[8p-Z19-1~24] 3.8 Optical measurement, instrumentation, and sensor

[8p-Z19-7] High-speed interferometry using frequency spacing tunable broadband optical comb

〇Samuel Choi^1,2, Yuto Ohwada¹, Takamasa Suzuki¹, Yosuke Tanaka³, Hiroshi Hibino^4,2 (1.Niigata Univ., 2.AMED-CREST, AMED, 3.TUAT, 4.School of Medicine, Niigata Univ.)

Keywords:Optical comb, high-speed real-time measurement, optical coherence tomography

We developed optical comb-based interferometry that enables high-speed tomographic measurement with an axial scan rate of 1 MHz. 1550 nm optical comb was synthesized via a dual-drive Mach-Zehnder modulator with nonlinear broadening. Broadband comb with a span of 60 nm could be generated by nonlinear self-phase modulation in 200 m dispersion-shifted fiber. The frequency spacing could be varied ranging from 8 to 10 GHz, which realized low-coherence interferometric measurement without mechanical movement in the interferometer. In this experiment, the RF signal was driven at 8 GHz and modulated by frequency modulation with a deviation of 20 MHz and a duration of 1 MHz to perform the high-speed depth scan. We conducted displace and tomographic measurements with a common-path interferometer that was feasible with the high order interference characteristic of this light source. The real-time high-speed depth scan of 1 MHz was demonstrated.