Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Takashi Goh

Masayuki Okuno

Masao Kato

Hiroshi Yamazaki

Takashi Yamada

Shinji Mino

Motohaya Ishii

Takashi Saida

Ken Tsuzuki

Katsunari Okamoto

Toshio Watanabe

Toshikazu Hashimoto

Hiroshi Takahashi

Takayuki Mizuno

Kenya Suzuki

Hidehiko Takara

Masahiro Yanagisawa

Makoto Abe

Ryoichi Kasahara

Akira Himeno

Takeshi Kitagawa

Shunichi Souma

Yoshiyuki Doi

Koichi Takiguchi

Kiyofumi Kikuchi

Kazushige Yonenaga

Mitsuru Nagano

Masahiko Jinno

Kohki Shibahara

Atsushi Murasawa

Atsushi Mori

Yasuyuki Inoue

Yusuke Nasu

Shin Kamei

Masashi Miyata

Tsutomu Kitoh

Keita Yamaguchi

Shunichi Soma

Mitsumasa Nakajima

Tomoyuki Yamada

Hiroshi Terui

Yohei Sakamaki

Mikitaka Itoh

Kazunori Seno

Akimasa Kaneko

Tomohiro Shibata

Yasuaki Hashizume

Fumihiro Ebisawa

Kuninori Hattori

Tomoyo Shibazaki

Takao Fukumitsu

Yuichi Kikuchi

Takanori Ishikawa

Hisanobu Tanigawa

Mikitaka Ito

Ryosuke Saito

Provided is an optical signal processing device that can operate simultaneously for a plurality of wavelength bands. The optical signal processing device includes a WDM coupler array including a plurality of WDM couplers for separating the C band and the L band for the respective ports; input/output port groups provided for the C band and the L band, respectively; a micro lens array; a diffraction grating; a lens; and a spatial light modulator arranged in this order. The spatial light modulator collects light at different positions for the respective wavelengths, thus allowing all wavelengths to be independently subjected to a phase modulation. Light subjected to the desired phase modulation by the spatial light modulator is reflected and is deflected to have an angle corresponding to any desired port of the input/output port group, and then is optically-coupled to an input/output port depending on the deflection angle.

Optical signal processing device

A multi-stage interferometer circuit of the present invention includes: a multiplexing port; (N&#x2212;1) stages of lattice type two-beam interferometers, wherein each stage includes a two-beam delay circuit having a path length difference of an integral multiple of M&#xb7;&#x394; L/2, and wherein the two-beam delay circuit of the lattice type two-beam interferometer of the first stage is connected to the multiplexing port; an M-beam interferometer including: two sets of 1&#xd7;(M/2) optical couplers connected to the first optical coupler of the lattice type two-beam interferometer at the final stage; an M-array delay circuit, each delay circuit of which has a delay length different from each other by &#x394;L; and M&#xd7;M optical couplers; and M demultiplexing ports, wherein one or more transversal filters are arranged inside the multi-stage interferometer circuit so that the light guided between the demultiplexing port and the multiplexing ports passes therethrough at least once.

Multi-stage interferometer circuit with waveform shaping function

There is provided a multi-flow optical transceiver that includes (a) a plurality of wavelength-tunable light sources, (b) a plurality of optical modulation units which modulates light with an input signal, (c) an optical multiplexing/demultiplexing switch which couples light from at least one of the wavelength-tunable light sources to at least one of the optical modulation units with any power, (d) an optical coupling unit which couples a plurality of lights, modulated by a plurality of the optical modulation units, to at least one waveguide, (e) at least one multiple carrier generating unit which generates multiple carries, arranged at equal frequency intervals, from light of the wavelength-tunable light source, and (f) a wavelength separation unit which branches the multiple carriers from the multiple carrier generating unit for each wavelength.

Multi-flow optical transceiver, multi-flow optical transponder and multi-flow optical node

A waveguide type optical switch that can reduce the number of intersections in a matrix optical switch having the configuration of connecting unit optical switches and optical combining devices or optical branching devices to have a connecting function from 'multiple inputs to one output' to 'one input to multiple outputs'. To reduce the number of intersections in an entire matrix optical switch, an optical combining device of M inputs and one output is divided into (M&#x2212;1) pieces of unit optical combining elements each having two inputs and one output, which are arranged immediately after (N&#x2212;1) pieces of respective output ports excluding one piece of the output port closer to the input in the matrix optical switch out of N pieces of the output ports in the optical switch of one input and N outputs.

Waveguide type optical switch

A multi-flow optical transceiver provided with a plurality of wavelength-tunable light sources, a plurality of optical modulation units which modulates light with an input signal, an optical multiplexing/demultiplexing switch which couples light from at least one of the wavelength-tunable light sources to at least one of the optical modulation units with any power, and an optical coupling unit which couples a plurality of lights, modulated by a plurality of the optical modulation units, to at least one waveguide.

An optical modulator comprises an input optical splitting unit for bifurcating input light; a final optical coupling unit for coupling optical signals in a polarization state orthogonal to each other; an intermediate optical coupling unit provided in an intermediate position between the input optical splitting unit and the final optical coupling unit; first and second optical paths for connecting the input optical splitting unit and the intermediate optical coupling unit, optical path lengths of the first and second optical paths are approximately equal; third and fourth optical paths for connecting the intermediate optical coupling unit and the final optical coupling unit, optical path lengths of third and fourth optical paths are approximately equal; and three binary phase modulation unit arranged one by one in each of the three optical paths of the first, second, third and fourth optical paths.

Optical modulator

An optical modulation circuit includes: a first Mach-Zehnder modulating portion including a first output port and a second output port, wherein the first Mach-Zehnder modulating portion is push-pull driven by a main signal; a second Mach-Zehnder modulating portion connected to the first output port of the first Mach-Zehnder modulating portion, wherein the second Mach-Zehnder modulating portion is push-pull driven by a correction signal; and an asymmetric light combining portion combining an optical signal outputted from an output port of the second Mach-Zehnder modulating portion with an optical signal outputted from the second output port of the first Mach-Zehnder modulating portion in a light intensity coupling ratio of r to 1&#x2212;r, wherein an optical path length from the first output port to the asymmetric light combining portion is substantially equal to an optical path length from the second output port to the asymmetric light combining portion.

Light modulation circuit

In a nest MZI modulator in which each arm includes a child MZI, the power consumption is reduced. The hybrid integrated-type nest MZI modulator of the embodiment 1a is configured so that, instead of placing a relative phase adjusting section in a parent MZI, a bias electrode Bias 90&#xb0; in which an electric field is applied in the same direction to the polarization direction in both of the upper and lower arms is placed in each child MZI (see FIG.B). The bias electrode Bias 90&#xb0; provided in each child MZI constitute the entirety of a relative phase adjusting section. The optical signals are subjected to a phase change after the output from the child MZI (see FIG.A), because such relative phase adjusting section can subject the optical signals of the upper and lower arms of the child MZI to a shift change in the same direction, respectively.

Advanced-format optical modulator with low power consumption and low-loss characteristics

An object of the present invention is to provide a temperature-independent optical frequency shifter for generating sub-carriers with a miniaturizable configuration, as well as to provide an all-optical OFDM modulator using the same that is compact, has low temperature dependence, and is even compatible with different frequency grids. Provided is an optical frequency shifter and an optical modulator using the same, the optical frequency shifter comprises one input optical port, a 1-input, 2-output optical coupler optically connected thereto, two Mach-Zehnder modulation units individually optically connected to the two outputs thereof, a 2-input, 2-output optical coupler optically connected to the individual outputs thereof, and two output optical ports optically connected to the outputs thereof, wherein the two Mach-Zehnder modulation units are driven by periodic waveforms at the same frequency whose phases differ from each other by (2p+1)&#x3c0;/2 (p: integer).

Optical frequency shifter and optical modulator using the same

An optical modulator that supports a plurality of modulation formats is provided. The optical modulator includes: a distribution part including an optical demultiplexing/variable-branching switchable circuit; an optical modulator array; and an aggregation part including a combining ratio variable combining circuit and/or an optical multiplexing/variable-combining switchable circuit. The distribution part forms any or a combination of a variable 1&#xd7;M demultiplexer/brancher, a combination of one or more fixed ILFs and an optical switch and a combination of a plurality of variable optical couplers and an optical switch; the optical modulator array includes a plurality of optical modulators; the aggregation part includes a structure of any or a combination of one or more variable optical couplers, a combination of a plurality of variable attenuators, an M&#xd7;1 variable coupler, a variable M&#xd7;1 demultiplexer/brancher and a combination of one or more fixed ILFs and an optical switch.

A interferometer type polarization beam combiner and splitter, which can combine or split polarized light over a wide band, is provided. The interferometer type polarization beam combiner and splitter includes: an optical splitter; an optical coupler; an optical path length difference imparting unit, which includes a plurality of optical waveguides arranged between the optical splitting unit and the optical coupling unit; one or two input/output ports connected to the optical splitter; and two input/output ports connected to the optical coupler. A half-integer of a wavelength of &#x3bb;c is set as a normalized phase difference, for the optical path length difference imparting unit, between two polarization states, and means for generating a difference in refractive index dispersion is provided between the optical waveguides of the optical path length difference imparting unit, so that the change rate of the transmittance with respect to wavelength is suppressed for the two polarization states.

Wideband interferometer type polarization light beam combiner and splitter

In an optical component configured to fix to a mount an optical device chip in which waveguide type optical devices having different thermal expansion coefficients are butt-jointed, deterioration in reliability due to thermal stress is suppressed. The optical component () comprises an optical device chip () including an LN waveguide (), a first PLC waveguide (), a second PLC waveguide (), and a fiber alignment member (), a mount (), and optical fibers (). Each of connection faces between the first PLC waveguide and the fiber alignment member is configured as an tilted structure, and each of connection faces between the LN waveguide, and the first and second PLC waveguides is configured as a right-angled structure. In the right-angled structure, the connection faces are connected by an adhesive having a lower Young's modulus than that of an adhesive used on the connection faces of the tilted structure.

Optical component

Disclosed is an optical modulator which substantially lowers loss and has little attenuation in the intensity of an optical signal after modulation. The optical modulator includes a 1&#xd7;2 RZ pulse carver wherein optical phase shifters used for modulation are arranged along two arm waveguides held between a 1&#xd7;2 coupler and a 2&#xd7;2 coupler, two interferometric modulators connected respectively to two output ports of the 2&#xd7;2 coupler, and a 2&#xd7;1 coupler for combining the outputs of the interferometric modulators.

Excess optical power in a waveguide device is appropriately terminated. According to one embodiment of the present invention, the waveguide device comprises a termination structure filled with a light blocking material for terminating light from the end section of a waveguide. This termination structure can be formed by forming a groove on an optical waveguide by removing the clad and core, and filling the inside of that groove with a material attenuating the intensity of the light (light blocking material). In this manner, light that enters into the termination structure is attenuated by the light blocking material, and influence on other optical devices as a crosstalk component can be suppressed. With such termination structure, not only the influence on optical devices integrated on the same substrate, but also the influence on other optical devices directly connected to that substrate can be suppressed.

Waveguide device and module

An optical 90-degree hybrid circuit includes a first demultiplexing optical coupler having two or more first input ports and two or more first output ports, a second demultiplexing optical coupler having two or more second input ports and two or more second output ports, two first arm waveguides connected to the first output ports, two second arm waveguides connected to the second output ports, a 90-degree phase shift section installed in one of the four arm waveguides, a first optical coupler and a second optical coupler connected to the first arm waveguides and the second arm waveguides, a first optical waveguide for connecting an optical splitter and the first input ports, and a second optical waveguide for connecting the optical splitter and the second input ports, wherein an optical length of the first optical waveguide is different from that of the second optical waveguide.

Optical 90-degree hybrid circuit

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Atsugi, Japan

Takashi Goh