Low-complexity and high-flexibility design of a wavelength-selective switch using Raman amplifiers and directional couplers

A low-complexity and high-flexibility design for a wavelength-selective optical switch using waveguide-type Raman amplifiers and directional couplers is proposed. This switch can be used as a core device in large-scale WDM packet routing networks. By relaxing some constraints in existing research, our design provides the following characteristics: i) lower complexity, because fewer units of Raman amplifiers and directional couplers are needed; ii) higher flexibility of power gain, because a wide range of configurable power gain for both unswitched and switched wavelengths is provided, so that equal power gain or equal power level output for all WDM wavelengths may be obtained. In addition to theoretical analysis, we provide a set of concise guidelines to control the configurable power gain under practical consideration.