Omnidirectional beam steering using aperiodic optical phased array with high error margin.

We propose a pattern-search-like algorithm to design an aperiodic optical phased array for extensive applications in light detection and ranging and free-space communication. The designed phased array with 128 isotropic elements achieves a scan range, peak side-lobe level, minimum beam width, and mean pitch of ± 82°, -14.34 dB, 0.062°, and 9.75 μm, respectively. To our knowledge, it has the widest steering range, narrowest divergence, and largest mean pitch for the same waveguide number. The minimum pitch can be greater than 2.67λ to avoid cross-coupling. The calculated relationship between the machine error and side-lobe level indicates that the designed structure has a higher error tolerance than its uniformly spaced counterpart.