Efficient wide-band and tunable midspan spectral inverter using cascaded nonlinearities in LiNbO3 waveguides

We report on efficient (-7-dB fiber-to-fiber), wide-band (over 70 nm), tunable, and excess-noise-free mid-span spectral inverters based on cascaded second-order nonlinearities in periodically poled LiNbO/sub 3/ waveguides. We demonstrate their performance in a 4/spl times/10 Gb/s transmission over 150 km of standard single-mode fiber.