Fiber designs for wavelength tunable ultra-short pulse lasers

• US 9,502,852 B2
• Filed: 10/09/2012
• Issued: 11/22/2016
• 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, Pedersen, Martin E. V., Xu, Chris, Cheng, Ji
• Primary Examiner(s): King, Joshua
• Application Number:
  US14/349,269
• Publication Number:
  US 20140254616A1
• Time in Patent Office: 1,505 Days
• US Class Current: 1/1
• 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 comprising a higher order mode fiber;

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,

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

A_eff greater than 3 fs at the input wavelength, wherein D is the dispersion coefficient of the fiber and A_eff is the effective area of the fiber;

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;

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;

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.

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

3. 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; and

wherein D is the dispersion coefficient of the fiber and Aeff is the effective area of the fiber;

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;

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;

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;

wherein the first designed HOM fiber comprises a central core, a 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 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 about 1.75 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.

4. 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 comprising a higher order mode fiber;

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;

wherein the first designed fiber at the higher order mode has a D·

A_eff greater than 3 fs at the input wavelength, wherein D is the dispersion coefficient of the fiber and A_eff is the effective area of the fiber;

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.