Koji Nakazato

Thermal and mass analyses of fluorination process with ammonium bifluoride

Mixtures of ZrO 2 or ZBLAN/NH 4 FHF were mainly analyzed in the range of room temperature to 600 o C by TG-DTA and mass spectroscopy simultaneously in order to determine the best temperature for the fluorination process. Four endothermic peaks with weight reduction were found by TG-DTA, and clearly assigned by mass spectrum. The first peak around 100 o C is caused by the ZrO 2 /NH 4 FHF reaction, and the second to fourth peaks are attributed to decomposition of (NH 4 ) x-4 ZrF x

A study of the control of Nd3+ energy levels in fluorozirconate glasses

Abstract Nd3+-doped ZBLAN single-mode fibers have been fabricated and optical amplification around 1340 nm has been obtained. However no gain has been observed in the 1300 nm region, which is used in most of the current telecommunication systems. This problem is because of the existence of the excited state absorption (ESA). In order to improve gain characteristics around 1300 nm, ESA and fluorescence wavelengths must be controlled by changing the ligand field around Nd3+ ions. Some Nd3+-doped fluorozirconate-based glasses, in which other alkali elements were substituted for Nd were prepared and absorption, fluorescence and lifetime characteristics of the Nd3+ ions in the glasses were examined. As a result, it was found that the ESA wavelength was shifted by the alkali elements systematically.

Performance of Pr-doped Fluoride Fiber Amplifier for Multichannel AM-VSB Transmission

System performance of Pr-doped fluoride fiber amplifier was examined for multichannel AM-VSB video signal transmission for the first time. For CNR of 51 dB, the loss budget of 15.1 dB was obtained with the amplifier.

Erbium-Doped Extremely High-dn Single-Mode Fibers

An erbium-doped single-mode fiber with Δn( ESI ) of 3.5 % was fabricated, and the gain coefficient of 5.4 dB/mW was obtained. Its high normal dispersion of -100 ps/km/nm is useful for a dispersion compensator.