Fiber delivery of short laser pulses

• US 9,774,161 B2
• Filed: 02/18/2015
• Issued: 09/26/2017
• Est. Priority Date: 02/18/2015
• Status: Active Grant

• Current Assignee: TOPTICA Photonics AG
• Original Assignee: TOPTICA Photonics AG
• Inventors: Zach, Armin, Herda, Robert
• Primary Examiner(s): Niu, Xinning
• Application Number:
  US14/624,773
• Publication Number:
  US 20160240997A1
• Time in Patent Office: 951 Days
• CPC Class Codes: H01S 2301/085 solitons
• CPC Class Codes: H01S 2302/02 THz - lasers, i.e. lasers with emission in the wavelength range of typically 0.1 mm to 1 mm
• 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 3/06712 Polarising fibre; Polariser
• CPC Class Codes: H01S 3/06725 Fibre characterized by a specific dispersion, e.g. for pulse shaping in soliton lasers or for dispersion compensating [DCF]
• CPC Class Codes: H01S 3/10061 Polarization control
• CPC Class Codes: H01S 3/108 using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering mode locking using a non-linear element H01S3/1112

Abstract

A method and system for delivering laser pulses achieves the delivery of high quality laser pulses at the location of an application. The method includes the steps of: generating laser pulses, amplifying the laser pulses, temporally stretching the amplified laser pulses, and propagating the amplified laser pulses through an optical delivery fiber of desired length, wherein the laser pulses are temporally compressed in the optical delivery fiber and wherein the laser pulses undergo nonlinear spectral broadening in the optical delivery fiber.

Claims

1. Method for delivering laser pulses, comprising the steps of:

generating laser pulses,

amplifying the laser pulses,

temporally stretching the amplified laser pulses, and

propagating the amplified laser pulses through an optical delivery fiber having a length of at least 2 meters,

wherein the laser pulses are temporally compressed in the optical delivery fiber,

wherein the laser pulses undergo nonlinear spectral broadening in the optical delivery fiber so that the spectrum of the laser pulses is broadened by at least a factor of 1.2 in the optical delivery fiber,

wherein the laser pulses have a first spectral bandwidth before the temporal stretching,

wherein the laser pulses have a second spectral bandwidth at an end of the optical delivery fiber,

wherein the second spectral bandwidth is larger than the first spectral bandwidth, and

wherein the spectral bandwidth of the amplified and temporally stretched laser pulses is 10-50 nm, while the spectral bandwidth of the laser pulses after propagation through the optical delivery fiber is up to 120 nm.

2. Method of claim 1, wherein the pulse duration of the laser pulses at the end of the optical delivery fiber is less than 100 fs.

3. Method of claim 1, wherein the pulse duration of the temporally stretched laser pulses is at least 1 ps.

4. Method of claim 1, wherein the laser pulses are amplified without nonlinear spectral broadening.

5. Method of claim 1, wherein the amplified laser pulses have a parabolic spectrum.

6. Method of claim 1, wherein the energy of the amplified laser pulses is up to 20 nJ.

7. System for delivering laser pulses, comprising:

a laser source generating laser pulses;

an optical amplifier amplifying the laser pulses;

an optical stretcher temporally stretching the amplified laser pulses; and

an optical delivery fiber having a length of at least 2 meters, through which the stretched laser pulses are propagated,

wherein the laser pulses are temporally compressed in the optical delivery fiber,

wherein the laser pulses undergo nonlinear spectral broadening in the optical delivery fiber so that the spectrum of the laser pulses is broadened by at least a factor of 1.2 in the optical delivery fiber, and

wherein the laser pulses have a first spectral bandwidth before the temporal stretching,

wherein the laser pulses have a second spectral bandwidth at an end of the optical delivery fiber,

wherein the second spectral bandwidth is larger than the first spectral bandwidth, and

wherein the spectral bandwidth of the amplified and temporally stretched laser pulses is 10-50 nm, while the spectral bandwidth of the laser pulses after propagation through the optical delivery fiber is up to 120 nm.

8. System of claim 7, wherein the optical amplifier is a parabolic amplifier.

9. System of claim 7, wherein the optical stretcher comprises a section of dispersion compensating optical fiber.

10. System of claim 7, wherein the optical delivery fiber comprises a section of single mode optical fiber having anomalous dispersion.

11. System of claim 7, wherein the optical delivery fiber comprises a section of large mode area fiber.

12. System of claim 7, wherein the length of the optical delivery fiber is at least 5 meters, most preferably at least 10 meters.

13. System of claim 7, wherein the wavelength of the laser pulses is between 1500 nm and 1600 nm.

14. System of claim 7, wherein the optical amplifier and the optical stretcher are physically the same optical fiber.

15. System of claim 7, wherein the optical delivery fiber comprises sections of different types of optical fibers.

16. System of claim 15, wherein the optical delivery fiber comprises sections of increasing nonlinearity or decreasing dispersion in propagation direction.

17. System of claim 7, wherein the optical stretcher and the optical delivery fiber are polarization maintaining.

18. System of claim 7, wherein the optical delivery fiber is terminated by a nonlinear frequency-converting element.

19. System of claim 18, wherein the nonlinear frequency-converting element is a Terahertz-radiation generating antenna.