System and method embodiments are provided for a photonic switch chip for scalable reconfigurable optical add/drop multiplexer (ROADM). The embodiments enable a low-cost pay as you grow ROADM that scales as both the number of wavelengths added or dropped increases and the size of the node in terms of number of directions increase. In an embodiment, a ROADM includes an M degree optical cross-connect tandem component comprising M wavelength selective switch (WSS) coupled to M wavelength division multiplexing (WDM) node interfaces, where M is equal to a number of input or output directions; a routing stage wavelength selector switch (WSS) comprising a plurality of WSSs connected to the tandem component; and an N by M combiner/distributor for add/drop coupled to the routing stage WSS, wherein the combiner/distributor comprises one or more photonic integrated circuit (PIC) chips, and wherein N is a maximum number of add/drop wavelengths.