OPTICAL WAVELENGTH CONVERTER

摘要

In accordance with the invention there is provided an optical wavelength conversion device. The conversion device comprises a micro-structured optical waveguide, which includes sections with a non-linear material having an index of refraction which changes as a non-linear function of light intensity. The optical waveguide includes a light guiding core region, and the waveguide is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. The conversion device further comprises a first optical light source for introducing light into the waveguide in a mode guided along the core, and a second intensity modulated light source for introducing encoding light into the waveguide in such a manner that it illuminates the sections filled with a non-linear material. The second light source has an intensity modulation sufficient to change the refractive index of the non-linear material by an amount sufficient to encode or modulate the light from the first optical light source accordingly, whereby the encoding takes place through the effect of leaking light from the first light source from the inside of the guiding core to the outside of the guiding core. The micro-structured optical waveguide may comprisean optical fibre, in which the light from the first light source may be guided by different types of waveguiding principles including total internal reflection or by photonic bandgap effects. In an alternative embodiment the micro-structured optical waveguide may comprise an optical planar waveguide. The conversion device includes embodiments in which the encoding light from the secondlight source and the light to be encoded or modulated from the first light source are co-propagating, are counter-propagating, or where the encoding light has a propagation direction different to the propagation direction of the light to be encoded. According to the invention there is also provided a micro-structured optical waveguide, which may have an axial direction, which waveguideincludes sections that are elongated in the axial direction and comprise a non-linear material having an index of refraction whichchanges as a non-linear function of light intensity. This optical waveguide, which may be an optical fibre, includes a light guiding core region, and the waveguide is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. There is furthermore provided an optical switching device and an optical intensity limiting device which may be based on the micro-structured optical waveguide of the invention.