SINGLE WRITING SYSTEM FOR WIDE-AREA THERMAL ASSIST AND MAGNETIC RECORDING DISK DRIVE USING RECTANGULAR OPTICAL WAVEGUIDE

PROBLEM TO BE SOLVED: To minimize a temperature drop between peak temperature of a medium and temperature of a medium at a trailing edge of a writing pole while keeping a laser output necessary in a single writing system low.SOLUTION: A thermally-assisted recording disk drive uses a single recording system and a rectangular waveguide as a wide-area heat source. The waveguide generates an almost elliptical light spot for heating an area of a recording layer over a plurality of data tracks. A waveguide core positions peak light intensity near a trailing edge of a writing pole tip where writing occurs, and has an aspect ratio for achieving a desired heating area size at the same time. Large cross track width of the waveguide core increases the volume of a recording layer heated by the light spot, and lowers a cooling speed. Thus, a peak temperature point of the heating area is moved to the vicinity of the writing pole tip, and a temperature drop between peak temperature and temperature at the trailing edge of the writing pole tip where writing occurs is lowered.