Optimal length of a nonlinear crystal for type e-oo optical parametric oscillation

The dependence of the optimal length of a nonlinear wave interaction region on the angle of birefringence in the direction of phase matching is determined for ah optical parametric oscillator utilizing an anisotropic uniaxial crystal with a quadratic nonlinearity. The analysis is made assuming a strong feedback at both parametric frequencies and the optimal focusing of the interacting waves.