Published papers

低損失・広帯域GI型POFの現状と将来展望につき解説した。

プラスチック光ファイバの低損失、広帯域化を目的とし、その製造方法、評価方法および測定結果に付き、報告した。

We demonstrate efficient and photostable laser action in graded index polymer fiber lasers with organic dyes such as Rhodamine, Perylene and Pyrromethene. Slope efficiency of 47% and output of 2.6 mJ have been obtained with a Rhodamine 6G-doped fiber laser. Moreover, we encapsulated rare ions to incorporate them into polymer matrix and studies spectroscopic properties of europium chelates in polymer hosts. Superfluorescent polymer fiber source based on Eu chelate-doped polymer optical fiber was demonstrated.

This paper focuses on the transmission and display technologies for the broadband network systems by newly developed photonics polymers as high bandwidth POF and HSOT polymer.

高速通信用途として注目を集め始めたGI型POFについて解説した。

We have proposed a highly scattering optical transmission (HSOT) polymer for use as a high efficiency light source medium. This polymer contains specified internal microscopic heterogeneous structures for controlling light transmission properties. A LCD backlighting system having a new light pipe made of this polymer has twice the brightness of the conventional one. A light scattering phenomenon inside the HSOT polymer was quantitatively analyzed by a ray tracing simulation based on the Mie scattering theory and the Monte Carlo method. The illumination of the backlight which is optimized by using the simulation program has enough uniformity of intensity and colors because of specified multiple light scattering phenomena inside the HSOT polymer. We propose the new backlighting system having fewer components and twice efficiency of the conventional one.

GI型のPOFの最新モード分析の結果及び屈折率分布デザインの検討結果に付き報告した。

アクセス系やLAN等、システムの低価格性が期待されるネットワークにおいて実用化が期待される、大口径、低損失、広帯域屈折率分布型(GI)型ポリマー光ファイバー(POF)に関して、近年得られてきた、材料検討による実験的なアプローチ、及び理論的な解析を通した低損失化・広帯域化技術について述べる。

A new new concept LCD backlighting system using the highly sacattering optical transmission (HSOT) polymer has the twice the brightness of the conventional backlight and uniform illumination. Light scattering phenomenon of a spheircal perticle inside the HSOT polymer is caluculated in detail by the Mie scattering theory. It was confirmed theoretically that, the color illuminated from the HSOT backlight could be controlled by the sphesified scatter leading to a high efficiency and high-visual quarity LCD backlighting system.

Gain dynamics such as signal wavelength dependence and pump wavelength dependence for organic dye-doped GI POFA are characterized. A Rhodamine B-doped POFA, 1m in length and 0.3mm in core diameter, has exhibited more than 20 dB gain at signal wavelengths from 560nm to 600nm when optically pumped at 532nm. The maximum gain of 37dB was achieved with a Rhodamine B-doped POFA pumped at 550nm, which was optimum pump wavelength. For an Oxazine 4-doped POFA, signal gain of 20dB was obtained when pumped at 605nm. It is shown that pumping at absorption maximum wavelengths optimizes amplifier performance.

Recent progress of the GI POF is reviewed. The low-loss perfluorinated (PF) polymer based GI POF experimentally achieved gigabit transmission for more than 200m in the range of visible to infrared region. In addition, improvement of the thermal and long term stability of the bandwidth of the GI POF with using a new dopant material is described.

The status of the POF for high-speed data communication is reviewed. Recently, low-loss, and high-bandwidth perfluorinated GI POF which has no serious absorption loss from visible to near infrared region was successfully prepared at Keio university. Since the core diameter of GI POF is much larger than that of the multimode silica fiber, 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.

A copolymer of MtMA and BzMA, Poly (MtMA/BzMA) was synthesized to construct a polymer slab waveguide-type optical isolator operating in the blue wavelength region. This isolator is based on the simultaneously occurring reciprocal and nonreciprocal TE-TM mode conversions in a three-layered slab waveguide which consist of the poly (MtMA/BzMA) copolymer core on a fused quartz substrate. When a high magnetic field of about 18kOe was applied to a device with a core thickness of 4.5µm and a 5cm propagation length, a pulsed optical isolator operation with an isolation ratio of approximately 15dB was obtained at a wavelength o 441.6nm, for the first time.

The development of the perfluorinated (PF) polymer based GI POF for high-speed data communication is described. It was experimentally confirmed that gigabit data transmission for 500-1000m at 1.3µm wavelength was achieved by the low loss PF polymer based GI POF. The thermal stability of PMMA based GI POF is discussed. We selected several kinds of dopants that can maintain a high glass transition temperature (Tg) of the GI POF core. By using the newly selected dopants, we succeeded in maintaining the parabolic refractive index profile of GI POF with no degradation even at 85 to 90℃ for more than 5000h.

高速ポリマー光ファイバーの特性評価と実際のマルチメディアネットワークへの応用検討

Recent progress in the GI POF is reviewed. The low-loss perfluorinated (PF) polymer-based GI POF achieved gigabit transmission experimentally over more than 100m in the visible to near-infrared region. In addition, improvement of thermal and ling-term stability of the bandwidth of the GI POF by using a new dopant material is described.

時々刻々と進歩する科学技術の中で近年の液晶ディスプレイの発展は非常に目覚しいものであり、今だ留まるところを知らず、さらなる性能向上を遂げている。その中で液晶パネルを背面から照射するための平面光源(バックライト)の性能は、消費電力に始まり、薄型軽量、輝度の角度特性、色の均一性等にいたるまで、液晶ディスプレイの性能を広範囲にわたって支配するものである。 　この液晶バックライトシステムにも目的に応じて様々な構成が考えられるが、ここでは特に、低消費電力化を課題とする液晶ディスプレイを対象とした、光散乱ポリマー導光体を用いた高効率バックライトシステムについて詳細に紹介する。

LAN等のシステムの低価格性が期待されるネットワークにおいて実用化が期待される、大口径、低損失、広帯域GI－POFに関し、近年得られてきた材料検討による実験的なアプローチ、及び理論的な解析を通した低損失・広帯域化技術について紹介している。

有機色素添加ポリマー光ファイバーの光増幅特性を明らかにした。さらに、希土類イオンを有機物の配位子で取り囲むことで、ポリマー中に高濃度に添加することを可能にした。希土類添加ポリマー光ファイバーを用いて初めて光り増幅現象を確認した。