title: Absolute distance measurement using frequency-sweeping heterodyne interferometer calibrated by an optical frequency comb.
abstract: We present a frequency-sweeping heterodyne interferometer to measure an absolute distance based on a frequency-tunable diode laser calibrated by an optical frequency comb (OFC) and an interferometric phase measurement system. The laser frequency-sweeping process is calibrated by the OFC within a range of 200 GHz and an accuracy of 1.3 kHz, which brings about a precise temporal synthetic wavelength of 1.499 mm. The interferometric phase measurement system consisting of the analog signal processing circuit and the digital phase meter achieves a phase difference resolution better than 0.1 deg. As the laser frequency is sweeping, the absolute distance can be determined by measuring the phase difference variation of the interference signals. In the laboratory condition, our experimental scheme realizes micrometer accuracy over meter distance.
authors.affiliation: State Key Lab of Precision Measurement Technology & Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China. wu‑xj09@mails.tsinghua.edu.cn
authors.forename: Xuejian
authors.initials: X
authors.lastname: Wu
authors.forename: Haoyun
authors.initials: H
authors.lastname: Wei
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Libing
authors.initials: L
authors.lastname: Ren
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Jitao
authors.initials: J
authors.lastname: Zhang