Characteristics of Wavelength-Tunable Harmonically Mode-Locked Short-Cavity Fiber Ring Laser Using a Bismuth-Oxide-Based Erbium-Doped Fiber and a Bismuth-Oxide-Based Highly Nonlinear Fiber

We propose and experimentally demonstrate a wavelength-tunable harmonically mode-locked short-cavity fiber ring laser, employing a 151-cm-long bismuth-oxide-based erbium-doped fiber (Bi-EDF) and a 414-cm-long bismuth-oxide-based highly nonlinear fiber (Bi-HNLF). A 75-nm continuous wavelength tuning from 1535 to 1610 nm can be achieved by utilizing the wide gain bandwidth of the Bi-EDF. Ultra-high nonlinearity of the Bi-HNLF collaborates with spectral filtering by an optical bandpass filter to suppress the supermode noise quite effectively. Total length of the ring cavity including all optical components is as short as 10 m. Back-to-back bit-error-rate measurements also confirm bit-error-free operation throughout the entire wavelength tuning range.