Nec Corporation

Masahiko Fujiwara

Yuzo Shimada

Sakae Kitajo

Mikio Oda

Yoshinobu Kaneyama

Toshihide Kuriyama

Tatsuya Shiragaki

Keiro Komatsu

Shuji Suzuki

Kazuhisa Kaede

Masataka Itoh

Takahiro Shiozawa

Syuji Suzuki

Minoru Shikada

Masataka Ito

Akira Ajisawa

Masahiro Eda

The present invention provides a photo-electric combined substrate comprising an electric interconnection part having an electric interconnection layer and an electric insulating layer as well as an optical waveguide part consisting of a core and a clad, where the electric insulating layer in the electric interconnection part and the optical waveguide part are made of the same material; a ceramic substrate comprising an optical device and an electric device where a ceramic substrate has a concave where the concave is filled with a resin, and where at least an optical device is mounted on the ceramic substrate while an electric device on the resin in the substrate concave; and an optical waveguide comprising a core and a clad having a refractive index lower than that of the core, where the core is made of a fluorene-unit-containing epoxy acrylate resin.

Photo-electric combined substrate, optical waveguide and manufacturing process therefor

After an optical element and more preferably both an optical element and an electrical element are mounted on a substrate an upper clad of optical waveguide is formed, covering these elements, and thereby a structure of hermetic seal is achieved through the use of the upper clad

Optical module and manufacturing method thereof

An apparatus and a method for performing hitless switching between optical transmission lines such as optical fiber circuits are provided. An optical switch or optical switching network having input terminals and output terminals for selecting optical signals inputted to the input terminals to the output terminals with a selection ratio which can be varied continuously is used. An optical signal converter for generating an optical signal of light which does not interfere with another optical signal is attached to the optical switch. Further, a signal loop interconnecting one of the output terminals of the switch and the input of the optical signal converter is provided. When hitless switching between two optical transmission lines is performed, the same information signal is first inputted to the two transmission lines on the transmission side, then the optical signal from the two lines are transmitted to one of the output terminal (aimed output terminal) of the switch and another output terminal connected to the signal loop. The phase difference between the optical signals is detected and adjusted, and the optical switch is controlled so that the optical signal to be selected at the aimed output terminal is varied to the signal passing through the signal loop.

Hitless switching apparatus and method for optical network

A plurality of node apparatuses are connected by an optical transmission line. Each of the node apparatuses is assigned with a wavelength as an address different from the others. Therefore, when a first node apparatus transmits data to a second node apparatus, the data is of a wavelength corresponding to the address of the second node apparatus. The data transmission is carried out in a time slot defined by a frame pulse. The data of the corresponding wavelength is only received in the second node apparatus, and data of other wavelengths are passed through the second node apparatus. Consequently, media-access control is easily carried out independently in each node apparatus in an optical network system by using wavelength division multiplexing.

System for transmitting data using wavelength division multiplexing

A pendulum-like member is formed in a silicon substrate. Optical fiber portions which include endface mirrors are disposed on the substrate proper and on the pendulum member. The position of the pendulum member is adjusted by applying a voltage across the member and an adjacent section(s) of the substrate thus enabling the optical length of the device to be adjusted.

Tunable fiber Fabry-Perot etalon optical filter

An optical wavelength-division switching system comprises means for reproducing an electric signal for each channel from a wavelength division multiplexed optical signal, and means for converting the electric signal to a modulated optical signal. The means for reproducing the electric signal can be composed of an optical heterodyne or homodyne detection system, while the means for converting the electric signal can be composed of a distributed feedback laser diode having an optical frequency modulating characteristic so that the number of channels is much increased with the decrease of crosstalk.

Optical wavelength-division switching system with coherent optical

An optical switch circuit is configured as a matrix array to arbitrarily switch the connections between optical transmission channels. The optical switch circit comprises a plurality of optical splitter coupled to input transmission channels, a plurality of optical switches arranged on the matrix crosspoints, each switch comprising an optoelectronic element and a light modulating element functioning as an electrooptic element, and a plurality of optical combiners coupled to output transmission channels. Thus, a small-sized optical switch circuit suitable for integration is realized. With this circuit, small crosstalk and high speed switching without distortion of broadband signals are expected. Further, this circuit provides a wide adaptability such that light transmitted through multi-mode optical fiber can be switched.

Optical switch circuit

In a semiconductor layer which has in a semiconductor bistable etalon a refractive index variable, as a result of absorption by excitons, with the intensity of an optical beam incident thereon, an optical guide for the optical beam is surrounded by a cladding portion including atoms which reduce the refractive index in the cladding portion relative to the optical guide and serve as recombination centers for free carries produced by decomposition of the excitons. The semiconductor layer may be either a superlattice layer, such as a GaAs-GaAlAs layer, or a bulk semiconductor layer, such as a GaAs layer. After forming the semiconductor layer on an etch-stop layer which is formed on a semiconductor substrate for chemical etch of the substrate for a window, the atoms are injected into the surrounding portion as by bombarding an exposed surface of the semiconductor layer by hydrogen ions with a mask selectively formed on the exposed area to cover an area contiguous on the exposed surface to a columnar portion which becomes the optical guide. The hydrogen ions automatically become the atoms of the above-described type in the surrounding portion.

Device and method for providing optical bistability with free carrier

An optical switch having a plurality of channel waveguides. At least one of which is a gain-guided channel waveguide. In operation, a light beam incident on one end face of the optical switch through one of the channel waveguides exits from the switch through one or another of the channel waveguides in accordance with current injected into the gain-guided channel waveguide. As a result, a compact low-voltage optical switch is possible. The channel waveguides may run parallel to each other, or may come together in a center portion in a X-shape, separated by a relatively small distance, or as a third alternative may be formed in a Y-shape, with a small distance separating the branches of said Y-shape.

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Tokyo, Japan

Masahiko Fujiwara