Optoelectronic hybrid oscillating fiber-optic sensor with attosecond precision and reconfigurable sensitivity

The fiber-optic sensor is a great candidate in the field of metrology, developed to rely on the optical phase to convey valuable information. Some phase amplification methods have attracted wide attention due to their ability to improve measurement sensitivity; nevertheless, the precision is generally restricted in phase measurement. Here, we report a novel optoelectronic hybrid oscillating fiber-optic sensor by mapping the measurand loaded on the sensing fiber to the frequency shift of the microwave signal, which is generated by an all-electric oscillating cavity with a frequency conversion pair. Two branch signals assisted in twice frequency conversion are obtained by heterodyne interference, with the sensing information scaled up by two optical comb line frequencies contained, and then, the phase difference is cumulatively enhanced in the closed feedback loop. Thanks to the introduction of the oscillating cavity, a detection limit improvement of 42 dB at a 10 Hz frequency offset can be achieved in theory with a cavity delay of 1 mu s. mu s. The sensing precision depends on the cavity noise limit and is independent of the instrument and cavity delay. A proof-of-concept experiment is carried out to demonstrate sensors with a sensitivity of 8.3 kHz/ps and 22.3 kHz/ps for a range of 50 ps, and 62 kHz/ps and 162 kHz/ps for a range of 6.7 ps. The minimum Allan deviation reaches 2.7 attoseconds at an averaging time of 0.2 s with a frequency interval of 150 GHz, indicating that the proposal may pave a new path for sensing interrogation systems, especially for high-precision measurement. (c) 2024 Chinese Laser Press