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This paper is about designing a reliable actuator of a high-density und high-speed optical disk drive. The higher density the disk has and the faster spinning speed the disk drive has. the more power to its coils the actuator needs because the actuator is required to cope with higher servo bandwidth. This may cause a reliability problem by conducting excessive heat to its objective lens. In this study, the factors affecting on the temperature of the lens were found through numerical simulations and experiments. Design modification and amelioration has been successfully applied under design constraints

We presented experimental results including 50 GB capacity RF signals in a gap servo NFR system. Considerable cross-talk effects have been observed between gap and track error signals and the origins of them have been investigated

The external feedback effect on the relative intensity noise characteristics of 405 nm InAlGaN laser diode has been analyzed taking into account the spontaneous emission noise and the high frequency modulation of the injection current. A Langevin diffusion model was exploited to characterize its relative intensity noise. The spontaneous emission noise components were quantitatively evaluated from the optical gain properties of the InAlGaN multiple quantum well active regions by using the multiband Hamiltonian for the strained wurtzite crystals. The extracted parameters were applied to the rate equations taking into account the external feedback and external current modulation effects. The simulation results were investigated to optimize the relative intensity noise characteristics.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We introduce a method to align the angle of reference beam holographic data storage by using a photodiode in front of image sensor, the brightness of information data can be easily extracted. From the output of the photodiode, we can quickly find the optimal angle for readout beam