Abstract: An optical network system is disclosed by which flexible wavelength path setting can be performed in accordance with tree-shaped and star-shaped network topology. A central node includes a multiplexing section for multiplexing optical signals transmitted from user nodes and inputted thereto, and a central node side branching section for branching the optical signal multiplexed by the multiplexing section and supplying the branched optical signals to the user nodes. Each of the user nodes includes a transmission section capable of outputting an optical signal to which transmission wavelengths different from those of the other user nodes are set, and a reception section for extracting selected optical wavelength components from the branched light supplied thereto from the central node side branching section and extracting optical signals from the extracted optical wavelength components.

Abstract: A wavelength multiplexing processing apparatus for use with a wavelength division multiplexing system is disclosed which uses a single AWG to achieve reduction in cost, size and loss. The wavelength multiplexing processing apparatus includes a waveguide device wherein a plurality of incoming and outgoing waveguides, a first slab waveguide and a plurality of channel waveguides are formed on a substrate, a mirror array device and a lens device. The plane direction angles of reflecting mirrors which reflect optical signal components incoming thereto are set so that reflected light of an optical signal component incoming from one of the plural incoming and outgoing waveguides may go out from one of the plural incoming and outgoing waveguides.

Abstract: In the ring type optical communication system of the present invention, in each OADM arranged on a ring network, an optical signal which has the same wavelength as the add wavelength assigned to a local node, of the optical signals of each wavelength contained in WDM light input from on the ring, is extracted from a drop port Pd without being terminated by a rejection/add filter, and input to an optical switch. In the optical switch, either one of the optical signal extracted from the rejection/add filter, or the add light added onto the ring from the local node, is selected, and the selected light is applied to the add port Pa of the rejection/add filter. As a result, communication between a central station and optional OADM nodes, and multicast communication over a plurality of ring networks can be realized by means of a simple node configuration.

Abstract: An optical add/drop multiplexer of the invention includes: a wavelength blocker for blocking signal light having at least one wavelength out of a plurality of signal lights included in WDM light supplied from a transmission line and passing the other signal light; an optical coupler for multiplexing signal light having the same wavelength as that of the signal light blocked by the wavelength blocker to signal light passed through the wavelength blocker; a WDM amplifier for amplifying the WDM light multiplexed by the optical coupler and outputting the amplified light; and an optical branch coupler for branching the WDM light output from the WDM amplifier into two lights, extracting signal light having at least one wavelength different from the wavelength of signal light multiplexed by the optical coupler from one of the branched lights, and outputting the other branched light to the transmission line.

Abstract: For a WDM optical communication, on a substrate of an arrayed waveguide type wavelength multiplexing/demultiplexing device, input waveguide propagates a plurality of light and outputs WDM light; a first slab diffuses the WDM light outputted from the input waveguide; a channel waveguide array separates the WDM light and causes the separated six lights to propagate; a second slab condenses the separated six lights having propagated through the channel waveguide array; output waveguides causes the separated six lights condensed to propagate, and a waveguide interval in first neighborhoods connected to the first slab is set to become wider than a first waveguide interval in a first connection section for connecting the channel waveguide array to the first slab, which achieves a reduced chip size, cost-reduction of chips, and reduces loss.

Abstract: On each client nodes, the same downstream signal at an identical wavelength is selectively received by one drop port, and an upstream signal at a specific wavelength is sent to the optical ring network by one add port. On a single node, which serves as a server node, the upstream signals sent, one from each of the client nodes at the specific wavelength, is received by one and the same drop port in a time division manner. This arrangement makes it possible for the server node, the sender of multicast or broadcast distribution, to correctly receive an ACK signal according to IP, so that bi-directional communication becomes available between the sender (server) node, which initiates the multicast or broadcast communication, and other receiver (client) nodes.

Abstract: An optical transmission device improved in quality and reliability of OADM function and permitting configuration of highly-flexible, economical OADM networks. A wavelength tunable filter variably selects a wavelength according to a control frequency. A filter controller applies the control frequency to the filter while scanning wavelength over an entire signal bandwidth, to detect, from a reference wavelength monitor signal supplied thereto, a reference control frequency which permits the filter to select a reference wavelength and according to which wavelength is matched. On receiving a wavelength selection request, the controller obtains a target control frequency from the reference control frequency and the position of a target wavelength relative to the reference wavelength, and applies the obtained frequency to the filter. A reference wavelength filter transmits the reference wavelength therethrough. A light-receiving element monitors the transmitted reference wavelength to generate the monitor signal.

Abstract: For a WDM optical communication, on a substrate of an arrayed waveguide type wavelength multiplexing/demultiplexing device, input waveguide propagates a plurality of light and outputs WDM light; a first slab diffuses the WDM light outputted from the input waveguide; a channel waveguide array separates the WDM light and causes the separated six lights to propagate; a second slab condenses the separated six lights having propagated through the channel waveguide array; output waveguides causes the separated six lights condensed to propagate, and a waveguide interval in first neighborhoods connected to the first slab is set to become wider than a first waveguide interval in a first connection section for connecting the channel waveguide array to the first slab, which achieves a reduced chip size, cost-reduction of chips, and reduces loss.

Abstract: A planar optical waveguide device including a substrate having a first coefficient of thermal expansion; a lower cladding layer formed on the substrate, the lower cladding layer having a second coefficient of thermal expansion smaller than the first coefficient of thermal expansion; a core formed on the lower cladding layer; an upper cladding layer formed on the lower cladding layer so as to cover the core, the upper cladding layer having the second coefficient of thermal expansion; and a plurality of grooves formed in the upper and lower cladding layers on the opposite sides of the core so as to extend along the core. The planar optical waveguide device further includes a contraction material filling each groove and fixed to the upper and lower cladding layers. The contraction material may be provided by a thermosetting resin.

Abstract: A channel core pattern includes a plurality of core pattern elements having different lengths, another core pattern connected with the channel core pattern in series, and a refractive index of the channel core pattern is higher than a refractive index of the another core pattern.

Abstract: A wavelength multiplexing processing apparatus for use with a wavelength division multiplexing system is disclosed which uses a single AWG to achieve reduction in cost, size and loss. The wavelength multiplexing processing apparatus includes a waveguide device wherein a plurality of incoming and outgoing waveguides, a first slab waveguide and a plurality of channel waveguides are formed on a substrate, a mirror array device and a lens device. The plane direction angles of reflecting mirrors which reflect optical signal components incoming thereto are set so that reflected light of an optical signal component incoming from one of the plural incoming and outgoing waveguides may go out from one of the plural incoming and outgoing waveguides.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.

Abstract: A planar optical waveguide device including a substrate having a first coefficient of thermal expansion; a lower cladding layer formed on the substrate, the lower cladding layer having a second coefficient of thermal expansion smaller than the first coefficient of thermal expansion; a core formed on the lower cladding layer; an upper cladding layer formed on the lower cladding layer so as to cover the core, the upper cladding layer having the second coefficient of thermal expansion; and a plurality of grooves formed in the upper and lower cladding layers on the opposite sides of the core so as to extend along the core. The planar optical waveguide device further includes a contraction material filling each groove and fixed to the upper and lower cladding layers. The contraction material may be provided by a thermosetting resin.

Abstract: A ferrule assembly includes a ferrule having a through-hole, a first end portion, a second end portion, and an intermediate portion between the first and second end portions, and an optical fiber inserted and fixed in the through-hole. The ferrule has at the intermediate portion a cutaway flat portion allowing the optical fiber inserted in the through-hole to be semi-exposed, and the optical fiber has its entire circumference held by the ferrule at least at the first and second end portions of the ferrule.

Abstract: A channel core pattern includes a plurality of core pattern elements having different lengths, another core pattern connected with the channel core pattern in series, and a refractive index of the channel core pattern is higher than a refractive index of the another core pattern.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.

Abstract: An optical module including a substrate having a groove; an optical waveguide layer formed on the substrate, the optical waveguide layer including an optical waveguide core having first and second ends, the first end being aligned with the groove, and an optical waveguide cladding covering the optical waveguide core; a ferrule having a through hole; and an optical fiber inserted and fixed in the through hole. The ferrule has a flat cut portion for semicylindrically exposing a part of the optical fiber inserted and fixed in the through hole. The ferrule is fixed at the flat cut portion to the substrate so that the part of the optical fiber exposed to the flat cut portion is inserted into the groove of the substrate until one end of the optical fiber abuts against the first end of the optical waveguide core.