WAVELENGTH SHIFTING AND AMPLIFICATION OF OPTICAL PULSES THROUGH CASCADED 2ND-ORDER PROCESSES IN PERIODICALLY POLED LITHIUM-NIOBATE

We investigate the efficiency of wavelength shifting (generation of a pulse at the wavelength lambda(p) -Delta lambda from a signal at lambd a(p)+Delta lambda under the action of a pump at lambda(p)) and paramet ric amplification through a cascaded second-order process in a periodi cally poled lithium niobate crystal. Our results show that, in a 19-mm -long sample, at lambda(p) = 1.8 mu m and Delta lambda as large as 60 nm, wavelength shifting with unit gain can be obtained with a pump int ensity of 6 MW/cm(2), while amplification by a factor 10 requires 18 M W/cm(2). (C) 1998 American Institute of Physics.