Open AccessWaveform measurement technique for phase/frequency-modulated lights based on self-heterodyne interferometry
Author(s) -
Hidemi Tsuchida
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.004793
Subject(s) - waveform , optics , frequency modulation , frequency deviation , phase modulation , interferometry , beat (acoustics) , heterodyne detection , heterodyne (poetry) , physics , phase (matter) , signal (programming language) , modulation (music) , instantaneous phase , acoustics , phase noise , computer science , laser , telecommunications , radio frequency , radar , voltage , automatic frequency control , quantum mechanics , programming language
A novel technique is proposed and demonstrated for measuring the temporal waveforms of phase/frequency-modulated lights based on self-heterodyne interferometry with a delay time much shorter than the modulation period and on the unwrapped phase detection of heterodyne beat signals with real-time vector signal analysis. The technique makes use of an approximated relationship between the beat signal phase and the instantaneous frequency of modulated lights. The results of waveform measurements are presented for directly frequency-modulated and externally phase-modulated lights, which have been commonly employed for FWCW-LIDAR and serrodyne frequency translation, respectively. The temporal waveforms of triangular modulation are successfully measured with a frequency deviation as large as 15 GHz and the detailed investigation is presented on the deviation of measured waveform from ideal ones.