Systems and methods for controlling a pulsed laser by combining laser signals

• US 20100040095A1
• Filed: 08/18/2008
• Published: 02/18/2010
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: Rayd LLC
• Original Assignee: Raydiance, Inc. (Coherent Corp.)
• Inventors: Tong, Sha, Mielke, Michael M., Chang, Kok Wai, Waarts, Robert G.
• Granted Patent: US 8,125,704 B2
• Time in Patent Office: Days
• US Class Current: 372/25
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/10046 Pulse repetition rate control H01S3/11 takes precedence
• CPC Class Codes: H01S 3/10061 Polarization control
• CPC Class Codes: H01S 3/1302 by all-optical means, e.g. gain-clamping
• CPC Class Codes: H01S 3/2308 Amplifier arrangements, e.g. MOPA
• CPC Class Codes: H01S 3/2383 Parallel arrangements

Abstract

An ultra-short pulsed laser system comprises an optical combiner, optical amplifier, optical pulse compressor, and optical separator. The optical combiner is configured to combine a primary optical pulse with a secondary optical signal to generate a combined optical signal. The primary optical pulse and the secondary optical signal have a distinguishable characteristic. The optical amplifier is configured to optically amplify the combined optical signal. The optical pulse compressor is configured to compress at least the primary optical pulse contained within the optically amplified combined optical signal and output a compressed combined optical signal. The optical separator is configured to separate the compressed combined optical signal into an output primary optical pulse and an output secondary optical signal according to the distinguishable characteristic.

Claims

1. An ultra-short pulsed laser system, comprising:

an optical combiner configured to combine a primary optical pulse with a secondary optical signal to generate a combined optical signal, the primary optical pulse and the secondary optical signal having a distinguishable characteristic;

an optical amplifier configured to optically amplify the combined optical signal to generate an optically amplified combined optical signal;

an optical pulse compressor configured to compress at least the primary optical pulse contained within the optically amplified combined optical signal and output a compressed combined optical signal; and

an optical separator configured to separate the compressed combined optical signal into an output primary optical pulse and an output secondary optical signal according to the distinguishable characteristic.

2. The ultra-short pulsed laser system of claim 1, further comprising an optical source configured to generate the secondary optical signal using the primary optical pulse.

3. The ultra-short pulsed laser system of claim 1, wherein the secondary optical signal comprises a pulsed optical signal.

4. The ultra-short pulsed laser system of claim 3, wherein the pulsed optical signal is configured to be temporally displaced from the primary optical pulse such that the pulsed optical signal and the primary optical pulse do not overlap.

5. The ultra-short pulsed laser system of claim 3, wherein the pulsed optical signal has a temporal duration of greater than five times a temporal duration of the primary optical pulse.

6. The ultra-short pulsed laser system of claim 3, further comprising a controller configured to control a repetition rate of the pulsed optical signal according to a repetition rate of the primary optical pulse.

7. The ultra-short pulsed laser system of claim 3, further comprising an optical switch configured to permit either the pulsed optical signal or the primary optical pulse to be output to the optical amplifier during a given time window.

8. The ultra-short pulsed laser system of claim 1, wherein the distinguishable characteristic is wavelength.

9. The ultra-short pulsed laser system of claim 1, wherein a central wavelength of the secondary optical signal is outside a gain bandwidth of the optical amplifier.

10. The ultra-short pulsed laser system of claim 1, wherein the distinguishable characteristic is state of polarization.

11. The ultra-short pulsed laser system of claim 1, wherein the optical combiner comprises a polarization switch configured to generate the primary optical pulse and the secondary optical signal from a same optical pulse train.

12. The ultra-short pulsed laser system of claim 1, wherein the optical separator comprises an optical switch configured to selectively output the output primary optical pulse or the output secondary optical signal.

13. The ultra-short pulsed laser system of claim 1, wherein the optical amplifier comprises an optical fiber amplifier.

14. The ultra-short pulsed laser system of claim 1, wherein the optical amplifier comprises a polarization maintaining optical fiber.

15. The ultra-short pulsed laser system of claim 1, wherein the primary optical pulse comprises a chirped optical pulse.

16. The ultra-short pulsed laser system of claim 15, further comprising an optical pulse stretcher configured to chirp a received optical pulse and output the chirped optical pulse.

17. The ultra-short pulsed laser system of claim 16, wherein the optical pulse stretcher comprises an optical fiber.

18. The ultra-short pulsed laser system of claim 16, wherein the optical pulse stretcher comprises a fiber Bragg grating.

19. The ultra-short pulsed laser system of claim 16, wherein the optical pulse stretcher comprises a Bragg waveguide.

20. The ultra-short pulsed laser system of claim 1, wherein the optical pulse compressor includes a bulk optical grating.

21. The ultra-short pulsed laser system of claim 20, wherein the bulk optical grating is actively aligned using feedback provided by the secondary optical signal.

22. The ultra-short pulsed laser system of claim 1, wherein the secondary optical signal is configured to enable the optical amplifier to maintain an approximately equal gain independent of a time duration between individual primary optical pulses.

23. The ultra-short pulsed laser system of claim 1, wherein the optical separator includes a lens arrangement configured to focus the output primary optical pulse at a different distance from the lens arrangement than the output secondary optical signal along a same propagation direction.

24. The ultra-short pulsed laser system of claim 1, wherein the optical separator includes a lens arrangement configured to focus the output primary optical pulse at a first focal point separated by a distance from a second focal point of the output secondary optical signal, the distance configured to enable the first focal point to be used to align the second focal point to a target.

25. A method comprising:

combining a primary optical pulse with a secondary optical pulse into a combined optical signal, the primary optical pulse and the secondary optical pulse having a distinguishable characteristic, and either the primary optical pulse or the secondary optical pulse being present within a single time window out of a sequence of time windows of approximately equal duration;

optically amplifying the combined optical signal using an optical fiber amplifier; and

separating the amplified combined optical signal into an amplified primary optical pulse and an amplified secondary optical pulse according to the distinguishable characteristic.

26. The method of claim 25, further comprising maintaining an approximately constant gain of the optical fiber amplifier independent of a duration of time between two temporally adjacent instances of the primary optical pulse.

27. The method of claim 25, further comprising controlling a repetition rate of the amplified primary optical pulse using a repetition rate of the secondary optical pulse.

28. The method of claim 25, further comprising triggering the secondary optical pulse using the primary optical pulse.

29. The method of claim 25, further comprising dithering a state of polarization of the amplified secondary optical pulse, measuring a state of polarization of the polarization dithered amplified secondary optical pulse, and controlling a state of polarization of the primary optical pulse and a state of polarization of the secondary optical pulse based upon the measured state of polarization of the polarization dithered amplified secondary optical pulse.

30. The method of claim 25, further comprising selecting between the amplified primary optical pulse and the amplified secondary optical pulse, and directing the selected pulse to a target.

31. The method of claim 30, wherein a pulse duration of the amplified primary optical pulse is less than 10 picoseconds and a pulse duration of the amplified secondary optical pulse is greater than 1 nanosecond.