Nippon Telegraph and Telephone Corporation

Nagoya University

Japan Science and Technology Agency

Other

Kabushiki Kaisha Toshiba

Nec Corporation

Tokai National Higher Education and Research System

Ken-ichi Sato

Hiroshi Hasegawa

Yojiro Mori

Satoru Okamoto

Hiroshi Takahashi

Kenya Suzuki

Toshio Watanabe

Shin Kamei

Osamu Moriwaki

Atsushi Watanabe

Yoshihisa Sakai

Masafumi Koga

Kunihiko Takagi

Masazumi Shiraishi

Koh Ueda

Kouichi Takiguchi

Yuki Terada

Hiroto Ishida

Kosuke Sato

Tomonobu Niwa

Ryosuke Hirako

Yuto Iwai

Kiyo Ishii

Shoji Kakehashi

In the case of a OXC device having a route & select-type configuration of the conventional technique, when the port number is 20, then the entire device requires 120 WSSs having a 1&#xd7;9 configuration. In the case of a route & select-type OXC device having ports more than 20 ports, a large amount of expensive WSSs is required. Thus, such a device is impractical from the viewpoint of cost. Thus, the expansion depending on an increase of traffic at nodes was impossible, flexible scalability could not be provided, and a reasonable network operation from the viewpoint of economy was difficult. According to the OXC device of this disclosure, regardless of the input port number and the output port number of the device, WSSs having a smaller scale than the conventional technique are used and the WSSs are internally-connected from a viewpoint different from that of the conventional technique, thus providing the device having a significantly-reduced cost.

Optical cross-connect device

A wavelength routing SW is a large-scale optical switch device of a conventional technique, and it requires as many wavelength-tunable light sources as the number of input ports. For the wavelength-tunable light sources to achieve a stable oscillating operation across a wide wavelength range, a complicated control mechanism is necessary. This has been an obstacle in providing a large-scale optical switch device in terms of cost and circuit scale. A wavelength routing SW in the present disclosure includes N wavelength group generators, a splitting-selection unit, and MN tunable filters. Each wavelength group generator includes M fixed-wavelength light sources. Inexpensive general-purpose devices that require no control mechanism for wavelength tuning can be used as the fixed-wavelength light source. The channel loss in the optical switch device can also be reduced by using light sources with a limited narrow range of tunable wavelengths and the wavelength-dependent output port selecting function of an AWG.

Optical switch device

An optical network transmits a wavelength division multiplexing optical signal from a transmission to a reception node via a reconfigurable optical add/drop multiplexer and/or path cross-connect apparatuses. When optical or optical super channels made of successive optical subcarriers input from input optical fibers are routed or switched to an output optical fiber in the multiplexer and/or apparatus passed through by a wavelength division multiplexing optical signal transmitted from the predetermined transmission node to the predetermined reception node, the adjacent channels output to the same output fiber in each input fiber is collectively demultiplexed without being demultiplexed for the channels and is routed or switched to the output fiber. Channel routing paths and frequency arrangements are controlled such that the number of filtering times by a wavelength division filtering mechanism on one or both sides on the frequency axis of the channel becomes equal to or less than a predetermined value.

Optical network

An optical add-drop apparatus dropping a signal in input optical fibers in an optical cross-connect apparatus or adding a signal into output optical fibers from the cross-connect apparatus, optical cross-connect portions of the cross-connect apparatus connected such that a cross-connect portion internal connection output port is directly connected to an internal connection input port of another cross-connect portion and is indirectly connected via the other cross-connect portion to an internal connection output port of a further cross-connect portion, the add-drop apparatus having: photocouplers connected to part or all of the input fibers connected to each cross-connect portion; and drop signal receiving apparatuses each having optical switches each receiving and alternately selecting a signal output from photocouplers connected to respective different cross-connect portions of the cross-connect portions out of the photocouplers, the drop signal receiving apparatuses selecting a signal of a wavelength for each signal respectively output from the optical switches.

Optical cross-connect

An optical cross-connect apparatus optical nodes in an optical network, the optical nodes being mutually connected through internode connection optical fibers, the optical cross-connect apparatus having: optical cross-connect portions having internode connection input ports and internode connection output ports respectively connected to the internode connection optical fibers, and internal connection input and output ports, the optical cross-connect portions being connected such that an internal connection output port of a predetermined optical cross-connect portion is directly connected to an internal connection input port of another optical cross-connect portion and is indirectly connected via the another optical cross-connect portion to an internal connection output port of a further optical cross-connect portion, at least one optical cross-connect portion of the optical cross-connect portions including an internal connection input port and an internal connection output port for connecting to an optical cross-connect portion for expansion connected to none of the other optical cross-connect portions.

Disclosed is a spatial switching apparatus having a plurality of input terminals, an input optical signal of a single wavelength being input to each of the plurality of the input terminals, and a plurality of output terminals an output optical signal of a single wavelength being output from each of the plurality of the output terminals. The apparatus includes a signal wavelength converting portion having an electric signal converting element converting the input optical signal into an electric signal and a variable wavelength laser, the signal wavelength converting portion using the variable wavelength laser to convert an electric signal converted by the electric signal converting element into an optical signal of an arbitrary wavelength; and a spatial switching portion having a plurality of first cyclic AWGs performing output from a plurality of output ports corresponding to wavelengths of a plurality of input signals input from the variable wavelength laser.

Space switch device

An optical signal terminating apparatus for an optical path network includes: a variable filter selecting an optical signal of a predetermined wavelength path making up any one of a plurality of wavebands included in one wavelength division multiplexing light selected from a plurality of wavelength division multiplexing lights respectively transmitted in parallel via a plurality of optical fibers to a relay node in the optical path network, the variable filter dropping the optical signal to an electric layer, the variable filter including a waveband separator separating the wavelength division multiplexing light into a plurality of wavebands, a waveband selector selecting one waveband from a plurality of wavebands separated by the waveband separator, a wavelength separator separating one waveband selected by the waveband selector into wavelengths, and a drop wavelength selector.

Optical terminating apparatus for optical path network

An optical cross-connect apparatus includes: a plurality of optical cross-connect portions each having an inter-node connection input port and an inter-node connection output port respectively connected to each of the plurality of the inter-node connection optical fibers, an internal connection input port, and an internal connection output port, wherein for each of the plurality of the optical cross-connect portions, the internal connection output port of a predetermined optical cross-connect portion is directly connected to the internal connection input port of another optical cross-connect portion, or the internal connection output port of a predetermined optical cross-connect portion is directly connected to the internal connection input port of another optical cross-connect portion and is indirectly connected via the another optical cross-connect portion to the internal connection input port of yet another optical cross-connect portion.

Optical cross-connect apparatus

An optical communication network node apparatus is provided that considerably reduces the node apparatus in scale, especially, a switch device in scale relative to increase in the number of wavelength multiplexes. With a routing operation on the basis of a wavelength at an intra-ring traffic step, light output from a plurality of demultiplexers is subjected to add/drop and routing processes and is directly or indirectly distributed to a plurality of multiplexers, and at an inter-ring traffic step (including a routing operation on the basis of a wavelength group), among lights output from a plurality of demultiplexers, light of another wavelength preliminarily set for inter-ring transmission and different from the light of the wavelength preliminarily set for the intra-ring transmission is subjected to the routing process, and, therefore, the node apparatus is considerably reduced to a smaller scale as compared to a node apparatus that achieves concatenation in a manner capable of routing lights of all the wavelengths to arbitrary optical rings.

Routing method of optical communication network node apparatus and optical communication network node apparatus

A simple optical waveband multiplexer/demultiplexer operable to separate a wavelength-division multiplexed light beam WDM consisting of a plurality of wavebands WB each including a plurality of optical channels, into a predetermined plurality of wavebands WB, and output the separated plurality of wavebands WB from a plurality of output ports, wherein the wavelength-division multiplexed light beam WDM is transmitted through two array waveguides each capable of performing a demultiplexing function with a resolution corresponding to wavelengths of the optical channels, and a characteristic of sequentially shifting the output ports by one position with shifting of input ports by one position, whereby the wavelength-division multiplexed light beam WDM is separated into a plurality of wavebands WB each including the mutually different optical channels selected from the optical channels included in the wavelength-division multiplexed light beam WDM, and the separated wavebands WB are outputted from the plurality of output ports, respectively.

Optical waveband demultiplexer, optical waveband multiplexer, and optical waveband selective switch

The present invention discloses a packet transmission device and a packet transmission system which can realize high-capacity communication. The transmission device transmits packets over a wavelength division multiplexing (WDM) link by mapping the packets into an optical path signal directly without any other medium such as an SDH path. The present invention also discloses a packet transmission device and a packet transmission system which can realize high-capacity communication over an SDH transmission link by mapping the packets directly into an SDH section payload without adding any VC path overhead in order to use the entire SDH section payload area.

Packet transmission device and packet transmission system

An optical cross-connect system is provided with M fixed wavelength light sources and external modulators corresponding to respective optical paths, serving as light sources for wavelength conversion devices corresponded to M.times.N optical paths. By means of electrical signals for the converted optical signals carried on the M.times.N optical paths, CW lights input to the external modulators from the respective light sources are modulated, wavelength converted and then output. Accompanying this wavelength conversion, wavelength multiplexed light sources which can select lights from a plurality of fixed wavelength light sources and output to predetermined output ports, are used for the light sources of the plurality of wavelength conversion devices of the cross-connect system. In this way, the light sources of a plurality of wavelength conversion sections are commonalized using a fixed wavelength light source. As a result wavelength multiplexed light sources which can respectively output lights of optional wavelengths to a plurality of output ports using a plurality of fixed wavelength light sources are realized. Moreover, by using such wavelength division multiplexed communication light sources, then a highly realizable and economical optical cross-connect system is possible.

Optical cross-connect system

In a switch gear, such as a high-voltage enclosed switchboard and a vacuum load-break switch, of the type wherein items of electrical equipment including disconnecting devices and circuit-breaking devices are installed within a case, masses of a silicone gel are filled in compartments accommodating the electrical equipment instead of the sulfur hexafluoride used heretofore. An air space is left above the silicone gel in each compartment. This construction enables the provision of a safer switch gear of smaller size than heretofore.

Growing community of inventors

Nagoya, Japan

Ken-ichi Sato