Bright few-cycle fiber source using resonant dispersive wave emission in an optical fiber
View Patent ↗Methods and apparatus for generating ultrashort optical pulses. Pulses of an infrared source are launched into an optical fiber characterized by a zero-dispersion wavelength (ZDW), where the wavelength of the infrared source exceeds the ZDW of the optical fiber by at least 100 nm. A resonant dispersion wave (RDW) is generated in the optical fiber that has a central wavelength blue-shifted by more than 500 nm relative to the pump wavelength, and, in some cases, by more than 700 nm. The optical fiber has a core of a diameter exceeding the central wavelength of the RDW by at least a factor of five. In a preferred embodiment, the infrared source includes a master-oscillator-power-amplifier, embodied entirely in optical fiber, and may include an Erbium:fiber oscillator, in particular.
1. A method for generating ultrashort optical pulses, the method comprising:
a. coupling pump pulses of an infrared source characterized by a pump wavelength into an optical fiber characterized by a core diameter and a zero-dispersion wavelength, the pump wavelength exceeding the zero-dispersion wavelength of the optical fiber by at least 100 nm; and
b. generating resonant dispersion wave (RDW) emission in the optical fiber, the RDW emission spectrally isolated from the pump pulses and characterized by a central wavelength blue-shifted by more than 500 nm relative to the pump wavelength;
wherein the core diameter of the optical fiber exceeds the central wavelength of the RDW by at least a factor of five.
2. A method in accordance with claim 1 , wherein the RDW emission is characterized by a central wavelength blue-shifted by more than 700 nm relative to the pump wavelength.
3. A method in accordance with claim 1 , further comprising temporally compressing the RDW emission.
4. A method in accordance with claim 1 , wherein the pump pulse energy exceeds 40 nJ.
5. A method in accordance with claim 1 , wherein the RDW emission exceeds 1 nJ per pulse.
6. A method in accordance with claim 1 , wherein the infrared source includes a master-oscillator-power-amplifier.
7. A method in accordance with claim 1 , wherein the infrared source is based upon an Erbium-doped fiber mode-locked oscillator.
8. An apparatus for generating ultrashort optical pulses characterized by a central wavelength, the apparatus comprising:
a. a source of infrared pulses characterized by a wavelength;
b. an optical fiber characterized by a core diameter and a zero-dispersion wavelength (ZDW),
wherein the wavelength of the infrared pulses exceeds the ZDW of the optical fiber by at least 100 nm, and
wherein the core diameter of the optical fiber exceeds the central wavelength of the ultrashort optical pulses by at least a factor of five.
9. An apparatus in accordance with claim 8 , wherein the source of infrared pulses includes a master-oscillator-power-amplifier.
10. An apparatus in accordance with claim 8 , wherein the infrared source is based upon an Erbium-doped fiber mode-locked oscillator.
11. An apparatus in accordance with claim 8 , wherein the optical fiber is polarization-maintaining.
12. An apparatus in accordance with claim 8 , wherein optical energy is optically guided through all components.