Published papers

A sphere lens with a spherical GRIN was prepared by the modified suspension polymerization technique. GRIN spheres with quadratic- and linear-index distributions were obtained by two different methods to confirm the effect of the GRIN profile on the focusing property of the sphere lens. It was confirmed in both theory and experiment that the spherical aberration of such GRIN sphere was remarkably decreased compared with that of a homogenous sphere.

ポリマー中に理論的にある条件を満足させるように不均一構造を形成させることで優れた光散乱特性を実現する方法を示した。

In the copolymer of MMA and BzMA doped with TPED, a rotatory angle increased with increasing the TPED concentration and the Verdet constant increased with increasing the BzMA composition. A new plastic optical isolator which keeps the light beam polarization, was tested using this TPED-doped poly (MMA-BzMA) rod. The isolation of about 20dB was obtained though the insertion loss was high due to the light scattering caused by the dopant molecules.

屈折率傾斜型ポリマー材料について、その作製方法や光学特性および光学材料への応用について解説する。

高分子の光学特性の測定方法として、屈折率分布及び不均一構造について解説している。屈折率分布については、Maxwellの光線方程式をルンゲ?クッタ法を用いて直接数値積分して得られる結果と、実測して得られる結果とを一致させて求める方法を、ポリマー内部の不均一構造については、そのポリマーからの散乱光の角度依存性を測定し、これをデバイの式へ代入して求める方法を示している。（解説）

GI POFにつき簡潔に解説。

We propose a new concept, Highly Scattered Optical Transmission Polymer (HSOT Polymer) as a new light source medium in which the light is effectively scattered and illuminated from the surface during light transmission. Since the light scattering is caused inside the HSOT Polymer due to specific heterogeneous structure, surrounding device such as diffuser film asnd dot printing etc. which is indispensable in conventional ones are not necessary in our proposal. The intensity of illumination is about 50% stronger than that of conventional PMMA plate systems.

Low Loss, high bandwidth GI polymer optical fiber was successfully obtained by the interfacial-gel polymerization technique using PMMA and other dopant as the core material. The GI POF could cover whole bandwidth which is required for the B-ISDN and Optical Interconnection concept.

Polymer optical fiber amplifiers (POFA) of GI type, which have a gain in visible region, were successfully prepared by the interfacial-gel polymerization technique. The gain of 27 dB was observed at 591nm signal wavelength with 690W launched pomp power at 532 nm in a GI POFA with 0.5m length.

Amplification characteristics of GI type organic dye doped POFA are discussed. As an organic dye for optical amplification, Rhodamine 6G, Rhodamine B, Perylene Red are doped in the core region of POFs. These POFA can obtain optical gain in the visible region of wavelength from 570nm to 620nm. POFA is promising for extraordinary high power optical amplification in comparison with rare-earth ions doped silica fiber amplifier. For example, output power of 1kW with a gain of 30dB can be obtained by using a Rhodamine B doped POFA at a low dye concentration of 1ppm. Additionally, a novel solid-state POFA amplifier system is demonstrated.

Organic dye (Rhodamine B) doped POFA of GI type was successfully prepared for the first time. The GI-POF of only 500mm in length gave 27dB in gain at 591nm of signal wavelength. Additionally, absorption cross section and emission cross section of Rhodamine B in PMMA matrix were estimated, which were required to analyze amplification mechanism in the POFA.

Rhodamine B、Rhodamine 6G、Perylene Redを添加したポリマー光ファイバー増幅器をそれぞれ作製し、光増幅特性を実験的に確認し、報告している。信号光利得のファイバー長依存性について述べている。

organic dye (Rhodamine B) doped polymer optical fiber amplifier (POFA) of GI type was successfully prepared for the first time. The GI POFA of only 500nm in length gave 27dB in gain at 591nm of signal wavelength. Additionally, absorption cross section and emmision cross section of Rhodamine B in PMMA matrix were estimated, which were required to analyze amplification mechanism in the POFA.

光は、伝わる媒質が均一ならばまっすぐに進む。しかし、その道筋において媒質の形状や屈折率が変化すると、光は入射角に応じて反射や屈折率の現象を示してその進行方向を変える。私達のまわりでは、こういった光の現象を利用した、眼鏡やコンタクトレンズ、光ファイバー等の光学材料がいろいろ使われている。 従来の光学材料では、ほとんどのものが材料の形状を変化させることによって光線を制御しているが、近年、材料の形状に依存せず、材料中で光線を曲げることによってその進行方向を制御する材料が開発され、注目されている。 本稿ではその「光を曲げる材料」についてその作製方法および応用例について解説する。

High-Bandwidth GI POF and single-mode POF with good mechanical properties were successfully obtained by our interfacial gel polymerization technique. The bandwidth of the GI POF is about 1GHz・km which is two hundred times larger than that of the conventional SI POF. The minimum attenuation of transmission is 56dB/km at 688nm wavelength and 94 dB/km at 780nm wavelength. The single-mode POF in which the core diameter was 3-15µm and the attenuation of transmission was 200dB/km at 652nm wavelength was successfully obtained for the first time.

A Rhodamine B doped graded index polymer optical fiber was successfully prepared and the gain of 27dB was observed for the signal pules(591nm)by the excitation with SHG of Nd:YAG laser

The Origin of the excess light scattering invariably observed in purified PMMA glasses was investigated. The isotropic heterogeneous structure with a dimension of about 1000Å, which increases the scattering loss by at least 1 order of magnitude (to several hundred dB/km) is generated during polymerization below Tg at high conversion and is not due to high molecular weight, specific tacticities, formation of cross-links, or aging. It is clearly shown that the remaining monomer in concentrations of several wt% does not aggregate spontaneously at high conversion to cause excess scattering unless polymerization takes place. The excess scattering is, we believe, mainly due to voids caused by the volume shrinkage accompanying polymerization of remaining monomer trapped inside the polymer glass. The excess scattering model proposed in this paper shows that if a slight amount of monomer in the PMMA glass is polymerized in situ at high conversion, generating slightly localized voids due to the aggregation of the unreacted initiator, a rise of only 1 wt% in the conversion increases the scattering loss by several hundred dB/km, which can reasonably explain the experimental result in this paper.

高速伝送POFについての最近の結果を中心に述べる。

屈折率分布型光学機能材料の中でも、特に老視に用いることのできる２重焦点コンタクトレンズと、高帯域屈折率分布型光ファイバーのコネクタ部品として用いることが期待される低収差な屈折率分布型球レンズの作製方法、光学特性について解説している。（解説）

A Gradient-indax (GRIN) materials display unique and useful optical properties which are not achieved by conventional optical devices with a constant refractive indax. In this paaer, GRIN polymer materials for bifocal GRIN contact lens and GRIN polymer Optical Fibers are described. In the GRIN fiber, the bandwidth is about 1 GHz・km which is two hundred times larger than that of conventional step-index (SI) polymer optical fiber. The total attenuation of transmission is 90-100dB/km at 572-nm wavelength. The contact lens was obtained by polishing the GRIN sontactlens exactly satisfied the bifocal condition.