[en] A picosecond traveling-wave parametric device capable of controlled spectral bandwidth and wavelength in the infrared is reported. Intense 1.064 mu M picosecond pulses pass through a 4.5 cm long LiNbO³ optical parametric oscillator crystal set at its degeneracy angle. A broad band emerges, and a simple grating and mirror arrangement is used to inject a selected narrow-band into a 2 cm long LiNbO³ optical parametric amplifier crystal along a second pump line. Typical input energies at 1.064 mu M along both pump lines are 6-8 mJ for the oscillator and 10 mJ for the amplifier. This yields 1 mJ of tunable output in the range 1.98 to 2.38 mu M which when downconverted in a 1 cm long CdSe crystal mixer gives 2 mu J of tunable radiation over the 14.8 to 18.5 mu M region. The bandwidth and wavelength of both the 2 and 16 mu M radiation output are controlled solely by the diffraction grating