When a waveguide of second signal light outputted from a first optical coupler intersects a waveguide of first local light outputted from a second optical coupler, a waveguide of a first signal light outputted from the first optical coupler and a waveguide of a second local light outputted from the second optical coupler are each provided with a loss compensation intersecting waveguide that compensates for loss that occurs when the waveguide of the second signal light outputted from the first optical coupler intersects the waveguide of the first local light outputted from the second optical coupler.