Recent technologies for increasing memory density in random access memory optical disks including magnetic super resolution method, super resolution method in phase change disk, blue laser diode, near field optics, and photo chromic memory are reviewed.

Recent technologies for increasing memory density in random access memory optical disks including magnetic super resolution method, super resolution method in phase change disk, blue laser diode, near field optics, and photo chromic memory are reviewed.

In this paper, we discuss configurations of photonic ATM (Asynchronous Transfer Mode) switches and their advantages in terms of the number of optical switching devices to be implemented on the system, the number of wavelengths, throughput, broadcast function etc. In particular, we focus on photonic ATM switch architectures which can be built in the near future; that is, with presently available optical and electrical devices. For example, we assume the optical devices such as optical gate switches with 40 dB on/off ratio. In this context, we evaluate 17 types of photonic ATM switches; they are 6 types of input buffer type switches, 6 types of output buffer type switches, 4 types of shared buffer switches, and 1 proposed type. From our evaluation, for cell switching, wavelength division switching technologies are desirable compared with space division switching technologies in the sense that the former enables us to build a photonic ATM switch with the less number of optical gate switches. Furthermore, we propose a switch architecture equipped with optical delay line buffers on outputs and electric buffers on inputs. We show that our switch architecture is superior in the number of required optical gate switch elements under the given conditions.

A real-time read/write motion picture has been demonstrated by hole-burning holography using cryogenic Eu3+: Y2SiO5 crystal. In a holographic configuration the laser frequency was continuously scanned within the 7F0-5D0 absorption line while the object was in motion. This movie has no picture frames, and therefore is temporally continuous. This feature allows realization of high-speed and high-time-resolution motion recording.