| 摘要 |
A waveguide (and a method for fabrication of a waveguide) for electromagnetic waves, arranged in an optically non-linear crystal substrate (1), such as LiNbO3, LiTaO3 or KTiOPO4, whereby a periodically domain-inverted structure, with periodically reversed ferroelectric polarity, is provided in a channel waveguide (6), having a higher refractive index than other parts of the substrate. The regions of reversed ferroelectric polarity are achieved by means of a heat treatment yielding a domain-inversion governed by a periodic perturbation in the crystal surface, obtained by use of a periodic mask structure on the crystal surface. The periodic structure is arranged in such a way that it constitutes a quasi-phase-matching structure. Thereby the waveguide is capable of converting light or radiation of a certain wavelength (certain wavelengths) to light or radiation of another predetermined wavelength (other predetermined wavelengths) with high efficiency. |
