Heat assisted magnetic recording write apparatus having an inverse tapered waveguide

A heat assisted magnetic recording write apparatus comprising:

• a waveguide optically coupled to a laser of the heat assisted magnetic recording write apparatus to transfer energy from the laser towards a media facing surface in a transmission direction, the waveguide having an entrance proximate to the laser and an exit proximate to the media facing surface, and comprising a mode converter between the entrance and the exit,
• wherein the mode converter comprises:
• a core having sides diverging from a first width proximate to the entrance to a second width proximate to the exit in the transmission direction, the first width being less than the second width and a function of a characteristic wavelength of the energy,
• an inner cladding surrounding at least a portion of the core, and
• an outer cladding surrounding at least a portion of the inner cladding.

A write apparatus comprising:

• a waveguide having an entrance distal from a media facing surface of the heat assisted magnetic recording write apparatus and an exit proximate to the media facing surface, and comprising a mode converter between the entrance and the exit, wherein the waveguide is configured to direct energy from the entrance towards the exit via the mode converter in a transmission direction, and
• wherein the mode converter comprises:
• a core having a first width proximate to the entrance and a second width that is greater than the first width proximate to the exit in the transmission direction,
• an inner cladding surrounding at least a portion of the core,
• an outer cladding surrounding at least a portion of the inner cladding,
• a first high index layer above the core in a direction perpendicular to the transmission direction and between the inner cladding and the outer cladding, and
• a second high index layer between the inner cladding and the outer cladding below the core in the layer direction.