Electro-optically tunable filter with mesh structure to filter optical signal

A tunable electro-optical filter, comprising:

• a single electro-optical crystal having an input portion and an output portion, the output portion diametric to the input portion, wherein the electro-optical crystal changes its refractive index when an electric field is applied to it;
• an electrode covering and in electrical contact with a selected one of said portions of the electro-optical crystal;
• and
• electrically conductive material arranged to form a grid pattern on the non-selected one of said portions of the electro-optical crystal, said grid pattern adapted to filter a received wide band optical signal to provide a filtered optical signal of selected narrow passband, said grid pattern further adapted to cooperatively act with the electrode to apply an electric field to the electro-optical crystal.

A method of producing a narrow band optical signal from a wider band optical signal, comprising;

• placing a mesh formed of electrically conductive material and configured to operate as an optical filter on a first face of an electro-optical crystal;
• projecting the wider band optical signal through the mesh so that the wider hand signal is filtered by the mesh to produce the narrow band optical signal, and the narrow band signal is applied to the first face of the electro-optical crystal as the input thereto;
• and
• applying a voltage to the mesh and to an electrode located on a second face of the electro-optical crystal diametric to the first face to select the spectral position of the narrow band optical signal when the narrow band signal is outputted from the electro-optical crystal.

A tunable electro-optical filter, comprising:

• an electro-optical crystal having an input portion and an output portion, the output portion diametric to the input portion, wherein the electro-optical crystal changes its refractive index when an electric field is applied to it, the electro-optical crystal being further provided with first and second sides in diametrically opposing relationship with each other, both of said sides extending between the input and output portions of the electro-optical crystal;
• an electrically conductive mesh filter covering and in electrical contact with the input portion of the electro-optical crystal, wherein the electrically conductive mesh filter is adapted to filter a received optical signal and to provide an input signal of selected narrow passband;
• a first electrode covering and in electrical contact with said first side of the electro-optical crystal and contiguous to the electrically conductive mesh filter;
• a second electrode covering and in electrical contact with said second side of the electro-optical crystal, contiguous to the electrically conductive mesh filter and diametric to the first electrode;
• and
• a voltage source in electrical contact with the first electrode and the second electrode.