| 摘要 |
<p>An optical switch comprises a wavelength filter and a controller. The wavelength filter is provided with a first waveguide having a transmission passband of a predetermined basic mode and a second waveguide which is provided in at least a part of the first waveguide and which has a transmission passband which defines a finite value included in the transmission passband of the basic mode as a cutoff frequency. A pair of photo couplers which constitute a Mach-Zehnder interferometer are connected to opposite sides of a filter body consisting of the first waveguide and the second waveguide. In the case of a cascade connection of a plurality of wavelength filters, the cutoff frequency of the second waveguide of each wavelength filter may differ. The controller varies the cutoff frequency of the second waveguide within the transmission passband of the first waveguide to thereby control the filtering bandwidth of the wavelength filter.</p> |
