Abstract

We have confirmed, for what we believe to be the first time, the presence of a built-in field in fibers which have been optically conditioned to produce second harmonic (SH) radiation. It is now well accepted that the optical conditioning occurs through the mixing of the fundamental and SH seeding fields such that a periodic χ⁽²⁾ is established in the fiber.⁽¹⁾ The details of the mixing mechanism are still open to considerable debate, although most of the proposed models necessitate the existence of an internal dc electric field.^(1),(2),(3) a measurement of the magnitude of the internal field is thus of fundamental importance.

© 1990 Optical Society of America