Fig. 1. (a) Schematic illustration of the multi-beam OPA based on 2D grating. (b) Partial description of the half-wavelength waveguide array and 2D grating. (c) Optical field distribution in non-uniform and uniform waveguide array configurations. (d) Diffraction angles and efficiency of the 2D grating within the 1500 to 1600 nm wavelength range. (e) Illustrative diagrams of sub-FOVs generated by the four OPA units.

Fig. 2. The far-field distributions at (a) 0°, (b) 90°, (c) 150°, and (d) 180° phase difference between adjacent waveguides when a single OPA unit operates. The far-field distributions at (e) 0° and (f) –150° phase difference between adjacent waveguides when the four OPA units operate simultaneously. The far-field distributions at (g) 1500 nm and (h) 1600 nm wavelength. The normalized curve of light intensity for (i) lateral steering  and (j) longitudinal steering.

Fig. 3. (a) Schematic diagram of the steering range testing system. (b) The microscope image of the fabricated device. (c) The image of the packaged chip. (d) Synthesized far-field patterns of a single OPA unit when steering in a lateral direction. (e) Synthesized far-field patterns of a single OPA unit when steering in a vertical direction. (f) Synthesized far-field patterns of the entire packaged device, covering a lateral 360° FOV.

Fig. 4. (a) Measured beam power within the lateral steering range of −60° to 60° for a single OPA unit under an input power of 0 dBm. (b) Measured beam power at 0° when tuning the wavelength from 1500 to 1600 nm. (c) Measured beam power within the lateral 360° FOV.

Fig. 5. (a) Experimental setup of the parallel detection based on a DKS microcomb with the proposed multi-beam OPA. (b) Optical spectrum of the generated DKS microcomb with a 100 GHz line spacing. (c) Optical spectrum of the modulated comb lines. (d) Beat frequencies of a single comb line at various distances and corresponding ranging errors. (e) Beat frequencies of a single comb line at distinct velocities with corresponding velocimetry errors. (f) Parallel ranging results of 20 selected representative spectral channels. SNRs and ranging errors are presented, showing high consistency.

Table 1. Performance Comparison of State-of-the-Art OPAs^b,c