Large signal theory of mode characteristics and phase variations in degenerate four-wave mixing process/

Kazuhito Tajima, Hsiung Hsu

Yao Jian-Quan, Zhou Guosheng, Anthony E.. Siegman

Kazuhito Tajima, Hsiung Hsu

Large signal analyses for degenerate four-wave mixing (DFWM) have been reported for sometime(1-3). It was nevertheless not obvious why, in specific examples(1,2). DFWM exhibits hysteresis and bistability characteristics, whereas in the case of ideal phase conjugation(3), there is no such instability. The objective of this paper is to show that hysteresis and bistability are caused by phase variations in the interaction. These phase variations are detrimental to phase conjugation and may Indeed up-set the basic characteristies of phase conjugation.

K. Tajima, Hsiung Hsu

A large-signal theory of noncollinear degenerate four-wave mixing (DFWM) is presented, taking into account the pump depletion and the full nonlinear polarization density appropriate for the noncollinear geometry. Phases of all of the interacting fields, as well as the amplitudes, are obtained as functions of the spatial coordinate. Owing to the completeness of the set of analytic solutions, considerable physical insights into the physics of DFWM are obtained. The DFWM exhibits a variety of rich behaviors, including hysteresis and bistability, multistability, and multiple isolated branches. The authors show that all of these behaviors can be explained in a unified way, that is, in terms of mode hopping characteristics.>

Qiguang Yang, G. Xu, X. Liu +2 more

T. Mukai, Tadashi Saitoh

The optical nonlinearity in a semiconductor laser gain medium is investigated through copropagating nearly degenerate four-wave mixing (NDFWM) in a 1.5- mu m InGaAsP traveling-wave laser amplifier (TWA). The FWM signal output powers vary symmetrically with the sign of probe detuning with respect to the pump frequency, while the pump and probe output powers vary asymmetrically. The NDFWM conversion efficiency from the probe input to the FWM signal output is a maximum of 8.3 dB around zero detuning and has positive gain in the range of +or-6 GHz. This demonstrates highly efficient nonlinear interaction due to both large optical gain and large third-order susceptibility. The NDFWM efficiency is also investigated in connection with the TWA gain saturation characteristics and is found to be a maximum for operation around the saturation intensity of the TWA.>