A Study of Increase in Recording Density by Combining Magnetic Amplifying Signal and a Wobbled Groove

In the case of an optical recording disk, system information such as address is recorded on a disk as an emboss signal, like wobble signal. Since this wobble signal has a polarized component, in a system using polarization property as is used in magnetic optical disks, if signals are recorded in the wobbled area, RF signal may be subject to modulation caused by the polarized component. Up until now, in order to ensure the quality of recorded signal, different ways have been adopted, such as separating the wobbled area and recording area or separating the frequency bands for wobble signal and recorded signal. For the purpose of improving efficiency of recorded signal within an optical recording disk and increasing recording density, the possibility of increasing density by recording RF signal in a wobble track was explored. The results show that when using an optical system with a laser spot diameter of 0.96 μm and applying the NRZIplus modulation method for wobble signal, it is possible to do wobble recording at a recording line density of 0.96 μm/bit, considering the limit of read-out resolution of the read-out system.