Wavelength-Selective 1xK Switches Using Free-Space Optics and MEMS Micromirrors: Theory, Design, and Implementation

The design and performance of several generations of wavelength-selective 1xK sewitches are reviewed. These optical subsystems combine the functionality of a demultiplexer, per-wavelength switch, and multiplexer in a single, low-loss unit. Free-space optics is utilized for spatially separating the constituent WDM channels as well as for space-division switching from an input optical fiber to one of K output fibers (1xK functionality) on a channel-by-channel basis using a MEMS micromirror array. The switches are designed to provide wide and flat passbands for minimal signal distortion. They can also provide spectral equalization and channel blocking functionality, making them well suited for use in transparent WDM optical mesh networks.