In order to get more information about this topic you can read the papers

Mutually and self-pumped phase conjugation with fiber-like BTO crystals (Annual Report) Phase conjugation in fiber-like BTO-crystals with applied electric field (LASERS'98 Summary) Phase conjugation in fiber-like BTO-crystals with applied electric field (LASERS'98 Proc.)

or you can look at one of the posters.

Titel: Wechselseitig gepumpte und selbstgepumpte Phasenkonjugation in faserähnlichen BTO-Kristallen This Poster was presented at the Meeting of the German Society of Applied Optics 1998 in Bad Nenndorf, Germany	Titel: Phase conjugation in fiber-like BTO crystals with applied electric field This Poster was presented at the PR'99 1999 in Elsinore, Denmark