Package to die optical coupler having high coupling efficiency and alignment tolerance

An apparatus, comprising:

• a first waveguide disposed in or on an integrated circuit package, the first waveguide supporting a single or multiple optical modes;
• a waveguide set disposed in or on an integrated circuit die, the optical modes of the first waveguide being larger than a width of a subset of waveguides in the set of waveguides;
• a light combiner formed in or on the integrated circuit die and coupled at one end to the waveguide set;
• and
• a second waveguide formed in or on the integrated circuit die and coupled at a second end to the light combiner.

A method, comprising:

• propagating light in a first waveguide core disposed in or on an integrated circuit package;
• coupling the light to a subset of waveguide cores in a waveguide core set disposed in or on an integrated circuit die, the first waveguide core having a first index of refraction, each waveguide core in the waveguide core set having a second index of refraction, the first index of refraction being smaller than the second indices of refraction;
• merging light from the waveguide core set to a waveguide disposed in or on the integrated circuit die;
• and
• propagating the merged light to a waveguidc disposed in or on the integrated circuit die.

A system, comprising:

• a microprocessor package having a first waveguide disposed therein or thereon, the first waveguide having an optical mode;
• and
• a static random access memory (SRAM) die having:
• a waveguide set disposed therein or thereon, the optical mode of the first waveguide being larger than a width of a subset of waveguides in the set of waveguides;
• a light combiner formed in or on the SRAM die and coupled at one end to the waveguide set;
• and
• a second waveguide formed in or on the SRAM die and coupled at a second end to the light combiner.

An apparatus, comprising:

• a first waveguide core disposed in or on an integrated circuit die, the first waveguide core a first index of refraction and a first width;
• a set of waveguide cores disposed in or on the integrated circuit die, each waveguide core in the set of waveguide cores having a second index of refraction higher than the first index of refraction and a second width smaller than the first width;
• a cladding material disposed between the first waveguide core and the set of waveguide cores to mount the first waveguide to the set of waveguides;
• several waveguide combiners disposed in or on the integrated circuit die, each waveguide combiner coupled to at least two waveguide cores in the set of waveguide cores;
• and
• a planar waveguide formed in or on the integrated circuit die and coupled to the waveguide combiners.