Oki Electric Industry Co., Ltd.

Kozo Fujii

Akihiko Nishiki

Yukihiro Ozeki

Ichiro Koiwa

Masatoshi Kagawa

Hiromi Tsuji

Hideo Sawai

Yoshitaka Terao

Naoyuki Shiozawa

Andrew R Pratt

In an optical element integrated module, first through n-th optical data signals are externally input to first ports of first through n-th optical circulators and are input to first through n-th optical/optical converters via second ports. The first through n-th optical/optical converters modulate first through n-th optical short pulse trains in accordance with the first through n-th optical data signals. First through n-th modulated optical data signals are input to the second ports of the first through n-th optical circulators and are input to an optical time division multiplexing section. The optical time division multiplexing section generates optical time division multiplexed signals by time division multiplexing the first through n-th modulated optical data signals.

Optical element integrated module

An optical time-division multiplexer branches input light into a plurality of optical paths with different optical lengths. At least one path includes a section of optical fiber with an optical length that is adjustable by physical stretching. The input light is separately modulated on each optical path, and the modulated light signals are recombined into a multiplexed output light signal. Adjustment of the optical length of the optical fiber can compensate for changes in input wavelength and adjust the phase of successive pulses in the multiplexed output signal to provide a &#x3c0;-radian shift that enables long-haul optical transmission.

Optical time-division multiplexer using optical fiber for phase adjustment

A semiconductor optical modulator having an electroabsorptive layer and a pair of modulating voltage electrodes also has a direct-current voltage electrode, from which an unmodulated electric field can be applied to the electroabsorptive layer to adjust the output optical power level. The output optical power level can thus be adjusted without the need for an external attenuator, and without shifting the modulating voltage away from the part of the extinction ratio characteristic having the best linearity. An optical multiplexing module using semiconductor optical modulators of this type can generate a multiplexed output signal with a uniform optical power level simply by controlling the direct-current voltages applied to the semiconductor optical modulators.

Semiconductor optical modulator, optical multiplexing module, and control method thereof

This invention provides an improved optical amplifier, which comprises a rare earth doped optical fiber for amplifying the optical signal, at least one pump laser for providing a pump signal to the rare earth doped optical fiber, a wavelength division multiplexer for extracting a backward amplified spontaneous emission (ASE) signal in the C-band wavelength (1525-1565 nm) differ from the L-band wavelength (1565-1610 nm) containing the optical signal to be transmitted, a gain controller for controlling a power level of the pump signal based on a received power of the backward ASE signal.

Optical amplifier

An alignment system finds the coordinates of a first point on a photosensitive optical fiber by scanning an ultraviolet beam across the fiber several times at successively decreasing speeds and detecting light returned from the fiber. The coordinates of a second point on the fiber are found similarly. On the basis of the coordinates of the first and second points, the alignment system automatically aligns the fiber in a direction suitable for the formation of an optical filter in the fiber.

Initial alignment system for use in manufacturing an optical filter

Alignment method for optical fibers for use in manufacturing an optical

A gas discharge panel with a plurality of electrically conductive oxide cathode electrodes and a plurality of anode electrodes that are arranged in a matrix in a sealed container. This electrically conductive oxide cathode electrode is formed using, for example, lanthanum chromite, lanthanum calcium chromite, alumina-doped zinc oxide, or antimony-doped tin oxide.

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Kanagawa, Japan

Kozo Fujii