Masao Funada

780nm VCSELs for home networks and printers

A 780 nm multi-mode VCSEL, to meet the requirements for a new GI plastic optical fiber, are reported. It has 4 spots driven simultaneously like a single spot and hence the optical power needed from each spot is reduced to 1/4. As a result, the MTTF obtained is well over 200,000 hr at 60/spl deg/C under 3 mW operation, with a narrow beam divergence angle of less than 18/spl deg/ (1/e/sup 2/). This VCSEL also shows wide-open 5 Gbps eye diagrams at standard driving conditions, which is sufficient for most home network applications. Applications using this VCSEL and Lumistar, such as optical DVI (digital visual interface) and GBIC (Gigabit interface connector) modules are shown too. Furthermore, a 780 nm VCSEL array with independently addressable 32 spots, for laser beam printer applications, is reported. Each spot has a single-mode optical power of more than 1.2 mW at 60/spl deg/C and their uniformity is within /spl plusmn/1%. A high resolution of 2400 DPI and a print speed of 12.5 ppm, in color, was achieved by incorporating this array as an optical source.

Proposal for a novel optical bus system using optical sheet bus technology

Conventional electrical bus system technologies are encountered their physical borders in terms of transmission length and parasitic capacity of lines, and thus, many optical interconnection technologies are proposed to solve the problems in the electrical circuits. In this paper, we propose a new optical bus with sheet like shape technology using diffusion controlled light transmission in the multi- planar waveguides that makes capability of broadcasting, simultaneous bidirectional transmission, easy alignment and plural multiplex transmission. We have fabricated a basic model using optical sheet bus technology for the first time and evaluate them at 500MHz clock operation as follows: (1) synchronous broadcasting transmission to control transmission delay; (2) simultaneous bidirectional transmission in the same waveguide; (3) multiplex transmission such as time division multiplexing, wavelength division multiplexing and so on. Through this fabrication and evaluation, we can pick up some approach to put the optical sheet bus technology into practice with feature as follows: (a) simple design rule for multi-accessible bus systems like as shared memory bus systems, which needs faster speed; (b) added-value of multiplex transmission ways that reduce circuit frequency, minimize power consumption, maximize transmission bandwidth, and bring about no-wait communications for the bus systems.