The theoretical analysis and experimental results of the wavelength tunability of a tandem optical parametric oscillator (TOPO) based on a single nonlinear crystal are presented. TOPO is a configuration wherein the signal laser is used as a pump laser to generate secondary optical parametric oscillator (OPO). The cascaded parametric interactions are achieved synchronously in a single-grating-period MgO doped periodically poled lithium niobate (PPMgOLN). Tunable multiple-wavelength mid-infrared (
