Thin film optical waveguide and optical deflecting device

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which guides a light beam;
• an optical buffer layer which is provided between the substrate arid the piezoelectric waveguide layer, the optical buffer layer having a refractive index smaller than a refractive index of the piezoelectric waveguide layer and having a thickness such that the waveguide layer has a propagation loss of not more than 2 dB/cm for a zero mode guided light beam guided by the waveguide layer, and a propagation loss of not less than 4 dB/cm for a first mode guided light beam guided by the waveguide layer;
• light emergence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• and
• generating means for generating surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer.

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• and
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer.

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer;
• and
• an optical buffer layer which is provided between the substrate and the piezoelectric waveguide layer and has a refractive index smaller than a refractive index of the piezoelectric waveguide layer.

An optical deflecting device comprising:

• a substrate:
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer;
• and, an optical buffer layer of a SiO.sub.2 thin film which is provided between the substrate and the piezoelectric waveguide layer.

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• and
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer, wherein:
• the piezoelectric waveguide layer is a ZnO thin film;
• and
• the following condition is fulfilled:
• 1.0<hK<5.0(K=2 .pi./.LAMBDA.)
• wherein, h is a thickness of the ZnO thin film,
• and .LAMBDA. is wavelengths of the Sezawa waves.

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• and
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer, wherein:
• the piezoelectric waveguide layer is a ZnO thin film;
• and
• the following condition is fulfilled:
• 2.0<hK<2.9(K-2 .pi./.LAMBDA.)
• wherein, h is a thickness of the ZnO thin film,
• and A is wavelengths of the Sezawa waves.

An optical deflecting device comprising:

• a silicon substrate;
• a piezoelectric waveguide layer which is provided on the substrate;
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• generating means for generating Sezawa waves as surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer;
• and
• an optical buffer layer of a SiO.sub.2 thin film which is provided between the substrate and the piezoelectric waveguide layer.

A thin film optical waveguide comprising:

• a substrate;
• a waveguide layer which guides a light beam;
• and
• an optical buffer layer which is provided between the substrate and the waveguide layer, the optical buffer layer having a refractive index smaller than a refractive index of the waveguide layer wherein:
• the waveguide layer and the optical buffer layer are ZnO and SlO.sub.2, respectively;
• a guided light beam with a wavelength of 780 nm is guided by the waveguide layer;
• and
• the waveguide layer and the optical buffer layer have a thickness of h.sub.1 .mu.m and a thickness of h.sub.2 .mu.m, respectively, which meet the following conditions:
• h.sub.2 .ltoreq.-0.035h.sub.1 +0.325(.mu.m)
• h.sub.2 .gtoreq.-0.050h.sub.1 +0.450(.mu.m)
• h.sub.1 .gtoreq.0.300(.mu.m).
• 20.

An optical deflecting device comprising:

• a substrate;
• a piezoelectric waveguide layer which guides a light beam;
• an optical buffer layer which is provided between the substrate and the piezoelectric waveguide layer, the optical buffer layer having a refractive index smaller than a refractive index of the piezoelectric waveguide layer wherein:
• the waveguide layer and the optical buffer layer are ZnO and SiO.sub.2, respectively;
• a guided light beam with a wavelength of 780 nm is guided by the waveguide layer;
• and
• the waveguide layer and the optical buffer layer have a thickness of h.sub.1 .mu.m and a thickness of h.sub.2 .mu.m, respectively, which meet the following conditions:
• h.sub.2 .ltoreq.-0.035h.sub.1 +0.325(.mu.m)
• h.sub.2 .gtoreq.-0.050h.sub.1 +0.450(.mu.m)
• h.sub.1 .gtoreq.0.300(.mu.m).
• light incidence means for making a light beam couple to the piezoelectric waveguide layer;
• light emergence means for making a guided light beam progressing in the piezoelectric waveguide layer emergent therefrom;
• and
• generating means for generating surface acoustic waves which are propagated on the piezoelectric waveguide layer in such a direction as to cross the guided light beam progressing in the piezoelectric waveguide layer.