Abstract: An optical multiplexer-demultiplexer has a diffraction grating formed from a plurality of mutually intersecting sub-gratings. Each sub-grating has a grating vector. The diffraction grating as a whole has a combined high-order grating vector equal to a sum of integer multiples of the grating vectors of the sub-gratings. The diffraction grating reflects incident optical signals by Bragg reflection. The difference between the propagation vector of an incident optical signal and the propagation vector of the reflected optical signal is equal to the combined high-order grating vector. A small change in wavelength of the incident optical signal can therefore produce a large change in propagation direction of the reflected optical signal.

Abstract: A Y-branch waveguide includes a single merging side waveguide, two branching waveguides, and a junction area waveguide provided between the merging side waveguide and the branching waveguides and formed in a tapered shape being thicker at the branching than at the merging side. The junction area waveguide and the branching waveguides are connected by two straight waveguides parallel to each other. The straight waveguides extend in the same direction as the direction of propagation of light inside the junction area waveguide, when light is injected from the merging side waveguide.

Abstract: A disclosed optical device comprises: at least one input waveguide path; a multi-mode waveguide path; a core layer having a plurality of output waveguide paths; and a clad layer having therein the core layer. The multi-mode waveguide path is formed in an island. In a region including the multi-mode waveguide path and a portion of the clad layer which has therein the multi-mode waveguide path along the propagation direction of a concerned optical axis, an average value of the refractive index along the propagation direction is set at a desired value.

Abstract: The wavelength router comprises two flat waveguides, and these flat waveguides are connected by connecting waveguides. In each flat waveguide, optical path converters are created at connecting sections with the connecting waveguides. The optical path converters convert the light propagation direction in the flat waveguide to the light propagation direction in the connecting waveguides, or perform inverted conversion of this conversion. By this configuration, a compact element with a high wavelength resolution can be implemented.

Abstract: A curved waveguide and a linear waveguide are formed in a planar waveguide, and the curved waveguide has a discontinuous structure broken by the planar waveguide. A light signal input to the curved waveguide is reflected at a discontinuous surface of the curved waveguide thereof, and each light is wave-divided and focused on a linear waveguide. Furthermore, each light signal having each wavelength input to the linear waveguide is wave-divided and focused on the discontinuous portion of the curved waveguide.

Abstract: K×K optical switch unit according to the present invention is comprised of input ports 1-1, . . . 1-36, 1×M optical matrix switches 5-1-1, . . . 5-4-9 connected with the input ports 1-1, . . . 1-36, N×N optical matrix switches 7-1-1, . . . 7-4-2, and 10-1-1, . . . 10-4-2 connected with the 1×M optical matrix switches 5-1-1, . . . 5-4-9, an M×1 optical matrix switches 13-1-1, . . . 13-4-9 connected with the N×N optical matrix switches 7-1-1, . . . 7-4-2, and 10-1-1, . . . 10-4-2, and output ports 2-1, . . . 2-36 connected with the M×1 optical matrix switches 13-1-1, . . . 13-4-9, where K=M×N, M and N are integers more than 1.

Abstract: A lightwave system comprises an optical signal bus; an input/output interface including a first, a second and a third port, an optical signal inputted to the first port being outputted from the second port, an optical signal inputted to the third port being outputted from the first port; an optical tap, through which the optical signal which is outputted from the second port of the input/output interface is sent to the optical signal bus; a variable wavelength filter, through which an optical signal having a designated wavelength is outputted from the optical signal bus, thereby being sent to the third port of the input/output interface; and a controller which designates the wavelength of the optical signal which is to be sent from the optical signal bus through the variable wavelength filter.

Abstract: An optical directional coupler includes a first waveguide, a second waveguide and a plurality of bridge waveguides connecting the first waveguide and the second waveguide.

Abstract: An optical switch circuit network includes r input optical switches 102a each having n input ports, m 1×r optical switches 125a, and an n×m optical switch for switching a path connecting the input ports and the 1×r optical switches, and r output optical switches 125 each having r×1 optical switches, n output ports, and an m×n optical switch for switching a path connecting the output ports and 1×r optical switches. The i-th 1×r optical switch of each input optical switch is connected to the i-th r×1 optical switch of each output optical switch.

Abstract: An optical switch (26) comprises an input switching element (12) having a plurality of light input ports (10) and an output switching element (16) having a plurality of light output ports (14). The input switching element (12) comprises a plurality of input optical deflector sets (20), each set consisting of a plurality of optical deflectors (18a, 18b), at each light input port (10). The input optical deflectors in each set are arranged in the incident direction of an optical signal that is input to one of the light input ports. The output switching element (16) comprises a plurality of output optical deflector sets (24), each set consisting of a plurality of optical deflectors (22a, 22b), at each light output port (14). The output optical deflectors in each set are arranged in the emergent direction of an optical signal that is output from one of the light output ports.

Abstract: The present invention has an object to provide a wavelength division demultiplexer having high wavelength dispersion properties using a fine photonic crystal. The wavelength router has a wavelength division demultiplexer for each of a plurality of input ports, and a wavelength division multiplexer for each of a plurality of output ports. The wavelength division demultiplexer and wavelength division multiplexer are formed of a phonotic crystal. The shapes of the entrance surface and exit surface of the photonic crystal are different. The second boundary of the wavelength division demultiplexer and first boundary of the wavelength division multiplexer are of a curved surface.

Abstract: A lightwave system comprises an optical signal bus; an input/output interface including a first, a second and a third port, an optical signal inputted to the first port being outputted from the second port, an optical signal inputted to the third port being outputted from the first port; an optical tap, through which the optical signal which is outputted from the second port of the input/output interface is sent to the optical signal bus; a variable wavelength filter, through which an optical signal having a designated wavelength is outputted from the optical signal bus, thereby being sent to the third port of the input/output interface; and a controller which designates the wavelength of the optical signal which is to be sent from the optical signal bus through the variable wavelength filter.

Abstract: The present invention seeks to increase the number of wavelengths capable of being handled while reducing the sub peak and beat noise. A wave router acording to the invention has three acoustooptical filter elements; two wavelength division multiplicity reduction elements; and two wavelength division multiplexers. The wavelength division multiplicity reduction elements have three output ports and one input port, and the wavelength division multiplexing optical signal input to this input port is de-multiplexed and thereafter output from the three output ports. The acoustooptical filter elements are connected to the output ports of the wavelength division multiplicity reduction element, and the optical signal contained in the output light from thee output ports are selectively output in accordance with the wavelength.

Abstract: An optical switch includes an input side switching element having a plurality of optical input ports and an output side switching element having a plurality of optical output ports. The input side switching element is provided with an input side optical deflection element group consisting of two optical deflection elements at each of optical input ports. These optical deflection elements are arranged along the direction of incidence of optical signals that are directed into the optical input ports. Respective optical output ports of the output side switching element are provided with a group of output side optical deflection elements consisting of two optical deflection elements. These optical deflection elements are arranged along the direction of emission of optical signals emitted from the optical output ports. With an optical switch of this construction, setting of the deflection angle of the light beams propagated through the space can be achieved with excellent accuracy.

Abstract: Disclosed herein is an optical multiplexing/demultiplexing device having a structure wherein a curved waveguide for input, linear waveguides for output, and a planar waveguide are provided within a substrate, and the curved waveguide is made discontinuous by the planar waveguide and the curved waveguide and planar waveguide are separated from each other with an equal interval interposed therebetween. A light signal inputted to the curved waveguide is reflected by discontinuous surfaces of the curved waveguide. Afterwards, the respective reflected light signals are distributed to their corresponding linear waveguides through the planar waveguide every wavelengths and focused thereon. Further, the light signals of the respective wavelengths, which are inputted to the linear waveguides, are multiplexed by and focused on the discontinuous portions of the curved waveguide.

Abstract: An optical switch in which operational ranges of both a bar state and a cross state are wide is provided. By applying voltages of +V, −V, −V and+V independently to a first electrode 20A, a second electrode 20B, a third electrode 20C and a fourth electrode 20D, switching control to the bar state or the cross state is carried out.

Abstract: The wavelength router comprises two flat waveguides, and these flat waveguides are connected by connecting waveguides. In each flat waveguide, optical path converters are created at connecting sections with the connecting waveguides. The optical path converters convert the light propagation direction in the flat waveguide to the light propagation direction in the connecting waveguides, or performs inverted conversion of this conversion. By this configuration, a compact element with a high wavelength resolution can be implemented.

Abstract: This optical switch element 11 comprises mutually intersecting first and second optical waveguides 17a and 17b; a cylindrical-shape optical wave-guiding member 21 near the intersecting part 19; and a heater 23 to control the refractive index of the optical wave-guiding member. Signal light input to a first input port 17ai is selectively output from either a first output port 17ao or from a second output port 17bo. In this optical switch element, the optical wave-guiding member, optical waveguides and cladding are formed such that, when signal light is output from the first output port, the refractive indices of the optical wave-guiding member and cladding are effectively the same.

Abstract: An optical wavelength filter having an optical coupler, for suppressing the generation of a double peak, which is caused by a difference of propagation constants between intrinsic modes of light in an optical coupler. The optical wavelength filter comprises first and second optical couplers for exciting multiple modes of light in each wavelength of WDM light, and for providing a phase difference of &pgr;/2 between different modes of multiple modes of light, and a mode converter, which is provided between the first and second optical couplers. The mode converter performs mode conversion between the modes of light belonging to a specific wavelength, whereby the phase difference of each mode of light constituting the light of a specific wavelength, and the phase difference between the modes of light constituting the light of another wavelength is independently adjusted so as to output light of a specific wavelength and light of another wavelength from separate output ports.

Abstract: An optical switch includes an optical input terminal, a first deflector disposed to receive light from the optical input terminal, controlled to change its deflection angle, second deflectors arranged in a substrate, the first deflector transmits light from the optical input terminal to one of the second deflectors selectively, and optical output terminals disposed to receive light from the second deflectors, the second deflectors transmit light from the first deflector to the optical output terminals.