Abstract

A compact coherent blue light source is strongly desired for higher density optical disc systems. Several types of blue second-harmonic generation (SHG) have been reported thus far.^1-3. Among them, only Cerenkov radiation SHG is free from the severe phase-matching constraint and is rather stably obtained regardless of the small changes in a temperature and of a fundamental wavelength. However, the wave front has alarge abberation fora proton-exchanged LiNbO₃ waveguide¹ because of a large (16°) radiation angle. The aberration becomes much smaller if the radiation angle is reduced to less than 1°. Realizing a small (<1°)radiation angle and a high SHG efficiency at the same time is the objective of this research.

© 1991 Optical Society of America