Multi-clad fiber based optical apparatus and methods for light detection and ranging sensors
View Patent ↗Methods and apparatus for light detecting and range sensing. In one approach, a light detecting and ranging (LiDAR) sensor uses an optical directing device; a multi-clad optical fiber, a light source, and a detector. The light source is optically coupled to the multi-clad optical fiber which is configured to receive optical rays transmitted from the light source and route the rays on an optical path leading to the optical directing device. The optical directing device is configured both to direct the transmitted optical rays routed through the multi-clad fiber towards a target to be sensed and direct optical rays reflected from the target on an optical path leading to the multi-clad optical fiber. The multi-clad optical fiber is configured to receive the reflected optical rays and route the reflected optical rays on an optical path leading to the detector. The detector is configured to detect the reflected optical rays.
1. A LiDAR sensor comprising:
a laser;
a single-mode fiber positioned to receive optical rays output from the laser;
an optical circulator comprising a first port, a second port, and a third port, the optical circulator configured to direct optical rays from the first port to the second port and optical rays from the second port to the third port, the optical circulator further positioned to receive optical rays from the single-mode fiber at the first port;
a multi-clad fiber comprising a core, an inner cladding, and an outer cladding, the core positioned to receive optical rays from the second port of the optical circulator and direct the optical rays from the second port toward a target, and the inner cladding positioned to receive optical rays reflected from the target, wherein the core of the multi-clad fiber is positioned to receive optical rays reflected from the target and direct the received optical rays to the second port of the optical circulator;
a first optical detector positioned to receive the optical rays, reflected from the target, from the inner cladding of the multi-clad fiber;
a multi-mode fiber positioned to receive optical rays from the core of the multi-clad fiber via the third port of the optical circulator; and
a second optical detector positioned to receive optical rays from the multi-mode fiber.
2. The LiDAR sensor of claim 1 , further comprising an optical directing device focusing light from the multi-clad fiber toward the target, and focusing reflected light from the target toward the multi-clad fiber.
3. The LiDAR sensor of claim 2 , wherein the optical directing device consists of a single lens.
4. The LiDAR sensor of claim 2 , wherein the optical directing device consists of a single mirror.
5. The LiDAR sensor of claim 2 , wherein the optical directing device comprises at least one lens or mirror, and wherein both outgoing optical rays from the multi-clad fiber and reflected optical rays from the target are directed by the at least one lens or mirror.
6. The LiDAR sensor of claim 2 , further comprising a transverse motion device configured to dynamically change a position of the multi-clad fiber relative to the optical directing device, such that the multi-clad fiber is positioned to direct and receive optical rays from different locations on one or more targets.
7. The LiDAR sensor of claim 6 , wherein the optical directing device focuses light from the multi-clad fiber toward the target and focuses reflected light from the target toward the multi-clad fiber, and wherein the dynamically changing position of the multi-clad fiber substantially maintains a focal relationship with the optical directing device.
8. The LiDAR sensor of claim 6 , wherein the transverse motion is in an oscillatory pattern.
9. The LiDAR sensor of claim 8 , wherein the transverse motion oscillates at a frequency between 5 Hz and 5000 Hz.
10. The LiDAR sensor of claim 1 , wherein the first and the second optical detectors comprise avalanche photodiodes.
11. The LiDAR sensor of claim 1 , wherein the LiDAR sensor is a three-dimensional LiDAR sensor.
12. The LiDAR sensor of claim 1 , wherein the inner cladding splits from the multi-clad fiber at a splicing location to direct the optical rays, reflected from the target, to the first optical detector.
13. The LiDAR sensor of claim 1 , wherein the inner cladding directs the optical rays, reflected from the target, to the first optical detector via a plurality of optical coupling elements.
14. The LiDAR sensor of claim 13 , wherein the plurality of optical coupling elements comprises a mirror.
15. The LiDAR sensor of claim 14 , wherein the mirror includes a hole through which the optical rays from the second port are directed to be received by the multi-clad fiber and outputted to the target.
16. The LiDAR sensor of claim 14 , wherein the plurality of optical coupling elements further comprises a plurality of lenses.
17. A compound LiDAR sensor, comprising a plurality of LiDAR sensors, each of the plurality of LiDAR sensors comprising:
a laser;
a single-mode fiber positioned to receive optical rays output from the laser;
an optical circulator comprising a first port, a second port, and a third port, the optical circulator configured to direct optical rays from the first port to the second port and optical rays from the second port to the third port, the optical circulator further positioned to receive optical rays from the single-mode fiber at the first port;
a multi-clad fiber comprising a core, an inner cladding, and an outer cladding, the core positioned to receive optical rays from the second port of the optical circulator and direct the optical rays from the second port toward a target, and the inner cladding positioned to receive optical rays reflected from the target, wherein the core of the multi-clad fiber is positioned to receive optical rays reflected from the target and direct the received optical rays to the second port of the optical circulator;
a first optical detector positioned to receive the optical rays, reflected from the target, from the inner cladding of the multi-clad fiber;
a multi-mode fiber positioned to receive optical rays from the core of the multi-clad fiber via the third port of the optical circulator; and
a second optical detector positioned to receive optical rays from the multi-mode fiber.
18. The compound LiDAR sensor of claim 17 , each of the plurality of LiDAR sensors further comprising:
an optical directing device focusing optical rays from the multi-clad fiber toward the target and focusing optical rays reflected by the target toward the multi-clad fiber.