Improvement of signal-to-noise ratio of a beat note by cascading an Yb-doped fiber amplifier in an Er-fiber comb. (14th September 2017)

• Record Type: Journal Article
• Authors: Liu, H; Cao, S Y; Yu, Y; Lin, B K; Lu, W P; Fang, Z J
• Is Part Of: Measurement science & technology. Volume 28:Number 10(2017:Oct.)
• Publication Date: 2017-09-14
• Subjects: Er-doped fiber femtosecond laser -- spectral enhancement -- beat note -- fiber optical frequency comb; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/1361-6501/aa80b5
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: Femtosecond optical frequency combs (FOFCs) make it possible to measure the absolute frequency of a laser, which greatly simplifies quantity traceability and comparison of the absolute frequency. In order to ensure the accuracy and reliability of the measurement, the signal-to-noise ratio (SNR) of the beat note ( f b ) between an FOFC and a laser should be above 30 dB. In this paper, an Er-doped FOFC (Er-FOFC) is employed, at a repetition rate of 305 MHz. The spectral intensity near the 1 µ m wavelength in an octave-spanning supercontinuum generated from the Er-FOFC is enhanced effectively by cascading an Yb-doped fiber amplifier after spectral broadening, which helps improve the SNR of the beat note between the comb light and an iodine-stabilized 532 nm laser. This method can effectively reduce the intensity requirements on the 1 µ m wavelength when the spectrum is directly broadened in an Er-FOFC.