Vertical cavity surface-emitting lasers (VCSELs) are becoming increasingly important for short-haul optical fiber transmission systems. Given the commercial success of GaAs-based 850 nm VCSELs, dramatic enhancements in transmission bandwidth and distance can be achieved in conventional single- and multi-mode fiber by extending the emission wavelength to the 1300 nm-1550 nm range. GaInNAs is a promising active layer material grown on GaAs that can achieve 1300 nm emission (Kondow et al., 1997), and electrically pulsed broad-area GaInNAs VCSELs (Larson et al., 1998; Coldren et al., 2000) have been realized. Here, we take advantage of the properties of GaAs-based materials-thermally-conductive high contrast mirrors and AlAs-oxide current apertures-to demonstrate for the first time low-threshold (/spl sim/1 mA) GaInNAs VCSELs emitting at a wavelength of 1200 nm under continuous-wave (CW) room temperature operation.

: The paper addresses the vulnerabilities of remotely accessible computerized information systems to electronic crime -- penetration of the information system for illicit copying, altering or destruction of selected information. A condensed survey of the probable threats and applicable countermeasures is presented. A particular emphasis is placed on the use of cryptographic techniques for protecting information in the communication lines and in computer files.

Recent advances in computer time-sharing technology promise information systems which will permit simultaneous on-line access to many users at remotely located terminals. In such systems, the question naturally arises of protecting one user's stored programs and data against unauthorized access by others. Considerable work has already been done in providing protection against accidental access due to hardware malfunctions or undebugged programs. Protection against deliberate attempts to gain access to private information, although recently discussed from a philosophical point of view, has attracted only fragmentary technical attention. This paper presents a discussion of the threat to information privacy in non-military information systems, applicable countermeasures, and system implications of providing privacy protection.

In many areas of the experimental sciences, increasing use is being made of general-purpose computers to control experimental apparatus and to record data from experiments. In most such applications the problem exists of connecting the apparatus to the computer so that data and control information may flow between the two. The problem is usually solved by placing a controller between the computer and the external equipment (Fig. 1). In this position the controller serves two functions: (a) It provides a suitable electrical and logical interface between the computer and the external equipment; and (b) It provides detailed control of the external equipment, thus leaving the computer free for other work.

This research has produced an experimental system for nondestructive readout in ferrite toroids and has developed methods of coupling the available signal energy into suitable detectors.

The random access, high-speed memories most frequently used today are of the magnetic core type, which have the ability to be read from and written into at speeds of the order of a few microseconds. In some applications another form of memory can be used that may be read at these high speeds, with capability of being changed in a few minutes. Memories of this type, in which the fast-read cycle is ...