Measurement and control of in-band dispersion in AWGs

The ever-increasing demand for higher speed communications has led us to the dense wavelength multiplexing architecture and high-speed transmissions. Arrayed waveguide gratings (AWGs) have proven to be an important building block for high performance DWDM networks. In such high-speed applications, the dispersion of the AWG is a critical parameter. In this paper, we review the dispersion properties of AWGs based on its filtering properties. We also report the methods employed for measurement of chromatic dispersion and polarization mode dispersion in AWGs. In particular, we discuss the effect of different measurement parameters on the results, and ways to improve the accuracy. In conclusion, AWGs can offer low dispersion (chromatic dispersion < 15 ps/nm and differential group delay < 0.2 ps), which makes them highly suitable for high-speed applications.