We produce periodically-poled lithium niobate (PPLN) jin two forms: as a bulk crystal with a thickness of up to 1 mm, and as a waveguide device. Bulk PPLN crystals are tailored for the production of tunable mid-infrared radiation through pumping by commonly-available lasers with wavelengths near 1m. Bulk PPLN devices can produce several W of average power between 2 and 4 micron.