Laser system for Lidar

1. A laser system comprising:

a seed laser configured to produce a sequence of seed light pulses, wherein the sequence of seed light pulses is produced with variable time intervals in a sweep cycle;

a pump laser configured to produce a pump light;

a fiber amplifier coupled to the seed laser and the pump laser; and

an adjustment laser configured to produce an adjustment light to be supplied to the fiber amplifier, wherein the adjustment light has a wavelength different from the seed light pulses and consumes population inversion in the fiber amplifier thereby attenuating a power of a light beam output by the fiber amplifier.

2. The laser system of claim 1 , wherein the adjustment light is generated when the output light beams of the laser system are detected having a power greater than a pre-determined threshold.

3. The laser system of claim 1 , wherein the adjustment light is generated when the output light beams of the laser system are detected having a power greater than a pre-determined threshold over a period of time.

4. The laser system of claim 1 , wherein the adjustment light is generated in response to receiving a position signal indicating a start or end of the sweep cycle.

5. The laser system of claim 1 , further comprising a Raman gain fiber connected to the output end of the fiber amplifier.

6. The laser system of claim 5 , further comprising a filter positioned at the output end of the Raman gain fiber to remove unwanted light output from the Raman gain fiber.

7. The laser system of claim 1 , wherein the sweep cycle corresponds to a scanning cycle along a fast scanning direction.

8. The laser system of claim 1 , wherein the pump light has constant amplitude.

9. The laser system of claim 1 , wherein the pump light has variable amplitude.

10. The laser system of claim 1 , further comprising a control unit configured to generate a command to the pump laser to synchronize the pump light with the sequence of seed light pulses.

11. The laser system of claim 10 , wherein the command is generated in response to receiving a position signal wherein the position signal is generated by a positional sensor of a scanner.

12. The laser system of claim 10 , wherein the control unit is configured to generate commands to both the adjustment laser and the pump laser.

13. A Lidar system comprising the laser system of claim 1 , wherein the Lidar system comprises a scanner, and light beams outputted from the laser system are directed to the scanner.

14. The Lidar system of claim 13 , wherein the scanner comprises a position sensor configured to measure an angle of a scanning mirror of the scanner.

15. The Lidar system of claim 14 , wherein the position sensor is an optic position sensor or positional sensitive detector.

16. The laser system of claim 1 , further comprising a filter to remove unwanted light output from the laser system.