High Conversion Efficiency, Mid-Infrared Pulses Generated via Burst-Mode Fiber Laser Pumped Optical Parametric Oscillator

Abstract

We present a mid-infrared optical parametric oscillator (OPO) with a high pump-to-idler conversion efficiency from 1.06 µm to 3.8 µm, which was quasi-synchronously pumped by a burstmode fiber laser. The pump pulse was specially designed with a rectangular profile in temporal, which was composed of hundreds of ultrashort sub-pulses. By applying the quasi-synchronous pumping scheme, the buildup time of the parametric signal pulse could be minimized. No back-conversion effect was observed when the pump peak power was increased. A maximum pump-to-idler conversion efficiency of 19.6% was achieved when the number of intra-burst sub-pulses was set to be 240. By increasing the number of intraburst sub-pulses to be about 480, the maximum average output power of 7.9 W at 3.8 µm was realized under pump power of 45.3 W. The corresponding pump-to-idler conversion efficiency was computed to be about 17.5%. The experimental results show an improvement of 40% in pump-to-idler conversion efficiency for this quasi-synchronously pumped OPO when compared with the conventional long laser pulse pumped OPO. INDEX TERMS Mid-infrared, optical parametric oscillator, quasi-synchronously pumped, burst-mode fiber laser.

Compact picosecond mid-IR PPLN OPO with controllable peak powers

“…At constant average power, a smaller burst-pulse window provided a higher pump peak power in each individual pulse. Apart from controlling peak pulse power, burst-mode OPOs have also been shown to allow an increase in conversion efficiency compared to standard long-pulse OPOs of the same pump peak power [18] due to a reduction in the signal build-up time similar to that found using rectangular-shaped pump pulses [19]. However, it is interesting to note that we observed a decrease in idler average power and hence a decrease in conversion efficiency from our burst-mode OPO, as can be seen from the black data points in Fig.…”

“…In order to improve the conversion efficiency of the burst-mode OPO, shaping the pump burst-window profile could be considered. For example, pumping with 'figure-of-h' shaped pulses [18], where a higher intensity at the beginning of the window can reduce the build-up time followed by moderate intensities to avoid the back-conversion, would result in an increase of the overall conversion efficiency. Further investigations are underway.…”

Supercontinuum generation in bulk solid-state material with bursts of femtosecond laser pulses

“…For what concerns laser wavelength conversion processes, generation second and fourth harmonics with femtosecond pulse bursts was demonstrated 20 . Burst-mode pumping was shown beneficial for increasing the pump-to-idler conversion efficiency in long-picosecond mid-infrared optical parametric oscillator 21 . In the femtosecond regime, burst-mode operation allowed efficient average power scaling of femtosecond optical parametric oscillators 22 , 23 and amplifiers 24 , 25 , as well as optical parametric chirped pulse amplifiers (OPCPA) 26 , 27 and spectral broadening-based extracavity post-compression schemes 28 , 29 , which deliver few optical cycle pulses.…”

4 mJ Rectangular- Envelope GHz-Adjustable Burst-Mode Fiber-Bulk Hybrid Laser and Second-Harmonic Generation

“…High peak power and high pulse energy burst-mode pulse lasers distinctively contain a bunch of high repetition rate pulses with durations ranging from the ultrafast regime (<10 ps) to several nanoseconds and possess a great number of applications [1][2][3][4][5][6][7][8][9]. For example, ultrafast burst-mode lasers have been demonstrated more efficient and accurate in cooled ablation material processing [1][2][3].…”

“…In scientific research, each intra-burst pulses could obtain larger energy extraction than uniform high repetition pulses which could be employed as the pump sources of synchronously pumped optical parametric oscillator (SPOPO) and promote the generated MIR laser pulse energies. [4][5][6][7]. In addition, a group of picoseconds pulses with adequate energy could improve the ranging precision in LIDAR application [8,9] and realize the simultaneous measurement of multi-physical-parameters in turbulent flows [10,11].…”