Applications of the Photorefractive Effect and Damage Induced Effects in Fibers
Annual rept. 1 Nov 1990-31 Oct 1991,
JOINT INST FOR LAB ASTROPHYSICS BOULDER CO
Pagination or Media Count:
One aspect of this work concerns the processes of self-organized second-harmonic generation in fibers. We have experimentally investigated the nature of grating formation in the glass fibers and found it to be reversible. That is, a grating can be repetitively written, erased, and re-written. We have also shown that the grating erasure follows a power-law time dependence and explain the dependence as a consequence of the transverse mode structure of the fields in the fiber. Numerical work has focused on the microscopic aspect of ionization from a model defect potential. We have integrated Schrodingers equation exactly in the one-dimensional case. Results so far indicate that a photovoltaic explanation of second-harmonic generation in fibers is robust against variation of the physical parameters of the model. The second aspect concerns the dynamics and self-organization of photorefractive optical circuits. We have produced circuits that self-organize according to the nature of their time dependent input. After self-organizing they process information in an adaptive and useful way. Our most highly developed circuit is a demultiplexer that separates signals from a multimode fiber.
- Electrooptical and Optoelectronic Devices
- Fiber Optics and Integrated Optics