Abstract

Diffraction gratings are commonly used in integrated optics systems as frequency filters, Bragg reflectors, couplers, elements of multiplexing and demultiplexing devices and distributed feedback lasers. Traditional waveguide gratings have constant parameters and are sensitive for any production imperfections. Optically induced gratings are adjustable and therefore independent on fabrication errors and on the influence of external conditions. The grating created by two mutually coherent external waves interfering in a nonlinear material can be used for the same purposes as stable grating but obtained elements can be tuned in real-time by vary ing external waves parameters [1]. The grating created in photorefractive material does not require permanent illumination. It can be created by a short pulse of the external waves and last until the arrival of the next pulse which can renew or erase it [2].

© 2002 Optical Society of America