
variation from filter to filter complicates this). For example, the 0.3-dB down point
on the passband becomes the 3-dB down point after 10 cascades. The passband
shape is stretched downward around the maxima. Thus, the more maxima (pro-
vided the maxima are at the same magnitude), the more the passband is
“held open.”
As shown in Section “Parabola-Type AWG,” one way to add more maxima to
an AWG passband is image mismatching, i.e., the image from the input waveguide
does not match the image that an output waveguid e would make. Such a method is
compact and robust. However, image mismatching adds optical loss. This section
addresses adding maxima without ...