中国物理B ›› 2022, Vol. 31 ›› Issue (7): 74207-074207.doi: 10.1088/1674-1056/ac5608

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Precise determination of characteristic laser frequencies by an Er-doped fiber optical frequency comb

Shiying Cao(曹士英), Yi Han(韩羿), Yongjin Ding(丁永今), Baike Lin(林百科), and Zhanjun Fang(方占军)   

  1. Division of Time and Frequency Metrology, National Institute of Metrology, Beijing 100029, China
  • 收稿日期:2021-12-22 修回日期:2022-02-08 接受日期:2022-02-17 出版日期:2022-06-09 发布日期:2022-07-19
  • 通讯作者: Shiying Cao E-mail:caoshiying@nim.ac.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFF0200204).

Precise determination of characteristic laser frequencies by an Er-doped fiber optical frequency comb

Shiying Cao(曹士英), Yi Han(韩羿), Yongjin Ding(丁永今), Baike Lin(林百科), and Zhanjun Fang(方占军)   

  1. Division of Time and Frequency Metrology, National Institute of Metrology, Beijing 100029, China
  • Received:2021-12-22 Revised:2022-02-08 Accepted:2022-02-17 Online:2022-06-09 Published:2022-07-19
  • Contact: Shiying Cao E-mail:caoshiying@nim.ac.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2016YFF0200204).

摘要: Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and coherently. Therefore, any optical frequency in visible to near-infrared region can be directly traced to a microwave frequency. As a result, the length unit "meter" is directly related to the time unit "second". This paper validates the capability of the national wavelength standards based on a home-made Er-doped fiber femtosecond optical frequency comb to measure the laser frequencies ranging from visible to near-infrared region. Optical frequency conversion in the femtosecond optical frequency comb is achieved by combining spectral broadening in a highly nonlinear fiber with a single-point frequency-doubling scheme. The signal-to-noise ratio of the beat notes between the femtosecond optical frequency comb and the lasers at 633, 698, 729, 780, 1064, and 1542 nm is better than 30 dB. The frequency instability of the above lasers is evaluated by using a hydrogen clock signal with a instability of better than 1×10-13 at 1-s averaging time. The measurement is further validated by measuring the absolute optical frequency of an iodine-stabilized 532-nm laser and an acetylene-stabilized 1542-nm laser. The results are within the uncertainty range of the international recommended values. Our results demonstrate the accurate optical frequency measurement of lasers at different frequencies using the femtosecond optical frequency comb, which is not only important for the precise and accurate traceability and calibration of the laser frequencies, but also provides technical support for establishing the national wavelength standards based on the femtosecond optical frequency comb.

关键词: optical frequency measurement, phase lock, Er-doped fiber laser, fiber optical frequency comb

Abstract: Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and coherently. Therefore, any optical frequency in visible to near-infrared region can be directly traced to a microwave frequency. As a result, the length unit "meter" is directly related to the time unit "second". This paper validates the capability of the national wavelength standards based on a home-made Er-doped fiber femtosecond optical frequency comb to measure the laser frequencies ranging from visible to near-infrared region. Optical frequency conversion in the femtosecond optical frequency comb is achieved by combining spectral broadening in a highly nonlinear fiber with a single-point frequency-doubling scheme. The signal-to-noise ratio of the beat notes between the femtosecond optical frequency comb and the lasers at 633, 698, 729, 780, 1064, and 1542 nm is better than 30 dB. The frequency instability of the above lasers is evaluated by using a hydrogen clock signal with a instability of better than 1×10-13 at 1-s averaging time. The measurement is further validated by measuring the absolute optical frequency of an iodine-stabilized 532-nm laser and an acetylene-stabilized 1542-nm laser. The results are within the uncertainty range of the international recommended values. Our results demonstrate the accurate optical frequency measurement of lasers at different frequencies using the femtosecond optical frequency comb, which is not only important for the precise and accurate traceability and calibration of the laser frequencies, but also provides technical support for establishing the national wavelength standards based on the femtosecond optical frequency comb.

Key words: optical frequency measurement, phase lock, Er-doped fiber laser, fiber optical frequency comb

中图分类号:  (Fiber lasers)

  • 42.55.Wd
42.65.Re (Ultrafast processes; optical pulse generation and pulse compression) 06.30.Ft (Time and frequency)