Large N x N waveguide grating routers

We show how the grating diffraction properties of a N/spl times/N 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 nonblocking N/spl times/N cross connect. We motivate why for large N, the N optical channels 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 40/spl times/40 and a 80/spl times/80 WGR.