High-Speed 1 THz Photonic Continuous Wave Phase-Sensitive Radar with Micrometer Precision

Abstract This paper presents a high-speed photonic continuous wave phase sensitive radar system operating at 1 THz with a measurement rate of 20 kHz and micrometer precision. The system utilizes a monolithic dual-mode distributed feedback laser with a Y-shaped cavity, featuring rapid individual tunability of the modes via current modulation. This design generates a narrowband frequency-modulated beat signal for phase sampling, while additionally featuring a high potential for photonic integration. The laser’s wavelength modulation dynamics are thoroughly analyzed, and the THz radar system performance is characterized using a reflection target mounted on a motorized stage. The system achieves a precision of 2.6 cm for absolute positioning and 0.88 $$\upmu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>μ</mml:mi> </mml:math> m for relative position changes with a measurement rate of 20 kHz. The high measurement rate and micrometer precision are demonstrated in a possible field of application by sampling the position of a small metal plate mounted on a loudspeaker membrane playing up to 1 kHz of acoustic frequencies, while this target is concealed behind an optically opaque barrier.