Abstract: An optical packet network system of a ring type, capable of preventing degradation of an optical signal, can be implemented by providing a mechanism relatively simple in structure, capable of erasing light noise if the optical packet signal does not exists. In the optical packet network system made up by interconnecting respective nodes adjacent to each other, and connecting a sending source of an optical packet signal to a ring, a light noise removal function block is provided between the respective nodes adjacent to each other.

Abstract: A semiconductor optical switch may include an optical waveguide, a first electrode, and a first reflector. The optical waveguide may include a branching point, a first incoming path and first and second outgoing paths. The first electrode is provided at the branching point to give carrier injection into the branching point to allow that the branching point reflects an optical signal that is propagating through the first incoming path so that the reflected optical signal propagates through the second outgoing path. The first electrode may give no carrier injection into the branching point to allow that the branching point allows the optical signal to transmit through the branching point and propagate through the first outgoing path. The first reflector is provided on the first outgoing path. The first reflector reflects a leakage of light that has propagated from the branching point.

Abstract: A semiconductor optical switch may include an optical waveguide, a first electrode, and a first reflector. The optical waveguide may include a branching point, a first incoming path and first and second outgoing paths. The first electrode is provided at the branching point to give carrier injection into the branching point to allow that the branching point reflects an optical signal that is propagating through the first incoming path so that the reflected optical signal propagates through the second outgoing path. The first electrode may give no carrier injection into the branching point to allow that the branching point allows the optical signal to transmit through the branching point and propagate through the first outgoing path. The first reflector is provided on the first outgoing path. The first reflector reflects a leakage of light that has propagated from the branching point.

Abstract: An optical switch changes over transmission paths of an optical signal by a refractive index change. The optical switch has an optical waveguide layer having an optical waveguide whose output path of an optical signal branches into two, and reflection diffusing ditches which are provided in a portion outside the optical waveguide in the optical waveguide layer, wherein the portion is closed to a branch portion of the optical waveguides. The reflection diffusing ditches extend in a direction crossing a traveling direction of the optical signal.

Abstract: A light signal switching apparatus has an input port and output ports, and outputs an output light from a desired output port. The apparatus has a splitter polarizing an input light into first and second polarized light whose polarization planes are different mutually by 90 degrees, a first polarization controller rotating a polarization plane of the second polarized light by 90 degrees to output a third polarized light, a first optical switch switching a path of the first polarized light to the desired output port side, a second optical switch switching a path of the third polarized light to the desired output port side, a second polarization controller rotating a polarization plane of the first polarized light by 90 degrees to output a fourth polarized light, and a combiner combining the third polarized light with the fourth polarized light, to output a combined light to the desired output port.

Abstract: An optical switch in which the adverse effect of heating can be restrained is realized.

Abstract: An optical packet network system of a ring type, capable of preventing degradation of an optical signal, can be implemented by providing a mechanism relatively simple in structure, capable of erasing light noise if the optical packet signal does not exists. In the optical packet network system made up by interconnecting respective nodes adjacent to each other, and connecting a sending source of an optical packet signal to a ring, a light noise removal function block is provided between the respective nodes adjacent to each other.

Abstract: An optical switch has an input port, output ports, optical waveguides whose output path of an optical signal branch into two. A first stage optical switch section is provided in a branching portion of the optical waveguide, which switches a propagating path of an optical signal to a path leading to the desired output port. A subsequent stage optical switch section is provided in a branching portion of the optical waveguide subsequent to the first stage optical switch section, which switches a propagating path of a leakage light, which is leaked from the first stage optical switch section, to a path which does not propagates the leakage light to any of the output ports. The first stage optical switch section and the subsequent stage optical switch section switch a path of an optical signal according to a refractive index change caused by a carrier injection.

Abstract: A matrix optical switch that can switch the transmission path of an optical signal without requiring a driving unit for each optical switch is realized. A matrix optical switch for switching a transmission path of an optical signal by connecting plural input sides and plural output sides, respectively, comprises: a semiconductor optical waveguide substrate; a photo mask choosing system for selecting and arranging one photo mask from plural photo masks each of which has printed thereon a pattern connecting plural input sides to plural output sides; and a light source for casting output light having larger energy than a band gap of the semiconductor optical waveguide substrate onto a photon injection area between the plural input sides and the plural output sides on the semiconductor optical waveguide substrate via the selected photo mask.

Abstract: An optical switch changes over transmission paths of an optical signal by a refractive index change. The optical switch has an optical waveguide layer having an optical waveguide whose output path of an optical signal branches into two, and reflection diffusing ditches which are provided in a portion outside the optical waveguide in the optical waveguide layer, wherein the portion is closed to a branch portion of the optical waveguides. The reflection diffusing ditches extend in a direction crossing a traveling direction of the optical signal.

Abstract: An optical switch has an input port, output ports, optical waveguides whose output path of an optical signal branch into two. A first stage optical switch section is provided in a branching portion of the optical waveguide, which switches a propagating path of an optical signal to a path leading to the desired output port. A subsequent stage optical switch section is provided in a branching portion of the optical waveguide subsequent to the first stage optical switch section, which switches a propagating path of a leakage light, which is leaked from the first stage optical switch section, to a path which does not propagates the leakage light to any of the output ports. The first stage optical switch section and the subsequent stage optical switch section switch a path of an optical signal according to a refractive index change caused by a carrier injection.

Abstract: A light signal switching apparatus has an input port and output ports, and outputs an output light from a desired output port. The apparatus has a splitter polarizing an input light into first and second polarized light whose polarization planes are different mutually by 90 degrees, a first polarization controller rotating a polarization plane of the second polarized light by 90 degrees to output a third polarized light, a first optical switch switching a path of the first polarized light to the desired output port side, a second optical switch switching a path of the third polarized light to the desired output port side, a second polarization controller rotating a polarization plane of the first polarized light by 90 degrees to output a fourth polarized light, and a combiner combining the third polarized light with the fourth polarized light, to output a combined light to the desired output port.

Abstract: An optical switch has an optical waveguide whose output path of an optical signal branches into two, a carrier injection section which is provided to a branch portion of the optical waveguide and to which carriers are injected, and a refractive index change section which is provided to a optical waveguide layer of the optical waveguide and in which a refractive index changes in a case that carrier are injected to the carrier injection section, wherein the refractive index change section includes a quantum well layer.

Abstract: The present invention aims at achieving an optical signal processing system which converts a higher speed optical signal to electrical signals by time-demultiplexing the signal with low-speed electrical signals. The present invention offers an improved optical signal processing system that converts a serial pulse train optical signal with transmission speed N to parallel pulse train electrical signals.

Abstract: In an optical switch, a carrier-accumulating layer in which injected carriers are accumulated is provided on a semiconductor substrate having a waveguide formed thereon so that injected effective carriers tend to be accumulated in an effective part, and the burden on a driving circuit is thus reduced to realize high-speed operation. At the same time, when a clad on the carrier injection side, of clad layers formed on both sides of the waveguide, is a second clad layer, and a clad on the substrate side is a first clad layer, a third clad layer is formed on the first clad layer to reduce propagation loss in the waveguide.

Abstract: A matrix optical switch that can switch the transmission path of an optical signal without requiring a driving unit for each optical switch is realized. A matrix optical switch for switching a transmission path of an optical signal by connecting plural input sides and plural output sides, respectively, comprises: a semiconductor optical waveguide substrate; a photo mask choosing system for selecting and arranging one photo mask from plural photo masks each of which has printed thereon a pattern connecting plural input sides to plural output sides; and a light source for casting output light having larger energy than a band gap of the semiconductor optical waveguide substrate onto a photon injection area between the plural input sides and the plural output sides on the semiconductor optical waveguide substrate via the selected photo mask.

Abstract: An optical switch in which the adverse effect of heating can be restrained is realized.

Abstract: In an optical switch, a carrier-accumulating layer in which injected carriers are accumulated is provided on a semiconductor substrate having a waveguide formed thereon so that injected effective carriers tend to be accumulated in an effective part, and the burden on a driving circuit is thus reduced to realize high-speed operation. At the same time, when a clad on the carrier injection side, of clad layers formed on both sides of the waveguide, is a second clad layer, and a clad on the substrate side is a first clad layer, a third clad layer is formed on the first clad layer to reduce propagation loss in the waveguide.

Abstract: The present invention aims at achieving an optical signal processing system which converts a higher speed optical signal to electrical signals by time-demultiplexing the signal with low-speed electrical signals.