Nippon Telegraph and Telephone Corporation

Other

Senichi Suzuki

Hiroshi Takahashi

Masahiro Yanagisawa

Toshikazu Hashimoto

Tsutomu Kitoh

Takashi Saida

Motohaya Ishii

Yohei Sakamaki

Yasuhiro Hida

Munehisa Tamura

Ikuo Ogawa

Tomohiro Shibata

Akimasa Kaneko

Masaru Kobayashi

Kenji Yokoyama

Yasuyuki Inoue

Shin Kamei

Katsunari Okamoto

Masao Kawachi

Koichi Arishima

Motohiro Nakahara

Yoshiteru Abe

Shin Sumida

Kuniharu Kato

Shuichiro Asakawa

Mitsuru Harada

Koichi Takiguchi

Takeshi Kitagawa

Fumiaki Hanawa

Fumihiro Ebisawa

Ryou Nagase

Kuninori Hattori

Takaharu Ohyama

Hiroaki Yamada

Takashi Yoshida

Masaki Koutoku

Atsushi Takahara

Yuji Akatsu

Kazutosi Kato

Junichi Akahani

Kennosuke Fukami

A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) () which inputs signal light, mode coupling part () for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part () for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) () which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Planar lightwave circuit, design method for wave propagation circuit, and computer program

The present invention provides an optical functional circuit where a holographic wave propagation medium is applied and a circuit property is excellent such as small transmission loss and crosstalk. The optical functional circuit where a plurality of circuit elements are formed on a substrate includes the wave propagation medium for converting an optical path of a leakage light so that the leakage light that is not emitted from a predetermined output port of the circuit element is not coupled to a different circuit element. This wave propagation medium is constituted by an optical waveguide that is provided with a clad layer formed on the substrate and a core embedded in the clad layer, and a part of the optical waveguide is formed in accordance with a refractive index distribution which is multiple scattered.

Optical functional circuit

A wave transmission medium includes an input port-and an output port-. A field distributionand a field distributionare obtained by numerical calculations. The field distributionis a field distribution of the propagation light (forward propagation light) launched into the input port-. The field distributionis a field distribution of the phase conjugate light (reverse propagation light) resulting from reversely transmitting from the output port side an output field that is expected to be output from the output port-when an optical signal is launched into the input port-. According to the field distributionsand, a spatial refractive index distribution is calculated such that the phase difference between the propagation light and reverse propagation light is eliminated at individual points (x, z) in the medium.

Wave transmission medium and waveguide circuit

A multistage Mach-Zehnder interferometer type optical circuit including any number of symmetrical Mach-Zehnder interferometers and any number of asymmetrical Mach-Zehnder interferometers connected in cascade. In the optical circuit, low coherence light is used first to obtain individual phase control conditions of the symmetrical Mach-Zehnder interferometers without being affected by the asymmetrical Mach-Zehnder interferometers. Second, phase control conditions of the individual asymmetrical Mach-Zehnder interferometers are obtained by controlling the symmetrical Mach-Zehnder interferometers based on the first phase control conditions. Finally, the characteristic adjustment of the whole multistage Mach-Zehnder interferometer type optical circuit is carried out by controlling all the interferometers based on the phase control conditions of both the symmetrical Mach-Zehnder interferometers and asymmetrical Mach-Zehnder interferometers and setting the phase shift amounts of the individual interferometers at appropriate values.

Characteristic adjustment method of multistage Mach-Zehnder interferometer type optical circuit and multistage Mach-Zehnder interferometer type optical circuit

The object of the present invention is to provide a full-mesh optical wavelength division multiplexing transmission network device which is capable of exhibiting excellent communication quality and being mass produced, by reducing the accumulation number of coherent crosstalk lights, without any modification of constituent components constituting the conventional one. In the full-mesh optical wavelength division multiplexing transmission network device, provided is an N&times;N wavelength multi/demultiplexer having a periodic wavelength demultiplexing property in input/output combination, which performs input/output from/to first and second I/O port groups for optical signals and allows lightwaves traveling in opposite directions not to interfere with each other within the circut, thus reducing the accumulation number of coherent crosstalk lights in WDM wavelength lights and improving S/N of a received light. Particularly, by preventing the accumulation of adjacent crosstalk lights, communications with higher quality can be achieved.

Optical wavelength division multiplexing transmission network device

An optical wavelength division multiplexing transmission network system having a star-topology network is disclosed, which comprises an arrayed-waveguide grating type multiplexing/demultiplexing circuit having N input ports and N output ports, and N transmitting/receiving apparatuses, each apparatus including a transmitter, receiver, demultiplexer, multiplexer, and N 2-input and 2-output optical path switching elements corresponding to N wavelengths, so as to cope with a damage to a transmitting or receiving portion corresponding to a specific wavelength. Each switching element is independently switched between first and second connective conditions. In the first connective condition, the output port corresponding to a specific wavelength of the demultiplexer is connected to the input port corresponding to the specific wavelength of the receiver, and the output port corresponding to a specific wavelength of the transmitter is connected to the input port corresponding to the specific wavelength of the multiplexer; and in the second connective condition, the output port corresponding to a specific wavelength of the transmitter is connected to the input port corresponding to the specific wavelength of the receiver, and the output port corresponding to a specific wavelength of the demultiplexer is connected to the input port corresponding to the specific wavelength of the multiplexer.

Optical wavelength division multiplexing transmission network system using transmitting/receiving apparatuses having 2-input and 2-output optical path switching elements

In a light waveguide circuit including a plurality of waveguides having different length, a material (,) having a temperature coefficient of a refractive index including a symbol different from that of a temperature coefficient of an effective refractive index of the waveguide (,) is charged into a groove (,) formed by removing the upper clad and the core from the waveguide (,), or a groove (,) formed by removing the upper clad, the core and the lower clad from the waveguide (,). A difference in length of the removed portions between adjacent waveguides is proportional to a difference in length of the waveguides which were not removed and remained.

Optical waveguide circuit, its manufacturing method and optical waveguide module having the optical waveguide circuit

Growing community of inventors

Mito, Japan

Senichi Suzuki