Ultrabroadband 2D‐Dispersive Wavelength Selective Switch with 1.57 GHz Hyperfine Spectral Resolution and >1600 Channels

Abstract

Wavelength selective switches (WSSs) are key components in commercial reconfigurable optical add/drop multiplexer systems that are essential for future wavelength‐division multiplexing (WDM) networks. With rapidly increasing data transmission, there is a demand for high‐capacity WSSs. However, in a WSS, the number of channels, which is related to the ratio of its band coverage relative to spectral resolution, is limited within a certain range, since the 1D dispersion of the grating fails to utilize the 2D selectivity of the liquid crystal on silicon (LCoS) pixel array in the “disperse and select” architecture.. To surpass this limitation, here a virtually imaged phased array (VIPA) is employed into the WSS system to expand 1D‐dispersion into 2D space in order to fully utilize the 2D selectivity of LCoS. According to the experimental results, this VIPA‐grating‐based 2D WSS approach enables a spectral resolution that can be narrowed to 1.57 GHz (18 times improvement from 1D WSS, and massive (>1600) WDM channels can be predicted) and ultrabroadband spectral coverage across the S‐, C‐, and L‐bands of 20 THz. The data communication performance of the 2D WSS is also tested.