Fig. 1. Schematic of the one-dimensional optical phased array

Fig. 2. Flowchart of the hybrid bat algorithm

Fig. 3. The element envelope (dotted line) and the far-field distribution of the uniform optical phased array with 2 μm pitch (full line)

Fig. 4. Relationship between waveguide coupling strength and waveguide pitch

Fig. 5. Beam steering performance of 64 waveguide 1D OPA where the waveguide placement was optimized at the angle of 0°, 20°, and 40°

Fig. 6. Antenna arrangement of the optimized OPA

Fig. 7. The far-field pattern of the 1D aperiodic OPA

Fig. 8. Comparison of convergent curves of three optimization methods

Fig. 9. Beam scanning results obtained by the optimized 1D aperiodic OPA

Fig. 10. Far-field distribution of 2D OPA. (a) The uniform array; (b) the optimized aperiodic array