An Optical Phased Array Beam Steerer Sized by Emitter Pitch, Grating Lobes and Aperture Beamwidth

This paper presents a computed design for a silicon-photonic optical phased array of 1024 emitters steering a 1550 nm beam without moving parts. The sizing follows from applying the relevant intensity, thermal, nonlinear and geometric bounds at a single stated operating point, with every number produced by a deposited computation. The headline result is a total aperture of 128 micrometres, a grating-lobe-limited steering range of plus or minus 11 degrees, a beamwidth of 0.69 degrees, roughly 1037 resolvable spots across the two-dimensional field, and a worst-case phase-shifter dissipation of 20 W that the package must remove. The binding constraint is identified explicitly: thermal crosstalk between densely packed phase shifters and sidelobe power stolen by grating lobes at wide steering angles. The design is SIMULATED, NOT MEASURED: no hardware was built for this study, and all performance figures are predictions from stated assumptions, offered as a basis for a build decision and a measurement plan.