Transition response characteristics of heat-assisted magnetic recording and their performance with MTR codes

The response of a heat-assisted magnetic recording (HAMR) system is very sensitive to the laser spot position. The response is determined by transition characteristics like the center, curvature, and length. In this paper, by using the thermal Williams-Comstock model and the microtrack model, the effects of laser spot position on transition characteristics are investigated for both longitudinal and perpendicular recording from a read channel systems perspective. The general trend in their variation is determined and used to explain the resultant change in response. By simulation, we determine the post-Viterbi dominant error events for longitudinal HAMR system. Finally, we apply the well-known MTR codes to mitigate such errors and present their bit-error performance.