Published papers

有機色素をドープした屈折率分布型ポリマー光ファイバー増幅器を作製した。有機色素であるローダミンＢを用いて作製された長さ０.９ｍのポリマー光ファイバー増幅器において、0.3Ｗの信号光を約1200Ｗまで増幅すること（36dBの利得）に成功した。（解説）

様々なプラスチック光ファイバーの応用例（センサーやディスプレイ-、光通信など）を、その原理とともに示した。

ポリマーを光導波材料として用いる場合の特性について示し、特に光ファイバーとして応用した場合の接続特性、伝送帯域特性について明らかにしている。また、マルチメディア社会でのポリマー光ファイバーの活用についても論じている。

A new large core (0.5-1.0mm) GI POF was proposed to solve the connection problem of the single mode silica fiber indoor use for high speed multimedia network. The bending loss for 10-mm bending diameter was dramatically decreased from 20dB to less than 1dB by preparing the high numerical aperture GI POF. The band-width was 585.2 MHz km which was one hundred times larger than that of any existent SI POF, and the attenuation was 150dB/km at 650nm wavelength.

A GRIN CL is proposed to decrease spherical aberration and to increase the Diopter. A plastic radial GRIN rod was successfully obtained by using the vapor-phase diffusion copolymerization technique. The resulting index distribution of the GRIN rod was almost parabolic against the distance from the center axis, and Δn value was -0.030. The GRIN CL was prepared by grinding and polishing the rod. It is theoretically and experimentally concluded that using the radial GRIN can significantly improve the optical properties of CL’s.

High-bandwidth (2GHz km) GI POF was successfully obtained by the new interfacial-gel polymerization technique in which the unreactive component was used in order to obtain the quadratic refractive index distribution. This high-bandwidth GI POF makes it possible to transmit high-speed optical signals in the short range network which was not covered by SI type POF commercially available. The high-bandwidth GIPOF will open the way for great advantage in the high-speed multimedia network.

広帯域な特性を有するポリマー光ファイバーについて、その構造と伝送特性について明らかにした。（解説）

屈折率分布型ポリマー光ファイバーアンプに用いる有機色素を変えることにより、可視光領域における任意の波長の信号光の増幅の可能性を明らかにした。実験では用いる有機色素をローダミン6G、ローダミンB、ペリレンレッドと変えることにより、３つの信号光波長（571、591、621nm)での増幅現象を確認した。

POFの開発研究をもとに、最も光をよく通す高分子について平易に解説した。

近年シングルモード(SM)型のガラスファイバーが長距離幹線系に広く用いられ、Gbpsオーダーの高速通信が現実に行われるようになってきた。更に各家庭にまで高速情報を送り込むfiber to the home(FTTH)、LANを中心とした高速情報化社会に向けての研究が行われている。本稿では高速通信のためのポリマー光ファイバー（POF)について解説した。

High bandwidth (more than 500 MHz km) GI POF for near infra-red use was successfully fabricated by using partially fluorinated acrylate monomer. Since only three carbon-hydrogen bonds exist in a monomer unit, an absorption loss due to the stretching vibration of the carbon-hydrogen bonds was remarkably reduced compared with the conventional POF’s. The attenuation of the GI POF at 780 nm wavelength was 135dB/km, which is much lower than that of the PMMA core POF (800dB/km). The fluorinated polymer-based GI POF is satisfying a significant segment of high-speed multimedia network applications.

High-bandwidth GI POF has been successfully obtained which realizes 2.5 Gbit/s signal transmission over 100m spans for the first time by using a 650nm high-speed laser diode. In the letter the advantage of the GI POF for high-speed short-range optical communication is described.

A POFA of the GI type, with gain in the visible region, was successfully prepared for the first time, to our knowledge, with the interfacial-gel polymerization technique. An input signal of 0.85 W at 591 nm was amplified to 420 W (27dB gain) by injection of 690 W of pump power at523 nm in to a GI POFA with a 0.5m length. The efficiency of conversion of pump energy to signal amplification was more than 60%.

著者らにより初めて提案された、プラスチック光ファイバー光増幅器という新規なデバイスを紹介した論文である。プラスチック光ファイバー光増幅器の作製方法、光増幅特性、理論解析などについて詳細に紹介している。

A new method for preparing very large radial GRIN polymer plates is proposed . The resulting radial-GRIN plate has a diameter of 70mm of the GRIN region and Δn of 0.02. The optical characteristics of the large radial-GRIN lens were estimated by calculating the trajectory of a ray through GRIN lens which was based on Maxwell’s ray equation. It was confirmed that such large GRIN polymers are promising for eye glasses with no spherical aberration or multifocus properties.

広伝送帯域を実現する屈折率分布型ポリマー光ファイバーが、情報化社会でどのように利用されていくかを平易に解説。（解説）

これまでに開発されてきたプラスチック光ファイバーの経緯を示し、その種類、光学特性等を明らかにし、近未来の情報伝送媒体としての利用の可能性を明らかにしている。

マルチメディアにおけるＰＯＦの可能性を具体的に述べる。

A large core (0.5-1.0mm), high-bandwidth (586MHz km), and low-loss (150dB/km at 650nm of wavelength) GI POF was successfully realized. The high index gradient Δn (0.028) resulted in a significant improvement in the bending loss for less than 50mm bending diameter compared with previous GI POFs.

We successfully obtained a high-bandwidth (1GHz km) and low-loss (90dB/km at 0.572µm of wavelength) GI POF by using the interfacial-gel polymerization technique, in which we used an unreactive component to obtain the quadratic refractive-index distribution. This high-bandwidth GI POF makes it possible to transmit a high-speed optical signal in a short-rage network, which is not possible when we use the SI type of POF commercially available.