Power scaling of fiber-optic parametric oscillators using higher-order modes

The use of higher-order radially symmetric (Bessel) modes in large-core optical fibers to provide intramodal phase matching for four-wave mixing in parametric oscillators pumped at 1030 nm is investigated numerically. It is shown that a suitable choice of core diameter in a 4 cm fiber piece can lead to broad tunability of signal/idler bands in the range of 1120-1500 nm (signal) and 780-950 nm (idler), only by adjusting the recirculation timing, while keeping the pump wavelength fixed. Power scaling to theMWlevel appears feasible, ultimately limited by nonlinear intermodal coupling. The oscillator performance is insensitive to the exact method of fiber recirculation and back-coupling, but highly sensitive to the purity ofpumpmode excitation.