Kevin Richard Heim

Characterization of HAMR using pulsed laser light

Pulsed Heat Assisted Magnetic Recording (HAMR) is being developed to improve HAMR reliability. In conventional HAMR systems the laser is on and at a fixed power during the writing of the entire sector. In a pulsed HAMR implementation, the laser is turned on and off during the bit cell. For example, for a 50% duty cycle, the laser is on for half the bit cell and off for the remainder of the bit cell. Unlike traditional HAMR where the transitions are formed when the magnetic writer switches, in a pulsed implementation the transitions are formed during the pulsing of the laser. In this paper we show spin stand and drive recording performance of pulsed HAMR systems and compare the outcome to conventional recording. In particular, we show the importance and sensitivity of having proper alignment between the phase of the optical and magnetic signals and their effect on bit error rate (BER).