Design of arrayed-waveguide gratings using hybrid Fourier-Fresnel transform techniques

We describe how transform techniques may be applied to the design of arrayed-waveguide gratings (AWG´s). A hybrid Fourier-Fresnel transform model indicates that a flat AWG router passband over 30% of the device free-spectral range (FSR) is feasible. Minimized passband ripple is achieved by applying a subparabolic phase-profile (phase-exponent P=1.82) to the Fourier plane of the AWG. Simulations of a complex-apodized AWG with passband 3 dB width increased from 1 to 12 nm, with a near-trapezoidal amplitude response, and band-edge group delay of 70 ps reduced to 10 ps are presented for a device with a FSR of 40 nm