Fig. 1. (a) Schematic of the chip-scale Brillouin IFM via a lock-in amplifier (LIA). (b) Illustration of SBS interaction between the pump lightwave and probe lightwave. (c) Probe signal setting for system characterization and unknown RF detection based on the chip-scale Brillouin IFM.

Fig. 2. Experimental setup of the chip-scale Brillouin IFM via a lock-in amplifier. DFB, distributed-feedback laser; SSBM, single sideband modulator; LIA, lock-in amplifier; AWG, arbitrary waveform generator; OSC, oscilloscope; OSA, optical spectrum analyzer.

Fig. 3. (a) Frequency-to-power mapping curve for system characterization. (b) The Brillouin gain that a Costas frequency modulated signal carries.

Fig. 4. Frequency measurement error analysis (a) without curve fitting and (b) with curve fitting.