2020/02/26 by Sida Xing, Xing, Sida, Abijith S. Kowligy +7
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #Advanced Fiber Optic Sensors #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystal and Fiber Optics
paper · pdf · doi:10.48550/arxiv.2002.11763
openalex publication_date 2020/02/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report an all-polarization-maintaining fiber optic approach to generating\nsub-2 cycle pulses at 2 \μm and a corresponding octave-spanning optical\nfrequency comb. Our configuration leverages mature Er:fiber laser technology at\n1.5 \μm to provide a seed pulse for a thulium-doped fiber amplifier that\noutputs 330 mW average power at 100 MHz repetition rate. Following\namplification, nonlinear self-compression in fiber decreases the pulse duration\nto 9.5 fs, or 1.4 optical cycles. Approximately 32 % of the energy sits within\nthe pulse peak, and the polarization extinction ratio is more than 15 dB. The\nspectrum of the ultrashort pulse spans from 1 \μm to beyond 2.4 \μm and\nenables direct measurement of the carrier-envelope offset frequency using only\n12 mW, or ~3.5 % of the total power. Our approach employs only\ncommercially-available fiber components, resulting in a turnkey amplifier\ndesign that is compact, and easy to reproduce in the larger community.\nMoreover, the overall design and self-compression mechanism are scalable in\nrepetition rate and power. As such, this system should be useful as a robust\nfrequency comb source in the near-infrared or as a pump source to generate\nmid-infrared frequency combs.\n