TRAVELING-WAVE OPTICAL PARAMETRIC-AMPLIFIER - INVESTIGATION OF ITS PHASE-SENSITIVE AND PHASE-INSENSITIVE GAIN RESPONSE

We experimentally investigate the gain response of a frequency-degener ate but polarization-nondegenerate traveling-wave optical parametric a mplifier that consists of a type II phase-matched potassium titanyl ph osphate crystal pumped by a frequency-doubled Q-switched mode-locked N d:YAG laser. Both the optical phase-sensitive and phase-insensitive co nfigurations of the parametric amplifier are studied. Experimental res ults are in excellent agreement with the theory of an optical parametr ic amplifier when the Gaussian-beam nature of the various fields is ta ken into account. In the phase-sensitive configuration a gain of >100 (20 dB) could of gain-induced diffraction and phase fluctuations, howe ver, maximum deamplification in the orthogonal quadrature is limited t o <0.5 (-3 dB). (C) 1997 Optical Society of America.