摘要:

The status of the polymer optical fiber (POF) for high-speed data communication is reviewed. Recently, the 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 (300–1000 μm) of the GI POF is much larger than that of the multimode silica fiber (62.5 μm), 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.

ISSN:1058-725X    

DOI:10.1080/10587259808044447

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We have devised an indirect laser-heated pedestal growth method to obtain organic nonlinear optical (NLO) devices with high wavelength conversion efficiency through the second-order NLO effect of materials. Using the method, the growth direction of organic NLO crystal can be controlled and a long interaction length in the phase-matched direction is attained. As an organic NLO crystal, 2-adamanthylamino-5-nitropyridine (AANP) has been grown and its optical properties are characterized. The results show that Type II angle-tuned phase-matched wavelength conversion is possible in the wavelength region from 1.2 to 1.7 μm. To reduce the absorption of the AANP crystal in the 1.55 μm wavelength region, we have fabricated deuterated derivartives of AANP and succeeded in increasing the wavelength conversion efficiency.

ISSN:1058-725X    

DOI:10.1080/10587259808044448

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Structure of the green-phase of bis(diphenylglyoximato)Pt(II) formed by epitaxial growth with slow deposition rate was analyzed by electron microscopy. The phase is a tetragonal structure with the short Pt-Pt distance of about 0.33nm, which leads to an enhancement in χ(3).

ISSN:1058-725X    

DOI:10.1080/10587259808044449

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Second-harmonic generation (SHG) was observed in an unwound ferroelectric smectic C* liquid crystal using two counter-propagating fundamental waves. A remarkable enhancement occurred when SH light wavelength approached to the optical pitch of the helicoid. This enhanced signal based on a helicoidal distributed feedback action is proportional to the fourth power of the sample thickness in thick cells, and becomes larger compared with the conventional phase-matched SHG signal in relatively thick samples. The crossover points of the SH intensities in the two phase matching types shift toward thinner cell thickness in materials with a larger dielectric anisotropy.

ISSN:1058-725X    

DOI:10.1080/10587259808044450

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Optical transmission loss changes upon curing the mixture of epoxy/ethylene diamine were studied A UV-Vis spectrum measured during the cure process was utilized to monitor both cure process and transmission loss change simultaneously. It was found that initial homogeneity of the epoxy/EDA mixture was the key parameter to determine the optical transmission of the cured epoxy Slow heating up to the curing temperature allowed the mixture homogenous, thus resulted in a structure of very low transmission loss. Subsequent curing rate was also another factor affecting the uniformity of the cured structure

ISSN:1058-725X    

DOI:10.1080/10587259808044451

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Liquid crystalline monomer and photoactive monomers with various structures were synthesized and copolymerized. The resulting copolymers contain fixed LC unit and varying photoactive units. The phase transition temperatures are found to be affected by both comonomer structure and spacer length. The transition temperatures of itaconate bearing copolymer are found to be higher at smaller spacer length.

ISSN:1058-725X    

DOI:10.1080/10587259808044452

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We simply synthesized the triethoxysilane bearing the second-order nonlinear optical(NLO) active chromophore or chalcone derivatives. In order to improve the poor temporal stability of second-order NLO effect in sol-gel matrix, we introduced the photo-crosslink between the side chain. themselves. Photo-crosslink formation was confirmed with UV-VIS absorption and infrared vibrational spectroscopy. Under a polarized light, we investigated the decaying behavior of molecular order parameter after corona poling.

ISSN:1058-725X    

DOI:10.1080/10587259808044453

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A hybrid film where organic chromophores are attached to silica networks was fabricated by sol-gel process. The electro-optic coefficientr33was measured to be 16pm/V and the poled film retained 95% of its initialr33value after 800 hours at room temperature. A Mach-Zehnder modulator was fabricated, which supported the two lowest excited modes, TM00and TM10.

ISSN:1058-725X    

DOI:10.1080/10587259808044454

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two functionalized second-order nonlinear optical polyimides were synthesized by the polycondensation reaction between chromophore-containing dianhydride and diamine monomer. The molecular weights of the final polymers were determined to be Mn= 10000–11800. No melting was detected and they showed relatively low glass transition temperature at 160.7°C and 180.7 °C due to ether linkage in the polymer backbone. In the case of PI2-DANS, high optical quality films were prepared by spin casting. The second harmonic generation coefficients, d33and d31of PI2-DANS were measured to be 24 and 4.8 pm/V respectively. They exhibited no decay untilca.100 °C.

ISSN:1058-725X    

DOI:10.1080/10587259808044455

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

New polyimide derivatives containing hemicyanine dye were synthesized by mild Mitsunobu pathway. High χ(2)value of 100pm/V was obtained, which was higher value than those of other NLO-functionalized polyimides.

ISSN:1058-725X    

DOI:10.1080/10587259808044456

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor