Abstract: An optical communication equipment comprises shared optical sources 88a-88d to be shared by communication nodes 100a-100d, the wavelengths of optical signals 76a-76d are converted into desired wavelengths &lgr;a-&lgr;d according to the addressed information of the corresponding optical label signals 77a-77d by using the shared optical sources 88a-88d, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.

Abstract: A light-controlled light modulator can achieve high-speed, low-loss wavelength conversion. Continuous light with a wavelength &lgr;j is launched into an MMI coupler via a port, and is split into two parts by the MMI coupler, which are led to a loop-type interferometer. In the loop-type interferometer, the two parts travel separately around the loop as clockwise traveling light and counterclockwise traveling light, are combined by the MMI coupler again via a filter-equipped phase modulator, thereby being emitted to the port. In this state, signal light &lgr;i(s) with a wavelength &lgr;i is launched into the filter-equipped phase modulator via a port. Even when the wavelength &lgr;i of the signal light &lgr;i(s) is equal to the wavelength &lgr;j of the wavelength converted output light, the wavelength conversion can be achieved with preventing noise from being mixed into the output light emitted from a port.

Abstract: A light-controlled light modulator can achieve high-speed, low-loss wavelength conversion. Continuous light with a wavelength &lgr;j is launched into an MMI coupler via a port, and is split into two parts by the MMI coupler, which are led to a loop-type interferometer. In the loop-type interferometer, the two parts travel separately around the loop as clockwise traveling light and counterclockwise traveling light, are combined by the MMI coupler again via a filter-equipped phase modulator, thereby being emitted to the port. In this state, signal light &lgr;i(s) with a wavelength &lgr;i is launched into the filter-equipped phase modulator via a port. Even when the wavelength &lgr;i of the signal light &lgr;i(s) is equal to the wavelength &lgr;j of the wavelength converted output light, the wavelength conversion can be achieved with preventing noise from being mixed into the output light emitted from a port.

Abstract: An optical control device include a substrate having an electrooptic effect, the substrate having ridges with optical waveguides. A buffer layer is formed on the substrate surface, and electrodes are provided. The electrodes includes at least one ground electrode, and a central electrode that is formed on the buffer layer over a ridge. The width of the central electrode on the side where the central electrode contacts the buffer layer is larger than the width of the optical waveguide. Because of this construction, the optical control device can achieve constant characteristics and a broad bandwidth.

Abstract: An electrically controlled optical device effective index includes a traveling wave electrode, a shield conductor and a thick buffer layer of a low dielectric constant. The thickness of an overlaid layer disposed between the traveling wave electrode and the shield conductor as well as the thickness of the buffer layer is so determined that an effective index of a microwave transmitted through the traveling wave electrode approaches an effective index of light transmitted through an optical waveguide, and that a microwave conductor loss is reduced, and that a characteristic impedance of said traveling wave electrode approaches a characteristic impedance of an associated external microwave circuit.

Abstract: An electrically controlled optical device includes a traveling wave electrode structure, a shield conductor and a thick buffer layer having a low dielectric constant. The thickness of an overlaid layer disposed between the traveling wave electrode structure and the shield conductor, as well as the thickness of the buffer layer, is determined so that the effective index of a microwave transmitted through the traveling wave electrode structure approaches the effective index of light transmitted through an optical waveguide, so that the microwave conductor loss is reduced, and so that the characteristic impedance of the traveling wave electrode structure approaches the characteristic impedance of an associated external microwave circuit.