1：Experimental Design and Method Selection:

The system uses a double RF modulation technique where continuous wave light is modulated twice by the incoming RF signal. The AoA is determined by measuring the output RF signal power, which depends on the time delay related to the AoA. Theoretical analysis and simulations were conducted to model the system's frequency response and output power.

2：Sample Selection and Data Sources:

The experiment used simulated and actual RF signals, including single-frequency microwave signals at 2.65 GHz and 12.62 GHz, and a pseudorandom binary sequence (PRBS) signal at 2.65 GHz.

3：65 GHz and 62 GHz, and a pseudorandom binary sequence (PRBS) signal at 65 GHz. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a wavelength tunable laser, polarisation controllers, Mach-Zehnder modulators (MZM1: EOSpace AX-OMSS-20, MZM2: Fujitsu FTM7937EZ), a 180° hybrid coupler, power divider, electrical attenuator, electrical phase shifter, erbium-doped fibre amplifier (EDFA), optical filter, photodetector (Discovery Semiconductors DSC30S), vector network analyser, electrical signal analyser (Keysight N9000A), and arbitrary waveform generator.

4：Experimental Procedures and Operational Workflow:

The setup involved modulating light from the laser with the RF signal split into two paths, introducing a phase shift to emulate AoA, amplifying and filtering the optical signal, detecting it with a photodetector, and measuring the output RF power or spectrum using analysers. The phase shifter was adjusted to vary the time delay, and measurements were taken for different RF signals.

5：Data Analysis Methods:

Data were analysed by comparing measured output RF power and AoA with theoretical predictions using equations derived from the system model. Normalised power was used to account for input signal variations.