Read/Write Module for High Capacity Memory Disk

摘要

This SBIR program addresses the tracking and alignment sensitivity issues of apractical holographic storage system. To demonstrate the feasibility of this program, we plan to accomplish the following: (1) Characterize the storage medium. (2) Construct a preliminary tracking system. (3) Study the alignment sensitivity of Fourier transform holograms. (4) Design the final tracking system. After carefully studying potential markets for the holographic storage system, we have decided to use laser diodes as the light source and photopolymer as the recording medium. The decision was based on cost, size, reliability, availability, and convenience. We have decided to modify the tracking mechanism of existing optical disk systems and use it for the 3-D holographic disk system. We have procured a CD-ROM and interfaced it to a PC. We plan to create a preliminary recording medium by lamenating a layer of photopolymer onto a CD-ROM disk. We have partially dissected the CD-ROM. We will obtain tracking signal from the CD-ROM and use it to drive the readout mechanism. (The recording will be performed off-line using another setup.) The readout mechanism is consisted of a laser diode, optics and an output detector. The tracking signal will be used to rotate the holographic disk to a specified location, to synchronize the firing of the laser diode, and to coordinate the capture of the reconstruction by the detector array. We have studied the operation principles, the physical specifications, the logical specifications, and the addressing scheme of CD-ROM. We have learned the interface protocol and acquired the control subroutines library. We are developing computer software to monitor the status and to control the movements of the head of the CD-ROM.