitter 211 is connected between the polarization beam splitter 411 and the plurality of grating devices 20 for splitting the first light beam into a plurality of beams to be supplied to the respective first waveguides 23 of the plurality of grating devices 20. The second beam splitter 212 is connected between the polarization beam splitter 411 and the plurality of grating devices 20 for splitting the second light beam into a plurality of beams to be supplied to the respective first waveguides 24 of the plurality of grating devices 20. Therefore, in each grating device 20, the first waveguide 23 obtains a first light beam in TE mode, the second waveguide 24 obtains a second light beam in TM mode, and obtains exit light beams with changed propagation directions by diffraction, respectively, and the exit angles of the first light beam and the second light beam at least one wavelength are not equal.
The plurality of grating devices 20 propagate a first light beam of a TE mode in the first waveguide 23 and a second light beam of a TM mode in the second waveguide 24, respectively, and obtain an outgoing light beam of which the propagation direction is changed by diffraction. In the case where the wavelength ranges of the laser light sources are equal, the exit angle range in which the plurality of grating devices 20 employ wavelength modulation is a combination of a first exit angle range in which the first waveguide 23 exits the light beam and a second exit angle range in which the second waveguide 24 exits the light beam. For example, the first exit angle range is separate from, continuous with, or partially overlapping the second exit angle range. The range of the exit angle of the grating device 20 modulated with the combination of the first waveguide and the second waveguide is larger than the range of the exit angle of the grating device modulated with a single waveguide.
The optical transmission module 410 according to this embodiment simultaneously generates a plurality of outgoing beams having the same outgoing angle using a plurality of grating devices 20, and thus can expand a single beam of line scanning into a plurality of beams of surface scanning, further expanding the detection range of the laser radar. Further, the source light beam generated by the light source 103 is unpolarized light, and the polarization beam splitter 411 converts the unpolarized light into the first light beam in the TE mode and the second light beam in the TM mode, which can not only reduce the optical components of the polarization controller, but also reduce the light loss introduced by the polarization controller.
Fig. 9 shows a schematic diagram of an optical splitter in an optical transmit module. The first beam splitter 211 and the second beam splitter 212 each include a plurality of cascaded Y-type beam splitters, and split the single source beam into a plurality of beams, each of which is provided to a corresponding grating device.
Fig. 10 is a graph showing the result of simulation calculation of the optical splitter in the optical transmission module. The first beam splitter 211 and the second beam splitter 212 are implemented using multi-mode interference couplers, and split a single source beam into a plurality of beams, each of which is provided to a corresponding grating device. The first and second splitters 211 and 212 may also be implemented using star couplers.
Fig. 11 shows a schematic block diagram of a lidar in accordance with a sixth embodiment of the invention. The laser radar 1000 includes a light source 101, a light emitting module 110, a lens 104, a light detection module 105, and a signal processing module 106. The internal structure of the light emitting module 110 is shown in fig. 5.
In this embodiment, where lidar 1000 is a scanning lidar, light source 101 may continuously generate a narrow-band beam of multiple wavelengths. The optical transmitter module 110 is connected to the light source 101 to receive the source light beam and generate a plurality of outgoing light beams with outgoing angle values corresponding to a plurality of wavelengths by diffraction, and the outgoing light beams are irradiated on the object 108. The lens 104 is positioned between the object 108 and the light detection module 105 for enhancing the intensity of the reflected light beam. The light detection module 105 acquires a reflected light beam reflected from the object and generates a detection signal. The signal processing module 106 is connected to the light detection module 105 to acquire a detection signal, and performs signal processing to obtain the distance of the object 108.
Fig. 12 is a flowchart showing a part of the steps of a light detection method of a laser radar according to a sixth embodiment of the present invention. The method is applied to the laser radar 1000 shown in fig. 11, wherein the light source 101 can continuously generate a plurality of wavelengths and a narrow-band light beam of TE mode, and the structure of the light emitting module 110 is shown in fig. 5.
As described above, the light detection method includes generating an outgoing light beam and detecting a reflected light beam, and further includes the following steps S01 to S10.
In step S01, the optical switch 1111 in the optical transmit module 110 is switched to the second path, such that the polarization rotator 1112 is connected with the optical switch 1111 and converts the TE mode source beam into the TM mode second beam. The second waveguide 24 of the grating device 20 propagates the second light beam in the TM mode and generates a corresponding exit light beam.
In step S02, the wavelength of the source beam generated by the light source 101 is set to a minimum value. The second waveguide 24 of the grating device 20 produces an exit beam with an exit angle corresponding to the wavelength.
In step S03, the light source 101 is adjusted to change the wavelength of the source beam over time. The second waveguide 24 of the grating device 20 produces an exit beam with an exit angle corresponding to the wavelength.
In step S04, the light detection module 105 acquires the reflected light beam reflected from the object and generates a detection signal.
In step S05, it is determined whether the wavelength of the source light beam generated by the light source 101 has reached the maximum value, and if not, steps S03 to S05 are repeated, and if yes, step S06 is performed.
In step S06, the optical switch 1111 in the optical transmission module 110 is switched to the first path so that the first waveguide of the grating device 20 is connected with the optical switch 1111. The first waveguide 24 of the grating device 20 propagates the second beam in TE mode and generates a corresponding exit beam.
In step S07, the wavelength of the source beam generated by the light source 101 is set to a minimum value. The exit angle of the exit beam generated by the first waveguide 23 of the grating device 20 corresponds to the wavelength.
In step S08, the light source 101 is adjusted to change the wavelength of the source beam over time. The exit angle of the exit beam generated by the first waveguide 23 of the grating device 20 corresponds to the wavelength.
In step S09, the light detection module 105 acquires the reflected light beam reflected from the object and generates a detection signal.
In step S10, it is determined whether the wavelength of the source light beam generated by the light source 101 has reached the maximum value, and if not, steps S08 to S10 are repeated, and if yes, the process returns to step S01.
Fig. 13 shows a schematic block diagram of a lidar in accordance with a seventh embodiment of the invention. Lidar 2000 includes a light source 103, a light emitting module 410, a lens 104, a light detection module 205, and a signal processing module 206. The internal structure of the optical transmission module 410 is shown in fig. 8, in which a polarization beam splitter 411 simultaneously supplies a first light beam of a TE mode and a second light beam of a TM mode.
In this embodiment, where lidar 2000 is a flash lidar, light source 103 may generate a broadband light beam at multiple wavelengths. The optical transmitter module 410 is connected to the light source 103 to receive the source light beam and generate a plurality of outgoing light beams with outgoing angle values corresponding to a plurality of wavelengths by diffraction, wherein the outgoing light beams irradiate on the object 108. The lens 104 is positioned between the object 108 and the light detection module 205 for enhancing the intensity of the reflected light beam. The light detection module 205 is, for example, an array detection module including a plurality of detection units, respectively acquires reflected light beams of respective wavelengths reflected from an object and generates detection signals. The signal processing module 206 is connected to the light detection module 205 to acquire a detection signal, and performs signal processing to obtain the distance of the object 108.
Fig. 14 is a flowchart showing a part of the steps of a light detection method of a laser radar according to a seventh embodiment of the present invention. The method is applied to the laser radar 2000 shown in fig. 13, in which the light source 103 can simultaneously generate broadband light beams of a plurality of wavelengths, and the structure of the light emitting module 410 is shown in fig. 8.
As described above, the light detection method includes generating an outgoing light beam and detecting a reflected light beam, and further includes the following steps S01 to S03.
In step S01, the polarization splitter 411 in the optical transmission module 410 simultaneously provides the first light beam of the TE mode of the multiple wavelengths and the second light beam of the TM mode of the multiple wavelengths.
In step S02, the grating device 20 in the light emitting module 410 simultaneously emits the first light beam of the TE mode and the second light beam of the TM mode.
In step S03, the light detection module 205 acquires a plurality of reflected light beams reflected from the object and generates a plurality of detection signals.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.

Claims (21)

1. A grating device, comprising:
a substrate;
a barrier layer on the substrate;
a first waveguide over a first region of the barrier layer; and
a second waveguide over a second region of the barrier layer,
wherein the grating device selectively propagates a first light beam in the first waveguide and/or a second light beam in the second waveguide, the first and second light beams propagating in opposite directions to each other, an exit light beam changing the propagation direction being obtained by diffraction, the first and second light beams being respectively TE mode and TM mode and having unequal exit angles at least one wavelength.
2. The grating device of claim 1, wherein the first and second waveguides are each an array of a plurality of strips parallel to each other and perpendicular to a direction of propagation of the first and second light beams.
3. The grating device of claim 2, wherein a fill factor of the first waveguide is greater than a fill factor of the second waveguide, the fill factor being a ratio between a width of the plurality of stripes and a repetition period.
4. The grating device according to claim 1, wherein the exit angle of the exit beam is modulated according to the wavelength of the first and second beams.
5. The grating device according to claim 4, wherein the first light beam produces an exit beam of a first exit angle range and the second light beam produces an exit beam of a second exit angle range, the first exit angle range being separate, continuous or partially overlapping with the second exit angle range.
6. The grating device of claim 1, further comprising: a slot for separating the first waveguide and the second waveguide.
7. The grating device of claim 1, further comprising: a cladding layer over the first waveguide and the second waveguide.
8. An optical transmit module comprising:
a polarization controller for generating a first beam in a TE mode and a second beam in a TM mode from the source beam; and
at least one grating device connected to the polarization controller to obtain the first beam and the second beam,
wherein the at least one grating device respectively comprises:
a substrate;
a barrier layer on the substrate;
a first waveguide over a first region of the barrier layer; and
a second waveguide over a second region of the barrier layer,
the at least one grating device selectively propagates a first light beam in the first waveguide and/or a second light beam in the second waveguide, the first and second light beams propagating in opposite directions to each other, an exit light beam changing the propagation direction being obtained by diffraction, the exit angles of the first and second light beams at least one wavelength being unequal.
9. The optical transmit module of claim 8, wherein the source light beam is polarized light in one of a TE mode and a TM mode, the polarization controller comprising:
an optical switch for selectively providing a source beam to the first path or the second path, the source beam being the first beam; and
a polarization rotator connected to the optical switch via the second path and converting the source beam into a second beam of light of a different polarization mode,
wherein the optical switch provides the first optical beam to the first waveguide via the first path and the polarization rotator provides the second optical beam to the second waveguide via a third path.
10. The optical transmit module of claim 8, wherein the source light beam is TE mode and TM mode tunable polarized light, the polarization controller comprising:
an optical switch connected to the first waveguide via a first path and to the second waveguide via a second path,
wherein the optical switch provides the TE mode source beam to the first path as a first beam and the TM mode source beam to the second path as a second beam.
11. The optical transmit module of claim 8, wherein the source light beam is unpolarized light, the polarization controller comprising:
a polarization splitter connected to the first waveguide via a first path and to the second waveguide via a second path,
wherein the polarizing beam splitter provides a first path for a first beam that polarizes the source beam in the TE mode and a second path for a second beam that polarizes the source beam in the TM mode.
12. The light emitting module of claim 8, wherein the at least one grating device comprises a plurality of grating devices sharing the substrate and the blocking layer.
13. The optical transmit module of claim 12, further comprising:
a first beam splitter connected between the polarization controller and the plurality of grating devices for splitting the first light beam into a plurality of beams to be provided to respective first waveguides of the plurality of grating devices; and
a second beam splitter connected between the polarization controller and the plurality of grating devices for splitting the second light beam into a plurality of beams to be provided to respective second waveguides of the plurality of grating devices.
14. An optical transmit module as claimed in claim 8, wherein the exit angle of the exit beam is modulated in dependence on the wavelength of the first and second beams.
15. An optical transmit module as claimed in claim 14, wherein the first light beam produces an output light beam of a first output angular range and the second light beam produces an output light beam of a second output angular range, the first output angular range being separate from, continuous with or partially overlapping with the second output angular range.
16. A method of light detection, comprising:
generating a first light beam and a second light beam with different polarization modes by using the source light beam;
selectively propagating a first light beam in a first waveguide and/or a second light beam in a second waveguide, the first and second light beams propagating in opposite directions to each other to produce an emergent beam having an emergent angle corresponding to a wavelength and polarization mode of the first and second light beams;
irradiating the object with the emergent light beam;
acquiring a reflected light beam from the object to generate a detection signal; and
performing signal processing on the detection signal to obtain a distance of the object,
wherein the first and second light beams have unequal exit angles at least one wavelength.
17. The light detection method of claim 16, wherein the source light beam is polarized in one of a TE mode and a TM mode, the generating an exit light beam step comprising:
selectively providing a source beam to the first path or the second path, the source beam being the first beam;
converting the source light beam into a second light beam of a different polarization mode;
providing the first light beam to the first waveguide via the first path; and
providing the second light beam to the second waveguide via the second path.
18. The light detection method of claim 16, wherein the source beam is a TE mode and TM mode tunable polarized light, and the step of generating the exit beam comprises:
providing a source beam of TE mode to a first path as a first beam; and
the TM mode source beam is provided as a second beam.
19. The light detection method of claim 16, wherein the source beam is a broadband beam, the generating an exit beam step comprising:
providing a first light beam that polarizes the source light beam into a TE mode to a first path; and
polarizing the source beam to a second beam of TM mode provides a second path.
20. The light detection method of claim 16 wherein the exit angle of the exit beam is modulated according to the wavelength of the first and second beams.
21. The light detection method of claim 20 wherein the first light beam produces an exit light beam of a first exit angular range and the second light beam produces an exit light beam of a second exit angular range, the first exit angular range being separate from, continuous with, or partially overlapping the second exit angular range.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102402019A (en) * 2011-12-14 2012-04-04 北京大学 Polarization beam splitter based on sub-wavelength fully etched grating
US9019509B2 (en) * 2013-06-28 2015-04-28 The Charles Stark Draper Laboratory, Inc. Chip-scale star tracker
CN106842232A (en) * 2016-12-12 2017-06-13 清华大学 A kind of laser radar apparatus and detection method
CN108700790A (en) * 2016-01-22 2018-10-23 国立大学法人横浜国立大学 Light deflector and laser radar apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108303701A (en) * 2018-01-19 2018-07-20 上海禾赛光电科技有限公司 Laser radar system, the launching technique of laser pulse and medium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102402019A (en) * 2011-12-14 2012-04-04 北京大学 Polarization beam splitter based on sub-wavelength fully etched grating
US9019509B2 (en) * 2013-06-28 2015-04-28 The Charles Stark Draper Laboratory, Inc. Chip-scale star tracker
CN108700790A (en) * 2016-01-22 2018-10-23 国立大学法人横浜国立大学 Light deflector and laser radar apparatus
CN106842232A (en) * 2016-12-12 2017-06-13 清华大学 A kind of laser radar apparatus and detection method

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