Abstract

A nondegenerate optical parametric amplifier (NOPA) is equivalent to two independent degenerate optical parametric amplifiers (DOPA's). Using this property and with a proper choice for the NOPA input state, one can produce squeezed-vacuum at the output of one DOPA and a spatio-temporally matched local oscillator (LO) at the output of the other. Using such a matched LO for detecting the squeezing generated by the first DOPA we have measured up to 5.8 dB of quadrature squeezing-the highest ever observed in a traveling-wave experiment [1]. In this paper we report that the above equivalence can also be utilized to generate sub-Poissonian light. The NOPA input state can be chosen in such a way that when the output of one DOPA is maximally amplified, which occurs for a given pump-phase setting, that of the other is maximally deamplified. If the amplified output is direct detected and used to lock the pump phase, then the output of the deamplified DOPA locks into an amplitude squeezed (sub-Poissonian) state. Upon direct detection the noise on the deamplified DOPA output falls below the shot-noise limit.

© 1994 Optical Society of America