Presentations

導光材料の本質的特性を中心に解説した。

We have proposed four techniques to prepare axial-, radial-, spherical-, and other novelGRIN materials. The technologies of obtaining GRIN polymer and the resulting products, proposed in our laboratory until now are summerized. Since the two-step copolymerization and photocoplymerization techniques have been frequently reported so far, we focus, in this paper, on the GRIN optical fiber and optical waveguide by the interfacial-gel copolymerization technique, and the spherical GRIN spher lens with a low spherical aberration by the suspension polymerization technique.

屈折率分布型有機材料の作製法、屈折率分布制御の可能性、応用について現状と問題点に付き述べた。

最近の屈折率分布型高分子材料とその光デバイスの開発現状に付き解説した。

ポリマーの化学構造と光学特性の関係を、透明ポリマーを光学材料として使う場合を例にとりわかりやすく説明した。

Several geometric polymer GRIN device, such as radial-, axial-, and spherical GRIN, are demonstrated. Further more, we propose a new technology to prepare strict GRIN waveguides as optical circuit.

ポリマーの屈折率、分散、透明性（散乱、吸収）、均質性（脈理）、耐熱性、光学特性の温度依存性、吸湿性などをポリマーの化学構造と関連付け、それらの改善の可能性について述べる。また、最近特許等について報告されている新しい光学ポリマー材料や、種々の屈折率分布形光学素子などの最近のどう光重合法について述べた。

屈折率が中心より球対称に現象するGRIN球レンズは、GRINロッドレンズや従来の凸レンズ光学系と異なり、光軸が存在しないためレンズの傾きによる軸ずれ収差が存在せず無収差マイクロレンズとして注目を浴びている。今回プラスチックGRIN球レンズを特殊なサスペンジョン複合により初めて作製することができた。作製方法並びにその光学特性について報告した。

まず、ポリマーの物理定数（屈折率、アッペ数、密度など）と化学構造の関係について述べた。次に、屈折率分布が中心軸から放射状に変化している Radial GRIN ロッドレンズ、屈折率が―軸方向に変化している Axcial GRIN レンズ、屈折率が球対象に変化している Spherical GRIN 球レンズについて、それらの製法と光学特性について解説した。

多元モノマー系光重合法によるファイバーの屈折率分布制御の可能性に付き概説し、今までに得られている屈折率分布パターンを紹介した。

Plastic GRIN (Gradient-Index) rods with various profiles of refractive-index distributions were successfully obtained by photocopolymerization process. We propose a mechanism to form radical GRIN by photocopolymerization in multimonomer systems. By developing the computer program which caluculates the physical constants of polymers from the chemical structure, and which predicts the index-profile of the GRIN rod on the basis of the abve mechanism, the index profiles of the fabricated GRIN rods were tightly controlled.

A light focusing plastic rod with some importants was fabricated by photocopolymerization. The relations between lens characteristics and preparative conditions were clarified.

現在到達できる最大屈折率ポリマーと最小屈折率ポリマーの値を理論的に予測した。

The attenuation is drawn to the fiber network in "the last one mile" to the residentioal area. The polymer optical fiber (POF) has been extensively developed especially in Japan to be utilized in this area with its advantage of great flexibility, easy handling and processing. The POF Consorium was founded in 1994 in Japan for the purpose of constructing POF-based multimedia society, and its membership consist over 50 companies and several universities. Very recently, the low-loss and high-bandwidth perfluorinated GI POF which has no serious absoption loss from visible to 1.3µm wavelength was successfully prepared at Keio University. The status of the POF for data communication in Japan is reviewed.

大口径である広帯域GI型POFの高速伝送特性、及び伝送損失特性を報告すると共に大口径である点が従来の光ファイバーと異なるPOFに関しての特性評価方法について報告した。

The status of the polymer optical fiber (POF) for high-speed data transmission is reviewed. Very recently, the low-loss ansd high-bandwidth perfluorinated GI POF which has no serious absorption loss from visible to 1.3-µm wavelength was successflly prepared at Keio University. Since the core diameter (300-1000µm) of the GI-POF is much larger than that of the multimode silica fiber (62.5µm), the serious modal noise in the conventional multimode silica fiber was virtually eliminated, resulting in stable giga bit order data transmission with inexpensive couplers and connectors.

We propose a new optical material, highly scattering optical transmission (HSOT) polymer, whisch consist of specified microscopic heterogenious structure. The HSOT polymer optimized by Monte Carlo's simulation was applied to the LCD backlight. As the result, this polymer materials increas backlight brightness twofold.

Very recently, we succeeded in preparing the low-loss and high-bandwidth graded-index plastic optical fiber (GI POF) from visible to near-infrared region. This paper reviews the updated highspeed data transmission performance of GI POF.

Recentry, information service which can be represented by the Internet service have become available to the general households, and broadband network has been to deliver video service which low cost and easy handling. Under shch circumstances, plastic optical fiber (POF) become remarkable as the transmission medium of the high speed information communication network system. The POF can be prepared with a large core diameter because of the high flexibility, which would enable easy connection and branching in the network system. Moreover, realization of high bandwodth can be achieved by making a graded-index type. In this paper, we report on the process of the studies and development of POF and the present situation of POF.