Abstract
Permanent photo-induced index gratings can be written internally1 or externally2 in high silica optical fibers using blue-green light (by two-photon absorption) or ultraviolet light (by one-photon absorption). The longest wavelength of light that can photoinduce gratings in the core of Ge-doped fibers is determined by the long wavelength cutoff (550 nm) for two-photon absorption.3 We show that grating fabrication can be extended to wavelengths>550 nm by resorting to a photoerasure process. To prepare a fiber for photoerasure it is exposed first to UV light pulses that increase the refractive index of the Ge-doped-core photosensitive fiber. The pulses have relatively low energy and are delivered at a slow pulse repetition rate to facilitate subsequent photoerasure. Light with wavelength >550 nm can write a grating by spatially selective erasure of the UV-induced increase in refractive index. Photobleaching of light-induced absorption4 using short wavelength light has been described before but, to our knowledge, long wavelength photoerasure of the index change is a new observation.
© 1992 Optical Society of America
PDF ArticleMore Like This
V. Grubsky, D. S. Starodubov, and J. Feinberg
BME.3 Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides (BGPP) 1997
Hiroaki Inoue, Hirohisa Sano, and Shinji Nishimura
WH6 Integrated Photonics Research (IPR) 1992
L. Dong, P. J. Wells, D. P. Hand, and D. N. Payne
JTuB2 Conference on Lasers and Electro-Optics (CLEO:S&I) 1991