Method and system for enhancing optical efficiency for an EAMR head

A waveguide for use in an energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer including a write pole configured to write to a region of the media, at least one coil for energizing the write pole, and a near field transducer (NFT) proximate to the ABS for focusing the energy onto the region of the media, the waveguide comprising:

• a first cladding layer;
• a core configured to direct the energy from the laser toward the ABS, the core having a core index of refraction;
• a second cladding layer, the core residing between the first cladding layer and the second cladding layer;
• and
• a mode shift compensator, the core residing between the mode shift compensator and the NFT, the mode shift compensator having a mode shift compensator index of refraction less than the core index of refraction;
• wherein at least a portion of the second cladding layer resides between the core and the NFT and wherein a portion of the first cladding layer resides between the core and the mode shift compensator.

An energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer comprising:

• a write pole configured to write to a region of the media;
• at least one coil for energizing the write pole;
• a near field transducer (NFT) proximate to the ABS for focusing the energy onto the region of the media;
• a waveguide including a first cladding layer having a first cladding index of refraction, a second cladding layer having a second cladding index of refraction, a core, and a mode shift compensator, the core residing between the first cladding layer and the second cladding layer, the core configured to direct the energy from the laser toward the ABS and having a core index of refraction, the core residing between the mode shift compensator and the NFT, the mode shift compensator having a mode shift compensator index of refraction less than the core index of refraction, the mode shift compensator index of refraction being less than the first cladding layer index of refraction and less than the second cladding layer index of refraction, the NFT residing in the second cladding layer.

An energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer comprising:

• a write pole configured to write to a region of the media;
• at least one coil for energizing the write pole;
• a near field transducer (NFT) proximate to the ABS for focusing the energy onto the region of the media;
• a waveguide including a first cladding layer, a second cladding layer, a core, and a mode shift compensator, the core residing between the first cladding layer and the second cladding layer, the core configured to direct the energy from the laser toward the ABS and having a core index of refraction, the core residing between the mode shift compensator and the NFT, the mode shift compensator having a mode shift compensator index of refraction less than the core index of refraction, the NFT residing in the second cladding layer;
• wherein at least a portion of the second cladding layer resides between the core and the NFT and wherein at least a portion of the first cladding layer resides between the core and the mode shift compensator.

A method for providing a waveguide for use in an energy assisted magnetic recording (EAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the EAMR transducer including a write pole configured to write to a region of the media, at least one coil for energizing the write pole, and a near field transducer (NFT) proximate to the ABS for focusing the energy onto the region of the media, the method comprising:

• providing a first cladding layer having a first cladding index of refraction;
• providing a mode shift compensator having a mode shift compensator index of refraction;
• providing a core configured to direct the energy from the laser toward the ABS, the core having a core index of refraction and residing between the mode shift compensator and the NFT, the mode shift compensator index of refraction being less than the core index of refraction;
• providing a second cladding layer having a second cladding layer index of refraction, the core residing between the first cladding layer and the second cladding layer, the mode shift compensator index of refraction being less than the first cladding layer index of refraction and less than the second cladding layer index of refraction.