Targeting the transition from a coaxial wave guide to a coplanar wave guide (CPW), a microwave and millimeter-wave wide-band coaxial-to-coplanar transition is proposed. This design connects the coaxial inner conductor to the CPW center conductor in a perpendicular manner to directly couple, on the same plane, the radial high-frequency electric field in the coax to the gap between the CPW's center conductor and ground plane. The performance of the proposed transition was compared with those of the conventional transition by experiments and electromagnetic field simulations, and it was found that the proposed method is independent of CPW shape and that it exhibits good matching performance in comparison to the conventional method especially in high-frequency bands above 15 GHz.

In this paper we modeled and analyzed the ridge type InGaAlAs/InP semiconductor laser with lateral current confinement structure, and optimized the design for the ridge wave guide with the current confinement. We proposed and fabricated the ridge type InGaAlAs/InP laser with a cost effective selective undercut etching method and demonstrated the improvement of the ridge laser performance. This paper provides a solution to solve the cost/yield issue for conventional BH (buried hetero-structure) type laser and performance issue for conventional ridge type laser.

The propagation characteristic of 670 nm laser light on the array of 10 µm diameter polystyrene micro-sphere was studied. For the linearly arranged array of micro-spheres from one to 12, the propagated light intensity was decreased from 700 mV to 45 mV. However, the propagated light intensity in the air was significantly decreased and it became 2 mV at 60 µm from the optical fiber light source. For the micro-sphere array on the curvilinear line, the light intensity at 12th micro-sphere became 35 mV. This fact means the light was propagated almost same as that on the linear line. Whereas it is expected that three dimensionally crossing optical wave-guide is possible to be fabricated by arranging the micro-spheres.

The dependence of a linear electro-optic (LEO) coefficient induced into boron-codoped germanosilicate fibre on thermal poling conditions (poling voltage, poling temperature and poling time) has been systematically carried out using a Mach-Zehnder interferometer. The LEO coefficient increases as a 2.7 power law with the poling voltage; it can be maximally induced into the silica fibre within a temperature range from 250 to 300; it exponentially increases with poling time until saturation but after that it then decreases. Possible mechanisms of thermal poling are discussed in the light of the experimental results.

The dependence of a linear electro-optic (LEO) coefficient induced into boron-codoped germanosilicate fibre on thermal poling conditions (poling voltage, poling temperature and poling time) has been systematically carried out using a Mach-Zehnder interferometer. The LEO coefficient increases as a 2.7 power law with the poling voltage; it can be maximally induced into the silica fibre within a temperature range from 250 to 300; it exponentially increases with poling time until saturation but after that it then decreases. Possible mechanisms of thermal poling are discussed in the light of the experimental results.

Improvement of fatigue behavior of a fusion spliced portion on a carbon-coated fiber is achieved by recoating carbon using a thermal-CVD process with a CO2 laser as a local heat source. The fatigue parameters, so-called n-values, of 121 and 94 are obtained on the non-spliced portion and the spliced portion, respectively. Assuming a life time prediction model, these high values have been proved to have an advantage in a long-term reliability and to be sufficient in a practical submarine cable use.

This paper was written for LSI engineers in order to demonstrate the effect of optical interconnections in LSIs to improve both the speed and power performances of 0.5 and 0.2 µm CMOS microprocessors. The feasibilities and problems regarding new micronsize optoelectronic devices as well as associated electronics are discussed. Actual circuit structures clocks and bus lines used for optical interconnection are discussed. Newly designed optical interconnections and the speed power performances are compared with those of the original electrical interconnection systems.

A film carrier with 48 peripheral-contacts, which is applicable to ultra-high speed GaAs digital integrated circuits (ICs) with a more than 10 Gbps operation, has been developed. The film carrier has been realized using the following newly developed techniques; (1) wave guides with a well-controlled characteristic impedance of 50 Ω, (2) precise vias of as small as 50 µm diameter conducting both sides of grounded metal planes on a polyimide film, and (3) a feed-through structure for high speed input signals with good impedance matching. The film carrier was molded by resin after ILB (inner lead bonding) to a chip with a copper plate heat spreader. As an application, the film carrier has been applied to a 3 Gbps operational 4-bit GaAs multiplexer IC, and has been proved to have excellent high-frequency characteristics.