Large NxN Waveguide Grating Routers

We show how the grating diffraction properties of a NxN waveguide grating router (WGR) can limit the size of N when the device operates with a unique set of N wavelengths as a strict-sense non-blocking NxN cross-connect. We motivate why the N optical channel should be chosen equally spaced in wavelength and not in frequency. Two different approaches to increase N are presented. We report on results obtained in a 40x40 and a 80x80 WGR.