Patent ID: 8908481

Claim:
A device, comprising: a laser unit configured to produce a laser light, the laser unit comprising a laser resonator having a length (L1) in a direction parallel to laser light emission; and a slider having a length (L2) in a direction perpendicular to a media-facing surface of the slider, the slider comprising: a main magnetic pole configured to write data to a magnetic medium; a near-field light-generating element configured to produce near-field light when laser light is provided thereto to assist the main magnetic pole in writing data to the magnetic medium by heating a local region of the magnetic medium; and a waveguide configured for guiding the laser light to the near-field light-generating element, the waveguide comprising a cladding surrounding a core, wherein an interval of a longitudinal mode of the laser resonator is equal to within about 5% of an integer multiplier of an optical interference period of the waveguide.