Patent ID: 6993217

Claim:
An optical switch device for switching optical signals, comprising: a waveguide grating which includes, output waveguides arranged with such a pitch as to realize a split wavelength gap equal to or smaller than half of a gap between operating wavelengths of optical signals, at least two input waveguides arranged with the pitch, phase-difference waveguides which make optical path differences between portions of light which propagate through the phase-difference waveguides, a first slab waveguide which spreads first light transmitted from the at least two input waveguides so as to output the first light into the phase-difference waveguides, and condenses second light transmitted from the phase-difference waveguides so as to output the second light into the at least two input waveguides, and a second slab waveguide which condenses third light transmitted from the phase-difference waveguides, for each of a plurality of wavelength components of the third light, so as to separately output the plurality of wavelength components of the third light into the output waveguides, and spreads fourth light transmitted from the output waveguides so as to output the fourth light into the phase-difference waveguides; and an optical switch unit which selects different optical signals in an identical wavelength band in a pair of adjacent ones of the output waveguides, and performs 2×2 switching of the different optical signals so that the switched optical signals are outputted from the at least two input waveguides.