An optical parametric amplifier based on periodically poled KTiOPO<sub>4</sub> was used to generate 3-ns pulses at 1.544 μm . The device was pumped by a Q-switched Nd:YAG laser, and the signal output-pulse energy reached 71 μJ ; the maximum gain was 66 dB. The seed source was an Er–Yb:glass microchip laser. A theoretical fit to experimental data gave an effective nonlinear coefficient of 9.7 pm/V , close to the highest values reported for periodically poled KTiOPO<sub>4</sub> . Furthermore, the broad parametric gain observed could be used for broadband pulse amplification.
© 2001 Optical Society of America
J. Hellström, G. Karlsson, V. Pasiskevicius, and F. Laurell, "Optical parametric amplification in periodically poled KTiOPO<sub>4</sub> seeded by an Er–Yb:glass microchip laser," Opt. Lett. 26, 352-354 (2001)