PIC-Based $1\times N$ Flexible WaveBand-Selective Switch

We propose an alternative optical switch supporting future trends in large-capacity optical networks, allowing flexible waveband definition and large radix output switching. The switch comprised two functional parts: an adaptive FIR lattice filter for carving an input spanning S+C+L bandwidth into up to four bands and a
$4\times N$
crossbar switch for a large addressing space. The flexible waveband selective switch (flex-WBSS) can be used in a route-and-select ROADM node, supporting ultrawide bandwidth spectral support and SDM link multipliers. The flex-WBSS can be implemented in a PIC-scale solution, affording significant size and cost savings over free-space based wavelength-selective switches.