All-Optical Wavelength-Selective Switch Consisting of Asymmetric X-Junction Couplers and Raman Amplifiers for Wide Wavelength Range

In this paper, we propose an all-optical integrated-optic switch to be used in wide wavelength range. Two architectures of the switch are described. One architecture is formed with two cascaded interferometers consisting of three asymmetric X-junction couplers, two Raman amplifiers, and an attenuator. The other is formed with three cascaded interferometers consisting of four asymmetric X-junction couplers and three Raman amplifiers. In both architectures, multiple signals at different wavelengths can be wavelength-selectively switched by pumping light in the waveguide-type Raman amplifiers. The wavelength range is found to be as wide as about 400 nm, which is ten times as wide as the range usable in the previously reported switch. The switching operation in the wide wavelength range is verified numerically. As a result, switching extinction ratio of larger than 20 dB is obtained for wavelength range from 1350 to 1750 nm.