57 research outputs found
Large aperture PPMgLN based high-power optical parametric oscillator at 3.8 µm pumped by a nanosecond linearly polarized fiber MOPA
No full textWe report a large aperture PPMgLN based OPO generating 21W of average output power at a slope efficiency of 45%. The OPO is pumped with the output from a polarization maintaining Ytterbium doped fiber MOPA operating at 1060nm producing 20ns pulses at a repetition rate of 100kHz and an average output power of 58W (after the isolators). A maximum of 5.5W of optical power was recorded at the idler wavelength of 3.82µm without thermal roll-off. The pulse rise/fall time plays a significant role in the OPO conversion efficiency and that further enhancements in the efficiency should be possible using pulses with faster rise and fall times
High power pulsed optical parametric oscillator at 3.5 micron pumped by a diode seeded Yb<sup>3+</sup>- doped fiber MOPA
No full textWe report a high power pulsed optical parametric oscillator (OPO) at 3.5µm using a MgO:PPLN as the gain medium pumped by 1062nm all-fiber MOPA. Output powers as high as 11W at an overall slope efficiency of 67% was achieved, with nearly 2.5W of power obtained at a wavelength of 3.5µm
Externally modulated diode seeded Yb<sup>3+</sup>- doped fiber MOPA pumped high power optical parametric oscillator
No full textHere we report a high power, pulsed optical parametric oscillator (OPO) at 3.5µm by using a MgO:PPLN crystal as the gain medium. The OPO itself was pumped by a semiconductor diode-seeded, Yb3+-doped fiber Master Oscillator Power Amplifier (MOPA) operating at 1062nm. An OPO output power as high as 11W at an overall slope efficiency of 67% was achieved, with nearly 2.7W and 8.2W of optical power obtained at 3.5µm and 1.5µm respectively. Due to the fast response time of the external modulator, it is possible to implement active pulse shaping on a nanosecond time-scale. Using adaptive pulse shaping of the seed laser (using an external modulator) we demonstrated a reduction in the impact of dynamic gain saturation and optical Kerr/Raman nonlinearities within the fibre MOPA obtaining shaped signal and idler pulses at the OPO output and reduced spectral bandwidths. We have also investigated the dependence of the OPO build-up time and energy transfer efficiency on pump pulse peak power and shape. The build-up time shows an exponential dependence on the pulse peak power and as expected decreases with an increase in pulse peak power. Analyzing the shift in spectral peak at 1.5µm it is possible to estimate the internal temperature of the crystal for various pump powers. Our experiments were pump-power limited and considerable scope remains for further power-scaling of the OPO output using this approach
PPMgLN based high power optical parametric oscillator pumped by Yb<sup>3+</sup>-doped fiber amplifier incorporates active pulse shaping
No full textWe 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 µm. Our experiments were pump-power-limited and considerable scope remains for further power scaling of such OPOs using this approach
Characterization of optical fibre sensor systems for applications at high temperatures
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
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