Introduction of "Optical wiring" is expected to meet an explosion of information amount circulated through the future networks. Opto-electronics technology has a potential to solve the so-called interconnection crisis of conventional "Metallic wiring". However, a lot of problems have remained especially in respect of the device assembling and circuit packaging. In this paper, advantages of optical wiring will be discussed first. Then the present status of the optical circuit packaging technology will be briefly overviewed. Finally Optical Surface Mount Technology (Optical SMT) which was proposed as a means to solve the board level interconnection problem will be introduced.

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We reviewed recent results in high-speed optical modulation. In addition to conventional modulators for digital intensity keying, we discussed novel modulation techniques for new function such as optical frequency shift, millimeter-wave generation, optical tunable delay, and so on.

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To support low-cost and user-friendly internet environments for widespread use, telecommunications networks must operate flexibly at high speed and with a wide bandwidth. Photonic network technology based on wavelength division multiplexing (WDM) systems is essential for this purpose, and the development of new optical devices is thus an important requirement. Recently, various optical devices composed of high-density planar lightwave circuits (PLCs) have been developed for photonic network applications. This paper reports recent progress on large-scale and highly functional PLC-type devices, including arrayed-waveguide grating filters, optical switches and adaptive filters.

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Recent progress on two types fiber-based passive optical devices: fiber gratings and fused-taper couplers, has been reviewed. Narrow-band high reflection FBG filters for add and drop multiplexing, low-reflection FBG mirrors for LD stabilizing, FBG dispersion compensators, and long period fiber gratings and slant/chirped FBGs for gain equalizer are discussed. Polarization beam combiners and polarization maintaining pump/signal combiners manufactured by fused-taper technology using PANDA fibers are also discussed.

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Dispersion compensation devices are indispensable for long-haul and high-speed optical transmission systems. Chromatic dispersion and polarization mode dispersion are two key principle parameters which we have to investigate in designing leading edge optical systems. Recently variable type dispersion compensation devices have become especially important as a means of realizing system architecture flexibility and therefore there are high expectations for such devices in the market. In this paper, the current status of compensation technology and related device technology trends are reviewed and examined, and a review of expected future trends is also included.

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This paper reports on the characteristics of a photoacoustic wave detector designed for skin tissue diagnoses. The detector was composed of a ring-shaped piezoelectric film and a quartz fiber for delivering nanosecond light pulses. We measured the detectability of absorbing layers in a gelatin skin model. It was shown that the sampling depth was greater than 4 mm and an absorbing layer as thin as 12 mm could be detected. A Monte Carlo simulation was also performed to analyze the behavior of the photons in the skin tissue. We conclude that the detector has applications for monitoring blood distribution in skin tissue.

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Lettuce was grown under pulsed-red LD light at variation pulse periods and DT ratios (illuminated duration/period), and the relative growth rate and photosynthetic rate per unit luminous energy were examined. Both the growth and photosynthetic rates generally increased (except at a pulse period of 10 ms) compared with continuous illumination. Particularly, both the growth and photosynthetic rates increased by 20 % or more at the pulse period of 400 µs and the DT ratio of 50 %. These results may be explained by the presence of a period of 200 µs duration in which light is unnecessary (period of electron transport) in the light reaction of photosynthesis. This study supports the feasibility of plant factories.

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