Two nonlinear crystals could make phase-insensitive all-optical transistor

Two nonlinear crystals could make phase-insensitive all-optical transistor

A report on cascaded second-order nonlinearities in optical materials opened the Nonlinear Optics sessions of the 1996 OSA Summer Topical Meetings (July 8?12, Maui, HI); sessions on adaptive optics and optical data storage were run concurrently. Cascading in second-

harmonic-generating crystals can be exploited to produce a phase-insensitive all-optical

transistor (AOT), unlike other proposed AOTs that require coherence between signal and pum¥waves. A grou¥from the University of Central Florida/CREOL (Orlando, FL) has proposed an AOT incorporating a pair of type II phase-matched second-order nonlinear crystals: the coupler and the amplifier. A beamsplitter divides the system pum¥beam into two orthogonally polarized components, one of which passes through the coupler, where it is modulated by a weak, temporally incoherent signal beam with a gain of less than unity. Before entering the amplifier crystal, the modulated beam recombines with the unmodulated pum¥component. In the crystal, small irradiance variations between the modulated and unmodulated beams result in the desired large modulations in the total transmitted fundamental radiation.

The grou¥has demonstrated the coupler and amplifier components of the AOT; work on a device combining the two is underway. Collaborator Eric Van Stryland presented experimental results from the demonstrations and mathematical models of the full AOT at the topical meeting.