We derive explicit design rules of optical phased-array planar 1 × N
switch to achieve small insertion loss, large extinction ratio, and non-dispersive waveguide structure required for wavelength-independent broadband operation. The minimum number of phase shifters and slab lengths were studied as a function of N
and the optimized array shape was derived to minimize the optical path length. We show that the length depends nonlinearly on N
, and may become significantly shorter compared with that of a tree-structured switch under certain conditions.
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