Yusuke Fujii

Black synthetic quartz glass layer for optical fiber cross-talk reduction fabricated by VAD method

In this report the new black-glass fiber-preform fabricated by the vapor-phase axial deposition (VAD) method to realize high-resolution optical bundle fibers is discussed with the Energy Dispersive X-ray (EDX) analysis and the transmittance spectrum measurement. The black glass consists of SiO2, GeO2, Bi2O3 and Al2O3. Firstly, the rod-shaped soot of SiO2 and GeO2 is prepared by blowing SiCl4 and GeCl4 into the oxyhydrogen burner. Then the soot is dipped into the solution of the Bi and Al compounds. After drying the soot with Bi and Al penetrated, the soot is consolidated into the glass preform by heating with the carbon heater at 1650 degrees Celsius. The diameter of the obtained preform is 10.5 mm and the black glass layer thickness is 2.6 mm located at the periphery. The Bi concentration distribution shows the content of several wt% in the black glass layer. The black glass preform is drawn into the black optical fiber being expected to make a clear image because of no light leaking from the neighboring optical fibers as compared to the conventional fiber endoscope.

Broadband optical amplification with water-free hexagonal double-clad Bi doped silica fiber

1.3 - 1.55 micron optical amplifiers for the long distance up-stream and down-stream networks for a future increase of fiber access networks in telecommunications are attractive. A bismuth-doped silica glass has a potential of the broadband spectrum as lasers and amplifier applications at 1.3 -1.55 micron. The bismuth-doped fiber lasers and amplifiers were discussed by the MOCVD method. In this report optical amplification characteristics at 1.3 - 1.55 micron are presented with the water free hexagonal double-clad bismuth-doped silica fiber (HDC-BDF) made by the vertical axial vapor-phase deposition (VAD) method. The bismuth and aluminum ions were vapor–phase doped into the silicon and germanium oxide. Pumping into the HDC-BDF was performed by using the tilt-polished fiber from the hexagonal surface with the multimode fiber pigtail of the pumping LD. 2 dB amplified gain was obtained with less than -40 dBm CW input signal power at 1310nm.

A wide range optical amplification in 1.3–1.5 micron with Bi-doped silica fiber

In this report the Bi-doped silica fiber (BDF) is fabricated by the vapor-phase axial deposition (VAD) method. A wide range optical amplified gain is measured in 1300-1600 nm with the BDF. 7dB gain is achieved with 4m D-shaped first-clad fiber at 1310 nm.

1.3 μm flat-gain optical amplification with bi doped silica fiber

1.3 μm optical amplifiers for the long-distance up-stream networks are attractive for a future increase of fiber access network in telecommunications. In this report an optical amplification with Bi doped silica fiber (BDSF) fabricated by the vapor axial deposition (VAD) method is presented at 1300 nm.

Comparing the effect of a Spot-Size Converter for kilometer-length of GI-MMF with and without connecter-splicing

This report compares the effect of a Spot-Size Converter in improving transmission characteristics of kilometer-length of GI-MMF with and without connecter-splicing. A simple calculation technique to simulate the eye-diagram is also proposed and verified.