Multigrating method for flattened spectral responsewavelength multi/demultiplexer

The authors successfully demonstrate a new method, called a multigrating method, for a flattened spectral response. It uses one-focal-point couplers and several interleaved monomode waveguide gratings. It has a bandwidth of 0.94 nm at –1 dB and of 1.8 nm at –20 dB. The loss penalty due to channel flattening is only 2.2 dB.