SEED SOURCE FOR HIGH POWER OPTICAL FIBER AMPLIFIER

• US 20110206076A1
• Filed: 08/11/2010
• Published: 08/25/2011
• Est. Priority Date: 01/18/2007
• Status: Abandoned Application

• Current Assignee: ESI-Pyrophotonics Lasers, Inc. (MKS Instruments Incorporated)
• Original Assignee: 6091571 Canada, Inc. (MKS Instruments Incorporated)
• Inventors: Murison, Richard, Reid, Benoit, Boula-Picard, Reynald, Panarello, Tullio
• Application Number:
  US12/854,552
• Publication Number:
  US 20110206076A1
• Time in Patent Office: Days
• US Class Current: 372/28
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 2201/17 Multi-pass arrangements, i.e. arrangements to pass light a plurality of times through the same element, e.g. by using an enhancement cavity
• CPC Class Codes: H01S 2301/03 Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/2308 Amplifier arrangements, e.g. MOPA
• CPC Class Codes: H01S 5/0057 for temporal shaping, e.g. pulse compression, frequency chirping
• CPC Class Codes: H01S 5/0085 for modulating the output, i.e. the laser beam is modulated outside the laser cavity

Abstract

Methods and systems are provided to reduce stimulated Brillouin scattering in high power optical fiber amplifiers. In an embodiment, a seed source includes a narrow linewidth semiconductor laser driven with a current ramp that simultaneously sweeps the optical power and the lasing frequency at a rate fast enough to reduce stimulated Brillouin scattering.

Claims

1. A method of generating laser pulses, the method comprising:

directly modulating a semiconductor laser to generate a plurality of optical pulses, each of the plurality of pulses having a frequency chirp substantially larger than a Brillouin gain bandwidth associated with an optical fiber; and

externally modulating each of the plurality of optical pulses to reduce a duration of each of the plurality of optical pulses.

2. The method of claim 1 wherein externally modulating each of the plurality of optical pulses is performed at a first time as each of the plurality of optical pulses passes through a modulator a first time and at a second time as each of the plurality of optical pulses passes through a modulator a second time.

3. The method of claim 1 wherein each of the plurality of optical pulses are characterized by a single frequency.

4. The method of claim 1 wherein each of the plurality of optical pulses are characterized by a plurality of frequencies.

5. The method of claim 4 wherein a linewidth of each of the plurality of frequencies is less than a Brillouin gain bandwidth of about 30 MHz.

6. The method of claim 1 wherein the frequency chirp is larger than 1 GHz.

7. The method of claim 6 wherein the frequency chirp is larger than about 10 GHz.

8. A method of generating laser pulses, the method comprising:

directly modulating a semiconductor laser to generate a plurality of optical pulses, each of the plurality of pulses having a frequency chirp substantially larger than a Brillouin gain bandwidth associated with an optical fiber;

amplifying the plurality of optical pulses to generate a plurality of amplified optical pulses; and

externally modulating the plurality of amplified optical pulses to reduce a temporal length of each of the plurality of amplified optical pulses.

9. The method of claim 8 wherein each of the plurality of optical pulses are characterized by a single frequency.

10. The method of claim 8 wherein each of the plurality of optical pulses are characterized by a plurality of frequencies.

11. The method of claim 10 wherein a linewidth of each of the plurality of frequencies is less than a Brillouin gain bandwidth.

12. The method of claim 8 wherein externally modulating each of the plurality of optical pulses is performed at a first time as each of the plurality of optical pulses passes through a modulator a first time and at a second time as each of the plurality of optical pulses passes through a modulator a second time.

13. The method of claim 8 wherein the frequency chirp is larger than about 1 GHz.

14. The method of claim 13 wherein the frequency chirp is larger than about 10 GHz.

15. The method of claim 8 wherein amplifying the plurality of optical pulses comprises passing the plurality of optical pulses through an optically pumped optical fiber amplifier including a length of rare-earth-doped optical fiber.