Integrated 40-$\lambda$ 1$\,\times\,$2 Wavelength Selective Switch Without Waveguide Crossings

A compact integrated 1×2 wavelength-selective switch (WSS) is demonstrated for which the structure is designed such that the WSS has no waveguide crossings. By employing a loopback configuration, only one arrayed-waveguide grating is needed in the WSS. The channel spacing is 100 GHz and the number of channels is 40. The measured transmission loss of the selected wavelength was <; 8.1dB, and the average crosstalk from two output ports were 23.0 and 40.7 dB.