OPTICAL PARAMETRIC AMPLIFICATION OF A 1.54-MU-M SINGLE-MODE DFB LASERIN A TI-LINBO3 WAVE-GUIDE

Optical parametric amplification of radiation from a 1.54-mu m single- mode DFB laser in a Ti:LiNbO3 waveguide has been investigated by measu ring the idler created in the nonlinear process. The pump was a freque ncy-doubled Nd:YAG laser at 532-nm wavelength, operated either Q-switc hed or both Q-switched and mode-locked, to avoid permanent surface dam age and to minimize photorefractive index changes. On comparison with theoretical predictions, the output was found to correspond to a pump power one order of magnitude below the true power in the waveguide. Th e highest gain obtained was 4.7 dB with 49 W of pump power in a 27-mm- long waveguide. Although the experimental results can be improved, it is obvious that the major difficulty to overcome is the large pump pow er required. The prospect of decreasing the power requirement by using materials with higher effective nonlinear coefficients or by using qu asi-phase-matching techniques is discussed. A more fundamental drawbac k is that the amplification is polarization dependent, and it is uncle ar it this can be handled.