Phase apodisation techniques for active passband control of arrayed waveguide grating optical routers

In this paper synthetic aperture techniques for broadening and flattening the passband of the arrayed waveguide grating are discussed. Broadening by a factor of greater than 20× is shown to be possible. It is demonstrated that by using a super-parabolic electrode with exponent P=2.1 the passband shape can be adjusted with minimum passband ripple. A novel passband flattening technique is also described which uses microlenses positioned in the output free space region. The main advantage of this approach is the enabling of active or passive control of each individual passband