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EP-4740040-A2 - COMBINING MULTIBAND SIGNALS IN LIDAR SYSTEMS

EP4740040A2EP 4740040 A2EP4740040 A2EP 4740040A2EP-4740040-A2

Abstract

The LIDAR system outputs a system output signal and receives a system return signal that includes light from the system output signal that was reflected by an object located outside of the LIDAR system. The LIDAR system includes data lines that each carries a different preliminary channel signal. A selection of the preliminary channel signals is beating at a beat frequency. Each of the preliminary channel signals in the selection of the preliminary channel signals is generated from light included in the system return signal. The LIDAR system includes bandpass filter components. Each of the bandpass filter components receives a different one of the preliminary channel signals and outputs a channel signal on a different filtered data line. The channel signal output by each of the bandpass filter components is a representation of the preliminary channel signal received by the bandpass filter component filtered by one or more bandpass filters included in the bandpass filter component.

Inventors

  • BEHROOZPOUR, Behnam
  • ASGHARI, MEHDI

Assignees

  • SiLC Technologies, Inc.

Dates

Publication Date
20260513
Application Date
20240808

Claims (15)

  1. 1. A system, comprising: a LIDAR system configured to output a system output signal and to receive a system return signal that includes light from the system output signal that was reflected by an object located outside of the LIDAR system; the LIDAR system including data lines that each carries a different preliminary channel signal, a portion of the preliminary channel signals beating at a beat frequency, each of the preliminary channel signals in the portion of the preliminary channel signals being generated from the system return signal; the LIDAR system including bandpass filter components that each receive a different one of the preliminary channel signals and outputs a channel signal on a different filtered data line, the channel signal output by each of the bandpass filter components being a representation of the preliminary channel signal received by the bandpass filter component filtered by one or more bandpass filters included in the bandpass filter component.
  2. 2. The system of claim 1 , wherein each of the bandpass filters has a passband with a different range of frequencies.
  3. 3. The system of claim 2, wherein the frequency ranges of the passbands from different bandpass filters overlap.
  4. 4. The system of claim 1, wherein the LIDAR system includes multiple channel waveguides and a selection of the channel waveguides receives the LIDAR input signal, the LIDAR input signal includes light from the system return signal, and the selection of the channel waveguides that receives the LIDAR input signal changes in response to changes in the location of the object relative to the LIDAR system.
  5. 5. The system of claim 4, wherein the portion of the preliminary channel signals beating at the beat frequency changes in response to changes in the selection of the channel waveguides that receives the LIDAR input signal.
  6. 6. The system of claim 4, wherein the portion of the LIDAR input signal received by one of the channel waveguides serves as a comparative signal, each of the channel waveguides can be associated with a channel index with a value from m=l to M and each of the data lines can also be associated with one of the channel indices, each of the preliminary data signals being generated from a different one of the comparative signals, the preliminary data signal carried by each of the data lines being generated from the comparative signal that is guided by the channel waveguide associated with the same channel index as the data line carry ing the preliminary data signal, and the channel indices for the data lines that carry the portion of the preliminary channel signals beating at the beat frequency matching the channel indices for the portion of the channel waveguides that receives the LIDAR input signal.
  7. 7. The system of claim 1, wherein the LIDAR system includes a signal adder configured to add the channel signal together.
  8. 8. The system of claim 1, wherein the LIDAR system includes electronics that include a beat frequency identifier configured to calculate the beat frequency.
  9. 9. The system of claim 1, wherein each of the bandpass filter components includes a current mirror and each of the current mirrors includes the one or more bandpass filters included in the bandpass filter component, each current mirror configured such that the channel signal output by each bandpass filter component is a copy of the preliminary channel signal received by the bandpass filter component.
  10. 10. The system of claim 1, wherein the current mirrors each include a filter line connecting the gates of different transistors or connecting the bases of different transistors.
  11. 11. The system of claim 10, wherein one of the bandpass filters is positioned along each of filter lines.
  12. 12. The system of claim 1, wherein the channel waveguides are configured such that a range of the beat frequencies carried by each of the preliminary data signals is different.
  13. 13. The system of claim 12, wherein each of the bandpass filters has a passband that encompasses the range of beat frequencies for the preliminary data signal received by the bandpass filter component that includes the bandpass filter.
  14. 14. The system of claim 1. wherein a portion of the preliminary channel signals is not beating at the beat frequency.
  15. 15. The system of claim 14, wherein the portion of the preliminary channel signals beating at the beat frequency changes in response to changes in a location of the object relative to the LIDAR system.

Description

COMBINING MULTIBAND SIGNALS IN LIDAR SYSTEMS RELATED APPLICATIONS [0001] This application is a continuation of U.S. Patent Application No. 18/241,766, filed September 1, 2023, entitled “COMBINING MULTIBAND SIGNALS IN LIDAR SYSTEMS”, and incorporated in its entirety. FIELD [0002] The invention relates to optical devices. In particular, the invention relates to LIDAR systems. BACKGROUND [0003] LIDAR systems output a system output signal. Objects in the path of the system output signal reflect the system output signal. A portion of the reflected light returns to the LIDAR system as a system return signal. The LIDAR system processes the system return signal to generate LIDAR data that indicates a radial velocity and/or distance between the objects and the LIDAR system. [0004] LIDAR systems can be classified as coaxial (sometimes called monostatic) or biaxial (sometimes called bistatic). In a coaxial LIDAR system, the path that the light travels after being output from the LIDAR system is also traveled by the reflected light returning to the LIDAR system. However, in biaxial systems, the path that the light travels after being output from the LIDAR system is different from the path traveled by the reflected light returning to the LIDAR system. [0005] There are a variety of circumstances where biaxial systems are preferable to coaxial systems. For instance, biaxial systems can often have reduced levels of loss in returned light signals. However, LIDAR systems typically include a beam steerer that steers the system output signal to different sample regions in a field of view. In biaxial systems, this change in the direction of the system output signal changes the angle between the returning light and the LIDAR system. This angle change can reduce the collection efficiency for the light returning to the LIDAR system. As a result, there is a need for an improved LIDAR system. SUMMARY [0006] A LIDAR system outputs a system output signal and receives a system return signal that includes light from the system output signal that was reflected by an object located outside of the LIDAR system. The LIDAR system includes data lines that each carries a different preliminary channel signal. A selection of the preliminary channel signals is beating at a beat frequency. Each of the preliminary channel signals in the selection of the preliminary channel signals is generated from light included in the system return signal. The LIDAR system includes bandpass filter components. Each of the bandpass filter components receives a different one of the preliminary channel signals and outputs a channel signal on a different filtered data line. The channel signal output by each of the bandpass filter components is a representation of the preliminary channel signal received by the bandpass filter component filtered by one or more bandpass filters included in the bandpass filter component. [0007] A LIDAR system outputs a system output signal and receives a sy stem return signal that includes light from the system output signal that was reflected by an object located outside of the LIDAR system. The LIDAR system includes data lines that each carries a different preliminary channel signal. A selection of the preliminary channel signals is beating at a beat frequency. Each of the preliminary channel signals that is included in the selection of the preliminary channel signals is generated from light included in the system return signal. The LIDAR system includes current minors that each receives a different one of the preliminary channel signals and outputs a channel signal on a different filtered data line. Each of the current mirrors includes a bandpass filter positioned such that each channel signal is a copy of one of the preliminary channel signals filtered by one of the bandpass filters. BRIEF DESCRIPTION OF THE FIGURES [0008] Figure 1 A is a topview of a biaxial LIDAR system. [0009] Figure IB is a schematic of a composite signal generator that is suitable for use in a LIDAR chip constructed according to Figure 5A. [0010] Figure 1C is a schematic of an example of a portion of the electronics that are suitable for use with the LIDAR system of Figure 1A. [0011] Figure ID is a graph illustrating the frequency versus time pattern for a system output signal and/or a LIDAR output signal. [0012] Figure 2A is a schematic of an example of a current mirror that serves as a bandpass filtration component. [0013] Figure 2B is a graph illustrating selection of bandpass filters for use in different composite signal generators. [0014] Figure 2C is a schematic of another example of a bandpass filtration component. [0015] Figure 3A through Figure 3F illustrate one possible example of the construction of components that are suitable for use with the LIDAR system. Figure 3A a topview of portion of a LIDAR chip having an interface between a free space region and reference waveguide. [0016] Figure 3B is a cross section of the LIDAR chip shown in Figure 3A