Fiber Designs For Wavelength Tunable Ultra-Short Pulse Lasers

• US 20140254616A1
• Filed: 10/09/2012
• Published: 09/11/2014
• Est. Priority Date: 10/06/2011
• Status: Active Grant

• Current Assignee: OFS Fitel LLC (Furukawa Electric Company Limited)
• Original Assignee: OFS Fitel LLC (Furukawa Electric Company Limited)
• Inventors: Gruner-Nielsen, Lars, Jakobsen, Dan P., Xu, Chris, Pedersen, Martin E.V., Cheng, Ji
• Granted Patent: US 9,502,852 B2
• Time in Patent Office: Days
• US Class Current: 372/6
• CPC Class Codes: G02B 6/03688 having 5 or more layers
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: H01S 2301/085 solitons
• 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 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/0675 Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/0804 Transverse or lateral modes

Abstract

Embodiments of the present invention generally relate to fiber designs for wavelength tunable ultra-short pulse lasers. More specifically, embodiments of the present invention relate to systems incorporating fiber designs for higher order mode fibers capable of soliton self frequency shifting where a system comprises a first fiber for shifting the wavelength from a pump wavelength to a transfer wavelength and a second fiber for shifting the pulse from the transfer wavelength to an output wavelength. In one embodiment of the present invention, a wavelength tunable short pulse fiber laser system comprises: a pulse generator for providing a pulse having an input wavelength; a mode-converter; a first designed fiber for shifting the pulse from the input wavelength to a transfer wavelength; and a second designed fiber for shifting the pulse from the transfer wavelength to an output wavelength.

Claims

1. A wavelength tunable short pulse fiber laser system comprising:

a pulse generator for providing a pulse having an input wavelength;

a mode-converter;

a first designed higher order mode fiber for shifting the pulse from the input wavelength to a transfer wavelength; and

a second designed higher order mode fiber for shifting the pulse from the transfer wavelength to an output wavelength.

2. The system of claim 1, wherein the mode-converter comprises a higher order mode fiber.

3. The system of claim 1, wherein the first designed fiber uses a higher order mode having D·

A_eff greater than 3 fs at the input wavelength.

4. The system of claim 1, wherein an effective index of a higher order mode of the first designed fiber does not overlap the effective index of any other guided mode of the first designed fiber at a wavelength range between the input wavelength and the transfer wavelength.

5. The system of claim 1, wherein an effective index of a higher order mode of the second designed fiber does not overlap the effective index of any other guided mode of the second designed fiber at a wavelength range between the transfer wavelength and the output wavelength.

6. The system of claim 1, wherein a ratio of the D·

A_eff of the first designed fiber and a D·

A_eff of the second designed fiber is less than a factor of 100.

7. The system of claim 1, wherein the mode-converter comprises is a long period grating mode-converter.

8. The system of claim 1, wherein the pulse generator comprises a mode-locked laser.

9. A wavelength tunable short pulse fiber laser system comprising:

a mode-locked laser for providing a pulse having an input wavelength;

a long period grating mode-converter;

a first designed HOM fiber for shifting the pulse from the input wavelength to a transfer wavelength; and

a second designed HOM fiber for shifting the pulse from the transfer wavelength to an output wavelength;

wherein the first designed fiber uses a higher order mode having D·

A_eff greater than 3 fs at the input wavelength,

10. The system of claim 9, wherein an effective index of a higher order mode of the first designed fiber does not overlap the effective index of any other guided mode of the first designed fiber at a wavelength range between the input wavelength and the transfer wavelength.

11. The system of claim 9, wherein an effective index of a higher order mode of the second designed fiber does not overlap the effective index of any other guided mode of the second designed fiber at a wavelength range between the transfer wavelength and the output wavelength.

12. The system of claim 9, wherein a ratio of the D·

A_eff of the first designed HOM fiber and a D·

A_eff of the second designed HOM fiber is less than a factor of 100.

13. The system of claim 9, wherein the first designed HOM fiber comprises a central core, an inner trench surrounding the core, a ring surrounding the trench, an outer trench surrounding the ring, and an outer cladding;

wherein the central core has a radius of between about 0.75 μ

m to about 2.0 μ

m, the inner trench has a width of between about 1.75 μ

m to 2.5 μ

m, the ring has a width of between about 2.0 μ

m to 5.0 μ

m, the outer trench has a width of between about1.75 μ

m to 4.5 μ

m, and the outer cladding has an outer radius of between about 50 μ

m to about 75 μ

m.

14. The system of claim 13, wherein the central core has a radius of about 1.25 μ

m, the inner trench has a width of about 2.09 μ

m, the ring has a width of about 3.51 μ

m, the outer trench has a width of about 2.84 μ

m, and the outer cladding has an outer radius of about 62.5 μ

m.

15. The system of claim 9, wherein the second designed HOM fiber comprises a central core, an inner trench surrounding the core, a ring surrounding the trench, an outer trench surrounding the ring, and an outer cladding;

wherein the central core has a radius of between about 0.85 μ

m to about 2.25 μ

m, the inner trench has a width of between about 0.5 μ

m to 2.5 μ

m, the ring has a width of between about 2.0 μ

m to 4.5 μ

m, the outer trench has a width of between about 1.75 μ

m to 4.5 μ

m, and the outer cladding has an outer radius of between about Aim to about 75 μ

m.

16. The system of claim 15, wherein the central core has a radius of about 1.35 μ

m, the inner trench has a width of about 1.10 μ

m, the ring has a width of about 3.15 μ

m, the outer trench has a width of about 3.09 μ

m, and the outer cladding has an outer radius of about 62.5 μ

m.

17. A method of wavelength shifting ultra-short pulses comprising:

providing a system comprising;

a pulse generator for providing a pulse having an input wavelength;

a mode-converter;

a first designed higher order mode fiber; and

a second designed higher order mode fiber;

propagating the pulse from the pulse generator to the mode-converter and converting the pulse from an input mode to a higher order mode;

propagating the pulse from the mode-converter fiber to the first designed higher order mode fiber and shifting the input wavelength to a transfer wavelength; and

propagating the pulse from the first designed higher order mode fiber and to the second designed higher order mode fiber and shifting the transfer wavelength to an output wavelength.

18. The method of claim 17, wherein the mode-converter comprises a higher order mode fiber.

19. The method of claim 17, wherein the first designed fiber at the higher order mode has a D·

A_eff greater than 3 fs at the input wavelength.

20. The method of claim 17, wherein an effective index of a higher order mode of the first designed fiber does not overlap the effective index of any other guided mode of the first designed fiber at a wavelength range between the input wavelength and the transfer wavelength;

and

wherein an effective index of a higher order mode of the second designed fiber does not overlap the effective index of any other guided mode of the second designed fiber at a wavelength range between the transfer wavelength and the output wavelength.

21. A higher order mode fiber comprising:

a central core having a radius of between about 0.75 μ

m to about 2.0 μ

m;

an inner trench surrounding the core having a width of between about 1.75 μ

m to 2.5 μ

m;

a ring surrounding the trench having a width of between about 2.0 μ

m to 5.0 μ

m;

an outer trench surrounding the ring having a width of between about 1.75 μ

m to 4.5 μ

m; and

an outer cladding having an outer radius of between about 50 μ

m to about 75 μ

m.

22. The higher order mode fiber of claim 21, wherein the central core has a radius of about 1.25 μ

m, the inner trench has a width of about 2.09 μ

m, the ring has a width of about 3.51 μ

m, the outer trench has a width of about 2.84 μ

m, and the outer cladding has an outer radius of about 62.5 μ

m.

23. A higher order mode fiber comprising:

a central core having a radius of between about 0.85 μ

m to about 2.25 μ

m;

an inner trench surrounding the core having a width of between about 0.5 μ

m to 2.5 μ

m;

a ring surrounding the trench having a width of between about 2.0 μ

m to 4.5 μ

m;

an outer trench surrounding the ring having a width of between about 1.75 μ

m to 4.5 μ

m; and

an outer cladding having an outer radius of between about 50 μ

m to about 75 μ

m.

24. The higher order mode fiber of claim 23, wherein the central core has a radius of about 1.35 μ

m, the inner trench has a width of about 1.10 μ

m, the ring has a width of about 3.15 μ

m, the outer trench has a width of about 3.09 μ

m, and the outer cladding has an outer radius of about 62.5 μ

m.