Article

Semiconductor saturable absorber mirror passively Q-switched fiber laser near 2 μm.

College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Applied Optics (Impact Factor: 1.78). 08/2012; 51(23):5664-7. DOI: 10.1364/AO.51.005664
Source: PubMed

ABSTRACT A passively Q-switched fiber laser near 2 μm is achieved with a semiconductor saturable absorber mirror (SESAM) as a saturable absorber. Stable Q-switched pulses are generated from an extremely compact setup with a central wavelength of 1958.2 nm. Under the bidirectional pump configuration, the repetition rate of the fiber laser can be widely tuned from 20 to 80 kHz by increasing the pump power at the same time the pulse width decreases from 1 μs to 490 ns. When the incident pump power is 1.3 W, the average output power, the pulse repetition rate, the pulse width, and the highest single pulse energy are 91 mW, 80 kHz, 490 ns, and 1.14 μJ, respectively. To further optimize the system configuration, the pulse width can be reduced to 362 ns when the cavity length is reduced.

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    • "The passively Q-switched fiber lasers which use semiconductor saturable absorber mirrors (SESAM) [5] or saturable absorber (SA) fibers [5]–[11] are much preferred due to their simple structure and high reliability. Yang et al. reported a configuration using SESAM and Tm/Ho-doped double clad fiber to achieve 1.14 J 490 ns pulses [5]. However, the pulse energy was limited by the low damage threshold of SESAM in their design. "
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    ABSTRACT: We demonstrated a passively Q-switched Yb-doped fiber laser in an all-fiber configuration that used a piece of a Yb-doped fiber with a smaller core than the gain fiber as a saturable absorber. The laser generated stable output pulses at 1064 nm with a narrow line width of less than 0.2 nm. The Q-switched pulses have a pulse width of 140 ns and pulse energy of 141 $muhbox{J}$ at a repetition rate of 100 kHz. The peak power of $sim$1 kW and high slope efficiency of 51% were obtained. The repetition rate of this laser can be varied from a few kHz to 100 kHz with a potential of reaching up to 250 kHz. Stimulated Raman scattering was observed, though at 70 dB below the laser emission. The estimated stimulated Raman threshold is 6.2 kW, which allows this laser to further scale up the power. Because of its high peak power and adequate average power, the laser can be used as a stand-alone module for some applications in material processing. It can be also used as a seed laser for further power amplification.
    IEEE Photonics Journal 06/2014; 6(3):1-7. DOI:10.1109/JPHOT.2014.2320745 · 2.33 Impact Factor
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    • "The passively Q-switched fiber lasers which use semiconductor saturable absorber mirrors (SESAM) [5] or saturable absorber (SA) fibers [5]–[11] are much preferred due to their simple structure and high reliability. Yang et al. reported a configuration using SESAM and Tm/Ho-doped double clad fiber to achieve 1.14 J 490 ns pulses [5]. However, the pulse energy was limited by the low damage threshold of SESAM in their design. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrated a passively Q-switched Yb-doped fiber laser in an all-fiber configuration that used a piece of a Yb-doped fiber with a smaller core than the gain fiber as a saturable absorber. The laser generated stable output pulses at 1064 nm with a narrow line width of less than 0.2 nm. The Q-switched pulses have a pulse width of 140 ns and pulse energy of 141 �J at a repetition rate of 100 kHz. The peak power of �1 kW and high slope efficiency of 51% were obtained. The repetition rate of this laser can be varied from a few kHz to 100 kHz with a potential of reaching up to 250 kHz. Stimulated Raman scattering was observed, though at 70 dB below the laser emission. The estimated stimulated Raman threshold is 6.2 kW, which allows this laser to further scale up the power. Because of its high peak power and adequate average power, the laser can be used as a stand-alone module for some applications in material processing. It can be also used as a seed laser for further power amplification.
    IEEE Photonics Journal 06/2014; Vol. 6(No. 3):1501207. · 2.33 Impact Factor
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    ABSTRACT: We present an all-fiber 1.94 μm nanosecond pulse laser in master oscillation-power amplifier configuration. A dual-FBGs gain-switched Tm3+-doped fiber laser is built and is used as the seed laser. The output characteristics of the amplifier are studied at different pulse repetition rates, and the maximum output energy of 500 μJ is achieved under incident pump power of 39 W. The emitting spectra are checked at 5 and 10 kHz, and no obvious nonlinear effects are observed in the spectrum of the amplified laser. The beam quality factor is M2 = 2.1 ± 0.03 measured by the traveling knife-edge method, and the laser beam spot is also monitored by an infrared vidicon camera.
    Chinese Physics Letters 05/2013; 30(5):054208. DOI:10.1088/0256-307X/30/5/054208 · 0.95 Impact Factor