Patent ID: 7330619

Claim:
An optical apparatus, comprising a substrate; a first planar optical waveguide formed on the substrate comprising a first transmission core and cladding; a second planar optical waveguide formed on the substrate comprising a second transmission core and cladding; a third planar optical waveguide formed on the substrate comprising a third transmission core and cladding; a laser positioned so as to launch at least a portion of its optical output to propagate along the first transmission core toward its proximal end; a photodetector positioned so as to receive at least a portion of an optical signal propagating along the second transmission core away from its proximal end; a first tap core segment connecting the first and third transmission cores at their respective proximal ends; and a second tap core segment connected to the proximal end of the second transmission core, wherein: the first and second tap core segments are positioned in a substantially parallel spaced-apart arrangement, so that a first fraction of the laser optical output propagating along the first transmission core toward its proximal end is transferred to propagate along the second transmission core away from its proximal end by optical transverse coupling between the first and second tap core segments; a second fraction of the laser optical output propagating along the first transmission core toward its proximal end is transferred to propagate along the third transmission core away from its proximal end by optical propagation along the first tap core segment; a volume between the tap core segments is substantially filled with cladding so that the second transmission core and the second tap core segment are spatially disjoint from the first tap core segment and the first and third transmission cores; and the second tap core segment and a proximal portion of the second transmission core form an obtuse angle with respect to one another, and respective proximal portions of the second and third transmission cores form an acute angle with respect to one another.