Transceiver apparatus, method and applications
View Patent ↗A transceiver for use in a lidar system includes an optical receiver and a transmitter. The optical receiver includes a circuit board including a detector, a cylindrical inner housing, a C-shaped outer housing that partially surrounds the inner housing, and a lens in the outer housing. The transmitter includes an optical fiber coupled to a light source and a collimator, and a pair of Risley prism rods for adjusting collimator alignment. The collimator and Risley rods sit in a groove formed by the inner housing and the outer housing. A lidar system using the transceiver and a transceiver assembly method are disclosed.
1. A transceiver, comprising:
an optical receiver comprising:
a circuit board including a detector configured to detect received light;
an inner housing having a first end attached to the circuit board and an opposing second end, wherein the inner housing encompasses the detector;
an outer housing that at least partially surrounds the inner housing, wherein an elongate groove or shelf is formed along a longitudinal intersection of the inner housing and the outer housing; and
a lens disposed in the outer housing adjacent the second end of the inner housing.
2. The transceiver of claim 1 , wherein the inner housing is a hollow cylinder, wherein the first end of the inner housing is centered about the detector.
3. The transceiver of claim 1 , wherein the outer housing is a partial, elongate, hollow cylinder having a C-shaped cross section.
4. The transceiver of claim 1 , wherein the outer housing has an inner diameter that is up to 2% larger than an outer diameter of the inner housing.
5. The transceiver of claim 1 , wherein the outer housing is slidably engageable over at least a portion of the inner housing.
6. The transceiver of claim 1 , wherein the circuit board, the inner housing, the outer housing, and the lens are characterized by substantially equal coefficients of thermal expansion.
7. The transceiver of claim 1 , further comprising a window hermetically attached to the second end of the inner housing, wherein the circuit board, the inner housing, and the window form a hermetically sealed volume that encloses the detector.
8. The transceiver of claim 7 , wherein a fluid is disposed within the hermetically sealed volume, wherein the fluid is at least one of an inert gas and dry air having a moisture content less than or equal to 2%.
9. The transceiver claim 1 , wherein the detector is bonded to an integrated circuit that is attached to the circuit board.
10. The transceiver of claim 1 , wherein the detector is an avalanche photodiode (APD).
11. The transceiver of claim 1 , further comprising an optical filter having a selected transmission bandwidth.
12. The transceiver of claim 1 , further comprising:
a transmitter configured to produce a transmission beam, comprising:
a transmission beam propagation medium; and
a collimator coupled to an output of the transmission beam propagation medium,
wherein the detector is configured to detect a portion of the transmission beam that is incident on and scattered by an object external to the transceiver assembly.
13. The transceiver of claim 12 , further comprising a transmission beam alignment component.
14. The transceiver of claim 13 , wherein the transmission beam alignment component is a prismatic component.
15. The transceiver of claim 14 , wherein the prismatic component includes a Risley prism.
16. The transceiver of claim 14 , wherein the prismatic component is two Risley prism rods linearly disposed adjacent an output end of the collimator.
17. The transceiver of claim 13 , wherein the transmission beam alignment component is a collimator holder connected to a portion of the outer housing.
18. The transceiver of claim 17 , wherein the collimator holder has an opening into which the collimator can be disposed in an adjustable manner.
19. The transceiver of claim 18 , wherein the opening has a tapered volume.
20. The transceiver of claim 19 , wherein the tapered volume provides at least one pivot collimator alignment point in contact with the collimator.
21. The transceiver of claim 12 , wherein the collimator is disposed in the elongate groove or shelf.
22. The transceiver of claim 12 , wherein the transmission beam propagation medium is an optical fiber.
23. The transceiver of claim 12 , wherein the transmission beam comprises pulses of light having:
a wavelength between 1400 nanometers and 1600 nanometers;
a pulse energy of less than 10 microjoules;
a pulse repetition frequency of less than 10 MHz; and
a pulse duration of 0.1 nanoseconds to 100 nanoseconds.
24. The transceiver of claim 12 , further comprising:
a second transmitter; and
a second detector.
25. The transceiver of claim 12 , wherein the transceiver is part of a lidar system comprising a scanner configured to scan the transmission beam across a field of regard of the lidar system.
26. A transceiver assembly method, comprising:
providing a circuit board including a light-sensitive detector;
providing an inner housing having a first end and an opposing second end;
providing an outer housing that is sized and shaped to at least partially surround the inner housing;
providing a lens;
attaching the inner housing to the circuit board at the first end in a manner to encompass the detector;
installing the lens into the outer housing, whereupon assembly, the lens is configured to focus a received light onto the detector;
sliding the outer housing over a portion of the inner housing;
translating the outer housing to a location such that the lens will focus the received light onto the detector; and
affixing the outer housing to the inner housing, wherein an elongate groove or shelf is formed along a longitudinal intersection of the inner housing and the outer housing.
27. The transceiver assembly method of claim 26 , further comprising:
attaching a window to the second end of the inner housing, wherein the circuit board, the inner housing, and the window form a hermetically sealed volume that encloses the detector.
28. The transceiver assembly method of claim 26 , further comprising:
providing a collimator and a collimator alignment receptacle attached to the outer housing, wherein the collimator alignment receptacle has an opening into which the collimator can be slidingly engaged;
aligning the collimator; and
affixing the collimator in the alignment receptacle.
29. The transceiver assembly method of claim 28 , wherein the alignment receptacle opening has a tapered volume that provides at least one pivot collimator alignment point; and
pivoting the collimator about the at least one pivot collimator alignment point.
30. The transceiver assembly method of claim 26 , further comprising:
providing a collimator and a plurality of Risley prism rods;
disposing the collimator and the plurality of Risley prism rods in the elongate groove or shelf;
rotating at least one of the Risley prism rods for aligning a transmission output from the collimator; and
affixing the aligned collimator and Risley prism rods in the elongate groove.