Method and apparatus for a hybrid mode-locked fiber laser

• US 8,630,320 B2
• Filed: 08/29/2008
• Issued: 01/14/2014
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: LadarSystems, Inc.
• Original Assignee: Deep Photonics Corporation
• Inventors: Munroe, Michael J., Dutton, David A., LaChapelle, Joseph G.
• Primary Examiner(s): Rodriguez, Armando
• Application Number:
  US12/202,002
• Publication Number:
  US 20090107962A1
• Time in Patent Office: 1,964 Days
• Field of Search: 372/6, 372/18, 372/25, 372/26
• US Class Current: 372/6
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence

Abstract

An apparatus for producing coherent pulsed light with a fiber-based master oscillator/fiber amplifier architecture includes a fiber-coupled mode-locked laser source. The fiber-coupled mode-locked laser source is configured to provide pulses having a pulse duration of less than 1 ns. The apparatus also includes a fiber-coupled amplitude modulator optically coupled to the fiber-coupled mode-locked laser source. The fiber-coupled amplitude modulator is capable of gate durations greater than 1 ns. The apparatus further includes a saturated fiber power amplifier optically coupled to the fiber-coupled amplitude modulator.

Claims

1. An apparatus for producing coherent pulsed light with a fiber-based master oscillator/fiber amplifier architecture, the apparatus comprising:

a fiber-coupled mode-locked laser source configured to provide pulses having a pulse duration of less than 1 ns;

a fiber-coupled amplitude modulator optically coupled to the fiber-coupled mode-locked laser source, the fiber-coupled amplitude modulator configured for gate durations greater than 1 ns to deliver gated pulse packets having more than one pulse per pulse packet; and

a fiber power amplifier optically coupled to the fiber-coupled amplitude modulator and configured for operating in a saturated mode from the pulse packets,

wherein the fiber-coupled amplitude modulator comprises at least one of a Mach-Zehnder modulator or an acousto-optic modulator, each modulator configured to deliver gated pulse packets having more than one pulse per pulse packet.

2. The apparatus of claim 1 wherein a wavelength of operation of the fiber-coupled mode-locked laser source ranges from about 1015 nm to about 1085 nm.

3. The apparatus of claim 1 wherein the fiber-coupled mode-locked laser source comprises a rare earth doped active fiber.

4. The apparatus of claim 1 wherein the fiber power amplifier comprises:

a preamplifier fiber gain stage optically coupled to the fiber-coupled amplitude modulator; and

an amplifier fiber gain stage optically coupled to the preamplifier fiber gain stage.

5. The apparatus of claim 1 further comprising a pulse compressor optically coupled to the fiber power amplifier.

6. The apparatus of claim 1 further comprising one or more frequency conversion stages optically coupled to the fiber power amplifier.

7. The apparatus of claim 5 wherein the one or more frequency conversion stages comprises a nonlinear crystal.

8. An apparatus for producing coherent pulsed light with a fiber-based master oscillator/fiber amplifier architecture, the apparatus comprising:

a fiber-coupled mode-locked laser source configured to provide pulses having a pulse duration of less than 1 ns and comprising a rare earth doped active fiber;

a fiber-coupled amplitude modulator optically coupled to the fiber-coupled mode-locked laser source, the fiber-coupled amplitude modulator configured for gate durations greater than 1 ns to deliver gated pulse packets having more than one pulse per pulse packet; and

a fiber power amplifier optically coupled to the fiber-coupled amplitude modulator and configured for operating in a saturated mode from the pulse packets.

9. The apparatus of claim 8 wherein a wavelength of operation of the fiber-coupled mode-locked laser source ranges from about 1015 nm to about 1085 nm.

10. The apparatus of claim 8 wherein the fiber-coupled amplitude modulator comprises at least one of a Mach-Zehnder modulator or an acousto-optic modulator, each modulator configured to deliver gated pulse packets having more than one pulse per pulse packet.

11. The apparatus of claim 8 wherein the fiber power amplifier comprises:

a preamplifier fiber gain stage optically coupled to the fiber-coupled amplitude modulator; and

an amplifier fiber gain stage optically coupled to the preamplifier fiber gain stage.

12. The apparatus of claim 8 further comprising a pulse compressor optically coupled to the fiber power amplifier.

13. The apparatus of claim 8 further comprising one or more frequency conversion stages optically coupled to the fiber power amplifier.

14. The apparatus of claim 13 wherein the one or more frequency conversion stages comprises a nonlinear crystal.

15. A method for producing coherent pulsed light with a fiber-based master oscillator/fiber amplifier architecture, the method comprising:

providing electromagnetic radiation pulses having a pulse duration of less than 1 ns from a fiber-coupled mode-locked laser source;

gating the electromagnetic radiation for a duration longer than 1 ns into gated pulse packets such that each pulse packet includes multiple electromagnetic radiation pulses; and

saturating a fiber power amplifier with the pulse packets to produce a coherent laser beam from the fiber power amplifier,

wherein the gating is performed by at least one of a Mach-Zehnder modulator or an acousto-optic modulator.

16. The method of claim 15 wherein a wavelength of the electromagnetic radiation pulses from the fiber-coupled mode-locked laser source ranges from about 1015 nm to about 1085 nm.

17. The method of claim 15 further comprising:

preamplifying the pulse packets in a fiber preamplifier gain stage; and

amplifying the preamplified pulse packets in an amplifier fiber gain stage.

18. The method of claim 15 further comprising:

compressing peaks in the coherent laser beam from the fiber power amplifier.

19. The method of claim 15 further comprising:

converting a frequency of peaks in the coherent laser beam from the fiber power amplifier.