Noncollinear double-ring optical parametric oscillators with periodically poled KTiOPO4

A pulsed self-seeded double-ring optical parametric oscillator realized with periodically poled KTiOPO4 is demonstrated. When pumped from two opposite directions, the cavity supported two automatically aligned, independent, counter-propagating parametric wave pairs whose wavelength could be continuously tuned by varying a single degree of freedom. The tuning range from 1189 nm to 1267 nm has been achieved for the resonant idler waves. The parametric rings could be cross-seeded by using a feedback arrangement. Here, Fourier-domain filtering was utilized to spectrally manipulate the output spectrum of the seeded ring oscillator. Parametric ring oscillator efficiencies of 46 % were achieved.