Serrodyne-Enabled Dual Electro-Optic Comb Interferometry for High-Precision Absolute Ranging and Integration-Ready Metrology.

Optical frequency combs (OFCs) have revolutionized precision metrology, enabling highly precise frequency and distance measurements. Dual electro-optic frequency comb ranging systems traditionally rely on acousto-optic modulators (AOMs) to shift the local oscillator frequency, mitigating frequency degeneracy but restricting tuning flexibility, response speed, and power efficiency. Here, an AOM-free dual electro-optic frequency comb ranging system is introduced, employing a serrodyne-modulated electro-optic modulator (EOM) for frequency shifting, achieving superior phase coherence and high-precision distance measurement. Experimental validation confirms nanometric ranging precision, with Allan deviation below 0.1 nm at 1 ms integration. The system effectively tracks high-frequency vibrations (up to 100 kHz) from a piezoelectric transducer and enables dynamic 3D surface imaging. Moreover, it detects nanoscale water surface vibrations through precise laser-ranging analysis. Notably, the system maintains high measurement precision across a wide spatial scale-from meter-level free-space ranging to nanometer-scale vibration sensing-demonstrating exceptional versatility. Compared to conventional AOM-based approaches, the method provides enhanced flexibility, reduced RF power consumption, and improved photonic integration compatibility, thus offering substantial benefits for precision metrology and high-resolution sensing applications.