HAMR read-write head with coupler and waveguide
Described are heat assisted magnetic read-write heads that include a coupler, a waveguide, a transducer, and appurtenant structures, as well as related methods.
1. An apparatus comprising:
an optical coupler that receives light from a light source at a coupler input facet, the optical coupler having a length extending from the input facet in a direction of light propagation through the coupler,
a waveguide coupled to the optical coupler at a coupler-waveguide interface,
a diffractive cavity coupled to the optical coupler between the input facet and the coupler-waveguide interface, wherein the diffractive cavity has a focusing structure that produces a lensing effect,
a near-field transducer coupled to the waveguide, that provides electromagnetic heating for a heat assisted magnetic recording write head.
2. An apparatus of claim 1 , the diffractive cavity is a disk-shaped cavity having a radius in a range from 0.5 to 3 microns.
3. An apparatus of claim 1 , the coupler having a length, measured from a coupler input facet to a location at a distal end of the coupler-waveguide interface, in a range from 7 to 40 microns.
4. An apparatus of claim 1 , the coupler having a width in a range from 1 to 5 microns.
5. An apparatus of claim 1 , the coupler having a thickness in a range from 0.7 to 1.2 microns.
6. An apparatus of claim 1 , comprising a laser adapted to emit light into the input facet, the laser having a length of at least 100 microns.
7. An apparatus of claim 1 wherein a refractive index of the diffractive cavity is the same as the refractive index of the waveguide.
8. An apparatus of claim 1 , wherein the waveguide is made of NbOx.
9. An apparatus of claim 1 , wherein the diffractive cavity is made of NbOx.
10. An apparatus of claim 1 , wherein the coupler comprises a straight portion that is in optical communication with the diffractive cavity, and the straight portion is made of SiON.
11. An apparatus of claim 1 , comprising cladding that surrounds the coupler, wherein the cladding is made of SiO 2 .
12. An apparatus of claim 1 , the coupler having a length, measured from a coupler input facet to a location at a distal end of the coupler-waveguide interface, in a range from 7 to 40 microns, and the apparatus comprising a laser adapted to emit light into the input facet, the laser having a length of at least 100 microns.
13. A method of recording data using an apparatus of claim 1 .
14. A method of recording data using a heat assisted magnetic recording head, the magnetic recording head comprising:
a light source,
an optical coupler that receives light from the light source at a coupler input facet, the optical coupler having a length extending from the input facet in a direction of light propagation through the coupler,
a waveguide coupled to the optical coupler at a coupler-waveguide interface,
a diffractive cavity coupled to the optical coupler between the input facet and the coupler-waveguide interface, wherein the diffractive cavity has a focusing structure that produces a lensing effect,
a near-field transducer coupled to the waveguide, that provides electromagnetic heating for a heat assisted magnetic recording write head,
the method comprising:
activating the light source to direct light into the coupler input facet,
allowing the light to propagate through the coupler and into the waveguide, to be received by the near-field transducer.
15. A method of claim 14 , the diffractive cavity having a radius in a range from 0.5 to 3 microns.
16. A method of claim 14 , the diffractive cavity having a height in a range from 70 to 170 nanometers.
17. A method of claim 14 , the coupler having a length, measured from a coupler input facet to a location at a distal end of the coupler-waveguide interface, in a range from 7 to 40 microns.
18. A method of claim 14 , wherein the light source is a laser having a length of at least 100 microns.
19. A method of claim 14 , the coupler having a length, measured from a coupler input facet to a location at a distal end of the coupler-waveguide interface, in a range from 7 to 40 microns, and the apparatus comprising a laser adapted to emit light into the input facet, the laser having a length of at least 100 microns.
20. A method of preparing a light guidance system comprising an apparatus of claim 1 , the apparatus comprising:
a laser light source,
an optical coupler that receives light excited by a light source at a coupler input facet, the coupler having a length extending from the input facet in a direction of light propagation through the coupler,
a waveguide coupled to the optical coupler at a coupler-waveguide interface,
a diffractive cavity coupled to the optical coupler between the input facet and the coupler-waveguide interface,
a near-field transducer coupled to the waveguide, that provides electromagnetic heating for a heat assisted magnetic recording write head,
wherein the light guidance system experiences mode hopping that varies based on a length of the laser,
the method comprising forming the laser to have a length that corresponds to a region of a minimum on a curve of mode hop effect versus laser length.