Function-transformable photonics integrated devices for intelligent, flexible-grid, multi-rate DWDM optical networks

Photonic devices (like filters, interleavers, grating, etc) are generally considered as “one-function-one-element” devices. Recently, we reported a new paradigm photonic device that can transform its inherent basic function to various functionalities (“multiple-functions-one-element”) [1]. We refer to this element as function-transformable-based multifunctional device. Here, we present such device that has five functions namely: (1) symmetric interleaver (SI), (2) asymmetric interleaver (AI), (3) band-wavelength add-drop filter (B-ADF), (4) dual-wavelength, channel passing (CP) add-drop filter (2λ-CP-ADF), and (5) dual-wavelength, channel dropping (CD) add-drop filter (2λ-CD-ADF). The new device is a pair of direct-coupled all-pass-filter (D-APF) and cross-coupled APF (C-APF) positioned in each of the two arms of Mach-Zehnder interferometer (MZI). These five functions are realized by changing MZI's path length difference and the values of coupler's coefficients.