Patent ID: 8467642

Claim:
A waveguide type optical device comprising: at least one input channel waveguide formed on a waveguide substrate; an input slab waveguide connected to the input channel waveguide; an arrayed waveguide formed with a plurality of channel waveguides connected to the input slab waveguide; a polarization mode converter provided on the arrayed waveguide; an output slab waveguide connected to the arrayed waveguide; a temperature-dependence compensating material that is provided on the input slab waveguide, on the output slab waveguide, on the arrayed waveguide on the input slab waveguide side of the polarization mode converter, or on the arrayed waveguide on the output slab waveguide side of the polarization mode converter, and compensates for temperature dependence of an optical path length difference among the channel waveguides of the arrayed waveguide; at least one output channel waveguide connected to the output slab waveguide, wherein the polarization mode converter eliminates polarization dependence of each channel from the input slab waveguide to the output slab waveguide; wherein the polarization mode converter compensates for an optical path length difference between polarization modes on the input slab waveguide side of the polarization mode converter with an optical path length difference between polarization modes on the output slab waveguide side of the polarization mode converter; wherein, when ΔL″ represents an asymmetric correction length to be used by the polarization mode converter to correct an inter-channel difference in length from the input slab waveguide to the polarization mode converter on the input slab waveguide side of the polarization mode converter, an asymmetric correction length to be used by the polarization mode converter to correct an inter-channel difference in length from the output slab waveguide to the polarization mode converter on the output slab waveguide side of the polarization mode converter is −ΔL″, and the following equation is satisfied: Δ L″=−Δ×ΔL′/ 2 where ΔL′ represents an inter-channel difference in length of an inserted portion of the temperature-dependence compensating material, and A represents a value obtained by dividing birefringence of the input slab waveguide, the output slab waveguide, or the arrayed waveguide on which the temperature-dependence compensating material is placed, by birefringence of the arrayed waveguide.