Near-field probe array with higher throughput for ultrahigh data rate of tera byte optical disk

Abstract

In order to meet the requirement for an ultrahigh data transfer rate in future optical communication systems, a parallel optical memory system has been developed using a VCSEL anay and three-dimensional microoptical adjustment. The concept, theoretical analysis and fabrication process for the anay head are discussed with emphasis on the microoptical issues such as the improvement of optical efficiency by surface plasmon enhancement and microlens focusing. The flat-tip microprobe structure was successfully prepared with the small metal aperture of 150 nm and 1 .25% optical throughput using metal-aperture Si or GaP semiconductor microprobes. From the finite difference time domain (FDTD) simulation, the optical throughput can be improved using a buried-type microprobe with an asymmetric metal-coated structure since this is a better structure for improving coupling efficiency between the propagating wave and surface plasmon. Since the focused beam promotes better optical throughput in the integrated VCSEL microprobe array, the microlens array is developed on the other side of the microprobe array using the thermal Reflow of photo-resist and a pattern transfer process to the semiconductor substrate. The alignment of optical axis between the optical components is critical to achieving the required optical efficiency in this system. Thus, three-dimensional micro-optical adjustment is being studied to focus a very small spot on the recording media. This three-dimensional approach will provide guidelines for new micro-optical components in future technology in the field of optical memory and other micro-optical systems.