Peipei Jiang

Compact dual-wavelength Nd:GdVO 4 laser working at 1063 and 1065 nm

We report a compact diode-laser pumped Nd:GdVO(4) laser with stable dual-wavelength output at 1063 nm and 1065 nm simultaneously. Two types of resonant cavity configurations were presented to support the stable dual-wavelength operation of the laser. Using a polarization beam splitter(PBS) included T-shaped cavity, we obtained a total power output over 5 W in two orthogonal polarized beam directions with 4 W in sigma polarization (1065.5 nm) and 1 W in pi polarization (1063.1 nm). By combining a half-wave-plate with the PBS in the laser cavity, a new configuration favoring one beam direction dual-wavelength output with same polarization direction was realized. A phenomenon of further line splitting was observed in both 1065 nm and 1063 nm.

PPMgLN-Based High-Power Optical Parametric Oscillator Pumped by Yb

We report a periodically poled magnesium-oxide-doped lithium niobate (PPMgLN) based optical parametric oscillator (OPO) pumped by a diode-seeded, linearly polarized, high-power, pulsed, ytterbium fiber master oscillator power amplifier (MOPA). Using adaptive pulse shaping of the seed laser (using an external modulator), we demonstrate a reduction in the impact of dynamic gain saturation and optical Kerr/Raman nonlinearities within the fiber MOPA, obtaining shaped signal and idler pulses at the OPO output and reduced spectral bandwidths. A maximum average output power of 26.5 W was obtained from the MOPA at 1062 nm. An output power as high as 11 W from the OPO at an overall slope efficiency of 67% was achieved, with 2.7 W of output power obtained at a wavelength of 3.5 mum. Our experiments were pump-power-limited and considerable scope remains for further power scaling of such OPOs using this approach.

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We have experimentally demonstrated a periodically poled magnesium-oxide-doped lithium niobate (PPMgLN)-based, fiber-laser-pumped optical parametric oscillator (OPO) generating idler wavelength of 3.82 μm. The pump fiber laser was constructed with a linearly polarized, semi-fiber-coupled acousto-optic Q-switched fiber oscillator and a polarization-maintaining fiber amplifier with pulse duration of 190 ns at the highest output power. The OPO was specifically configured in single-pass, singly resonant linear cavity structure to avoid the damage risk of the pump fiber laser, which is always a serious issue in the fiber-laser-pumped, double-pass, singly oscillating structured OPOs. Under the highest pump power of 25 W, an idler average output power of 3.27 W with one-hour peak-to-peak instability of 5.2% was obtained. The measured M2 factors were 1.98 and 1.44 for horizontal and vertical axis, respectively. The high power stability and good beam quality demonstrated the suitability of such technology for practical application.

-Doped Fiber Amplifier Incorporates Active Pulse Shaping

We report a fiber laser pumped dual-wavelength mid-infrared optical parameter oscillator (OPO) based on an aperiodic optical superlattice (AOS) structure. An aperiodically poled MgO-doped lithium niobate wafer was designed and fabricated as the nonlinear crystal for the OPO. Using a linearly polarized pulsed Yb fiber laser at 1.064??m as the pump source, mid-infrared emissions at 3.3 and 3.8??m were obtained simultaneously from the OPO. The total output power at the idler wavelengths of 3.3 and 3.8??m reached 3.07?W under the maximum pump power of 27?W. The pump-to-idler conversion efficiency was 11.4% with a ratio of about 1.2:1 for 3.3??m and 3.8??m.

High-power PPMgLN-based optical parametric oscillator pumped by a linearly polarized, semi-fiber-coupled acousto-optic Q-switched fiber master oscillator power amplifier

We experimentally demonstrated a compact fiber laser-pumped multichannel PPMgLN-based optical parametric oscillator (OPO) generating total OPO output power of 15.8, 15.2, 14.2, 12.9, and 8.8 W with idler output power of 4.7, 4.3, 4.1, 3.3, and 2.1 W at the wavelength of 3.43, 3.63, 3.72, 3.83, and 3.99 μm, respectively. The OPO was pumped by a fully fiberized polarization maintaining (PM) ytterbium-doped pulsed fiber master oscillation power amplifier (MOPA) operating at 1064 nm at a repetition rate of 65 kHz with effective pump power of 28.7 W. The MOPA system was constructed with an acousto-optic Q-switched fiber laser seed and only one stage PM fiber amplifier without any free space components, which makes the pump system compact and stable in the long-term. Comparisons on efficiencies and signal wavelength shifts between different channels showed that the idler absorption was the main factor preventing high average-power OPO operation with long idler wavelength.

A fiber laser pumped dual-wavelength mid-infrared optical parametric oscillator based on aperiodically poled magnesium oxide doped lithium niobate

We experimentally demonstrated an efficient optical parametric oscillator (OPO) with high parametric conversion from 1.0645 to 3.8 μm. An aperiodically poled magnesium oxide doped lithium niobate wafer was designed and fabricated as the nonlinear crystal of the OPO. A linearly polarized acousto-optic Q-switched Nd:YVO4 laser was used as the pump source. High pump-to-idler conversion efficiency of 18.5% was achieved with a slope efficiency of up to 21.5%. When compared with a periodically poled channel fabricated on the same wafer, under the condition of output coupler optimized for the periodically poled lithium niobate based OPO, an improvement of slope efficiency by 28.3% from 15.2% to 19.5% and total efficiency by 12.5% from 13.6% to 15.3% under the highest pump power of 11 W was realized for the pump-to-idler conversion.

High-power multichannel PPMgLN-based optical parametric oscillator pumped by a master oscillation power amplification-structured Q-switched fiber laser

We report a novel quasi-synchronously pumped PPMgLN-based high power mid-infrared (MIR) laser with picosecond pulse bunch output. The pump laser is a linearly polarized MOPA structured all fiberized Yb fiber laser with picosecond pulse bunch output. The output from a mode-locked seed fiber laser was directed to pass through a FBG reflector via a circulator to narrow the pulse duration from 800 ps to less than 50 ps and the spectral FWHM from 9 nm to 0.15 nm. The narrowed pulses were further directed to pass through a novel pulse multiplier through which each pulse was made to become a pulse bunch composing of 13 sub-pulses with pulse to pulse time interval of 1.26 ns. The pulses were then amplified via two stage Yb fiber amplifiers to obtain a linearly polarized high average power output up to 85 W, which were then directed to pass through an isolator and to pump a PPMgLN-based optical parametric oscillator via quasi-synchronization pump scheme for ps pulse bunch MIR output. High MIR output with average power up to 4 W was obtained at 3.45 micron showing the feasibility of such pump scheme for ps pulse bunch MIR output.

Efficient parametric conversion from 1.06 to 3.8 μm by an aperiodically poled cascaded lithium niobate

We experimentally demonstrated a high power mid-infrared optical parametric oscillator that was pumped by a linearly polarized, pulsed Ytterbium-doped fiber laser. Cascaded parametric conversion was realized to obtain a higher conversion efficiency from the pump of 1.06 μm to the expected idler ~ 3.8 μm. A monolithic aperiodically poled magnesium-oxide doped lithium niobate was designed to compensate the phase mismatches of the nonlinear conversions from the pump to idler and the primary signal to idler simultaneously. The highest idler output power of 4.35 W at 3.81 μm was obtained under the pump power of 24.8 W at 1063.5 nm with pump-to-idler conversion efficiency of 17.5% and slope efficiency of 21.3%.

Fiber laser pumped high power mid-infrared laser with picosecond pulse bunch output

We report on a high-power periodically poled MgO-doped lithium niobate (MgO:PPLN)-based femtosecond optical parametric amplifier (OPA), featuring a spectral seamless broadband mid-infrared (MIR) output. By modifying the initial chirp and spectrum of the mode-locked seed laser, the Yb fiber pump laser exhibits a final output power of 14 W with sub-200-fs pulse duration after power amplification and compression. When the OPA was seeded with a broadband amplified spontaneous emission (ASE) source, a damage-limited 0.6 W broadband MIR radiation was experimentally obtained under the pump power of 10.15 W at 82 MHz repetition rate, corresponding to an overall OPA conversion efficiency of 32.7%. The 3 dB bandwidth of the mid-IR idler was 291.9 nm, centering at 3.34 μm.

High Power Efficient 3.81

We report an acousto-optic Q-switched Nd:GdVO4 laser pumped flexibly tunable cascaded optical parametric oscillator (OPO) based on two separate multi-channel periodically poled magnesium oxide doped Lithium Niobate (PPMgLN). Even under lower pump power, long wavelength parametric output was found to be more easily generated than in single stage OPO. A cascaded idler output at 5.075 μm was found to be generated. A convenient method to monitor the occurring of the cascaded parametric process was also presented by measuring the spectrum of sum-frequency generation of the pump power and the cascaded signal power.