Widely wavelength tunable gain-switched Er^3+-doped ZBLAN fiber laser around 28 μm

Abstract

In this paper, we demonstrate a wavelength widely tunable gain-switched Er³⁺-doped ZBLAN fiber laser around 2.8 μm. The laser can be tuned over 170 nm (2699 nm~2869.9 nm) for various pump power levels, while maintaining stable μs-level single-pulse gain-switched operation with controllable output pulse duration at a selectable repetition rate. To the best of our knowledge, this is the first wavelength tunable gain-switched fiber laser in the 3 μm spectral region with the broadest tuning range (doubling the record tuning range) of the pulsed fiber lasers around 3 μm. Influences of pump energy and power on the output gain-switched laser performances are investigated in detail. This robust, simple, and versatile mid-infrared pulsed fiber laser source is highly suitable for many applications including laser surgery, material processing, sensing, spectroscopy, as well as serving as a practical seed source in master oscillator power amplifiers.

34 nm-wavelength-tunable picosecond Ho^3+/Pr^3+-codoped ZBLAN fiber laser

“…Nevertheless, ~3 μm wavelength tunable pulsed lasers with peak powers some orders of magnitude higher than that in the CW regime are highly demanded for nonlinear wavelength convertors and medical applications, such as cardiovascular surgery, vitreoretinal surgery, and dental tissue ablation [17][18][19][20][21][22]. To achieve flexible pulses with μs-or ns-pulse duration, various approaches including gain-switching [23][24][25] and Q-switching [26][27][28][29][30] have been utilized. Utilizing a pulsed pump source, we demonstrated a wavelength widely tunable gainswitched Er 3+ -doped ZBLAN fiber laser around 2.8 μm.…”

“…Utilizing a pulsed pump source, we demonstrated a wavelength widely tunable gainswitched Er 3+ -doped ZBLAN fiber laser around 2.8 μm. The stable single-pulse gainswitched laser pulses can be tuned over 170 nm (2699 nm~2869.9 nm) for various pump power levels [25]. Very recently, we demonstrated a five-watt passively Q-switched Er 3+doped ZBLAN fiber laser that could be tuned over a wavelength range of 90 nm from 2762.5 nm to 2852.5 nm [31].…”

Gain-switched Dy3+:ZBLAN fiber laser operating around 3 μm

“…Moreover, with increased pump power the time delay between the pump and signal pulses attributed to the buildup time decreases. This behavior is typical of a gain-switched laser [23][24][25][26]. It should also be noted that, although the input pump pulse has a multipeak shape, the mid-infrared pulses generated by the Dy 3+ :ZBLAN fiber laser have a near-Gaussian shape.…”

“…Gain-switched (GS) operation of a Dy 3+ :ZBLAN laser was predicted by numerical modeling in [19], but experimental results were not demonstrated, up to now. GS has proved a reliable, compact and relatively simple technique to generate nanosecond pulses at wavelengths around 3-3.55 μm [20][21][22][23][24][25]. In the GS regime the pulse operation is obtained by switching gain on/off by modulating the pump laser.…”

“…This laser was able to generate maximum average output power of 11.2 W with pulse energies up to 80 μJ and a pulse duration as short as 170 ns [21]. The longest wavelength achieved from gain switched Er 3+ :ZBLAN was 2.87 μm [23]. Therefore, the development of gain-switched laser with operating wavelength beyond 2.9 μm remains an interesting topic for research.…”