Optical frequency comb is a collection of laser modes with equal frequency intervals in the visible to near-infrared regions that enables direct comparison of optical frequencies with the microwave atomic frequency standards. Traditional solid state laser-based frequency comb systems were large, expensive and very difficult to operate for long periods of time during experiments. From the early stage of development, we proposed fiber lasers as a feasible means for achieving a reliable frequency comb. After we succeeded in developing an in-house fiber-based frequency comb at AIST, we made further advances, including calibration of optical telecommunication band, establishment of national standards of length, and development of a narrow-linewidth comb for optical lattice clocks.

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It is important to carry out research strategically and in a step-by-step manner in order to put new solar energy conversion technologies into practical use and to realize a society based on renewable energy. In this paper, we clarified the meaning of “solar hydrogen, ” compared various solar hydrogen production technologies, and discussed their feasibilities. Specifically, we showed the effectiveness of the “photocatalysis-electrolysis hybrid system, ” which was invented by AIST, as a promising candidate technology for low cost solar hydrogen production, based on preliminary cost estimations. The scenario toward the realization of the hybrid system is also discussed.

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In this article, we point out that in general, newly-designed highly functional cryptographic tools have significantly complicated structures that hinder user understanding. Furthermore, this fact may prevent these new technologies from being introduced into real world systems. We propose a new methodology for overcoming this barrier. We take proxy re-encryption as an example, and discuss how the barrier to user understanding is reduced by our proposed methodology.

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Glycans are called third class repeating biopolymers, after nucleic acids (first class) and proteins (second class). Elucidation of glycan functions has long been hampered by the difficulty in analyzing their structure. Recent progress in proteomics technology has accelerated progress in glycomics, which is the systematic study of glycans. Glycan profiling has increasingly attracted attention as a method that enables rapid analysis of complex features of glycans. Lectin microarray provides a novel platform and a simplified experimental procedure, which does not require glycan liberation and separation prior to the analysis. It is now being applied to tumor marker investigation, stem cell qualification, and biologics development. The author reviews the last 10 years of lectin microarray development, a period that began as a national project in which he has been actively involved.

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High quality video formats beyond HDTV are being developed, but these formats require data communication rates greater than 10 Gbps, which are not easily adaptable to household applications. Moreover, household usage requires ease of handling, robustness against poor connectivity, and affordable cost. Conventional silica optical fibers are not suitable for applications that involve high-speed, short-range communication, because of their fragility, and difficulty in achieving precise connectivity with a low cost connecting method. We proposed a novel expanded-beam interconnect using a graded-index plastic optical fiber (GI POF) with a glass spherical collimator lens uniquely fabricated by low cost ballpoint-pen technologies at both ends. Our power budget evaluation verified its suitability for consumer applications. Successful validation was then conducted by transmitting 4K-3D uncompressed video content.

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