Flat channel-passband-wavelength multiplexing and demultiplexing devices by multiple-Rowland-circle design

A new robust optical design for widening the channel passband of wavelength demultiplexers is presented. Instead of a traditional one-Rowland-circle design, a multi-Rowland-circle structure is proposed to tailor the focused image formed by the grating. The properties of channel passband can be controlled by adjusting the positions of the circles. Nearly perfect flat-channel passband was achieved by our simulation.