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High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction.

Li X, Yu X, Sun Z, Yan Z, Sun B, Cheng Y, Yu X, Zhang Y, Wang QJ - Sci Rep (2015)

Bottom Line: Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW.By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously.Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

View Article: PubMed Central - PubMed

Affiliation: Center for OptoElectronics and Biophotonics, School of Electrical and Electronic Engineering &The Photonics Institute, Nanyang Technological University, 50 Nanyang Ave., 639798, Singapore.

ABSTRACT
Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

No MeSH data available.


Related in: MedlinePlus

(a) The output power versus the pump power. Different color represents different operating regimes. (b) The repetition rate and orders of mode locking versus the pump power. The fundamental repetition rate to 21th harmonics mode-locking evolution versus the pump power, (c) the spectral evolution, (d) corresponding pule train evolution.
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f5: (a) The output power versus the pump power. Different color represents different operating regimes. (b) The repetition rate and orders of mode locking versus the pump power. The fundamental repetition rate to 21th harmonics mode-locking evolution versus the pump power, (c) the spectral evolution, (d) corresponding pule train evolution.

Mentions: With further increasing the pump power, our fiber laser can operate from the fundamental mode locking regime to the high-order harmonic mode-locking regime. Figure 5(a) shows the output power versus the pump power of our Tm/Ho co-doped fiber laser. The slope efficiency is around 4.8% through linear fitting as show in pink line. Considering the linear loss of around 60% induced by the side-polished fiber with SLG and other components, the slope efficiency is reasonable. Different operation regimes can be achieved under different pump power and are represented by using different colors. ASE regime is from 230 mW to 300 mW represented in the yellow color area. CW and unstable regimes are from 300 mW to 326 mW in blue color area. Fundamental mode locking regime can be obtained from 326 mW to 338.9 mW represented in the red color area. Number “1” is used to represent the fundamental mode locking regimes. High-order mode locking is in above 338.9 mW in green color. Figure 5(b) shows the repetition rate and orders of harmonic mode locking versus pump powers. Through increasing the pump power, the order of the mode locking increases. When the pump power is increased to 517.4 mW, our fiber laser can operate at the 21th harmonics mode locking, which gives an output of 10.1 mW with a repetition rate of 164.6 MHz. Because of the limitation of the damage threshold of the fiber components (500 mW), the pump power are not further increased. Figure 5(c) shows the spectra evolution at the fundamental, 5th, 8th, 11th, 15th, and 21th harmonic mode locking versus the different pump power. Figure 5(d) shows the corresponding pules-train evolution. Harmonics mode locking state can be partially explained by the soliton energy quantization theory44. Due to the soliton energy relocation and the interaction between the multiples solitons per round cavity round trip, the multiples at high pump power will form a special state, which have the equal separation in the fiber cavities, i.e. harmonics mode locking.


High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction.

Li X, Yu X, Sun Z, Yan Z, Sun B, Cheng Y, Yu X, Zhang Y, Wang QJ - Sci Rep (2015)

(a) The output power versus the pump power. Different color represents different operating regimes. (b) The repetition rate and orders of mode locking versus the pump power. The fundamental repetition rate to 21th harmonics mode-locking evolution versus the pump power, (c) the spectral evolution, (d) corresponding pule train evolution.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644976&req=5

f5: (a) The output power versus the pump power. Different color represents different operating regimes. (b) The repetition rate and orders of mode locking versus the pump power. The fundamental repetition rate to 21th harmonics mode-locking evolution versus the pump power, (c) the spectral evolution, (d) corresponding pule train evolution.
Mentions: With further increasing the pump power, our fiber laser can operate from the fundamental mode locking regime to the high-order harmonic mode-locking regime. Figure 5(a) shows the output power versus the pump power of our Tm/Ho co-doped fiber laser. The slope efficiency is around 4.8% through linear fitting as show in pink line. Considering the linear loss of around 60% induced by the side-polished fiber with SLG and other components, the slope efficiency is reasonable. Different operation regimes can be achieved under different pump power and are represented by using different colors. ASE regime is from 230 mW to 300 mW represented in the yellow color area. CW and unstable regimes are from 300 mW to 326 mW in blue color area. Fundamental mode locking regime can be obtained from 326 mW to 338.9 mW represented in the red color area. Number “1” is used to represent the fundamental mode locking regimes. High-order mode locking is in above 338.9 mW in green color. Figure 5(b) shows the repetition rate and orders of harmonic mode locking versus pump powers. Through increasing the pump power, the order of the mode locking increases. When the pump power is increased to 517.4 mW, our fiber laser can operate at the 21th harmonics mode locking, which gives an output of 10.1 mW with a repetition rate of 164.6 MHz. Because of the limitation of the damage threshold of the fiber components (500 mW), the pump power are not further increased. Figure 5(c) shows the spectra evolution at the fundamental, 5th, 8th, 11th, 15th, and 21th harmonic mode locking versus the different pump power. Figure 5(d) shows the corresponding pules-train evolution. Harmonics mode locking state can be partially explained by the soliton energy quantization theory44. Due to the soliton energy relocation and the interaction between the multiples solitons per round cavity round trip, the multiples at high pump power will form a special state, which have the equal separation in the fiber cavities, i.e. harmonics mode locking.

Bottom Line: Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW.By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously.Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

View Article: PubMed Central - PubMed

Affiliation: Center for OptoElectronics and Biophotonics, School of Electrical and Electronic Engineering &The Photonics Institute, Nanyang Technological University, 50 Nanyang Ave., 639798, Singapore.

ABSTRACT
Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

No MeSH data available.


Related in: MedlinePlus