Scanning lidar system and method with spatial filtering for reduction of ambient light
According to one aspect, an optical transceiver includes a substrate and a laser fixed to a first surface of the substrate, the laser generating output light for transmission along a transmission axis into a region. An optical detection element is fixed to a second surface of the substrate opposite the first surface, the optical detection element receiving input light reflected from the region along a reception axis through an opening in the substrate between the first and second surfaces of the substrate, the transmission axis and the reception axis being substantially parallel.
1. An optical transceiver device, comprising:
a substrate;
a laser fixed to a first surface of the substrate, the laser generating output light for transmission along a transmission axis into a region;
an optical detection element fixed to a second surface of the substrate opposite the first surface, the optical detection element receiving input light reflected from the region along a reception axis through an opening in the substrate between the first and second surfaces of the substrate; and
a beam splitting device fixed to and in direct contact with the first surface of the substrate at the opening in the substrate, the transmission axis and the reception axis contacting a surface of the beam splitting device, and the transmission axis and the reception axis being substantially parallel to each other where they contact the surface of the beam splitting device.
2. The optical transceiver device of claim 1 , wherein the transmission axis and the reception axis are substantially the same axis.
3. The optical transceiver device of claim 1 , further comprising a mask having at least one slit aligned with the opening in the substrate, such that the reflected light received by the detection element from the region passes through the slit.
4. The optical transceiver device of claim 3 , wherein the mask is formed at the first surface of the substrate.
5. The optical transceiver device of claim 3 , wherein the mask is formed at the second surface of the substrate.
6. The optical transceiver device of claim 1 , further comprising a bandpass filter, the light returning from the region impinging on the bandpass filter such that the light returning from the region is filtered by the bandpass filter.
7. The optical transceiver device of claim 6 , wherein the bandpass filter has a wavelength pass band which drifts with temperature, the bandpass filter being selected such that temperature drift of the pass band of the bandpass filter is determined according to temperature drift of a wavelength of the output light.
8. The optical transceiver device of claim 1 , wherein the optical detection element comprises a silicon photomultiplier (SiPM) detector.
9. The optical transceiver device of claim 1 , wherein the optical detection element comprises a multi-pixel photon counter (MPPC) detector.
10. The optical transceiver device of claim 9 , further comprising a mask having at least one slit aligned with the opening in the substrate, such that the reflected light received by the detector from the region passes through the slit before it reaches the detector.
11. The optical transceiver device of claim 10 , wherein the mask is formed at the first surface of the substrate.
12. The optical transceiver device of claim 10 , wherein the mask is formed at the second surface of the substrate.
13. The optical transceiver device of claim 1 , further comprising a polarizing beam splitter in an optical path between the laser and the detector, both the output light and the input light at least partially passing through the polarizing beam splitter.
14. The optical transceiver device of claim 1 , further comprising a polarizing beam splitter in an optical path between the laser and the detector, at least one of the output light and the input light at least partially passing through the polarizing beam splitter.
15. The optical transceiver device of claim 1 , further comprising a plurality of lasers fixed to a first surface of the substrate, the output light including a respective plurality of light beams generated by the plurality of lasers.
16. The optical transceiver device of claim 15 , further comprising a scanning device for scanning the plurality of light beams over the region.
17. The optical transceiver device of claim 16 , wherein the scanning device comprises a scanning mirror.
18. The optical transceiver device of claim 17 , wherein the scanning mirror is a micro-electromechanical system (MEMS) scanning mirror.
19. The optical transceiver device of claim 1 , wherein the optical detection element comprises an array of optical detectors.
20. The optical transceiver device of claim 19 , wherein the optical detectors comprise a silicon photomultiplier (SiPM).
21. The optical transceiver device of claim 19 , wherein the optical detectors comprise a multi-pixel photon counter (MPPC).
22. The optical transceiver device of claim 19 , wherein the array of optical detectors is a two-dimensional array.
23. The optical transceiver device of claim 1 , wherein the optical transceiver device is part of an automotive LiDAR detection system.
24. The optical transceiver device of claim 23 , wherein the LiDAR detection system is a coaxial system.