Line-width narrowing for nanosecond PPLN optical parametric generation (OPG) by injection seeding

Summary form only given. We report a nanosecond optical parametric generator (OPG) using periodically poled lithium niobate (PPLN). The line-width of the OPG radiation was reduced to about 500 MHz by injection seeding with a Rittrow- or Rittman-type LD. Although an injection seeded PPLN-OPG has previously been reported, our system has simpler wavelength tuning using a telecom-type LD. The OPG radiation was easily tuned by changing the wavelength of the injection seeder radiation, and was mode-hop free. The mode-hop free performance of the OPG radiation made gas spectroscopy easy to perform. An example is shown of the measured absorption spectrum of N/sub 2/O gas.