Abstract

There is a strong need for arrayed waveguide gratings (AWGs) with low-loss and box-like pass band over a broad spectral range. Most of the approaches proposed to implement flat-top AWGs suffer from increased insertion loss and large device size [1,2]. A Mach-Zehnder-interferometer (MZI) synchronized AWG [3] can provide a flattened pass band without introducing intrinsic loss. However, due the wavelength dependency of the directional couplers in the MZI, the achievable bandwidth is limited. We demonstrate a new pass-band flattening method by introducing 3-dB balanced couplers [4] to a MZI-synchronized AWG configuration over a broad spectral range (Fig. 1a). A low-loss cascaded AWG system is demonstrated when using this flat-top AWG as a primary filter.

© 2013 IEEE