Abstract: A coil component includes a core including a winding core portion and a first flange portion that is disposed on a first end portion of the winding core portion in a direction in which the winding core portion extends. A first curved portion is formed at a connection between a bottom surface of the winding core portion and the first flange portion. A ratio of a length of the first curved portion in a height direction to a distance in the height direction between the bottom surface and a first terminal electrode is no less than 20% and no more than 60% (i.e., from 20% to 60%).

Abstract: A coil component includes a core including a winding core portion, a first flange portion, and a second flange portion, and a first wire and a second wire that are wound around the winding core portion in the same direction and that form a winding portion. The winding portion includes a second intersecting portion along a third side surface of the winding core portion at a position on the winding portion nearest to the second flange portion.

Abstract: A coil component includes a core including a winding core portion and a first flange portion, a first wire and a second wire that are wound around the winding core portion in the same direction, and a first terminal electrode that is disposed on the first flange portion and that is connected to a first end portion of the first wire. The shape of an outer edge of the first terminal electrode includes a convex curve.

Abstract: An optical multiplexing apparatus of a low cost is capable of reliably multiplexing a plurality of optical signals having a narrow wavelength interval, while suppressing the nonlinear optical effect and the crosstalk, and a multiplexing method. The optical multiplexing apparatus includes a first optical multiplexer for multiplexing, among a plurality of optical signals that are input with directions of linear polarization of the neighboring wavelengths being differed to each other, optical signals having odd wavelength numbers while maintaining their polarization states. A second optical multiplexer multiplexes optical signals having even wavelength numbers while maintaining their polarization states, and a third optical multiplexer multiplexes, at an output unit thereof through first and second input units having sharp filtering characteristics, the optical signals multiplexed by the first and second optical multiplexing means, to output WDM signal light.

Abstract: The present invention is directed to the provision of a wavelength division multiplexing optical transmission apparatus and, more particularly, to a wavelength division multiplexing optical transmission apparatus having high wavelength stability unaffected by the temperature characteristics, aging, etc. of an arrayed-waveguide grating (AWG) and its peripheral components.

Abstract: The present invention is directed to the provision of a wavelength division multiplexing optical transmission apparatus and, more particularly, to a wavelength division multiplexing optical transmission apparatus having high wavelength stability unaffected by the temperature characteristics, aging, etc. of an arrayed-waveguide grating (AWG) and its peripheral components.

Abstract: The invention provides a wavelength division multiplexing optical transmitter wherein an unequally spaced arrangement of optical wavelengths can be realized readily and economically. The wavelength division multiplexing optical transmitter includes an optical transmission section for outputting a plurality of optical signals having wavelengths spaced by unequal distances from each other, and a wave multiplexer having an equally spaced wavelength optical multiplexing characteristic of multiplexing a plurality of optical signals having wavelengths spaced by a substantially equal distance from each other. The wave multiplexer being constructed such that, when the plurality of optical signals are inputted thereto from the optical transmission section, the wave multiplexer multiplexes the plurality of optical signals from the optical transmission section into a multiplexed optical signal and outputs the multiplexed optical signal.

Abstract: Pumping light from two pumping light sources is supplied to an optical coupler which splits it into two output beams and supplies the beams to erbium-doped optical fibers in the forward and backward paths, respectively. To avoid the detrimental effect caused by interference that occurs when the wavelengths of the two pumping light sources coincide perfectly with each other, the two pumping light sources are activated alternately by clock signals that are 180.degree. out of phase with each other. Alternatively, optical shutters may be provided between the optical coupler and the respective pumping light source, and these optical shutters may be opened alternately. If one or other of the pumping light sources stops due to failure, the average level of the pumping light supplied to the optical fibers will drop.

Abstract: An optical repeater having a loop-back function is provided in a transmission system including first and second transmission lines. The optical repeater includes a first optical amplifier connected to the first transmission line, a second optical amplifier connected to the second transmission line, a loop-back unit connected to both transmission lines, and a control unit. The control unit controls the loop-back unit to form a loop-back line when a loop-back instruction is detected. Therefore, optical signals are directly amplified without being converted into electrical signals, and a loop-back signal (return signal) and optical signals are not mixed in the optical repeater so that a loop-back operation can be correctly carried out in an optical repeater having a small size and low power consumption.