Mode locked laser system

• US 8,494,016 B2
• Filed: 07/29/2009
• Issued: 07/23/2013
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Legato Laser Technology Ltd.
• Original Assignee: Legato Laser Technology Ltd.
• Inventors: Karni, Yoram, Cohen, Guy
• Primary Examiner(s): Rodriguez, Armando
• Application Number:
  US13/000,015
• Publication Number:
  US 20110134942A1
• Time in Patent Office: 1,455 Days
• Field of Search: 372/18, 372/29.02, 372/29.03, 372/30, 372/32, 372/50.123, 372/29.023, 327/18, 327/29.02, 327/29.023, 327/30, 327/32, 327/50.123
• US Class Current: 372/18
• CPC Class Codes: H01S 5/065 Mode locking; Mode suppression; Mode selection ; Self pulsating
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters
• CPC Class Codes: H01S 5/4068 with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

A laser resonator cavity is presented. The laser resonator cavity comprises an optical manipulator of different longitudinal modes propagating along different optical paths. The optical manipulator is configured for adjusting a difference in optical lengths of the different optical paths thereby adjusting a frequency spacing between the different longitudinal.

Claims

1. A laser resonator cavity comprising:

a first section;

a second section;

a dispersive optical element between the first section and the second section for frequency dispersing light beams at different optical lengths along spatially separated optical paths, to define different longitudinal modes, in the second section; and

an optical manipulator for creating optical length changes along each optical path which is proportional to the optical frequency change of the light beam that travels along said each optical path.

2. The laser resonator cavity of claim 1, wherein said optical manipulator is configured for adjusting at least one of spatial shape, temporal shape and repetition rate of an output pulse.

3. The laser resonator cavity of claim 1, wherein the dispersive optical element includes a spectral beam splitter, configured for separating a combined light beam into the different longitudinal modes for propagating along the different spatially separated optical paths.

4. The laser resonator cavity of claim 3, comprising a mode locking assembly in the first section positioned to accommodate the combined light beam.

5. The laser resonator cavity of claim 2, wherein said optical manipulator comprises an intensity control assembly.

6. The laser resonator cavity of claim 1, wherein said optical manipulator comprises an intensity control assembly, thus enabling control of both amplitude and frequency of the different longitudinal modes.

7. The laser resonator cavity of claim 6, wherein the intensity control assembly comprises a plurality of intensity control units arranged across the different optical paths of the different longitudinal modes, the intensity control units being configured to adjust relative intensities of each of the different longitudinal modes propagating in the different paths, separately.

8. The laser resonator cavity of claim 1, wherein the second section includes a dispersion control assembly comprising rising different dispersion control media for positioning in the paths of the different longitudinal modes thereby independently adjusting the optical lengths of each of the different modes.

9. The laser resonator cavity of claim 1, comprising one or more gain media in the second section, the gain media comprising:

an array of optical gain sources arranged for accommodating the different optical paths of the different longitudinal modes propagating within the cavity for separately amplifying the different longitudinal modes.

10. The laser resonator cavity of claim 4, wherein said mode locking assembly comprises a saturatable absorber.

11. The laser resonator cavity of claim 1, wherein the optical manipulator includes a dispersion control assembly configured to increase the length of the optical path with an increase of the frequency of the longitudinal mode.

12. The laser resonator cavity of claim 1, wherein the optical manipulator includes a dispersion control assembly configured to decrease the length of the optical path with an increase of the frequency of the longitudinal mode.

13. The laser resonator cavity of claim 1, wherein the optical manipulator includes a dispersion control assembly configured to adjust the differences in the optical lengths such that frequencies (f_k=f₀+kδ

) of the different longitudinal modes are spaced by a constant equal amount δ

.

14. The laser resonator cavity of claim 8, wherein said dispersion control assembly comprises a multitude of dispersion control units which are arranged across the different optical paths of the different longitudinal modes propagating within the cavity, and the dispersion control units are configured to adjust the optical length of each of said different paths separately.

15. The laser resonator cavity of claim 14, wherein the dispersion control units have controllable optical lengths.

16. The laser resonator cavity of claim 14, wherein the dispersion control units are made of one or more materials having refraction index or indices varying in response to application of an external electric field.

17. The laser resonator cavity of claim 9, wherein said one or more gain media has one of the following configurations:

(a) comprises an array of semiconductor edge emitting laser sources;

(b) comprises a broad area semiconductor edge emitting laser source;

(c) comprises an array of semiconductor vertically emitting laser sources;

(d) comprises spaced apart laser gain medium regions having different lasing properties.