• High Power Laser Science and Engineering
  • Vol. 8, Issue 4, 04000e32 (2020)
Lian Zhou1, Yang Liu1、*, Gehui Xie1, Chenglin Gu1, Zejiang Deng1, Zhiwei Zhu1, Cheng Ouyang1, Zhong Zuo1, Daping Luo1, Bin Wu3, Kunfeng Chen3, and Wenxue Li1、2、*
Author Affiliations
  • 1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai200062, China
  • 2Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan030006, China
  • 3Science and Technology on Electronic Test & Measurement Laboratory, The 41st Research Institute of CETC, Qingdao266000, China
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    Schematic of the mid-IR comb. The mode-locked fiber oscillator serves as an NIR comb whose repetition rate is locked at 75 MHz. The CPA with two-stage fiber amplifiers scales the average power to 6.7 W. After the compressor, the system emits a pulse train with an average power of 4 W and a pulse duration of 194 fs, which corresponds to a pulse energy of 53 nJ. In the DFG module, the mid-IR pulse laser is generated in the PPLN by quasi-phase matching. SM LD, single-mode laser diode; YDF, Yb-doped fiber; WDM, wavelength division multiplexer; Col, collimator; FR, Faraday rotator; PBS, polarization beam splitter; ISO, isolator; MM LD, multimode laser diode; DC-YDF, double-cladding Yb-doped fiber; PCF, photonic crystal fiber; DM, dichroic mirror; PPLN, periodically poled lithium niobate.
    Fig. 1. Schematic of the mid-IR comb. The mode-locked fiber oscillator serves as an NIR comb whose repetition rate is locked at 75 MHz. The CPA with two-stage fiber amplifiers scales the average power to 6.7 W. After the compressor, the system emits a pulse train with an average power of 4 W and a pulse duration of 194 fs, which corresponds to a pulse energy of 53 nJ. In the DFG module, the mid-IR pulse laser is generated in the PPLN by quasi-phase matching. SM LD, single-mode laser diode; YDF, Yb-doped fiber; WDM, wavelength division multiplexer; Col, collimator; FR, Faraday rotator; PBS, polarization beam splitter; ISO, isolator; MM LD, multimode laser diode; DC-YDF, double-cladding Yb-doped fiber; PCF, photonic crystal fiber; DM, dichroic mirror; PPLN, periodically poled lithium niobate.
    Characterization of the chirped pulse amplification. (a) Normalized optical spectrum of NIR oscillator (blue curve) and amplified pulse (green line), centered at 1030 and 1038 nm with a spectral width of 30 and 12 nm, respectively. (b) Measured autocorrelation trace (blue line) of the amplified pulse with corresponding sech fitting (dotted green line).
    Fig. 2. Characterization of the chirped pulse amplification. (a) Normalized optical spectrum of NIR oscillator (blue curve) and amplified pulse (green line), centered at 1030 and 1038 nm with a spectral width of 30 and 12 nm, respectively. (b) Measured autocorrelation trace (blue line) of the amplified pulse with corresponding sech fitting (dotted green line).
    (a) The spectrum of the broadened signal laser after a long-pass filter at 1100 nm. (b) The spectrum and corresponding average power of the mid-IR comb. The mid-IR comb has a tunable coverage of 2.7–4.0 μm. The average powers are 30, 130, 190, 240, 250, and 187 mW centered at 2.7, 3.0, 3.3, 3.5, 3.7, and 4.0 μm, respectively.
    Fig. 3. (a) The spectrum of the broadened signal laser after a long-pass filter at 1100 nm. (b) The spectrum and corresponding average power of the mid-IR comb. The mid-IR comb has a tunable coverage of 2.7–4.0 μm. The average powers are 30, 130, 190, 240, 250, and 187 mW centered at 2.7, 3.0, 3.3, 3.5, 3.7, and 4.0 μm, respectively.
    The autocorrelation of mid-IR pulse at 3.5 μm. The pulse duration is 174 fs with Gaussian fitting.
    Fig. 4. The autocorrelation of mid-IR pulse at 3.5 μm. The pulse duration is 174 fs with Gaussian fitting.
    (a) Phase noise PSD and (b) relative intensity noise (RIN) of the repetition rate signal corresponding to NIR comb (origin), CPA (green), and mid-IR comb at 3.5 μm (blue).
    Fig. 5. (a) Phase noise PSD and (b) relative intensity noise (RIN) of the repetition rate signal corresponding to NIR comb (origin), CPA (green), and mid-IR comb at 3.5 μm (blue).
    (a) The measured repetition rate stability of NIR comb (blue) and mid-IR comb (orange) for 3 h. (b) The Allan variance of the NIR comb (blue) and mid-IR comb (orange).
    Fig. 6. (a) The measured repetition rate stability of NIR comb (blue) and mid-IR comb (orange) for 3 h. (b) The Allan variance of the NIR comb (blue) and mid-IR comb (orange).
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    Lian Zhou, Yang Liu, Gehui Xie, Chenglin Gu, Zejiang Deng, Zhiwei Zhu, Cheng Ouyang, Zhong Zuo, Daping Luo, Bin Wu, Kunfeng Chen, Wenxue Li. Mid-infrared optical frequency comb in the 2.7–4.0 μm range via difference frequency generation from a compact laser system[J]. High Power Laser Science and Engineering, 2020, 8(4): 04000e32
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    Category: Letters
    Received: Jun. 4, 2020
    Accepted: Aug. 5, 2020
    Published Online: Oct. 9, 2020
    The Author Email: Yang Liu (yliu@lps.ecnu.edu.cn), Wenxue Li (wxli@phy.ecnu.edu.cn)