Patent ID: 7013072

Claim:
An optical device comprising: a photonic waveguide which is formed in a photonic crystal having a three-dimensional periodic refractive index distribution, and in which the periodic refractive index distribution is locally disturbed; gain means for giving a gain to light propagating in said photonic waveguide; and reflecting means for reflecting light propagating in said photonic waveguide to reverse the propagating direction of the light, wherein resonance is generated by reversing the propagating direction of light propagating in said photonic waveguide by said reflecting means while a gain is given to the light by said gain means, wherein said photonic waveguide comprises a main waveguide portion substantially parallel to a principal surface of said photonic crystal and a branched waveguide portion connected at a substantially right angle to said main waveguide and extending toward the principal surface of said photonic crystal, and said reflecting means is formed at the end of said branched waveguide portion.