High-speed properties of a phase-modulation scheme based on electromagnetically induced transparency

Recently a cross-phase modulation scheme that yields giant Kerr nonlinearities by use of an electromagnetically induced transparency (EIT) was proposed [Schmidt and Imamoglu, Opt. Lett. 21, 1936 (1996)]. We analyze the high-speed properties of this scheme for short-pulse propagation. the high-speed properties of this scheme for short-pulse propagation. system and show that for short pulses one-photon losses are dominant. We demonstrate that over the entire width the attainable phase shift in an EIT scheme with a quasi-cm coupling field is orders of magnitude higher than in a conventional three-level scheme or in EIT schemes, in which matched pulses are used to create the transparency. (C) 1998 Optical Society of America.