Heat-assisted magnetic recording head with an integrated photodiode

A heat-assisted magnetic recording head comprising:

• a laser configured to emit electromagnetic radiation;
• a near-field transducer configured to focus and emit an optical near-field;
• a photodiode configured to receive a portion of the electromagnetic radiation;
• a primary waveguide comprising:
• a first segment adjacent to the laser;
• a second segment adjacent to the near-field transducer;
• and
• a third segment disposed between the first segment and the second segment of the primary waveguide;
• and
• a secondary waveguide comprising:
• a first segment adjacent to the photodiode;
• a second segment that is at an opposite end of the secondary waveguide from the first segment;
• and
• a third segment disposed between the first segment and the second segment of the secondary waveguide.

A heat-assisted magnetic recording head comprising:

• a laser configured to emit electromagnetic radiation;
• a near-field transducer configured to focus and emit an optical near-field;
• a photodiode configured to receive a portion of the electromagnetic radiation;
• a primary waveguide comprising:
• a first segment adjacent to the laser and coupled to a coupler that is configured to direct the electromagnetic radiation emitted by the laser into the primary waveguide;
• a second segment adjacent to the near-field transducer;
• and
• a third segment disposed between the first end and the second end of the primary waveguide;
• and
• a secondary waveguide comprising:
• a first segment adjacent to the photodiode;
• a second segment that is at an opposite end of the secondary waveguide from the first segment;
• and
• a third segment disposed between the first end and the second end of the primary waveguide,
• wherein the third segment of the primary waveguide and the third segment of the secondary waveguide are adjacent and substantially parallel to each other and are separated by a gap.

A heat-assisted magnetic recording head comprising:

• a laser configured to emit electromagnetic radiation;
• a near-field transducer configured to focus and emit an optical near-field;
• a primary waveguide configured to receive the electromagnetic radiation and propagate the electromagnetic radiation toward and proximal to the near-field transducer;
• a secondary waveguide configured to receive a portion of the electromagnetic radiation from the primary waveguide;
• and
• a photodiode configured to receive the portion of the electromagnetic radiation from the secondary waveguide and emit a signal that represents a magnitude of the electromagnetic radiation that the laser emits, the secondary waveguide further configured to mitigate reflections of the electromagnetic radiation from reaching the photodiode,
• wherein:
• the primary waveguide comprises an end adjacent to the laser,
• a segment of the primary waveguide that comprises the end of the primary waveguide is coupled to a coupler configured to direct electromagnetic radiation emitted by the laser into the primary waveguide, the coupler comprising an escape slab configured to disperse stray electromagnetic radiation, and
• the secondary waveguide comprises a first end and a second end, the first end being adjacent to the photodiode and a segment of the secondary waveguide that comprises the second end is coupled to the escape slab.