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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

The output characteristics of Tm/Ho co-doped mode-locked fiber laser at the fundamental repetition rate.(a) Output spectrum, inset: the spectral width is about 1.8 nm, (b) single pulse as observed from the high-speed oscilloscope, inset: corresponding pulse train, (c) RF spectra, inset: RF spectra at the fundamental frequency of ~7.8 MHz, (d) autocorrelation trace, with pulse width of 4.67 ps.
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f4: The output characteristics of Tm/Ho co-doped mode-locked fiber laser at the fundamental repetition rate.(a) Output spectrum, inset: the spectral width is about 1.8 nm, (b) single pulse as observed from the high-speed oscilloscope, inset: corresponding pulse train, (c) RF spectra, inset: RF spectra at the fundamental frequency of ~7.8 MHz, (d) autocorrelation trace, with pulse width of 4.67 ps.

Mentions: The typical output of the fiber laser (optical spectrum, oscilloscope trace, RF spectrum, and the corresponding autocorrelation trace) is shown in Fig. 4. Figure 4(a) shows the typical spectrum of fiber lasers with a center wavelength of 1879.4 nm. The spontaneous emission hump of single mode Tm/Ho co-doped fiber is located at 1880 nm when the length of the fiber is around 2 m, and thus the maximum gain can be obtained around this wavelength regime. Spectral sideband is observed, indicating that our fiber laser operates in the conventional soliton mode-locking regime. With the increase of the length of Tm/Ho co-doped fiber, the center wavelength can shift to longer wavelength side, which is due to secondary pumping phenomena in an un-pumped active fiber43. The inset of Fig. 4(a) shows the zoom-in spectrum, indicating spectral width of 1.8 nm. Figure 4(b) shows the oscilloscope trace of a single pulse obtained from a high-speed oscilloscope. The inset shows the pulse train with a period of 127.6 ns. Figure 4(c) shows the RF spectra with a span of 78 MHz. Nine frequency peaks can be observed within the range. The inset is the fundamental frequency of ~7.8 MHz. Figure 4(d) indicates that the pulse temporal profile is well fitted by a sech2 profile with a pulse width of 4.67 ps. The corresponding 3-dB spectral width is 1.8 nm, corresponding to a time-bandwidth product (TBP) of about 0.714. The TBP is larger than transform-limited sech2 pulse, which indicates the pulses are chirped. Compared with Ref. 31the output of our proposed fiber laser, with a total dispersion of about −1.757 ps2, is comparable. The pulse width can be further reduced by controlling the dispersion of the cavity.


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)

The output characteristics of Tm/Ho co-doped mode-locked fiber laser at the fundamental repetition rate.(a) Output spectrum, inset: the spectral width is about 1.8 nm, (b) single pulse as observed from the high-speed oscilloscope, inset: corresponding pulse train, (c) RF spectra, inset: RF spectra at the fundamental frequency of ~7.8 MHz, (d) autocorrelation trace, with pulse width of 4.67 ps.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: The output characteristics of Tm/Ho co-doped mode-locked fiber laser at the fundamental repetition rate.(a) Output spectrum, inset: the spectral width is about 1.8 nm, (b) single pulse as observed from the high-speed oscilloscope, inset: corresponding pulse train, (c) RF spectra, inset: RF spectra at the fundamental frequency of ~7.8 MHz, (d) autocorrelation trace, with pulse width of 4.67 ps.
Mentions: The typical output of the fiber laser (optical spectrum, oscilloscope trace, RF spectrum, and the corresponding autocorrelation trace) is shown in Fig. 4. Figure 4(a) shows the typical spectrum of fiber lasers with a center wavelength of 1879.4 nm. The spontaneous emission hump of single mode Tm/Ho co-doped fiber is located at 1880 nm when the length of the fiber is around 2 m, and thus the maximum gain can be obtained around this wavelength regime. Spectral sideband is observed, indicating that our fiber laser operates in the conventional soliton mode-locking regime. With the increase of the length of Tm/Ho co-doped fiber, the center wavelength can shift to longer wavelength side, which is due to secondary pumping phenomena in an un-pumped active fiber43. The inset of Fig. 4(a) shows the zoom-in spectrum, indicating spectral width of 1.8 nm. Figure 4(b) shows the oscilloscope trace of a single pulse obtained from a high-speed oscilloscope. The inset shows the pulse train with a period of 127.6 ns. Figure 4(c) shows the RF spectra with a span of 78 MHz. Nine frequency peaks can be observed within the range. The inset is the fundamental frequency of ~7.8 MHz. Figure 4(d) indicates that the pulse temporal profile is well fitted by a sech2 profile with a pulse width of 4.67 ps. The corresponding 3-dB spectral width is 1.8 nm, corresponding to a time-bandwidth product (TBP) of about 0.714. The TBP is larger than transform-limited sech2 pulse, which indicates the pulses are chirped. Compared with Ref. 31the output of our proposed fiber laser, with a total dispersion of about −1.757 ps2, is comparable. The pulse width can be further reduced by controlling the dispersion of the cavity.

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