Three-Dimensional Magneto-Optical Recording
- PDF / 956,814 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 36 Downloads / 162 Views
J3.1.1
Three-Dimensional Magneto-Optical Recording Akiyoshi Itoh Department of Electronics and Computer Science, College of Science and Technology, Nihon University 7-24-1 Narashinodai, Funabashi, 274-8501, Japan ABSTRACT In this report, the newly developed three-dimensional magneto-optical (MO) recording scheme and the experimental results are reported. A part of this work has been done as the national project of 3D-MO (3-dimensional MO) project. It started at September 1998 and ended March 2002 as a part of the national project “Nanometer-Scale Optical High Density Disk Storage System” and aimed at achieving 100 Gb/in2 in storage density. Three-dimensional MO recording is one of the prosperous candidates of next generation ultra high density recording. Magnetic amplifying MO system (MAMMOS) is employed for achieving the novel three-dimensional MO recording. Double-MAMMOS scheme consists of 2-recording layers of differing compensation temperature (Tcomp) and one readout layer was proposed and discussed. With write/read test it is succeeded to show the results corresponding to a 100 Gb/in2 (50 Gb/in2 x 2) recording density. We also proposed and showed results of simulations of a new type of Double-MAMMOS in which the recording layers can hold quadri-valued information by single writing process. INTRODUCTION MAMMOS [1, 2] and DWDD (domain wall displacement detection) method [3] are excellent techniques for achieving high areal recording density with an enhanced read out signal from recorded marks much smaller than the optical resolution limit by utilizing the magnetic characteristics of a magnetic multi layer structure. Recently, Tani and Awano et al. [4] reported a new concept of the zero field MAMMOS which does not require an application of the external magnetic field for the read out. On the other hand, we have proposed and achieved [5] the multi-wavelength read out system which can read a multilevel recorded signal at a high signal to noise ratio. The way of combining these techniques of utilizing multi-layer structure is interesting. This paper describes this approach toward a three dimensional MO recording scheme. We have successfully demonstrated the write/read test of ultra high density MO recording as high as 100 Gb/in2 (50 Gb/in2 x 2) by employing a new method of 3-dimensional magnetic amplifying MO system named Double-MAMMOS. EXPERIMENTAL DETAILS AND DISCUSSION The way to the Double-MAMMOS 1) Simply stacked MAMMOS First, the simply stacked MAMMOS structure shown in Figure 1, consists of recording
J3.1.2
layers and reading layers was discussed. However, the read out signal from the reading layer located at the far side of the incoming optical beam becomes smaller due to the penetration of the light through the other layers, so another configuration is necessary.
Figure 1. Simply stacked MAMMOS
Figure 2. 2-recording and 2-readout layers MAMMOS. A combination of 2-readout (R1, R2) and 2-storage (S1, S2) for MAMMOS. Two methods of copying and expanding domains from storage layers S1 and S2 are possible.
Data Loading...
