Abstract: A light source for Raman amplification to Raman-amplify signal light includes: plural incoherent light sources that output incoherent light; plural pumping light sources that output second-order pumping light; an optical fiber for Raman amplification to Raman-amplify the incoherent light with the second-order pumping light, and outputs the amplified incoherent light; and an output unit connected to the optical transmission fiber, receiving the amplified incoherent light, and outputting the amplified incoherent light as first-order pumping light having a wavelength that Raman-amplifies the signal light to the optical transmission fiber.

Abstract: A light source for Raman amplification to Raman-amplify signal light includes: plural incoherent light sources that output incoherent light; plural pumping light sources that output second-order pumping light; an optical fiber for Raman amplification to Raman-amplify the incoherent light with the second-order pumping light, and outputs the amplified incoherent light; and an output unit connected to the optical transmission fiber, receiving the amplified incoherent light, and outputting the amplified incoherent light as first-order pumping light having a wavelength that Raman-amplifies the signal light to the optical transmission fiber.

Abstract: A light source for Raman amplification to Raman-amplify signal light includes: plural incoherent light sources that output incoherent light; plural pumping light sources that output second-order pumping light; an optical fiber for Raman amplification to Raman-amplify the incoherent light with the second-order pumping light, and outputs the amplified incoherent light; and an output unit connected to the optical transmission fiber, receiving the amplified incoherent light, and outputting the amplified incoherent light as first-order pumping light having a wavelength that Raman-amplifies the signal light to the optical transmission fiber.

Abstract: A plurality of holes are formed in a ferrule. The holes are at sites penetrated by the tips of optical fibers. An opening is formed in the upper surface of the ferrule and an internal housing section is exposed from the opening. The housing section is at a site at which an optical fiber holding member is housed. The optical fibers are held by the optical fiber holding member. The optical fibers are multi-core fibers. In other words, the optical fibers have a specified axis of symmetry in a cross-section vertical to the longitudinal direction of the optical fibers and have orientation relative to a rotation direction having the longitudinal direction as the axis thereof.

Abstract: A light source for Raman amplification to Raman-amplify signal light includes: plural incoherent light sources that output incoherent light; plural pumping light sources that output second-order pumping light; an optical fiber for Raman amplification to Raman-amplify the incoherent light with the second-order pumping light, and outputs the amplified incoherent light; and an output unit connected to the optical transmission fiber, receiving the amplified incoherent light, and outputting the amplified incoherent light as first-order pumping light having a wavelength that Raman-amplifies the signal light to the optical transmission fiber.

Abstract: The present invention provides an optical communication method and an optical communication system in which eavesdropping is more difficult than in conventional techniques. An optical communication system in one embodiment of the present invention comprises: a photon pair generator which generates a correlated photon pair; a polarizer which is provided on an optical path of one photon of the correlated photon pair and direction of which is changeable based on information to be transmitted; a shutter which is provided between the photon pair generator and the polarizer on the optical path of the one photon of the correlated photon pair and which is capable of blocking the one photon of the correlated photon pair; and a photon detector which is provided on an optical path of another photon of the correlated photon pair.

Abstract: A plurality of holes are formed in a ferrule. The holes are at sites penetrated by the tips of optical fibers. An opening is formed in the upper surface of the ferrule and an internal housing section is exposed from the opening. The housing section is at a site at which an optical fiber holding member is housed. The optical fibers are held by the optical fiber holding member. The optical fibers are multi-core fibers. In other words, the optical fibers have a specified axis of symmetry in a cross-section vertical to the longitudinal direction of the optical fibers and have orientation relative to a rotation direction having the longitudinal direction as the axis thereof.

Abstract: The present invention provides an optical communication method and an optical communication system in which eavesdropping is more difficult than in conventional techniques. An optical communication system in one embodiment of the present invention comprises: a photon pair generator which generates a correlated photon pair; a polarizer which is provided on an optical path of one photon of the correlated photon pair and direction of which is changeable based on information to be transmitted; a shutter which is provided between the photon pair generator and the polarizer on the optical path of the one photon of the correlated photon pair and which is capable of blocking the one photon of the correlated photon pair; and a photon detector which is provided on an optical path of another photon of the correlated photon pair.

Abstract: Two Mach-Zehnder optical interferometer circuits are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit constituting a light input side circuit. Optical signals having a plurality of wavelengths are input to a light input terminal. A second point-symmetrically connected optical interferometer circuit having the same functional structure as the first point-symmetrically connected optical interferometer circuit is connected to a through port, which is an output terminal of the light input side circuit, as a first light output side circuit. A cross port, which is the other output terminal of the light input side circuit, is connected to a second light output side circuit having at least one of Mach-Zehnder optical interferometer circuits whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits.

Abstract: An optical waveguide comprising a core and a clad characterized in that a desired part is heated and transited to machining strain release state, the part transited to the machining strain release state is curved with a specified bending radius and transited to machining strain state. That part of the optical waveguide is heated to a temperature within a range between the bending point and softening point and transited to machining strain state. The optical waveguide is an optical fiber having the outer diameter not shorter than 50 ?m. The optical waveguide has the outer diameter not shorter than ten times of the mode field diameter of the optical waveguide. The optical waveguide has a bending radius of 5.0 mm or less and difference equivalent of refractive index &Dgr;1 between the core and clad falls within a range of 0.8-3.5%.

Abstract: An optical waveguide comprising a core and a clad characterized in that a desired part is heated and transited to machining strain release state, the part transited to the machining strain release state is curved with a specified bending radius and transited to machining strain state. That part of the optical waveguide is heated to a temperature within a range between the bending point and softening point and transited to machining strain state. The optical waveguide is an optical fiber having the outer diameter not shorter than 50 ?m. The optical waveguide has the outer diameter not shorter than ten times of the mode field diameter of the optical waveguide. The optical waveguide has a bending radius of 5.0 mm or less and difference equivalent of refractive index &Dgr;1 between the core and clad falls within a range of 0.8-3.5%.

Abstract: Two Mach-Zehnder optical interferometer circuits 13a and 13b are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit 5 constituting a light input side circuit 1. Optical signals having a plurality of wavelengths are input to a light input terminal 17. A second point-symmetrically connected optical interferometer circuit 7 having the same functional structure as the first point-symmetrically connected optical interferometer circuit 5 is connected to a through port 18, which is an output terminal of the light input side circuit 1, as a first light output side circuit 2. A cross port 19, which is the other output terminal of the light input side circuit 1, is connected to a second light output side circuit 3 having at least one of Mach-Zehnder optical interferometer circuits 13c and 13d whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits 13a and 13b.

Abstract: Two Mach-Zehnder optical interferometer circuits 13a and 13b are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit 5 constituting a light input side circuit 1. Optical signals having a plurality of wavelengths are input to a light input terminal 17. A second point-symmetrically connected optical interferometer circuit 7 having the same functional structure as the first point-symmetrically connected optical interferometer circuit 5 is connected to a through port 18, which is an output terminal of the light input side circuit 1, as a first light output side circuit 2. A cross port 19, which is the other output terminal of the light input side circuit 1, is connected to a second light output side circuit 3 having at least one of Mach-Zehnder optical interferometer circuits 13c and 13d whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits 13a and 13b.

Abstract: Two Mach-Zehnder optical interferometer circuits 13a and 13b are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit 5 constituting a light input side circuit 1. Optical signals having a plurality of wavelengths are input to a light input terminal 17. A second point-symmetrically connected optical interferometer circuit 7 having the same functional structure as the first point-symmetrically connected optical interferometer circuit 5 is connected to a through port 18, which is an output terminal of the light input side circuit 1, as a first light output side circuit 2. A cross port 19, which is the other output terminal of the light input side circuit 1, is connected to a second light output side circuit 3 having at least one of Mach-Zehnder optical interferometer circuits 13c and 13d whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits 13a and 13b.

Abstract: Two Mach-Zehnder optical interferometer circuits 13a and 13b are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit 5 constituting a light input side circuit 1. Optical signals having a plurality of wavelengths are input to a light input terminal 17. A second point-symmetrically connected optical interferometer circuit 7 having the same functional structure as the first point-symmetrically connected optical interferometer circuit 5 is connected to a through port 18, which is an output terminal of the light input side circuit 1, as a first light output side circuit 2. A cross port 19, which is the other output terminal of the light input side circuit 1, is connected to a second light output side circuit 3 having at least one of Mach-Zehnder optical interferometer circuits 13c and 13d whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits 13a and 13b.

Abstract: There are provided a power supply device for an optical functional component that supplies power to the optical functional component with reliability for a long term and enables easy exchange of the optical functional component, and an optical functional module having such a power supply device, where the power supply device is provided with a reception electrode 104, a power supply electrode 107-1 that supplies power to the reception electrode 104 while holding tight the reception electrode 104 on its side faces and thereby holding an optical functional component 105-1 detachably, and a protecting member 108 that is made of an insulating material and surrounds the power supply electrode 107-1 to prevent current leaks, and the power supply electrode 107-1 is comprised of two bent metallic members (107-1a and 107-1B) which are in intimate contact with the reception electrode 104 by elasticity.

Abstract: An optical waveguide comprising a core and a clad characterized in that a desired part is heated and transited to machining strain release state, the part transited to the machining strain release state is curved with a specified bending radius and transited to machining strain state. That part of the optical waveguide is heated to a temperature within a range between the bending point and softening point and transited to machining strain state. The optical waveguide is an optical fiber having the outer diameter not shorter than 50 ?m. The optical waveguide has the outer diameter not shorter than ten times of the mode field diameter of the optical waveguide. The optical waveguide has a bending radius of 5.0 mm or less and difference equivalent of refractive index &Dgr;1 between the core and clad falls within a range of 0.8-3.5%.

Abstract: Two Mach-Zehnder optical interferometer circuits 13a and 13b are accurately point-symmetrically connected to each other to form a first point-symmetrically connected optical interferometer circuit 5 constituting a light input side circuit 1. Optical signals having a plurality of wavelengths are input to a light input terminal 17. A second point-symmetrically connected optical interferometer circuit 7 having the same functional structure as the first point-symmetrically connected optical interferometer circuit 5 is connected to a through port 18, which is an output terminal of the light input side circuit 1, as a first light output side circuit 2. A cross port 19, which is the other output terminal of the light input side circuit 1, is connected to a second light output side circuit 3 having at least one of Mach-Zehnder optical interferometer circuits 13c and 13d whose transmittance characteristics are different from those of the Mach-Zehnder optical interferometer circuits 13a and 13b.

Abstract: There are provided a power supply device for an optical functional component that supplies power to the optical functional component with reliability for a long term and enables easy exchange of the optical functional component, and an optical functional module having such a power supply device, where the power supply device is provided with a reception electrode 104, a power supply electrode 107-1 that supplies power to the reception electrode 104 while holding tight the reception electrode 104 on its side faces and thereby holding an optical functional component 105-1 detachably, and a protecting member 108 that is made of an insulating material and surrounds the power supply electrode 107-1 to prevent current leaks, and the power supply electrode 107-1 is comprised of two bent metallic members (107-1a and 107-1B) which are in intimate contact with the reception electrode 104 by elasticity.

Abstract: The invention comprises three parts: The first parts provides a miniaturized functional optical module, which is provided with a lens-exchange type collimator enabling rapid and easy exchange of an optical functional component and/or lenses and being compact in size and excellent in durability. The second part provides a power supply device for an optical functional component that supplies power to the optical functional component with reliability for a long term and enables easy exchange of the optical functional component, and an optical functional module having such a power supply device. The third part provides an optical switch compact in size and greatly easy in handling, which is provided with a connector module having a plurality of optical fibers for light-beam input, a plurality of optical fibers for light-beam output corresponding to the plurality of optical fibers and a light-beam reflecting member.