Design of flat-field arrayed waveguide grating based on aberration theory

A new type flat-field arrayed waveguide grating (AWG) has been designed. The focal points of all wavelengths of operation distribute on a straight line. With parallel output waveguides, it's convenient to connect with fiber-array directly. Flat-field AWG could function as a spectrometer when the output waveguides are thrown off. The work based on the developed aberration theory of AWG. In this theory, the restrains imposing on the conventional Rowland-type AWG have been removed. Various restrains will generate new type structures. In the flat-field AWG design, the restrains come from the concurrent imaging theory. Three aberration-free points restrain three dominant geometry parameters of AWG, geometry of star couplers, phased array ports distribution, and length increment between adjacent paths. A 16-channel flat-field AWG is designed. As stigmatic points introduced, the aberration of the device is much lower than that of the conventional Rowland-type AWG.