Optical damage control via the Fe2+/Fe3+ ratio in proton-exchanged LiNbO3 waveguides.
Intensity thresholds for the onset of optical damage in alpha-phase proton-exchanged waveguides on undoped LiNbO(3) have been increased from the substrate value to a factor 500 greater. This has been achieved by increasing the exchange time, which in turn increases the [Fe(2+)]/[Fe(3+)] ratio in the guide. Intensity thresholds have been measured with a single-beam configuration, while [Fe(2+)]/[Fe(3+)] ratios have been determined from decay measurements during optical erasure of photorefractive gratings. In heavily Fe-doped guides, thresholds are too small to be measured, but the dependence of the Fe(2+) absorption on the exchange time appears similar to undoped samples.
Carnicero
J
J
Departamento de Física de Materiales C-IV, Universidad Autónoma de Madrid, Cantoblanco 28049-Madrid, Spain.
Carrascosa
M
M
Mendez
A
A
García-Cabañes
A
A
Cabrera
J M
JM