Wavelength selective optical switch device and method of controlling characteristics thereof

A wavelength selective optical switch device comprising:

• an incidence part where a signal beam made of light of a multiplicity of wavelengths enters;
• a wavelength dispersion element where a signal beam that has entered from the incidence part is spatially dispersed according to the wavelength thereof;
• a first condensing element that condenses the light dispersed by the wavelength dispersion element onto a two-dimensional plane;
• a wavelength selection element that uses a multilevel optical phased array arranged in a position to receive incident light developed on an xy-plane made of an x-axis direction and a y-axis direction perpendicular thereto developed according to a wavelength, having a multiplicity of pixels arrayed in a lattice on the xy-plane, and that cyclically changes the two dimensional phase shift characteristic of each pixel to a sawtooth wave pattern;
• a wavelength selection element drive part that drives an electrode for each pixel arrayed in an xy direction of the wavelength selection element, generates a composite wave of two or more sawtooth waves along the y-axis for all pixels on the y-axis that have an x-coordinate common with at least one pixel on the x-axis, changes a phase shift amount according to the composite wave, and transmits light of a wavelength applied to that pixel in a plurality of directions;
• a second condensing element that condenses the light of each wavelength transmitted by the wavelength selection element;
• and
• a wavelength combining element that respectively combines dispersed light condensed by the second condensing element for each incident position.