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Since 1997 we have tested the reliability of SC connectors installed outdoors in hot and humid environments. SC connectors with optimized ferrule end dimensions have maintained good optical performance for 20 years. more...

A new optical-connector-end polishing machine for On-Site was developed. This machine can polish a connector end with only one-step by a very simple mechanism. Using this machine, the end polishing of the optical connector can become very easy and fast. we characterized the one-step polishing process. As a result, it revealed that the machine has sufficient power for good polished planes unless only one-step. Polished planes had good precision met with the specification and the polishing had good reproducibility more...

The unsteady-state thermal conduction processes in triangular-profile (TP) optical fibers, which exhibited zero chromatic dispersion near 1.55 /spl mu/m, were studied theoretically with the explicit finite-difference method (FDM). It was estimated that these fibers would exhibit a high-temperature optical absorption on the basis of the high-temperature loss-increase mechanism proposed for step-index (SI) optical fibers. The core-center temperature of the TP fibers changed suddenly and reached over 7/spl times/10/sup 5/ K when a 1.064-/spl mu/m laser power of 1 W was inputted into the core layer heated at 2608 K. This rapid heating of the core initiated the "fiber fuse" phenomenon. The propagation rates of the fiber fuse, estimated at 1.064 /spl mu/m, were in fairly good agreement with the experimentally determined values. It was found that the threshold powers for initiating the fiber fuse are linearly proportional to the roots of the effective core areas of both the SI and the TP optical fibers. This coincides the experimental result reported by Seo et al. more...

The unsteady-state thermal conduction process in step-index single-mode (SM) optical fiber was studied theoretically with the explicit finite-difference method. We considered a high-temperature loss-increase mechanism, which includes two factors that bring about an increase in the absorption coefficients: 1) electronic conductivity due to the thermal ionization of a Ge-doped silica core and 2) thermochemical SiO production in silica glass. The core-center temperature changed suddenly and reached over 4/spl times/10/sup 5/ K when a 1.064-/spl mu/m laser power of 2 W was input into the core layer heated at 2723 K. This rapid heating of the core initiated the "fiber fuse" phenomenon. The high-temperature core areas were enlarged and propagated toward the light source. The propagation rates of the fiber fuse, estimated at 1.064 and 1.48 /spl mu/m, were in fair agreement with the experimentally determined values. We found that the threshold power for initiating the fiber fuse increases from 0.98 to 1.26 W when the input laser wavelength is increased from 1.06 to 1.55 /spl mu/m. more...

The unsteady-state thermal conduction process in single-mode (SM) optical fiber was studied theoretically with the explicit finite-difference method (FDM). In the numerical calculation it was assumed that the electrical conductivity of the core layer increased rapidly above 1323 K. The core-center temperature changed suddenly and reached over 3/spl times/10/sup 5/ K when an optical power of 1 W was input into the core layer heated at 1373 K. This rapid heating of the core initiated the "fiber fuse" phenomenon. The high-temperature core areas, whose radiation spectrum extended over a wide range from the infrared to the ultraviolet regions, were enlarged and propagated toward the light source at a rate of about 0.7 m s/sup -1/. This rate was in fair agreement with the experimentally determined value. more...

Unsteady-state thermal conduction process in the single-mode (SM) optical fiber was theoretically studied with the explicit finite-difference method. In the numerical calculation it was assumed that the electrical conductivity of the core layer increased rapidly above 1050 °C. The core-center temperature changed suddenly and reached over ten thousand Kelvin when the optical power of 1 W was input to the core layer heated above 1000 °C. This rapid heating phenomenon also occurred when the optical power was reflected at the edge wall of the thermally produced cavity in the core layer. The occurrence of this phenomenon was restricted by the decrease in either the input optical power or the normalized frequency of the SM optical fiber. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(11): 11–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10150 more...

We injection molded a plastic ferrule for a single-mode optical fiber connector. We used liquid crystalline polymer (LCP) as the molding material because of its fine mold replication ability and introduced an eccentricity control mechanism into the ferrule mold. As a result, we succeeded in molding plastic ferrules whose eccentricity was less than 1 /spl mu/m by optimizing the eccentricity control conditions. The connection loss of these low eccentricity plastic ferrules was around 0.2 dB and they exhibited an excellent reflection characteristic of 52.5 dB. These initial results were maintained during mating tests and temperature and humidity cycling tests. more...

Split alignment sleeves for single-mode (SM) optical fiber connection are fabricated with a precise injection-molding technique using a thermosetting epoxy resin. The fabricated plastic sleeves exhibit dimensional accuracy of 50 dB. The plastic sleeves exhibit good resistance in 500-cycle mating tests using zirconia and/or glass ceramic ferrules, and in vibration and impact tests as well. The initial optical characteristics are maintained in both short-term and long-term environmental durability tests. more...

The linear and the nonlinear optical properties of soluble phthalocyanines in the condensed states were investigated by the absorption and the electroabsorption spectra. By a Kramers-Kronig analysis of the electroabsorption spectra, the wavelength of the maximum refractive index changes is located at around 980 nm for the casted polymer film doped with binuclear phthalocyanine. more...

The large absorption coefficient /spl alpha/ of single-mode optical fiber at high temperatures is closely related to the generation of the fiber fuse phenomenon. We propose a high-temperature loss-increase mechanism, which includes three factors that bring about an increase in the /spl alpha/ values: 1) point-defect (Ge E' center) formation; 2) electronic conductivity due to the thermal ionization of a Ge-doped silica core; and 3) thermochemical SiO production in the silica glass. Ge E'-center formation and electronic conductivity in the Ge-doped silica core are dominant factors at temperatures near the critical temperature of 1323 K. However, these factors cannot explain the large /spl alpha/ values observed at high temperatures above 2273 K. By contrast, SiO gas and/or solid, which are thermochemically produced in the silica glass, exhibit large /spl alpha/ values of the order of 10/sup 4/ m/sup -1/ at 2293 K. The /spl alpha/ value estimated at 0.5 /spl mu/m is close to the experimental value reported in the fiber fuse experiments. more...

The evolution of the fiber fuse phenomenon in a single-mode fiber-optic connector was studied theoretically. A narrow air gap of the order of 1 /spl mu/m was assumed to be formed between the fiber end-faces in the connector as a result of the adhesion of dust to both the ferrule and the fiber end-faces. It was assumed that there was a thin water layer in the gap because condensable water molecules in the air could easily be trapped by the SiOH groups on the silica-glass surface. The water layer exhibited a large absorption coefficient of about 850 cm/sup -1/ at 1.48 /spl mu/m. The temperature distributions near the air gap were numerically calculated by using the explicit finite-difference method. When a high-power laser operating at 1.48 /spl mu/m was input into the connector, the temperature along the fiber-core center increased abruptly at the thin water layer. The air gap was heated above 4/spl times/10/sup 5/ K when the optical power was 2 W and the gap was 1 /spl mu/m. The heat in the air gap gradually diffused into the neighboring optical fiber over time. The temperature of the heated fiber reached over 1/spl times/10/sup 4/ K, which is high enough to initiate the fiber fuse phenomenon. more...

We have developed a new type of receptacle interface that enables us to achieve dense multi-fiber connection between a planar lightwave circuit based optical device and single-mode fibers on a printed circuit board. To obtain both a small size and good optical performance with this interface we devised a small fiber guide for aligning the fibers with waveguides, and also developed a refractive-index-matching gel that maintains stable optical performance. We fabricated sufficiently small (5 mm long) 32-fiber interfaces, and successfully obtained low connection and high return losses with average values of 0.17 and 60 dB, respectively. We also demonstrated that the interface can provide sufficient environmental durability. Our new interface eliminates the need for pigtail fibers on the board, and this will lead to the development of dense and low-cost optical interconnection on a board for advanced optical network systems. more...

We propose a new LC connector configuration to enhance mechanical durability, and uses a nutation test method to estimate the mechanical endurance of a fiber cable when an optical fiber is pulled obliquely. more...

Absorption and electroabsorption measurements were performed on the substituted tetrakis tert-butyl metal-free phthalocyanine (H2Pc(t-bu)4) solid solution. The complex third-order nonlinear susceptibilities were determined in poly(methyl methacrylate) films doped with H2Pc(t-bu)4. The real and imaginary parts of χ(3)(-ω;ω,0,0) were -5 × 10−13 and -4 × 10−13 esu, respectively, at 10 wt° doping of H2Pc(t-bu)4. In guest/host system, the aggregation reduced the optical nonlinear susceptibilities rather than optical absorption coefficients. more...

Split alignment sleeves for the single-mode optical-fiber connection of MU and SC-type ferrules were successfully fabricated for the first time with a precise injection-molding technique using a thermosetting epoxy resin. The optimum inner radii of the plastic sleeves were determined with a view to realizing both suitable gauge retention forces for the ferrules and a small fiber offset of 1 /spl mu/m between them. The adapters incorporating the plastic sleeves showed excellent performance with an average connection loss of 0.09 dB and a return loss of >50 dB. more...

We developed a fiber fuse terminator to ensure the safe operation of high power optical network systems. The performance of this fiber fuse terminator was satisfactory as regards an optical input of 2 W. more...

Plastic ferrules and split alignment sleeves for single-mode fiber-optic connectors were successfully fabricated by an injection molding process. The optical characteristics of these plastic components are compatible with single-mode SC-type connectors and they are also stable under hot and humid conditions. more...

In this paper, we describe a nondestructive method of observing changes in the microstructure of optical fibers subjected to CO2 laser irradiation for optical fiber splicing using synchrotron radiation micro-computed tomography (CT). In particular, we evaluated a method of enhancing the contrast between a GeO2-doped optical fiber core and a silica cladding by performing CT observations of the X-ray energy around the Ge-K absorption edge. Specifically, procedures for extracting a GeO2-doped core from a three-dimensional image of optical fibers by the cluster labeling method are proposed and evaluated. The approach enabled us to observe how inclusions at the optical fiber splicing interface influence the optical fiber core structure. We also expect this observation method to be used for improving such aspects of laser processing performance as insertion loss and mechanical strength for recently developed optical fibers. more...

We report the synthesis, and optical characterization of the planar binuclcar phthalocyanines metal free (-1)( H2Pc)2(t-bu)6 and (-l)(VOPc)2(t-bu)6. Several of their optical properties, including linear absorption, concentration dependence, electroabsorption, and transient optical response were measured. more...

The high-power characteristics of the MU-type fibre-optic connector are investigated systematically for the first time. It is clarified that a connector with a low insertion loss of below 0.25 dB suppressed the undesirable temperature increase to less than 10° with an optical input of 1 W, and appropriate ferrule endface cleaning prevented endface damage. more...

Plastic optical alignment sleeves for singlemode connection were successfully fabricated by the thermoset injection moulding process. The split sleeves exhibit excellent dimensional accuracy (± 2 µm) and have extremely smooth surfaces (Ra < 0.1 µm). They are compatible with SC-type connectors and the average optical loss is < 0.1 dB for singlemode SC plugs. more...